Entries |
Document | Title | Date |
20080211577 | AUDIO POWER AMPLIFIER USING VIRTUAL GROUND AND METHOD OF PROCESSING SIGNAL IN THE AUDIO POWER AMPLIFIER - An audio power amplifier provides a virtual ground to reduce power on/off noise and a method for processing a signal in the audio power amplifier. The audio power amplifier includes a switching amplifier to amplify a small output pulse width modulation (PWM) signal so as to generate a large output PWM signal, a pulse generating unit to generate a pulse signal having the same level as that of the PWM signal level, a first low pass filter to allow the large output PWM signal amplified by the switching amplifier to be low-pass filtered so as to restore the PWM signal to an audio signal, and a second low pass filter to allow the pulse signal generated by the pulse signal generating unit to be low-pass filtered so as to convert the pulse signal into a virtual ground voltage with respect to the restored audio signal. | 09-04-2008 |
20080211578 | Delta Sigma-Type AD converter, class-D amplifier, and DC-DC converter - A ΔΣ-type AD converter includes a subtractor which receives an analogue input signal and a feedback signal and which outputs a signal pertaining to a difference between the signals, an integrator which integrates a signal output from the subtractor, a comparator which binarizes a signal output from the integrator by comparing with a predetermined threshold value, a counter which measures respective pulse widths of a signal output from the comparator, and a PWM circuit which outputs a pulse signal of a predetermined period having a duty cycle responsive to a count value output from the counter and which feeds back the pulse signal as the feedback signal to the subtractor. The counter measures the respective pulse widths in each PWM frame period in synchronism with the PWM circuit, and the PWM circuit feeds back to the subtractor a pulse signal whose duty cycle is set in accordance with a value of the measured pulse width in a next PWM frame. A count value output from the counter is extracted as a converted digital output value. | 09-04-2008 |
20080218264 | CLASS D AMPLIFIER ARRANGEMENT - An amplifier arrangement for operation at supply voltages of at least 100V and at output powers of at least 1 kW includes a half-bridge formed from two switching elements connected in series, two supply voltage terminals, and an output connection between the switching elements. A bypass capacitor is in parallel with the switching elements, and a current path is through the switching elements and the bypass capacitor, where the current path has a length of 10 cm or less, the half-bridge and the bypass capacitor are arranged on an area of 30 cm2, and a resonant circuit formed by capacitances and inductances in the current path has a resonance frequency of 100 MHz or greater. | 09-11-2008 |
20080224773 | Digital input class-D amplifier - A digital input class-D amplifier includes a decoder which outputs a plurality of lines of time-series digital signals having a density of 1 or 0 conforming to an input digital signal, an error integrator which integrates a difference between a drive waveform to be applied to a load and a sum of the plurality of lines of time-series digital signals output from the decoder, and a modulation circuit which generates a pulse modulated with a pulse width or a pulse density based on a result of integration performed by the error integrator. The load is driven in accordance with the pulse generated by the modulation circuit. | 09-18-2008 |
20080246542 | Amplifier for a radio frequency transmitter for transmitting a transmit signal to an otological apparatus - There is described an amplifier for a radio frequency signal for transmitting a transmit signal to an otological apparatus. The amplifier comprises at least one power transistor for switching an output signal. A breaker gap of the power transistor is actively connected to a network such that a power loss converted in the power transistor is at least partially reduced during a switchover into a switched-on state and/or at least during a switchover into a switched-off state. The breaker gap of the at least one transistor is at least indirectly connected in series to a power supply source by way of a choke coil. The amplifier comprises a transmit coil as an output load, with the transmit coil comprising an inductor and being actively connected to the power transistor. The transmit coil is coupled to the choke coil in a transformer-like manner, with the choke coil thus being able to transmit an output power to the transmit coil. The transmit coil can generate a transmit signal from the output power. | 10-09-2008 |
20080252372 | Power-MOSFETs with Improved Efficiency for Multi-channel Class-D Audio Amplifiers and Packaging Thereof - A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (V | 10-16-2008 |
20080258811 | DISTRIBUTED CLASS G TYPE AMPLIFIER SWITCHING METHOD - An improved Class G type amplifier is provided which switches between multiple power rails depending upon the instantaneous amplitude of the input signal versus the power rails without excessive distortion. The low voltage (inner) amplifier includes a plurality of parallel amplifier devices, and the high voltage (outer) amplifier includes a plurality of parallel amplifier devices. A plurality of switches each couples the input signal to either a respective one of the inner amplifier devices or a respective one of the outer amplifier devices. The switches are activated sequentially, such that the switching from inner amplifier devices to outer amplifier devices or vice versa is staggered over time. This avoids having a single, large glitch in the output and spreads multiple smaller glitches over enough time so that some of the radiated glitch energy can fall within frequencies where amplifier feedback circuitry can eliminate its noise. The switches are sequentially activated by a series of delay elements. | 10-23-2008 |
20080265989 | Filterless class-D speaker driver with less switching - Methods for designing a filterless class-D amplifier and driver are described herein. In the exemplary embodiment, a feedback loop is used to stabilize the filterless class-D amplifier. A pulse width modulated (PWM) output signal is generated by adding a comparator input signal to a comparative signal, and comparing the sum to a peak voltage, which can be a peak value of the comparative signal. A limit of one PWM sample will be generated half per period of the comparative signal, resulting in lower dynamic switching noise and a decreased sensitivity to jitter noise than conventional filterless class-D amplifiers. | 10-30-2008 |
20080272842 | Calibrated feedback - A differential feedback amplifier is provided with a feedback network wherein that feedback network is adjustable so as to improve the PSRR of the amplifier. In another aspect of the present invention, a differential feedback amplifier is provided with a feedback network wherein that feedback network is adjustable so as to improve the CMRR of the amplifier. In a further aspect of the present invention, a Class D amplifier is provided with a passive differential feedback, summing with an input current at a differential virtual ground produced by an amplifier which is a sub-section of the Class D amplifier. | 11-06-2008 |
20080284511 | Device Comprising a Switching Amplifier and a Load | 11-20-2008 |
20080297248 | CLASS D AMPLIFIER CIRCUIT WITH BI-DIRECTIONAL POWER SWITCH - A Class D amplifier circuit in accordance with an embodiment of the present application includes a converter stage operable to provide a desired AC voltage and a Class D amplifier stage, connected to the converter stage. The Class D amplifier stage includes a first bi-directional switch connected to the converter stage, a second bi-directional switch, connected in series with the first bi-directional switch, wherein the first and second bi-directional switches are connected across the desired AC voltage provided by the converter stage and a controller operable to turn the first and second bi-directional switches ON and OFF such that a desired voltage is provided at a midpoint node positioned between the first bi-directional switch and the second bi-directional switch. | 12-04-2008 |
20080303590 | POWER AMPLIFIER WITH NOISE SHAPING FUNCTION - A power amplifier with noise shaping function is provided. The power amplifier includes a differential mode integrator, an integration and adjustment unit and a switch unit. The differential mode integrator is used for receiving a differential mode input signal and a differential mode output signal, and outputting a differential mode first signal. The integration and adjustment unit is coupled to the differential mode integrator for receiving the first signal and an output signal and outputting a single-end mode second signal. The switch unit is used for receiving the second signal and outputting the differential mode output signal to drive the load. The present invention uses a common mode input signal instead of the single-end input signal to eliminate the common mode noise, and uses a 2 | 12-11-2008 |
20080309406 | Full-Bridge Class-D Power Amplifier - The present invention relates to a full bridge class-D amplifier where one of the output terminals ( | 12-18-2008 |
20080315948 | Circuit architecture having differential processing for use in half bridges and full bridges and methods therefore - Circuit architecture is disclosed that includes one or more half bridges, the one or more half bridges including signal processing circuitry including first and second inputs and one or more outputs. The circuit architecture also includes a driver stage coupled to the one or more outputs of the signal processing circuitry and configured to create at least one output, one of the at least one outputs suitable to couple to a load. The circuit architecture further includes a first feedback loop coupling the at least one output of the driver stage to a first input of the signal processing stage, and includes a second feedback loop coupling the at least one output of the driver stage to a second input of the signal processing stage, where signals on the first and second feedback loops have inverted polarity. Methods and computer-readable media are also disclosed. | 12-25-2008 |
20090015327 | SWITCHING AUDIO POWER AMPLIFIER WITH DE-NOISE FUNCTION - The invention provides a switching audio power amplifier with de-noise function including a pulse width modulator, a de-noise circuit and a bridge circuit. The pulse width modulator performs pulse width moderation to generate the first and second PWM signals according to an input audio signal. The de-noise circuit receives the first and second PWM signals. And the bridge circuit conducts a driving current alternately flowing to and from a load according to the control signals output from the de-noise circuit. | 01-15-2009 |
20090021305 | Class D amplifier - Class D amplifier is resistant to interferences. Binary output signals y | 01-22-2009 |
20090027120 | CLASS-D AMPLIFIER WITH NOISE-IMMUNITY FEEDBACK - A class-D amplifier includes a switching transistor section, a filter, an analog to digital converter, and a feedback module. The switching transistor section is operably coupled to convert a serial input into a switched output signal. The filter is operably coupled to filter the switched output signal to produce an output of the class-D amplifier. The analog to digital converter is operably coupled to convert an analog input into a multi-bit digital signal based on a feedback signal, wherein the serial input corresponds to the multi-bit digital signal. The feedback module is operably coupled to the produce the feedback signal based on at least one varying property of the switching transistor section. | 01-29-2009 |
20090027121 | Class D amplifier circuit - A pulse monitor circuit detects the presence or non-presence of the output pulses output from an output stage circuit. The pulse monitor circuit outputs an up signal to the up/down counter when the output pulses do not exist at all and outputs a down signal to the up/down counter when the output pulses exist. The up/down counter outputs a signal for increasing the delay amount of a delay amount variable circuit when a count value is large, that is, when the output pulses disappear. In contrast, when the count value is small, that is, when the output pulses exist, the counter outputs the signal for reducing the delay amount of the delay amount variable circuit. | 01-29-2009 |
20090033419 | CLASS D AMPLIFIER WITH INCREASED EFFICIENCY - The present invention is a method of operating a speaker by converting an audio signal to a pulse-width modulated signal that has a plurality of positive pulses and a plurality of negative pulses as a function of the audio signal, then driving an H-bridge circuit interconnected to a speaker, wherein the H-bridge circuit comprises an A-side and a B-side, wherein the A-side comprises a first switching transistor and a second switching transistor, and wherein the B-side comprises a first switching transistor and a second switching transistor. For each positive pulse, the A-side of the H-bridge circuit is driven by pushing the first switching transistor of the A-side while grounding the second switching transistor of the A-side. For each negative pulse, the B-side of the H-bridge circuit is driven by pushing the first switching transistor of the B-side while grounding the second switching transistor of the B-side. | 02-05-2009 |
20090045873 | CLOSE-LOOP CLASS-D AUDIO AMPLIFIER AND CONTROL METHOD THEREOF - The present invention discloses a Class-D power amplifier and control method thereof. In one embodiment, the amplifier feeds back the signal at the output node to the inverting input of the comparator, and provides a high frequency triangular wave signal to the non-inverting input of the comparator. In addition, the non-inverting input of the comparator may be coupled to an offset voltage, while the inverting input of the comparator may be coupled to a fixed-frequency rectangular wave signal, a feedback signal which is derived from the output stage and an input signal. In use, the switching frequency may be at least substantially fixed, so as to reduce the influence on the system caused by electromagnetic interruption (EMI). Further, the control circuit is simple, and some devices can be integrated. | 02-19-2009 |
20090051427 | OUTPUT LIMITING CIRCUIT, CLASS D POWER AMPLIFIER AND AUDIO EQUIPMENT - An output limiting circuit includes a reference current generating portion for converting a predetermined constant voltage into a reference current by using a first resistor, an upper side clip voltage generating portion for converting the reference current into an upper side clip voltage with respect to a bias voltage of the operational amplifier by using a second resistor, a lower side clip voltage generating portion for converting the reference current into a lower side clip voltage with respect to the bias voltage of the operational amplifier by using a third resistor, and a gain adjusting portion for adjusting a gain of the operational amplifier so that a voltage level of the output signal does not exceed an upper side limit level corresponding to the upper side clip voltage and that the voltage level of the output signal does not exceed a lower side limit level corresponding to the lower side clip voltage. | 02-26-2009 |
20090072902 | LOW DISTORTION CLASS-D AMPLIFIER - An electronic class-D amplifier having an amplifier input to which an amplifier input signal may be applied, an amplifier output which may produce an amplifier output signal, an output switching stage, a pulse width modulator which includes an oscillator, wherein a first output of the oscillator produces a carrier reference signal, at least one servo-loop amplifier which includes an integrating feed forward transfer function, wherein the amplifier input is connected to an input of the servo-loop amplifier, a sample and hold element which includes a sample input and a control input, such that the sample and hold element samples a signal at the sample input when a sample command signal is applied to the control input, and the sample and hold element holds the value of the last sampled value of the signal at the sample input when the hold command signal is applied to the control input, and this said held value is applied to an output of the sample and hold element, the amplifier input is also connected to the sample input of the sample and hold element, an output of the sample and hold element is connected to a first input of an adder, and an output of the servo-loop amplifier is connected to a second input of the adder, an output of the adder is connected to a modulation input of the pulse width modulator, a second output of the oscillator is connected to the control input of the sample and hold element, an output of the pulse width modulator is connected to an input of the output switching stage, and an output of the output switching stage is connected to the amplifier output, wherein a negative feedback path connects an output of the output switching stage to an input of the servo-loop amplifier. | 03-19-2009 |
20090085659 | DIFFERENTIAL AMPLIFIER - An amplifier comprising an analog amplifier which outputs a first current and a second current. The amplifier also comprises a first digital amplifier coupled to the analog amplifier, the first digital amplifier amplifies a modified version of the first current to produce a third current. The amplifier also comprises a second digital amplifier coupled to the analog amplifier, the second digital amplifier amplifies a modified version of the second current to produce a fourth current. The amplifier also includes connections configured to provide the first, second, third and fourth currents through a load. | 04-02-2009 |
20090102557 | Class D amplifier - The invention is directed to a class D amplifier. According to the class D amplifier, sound data applied to an input terminal is supplied through a compensation circuit to a PWM circuit, from which a PWM signal is output. The PWM signal is converted to an analog signal through a first low pass filter, which is delivered to a speaker. On the other hand, the sound data is delayed by a delay circuit, and is converted to an analog signal by a digital to analog converter. The higher frequency components of the data are removed by a second low pass filter, and the rest of the data is furnished to a differential amplifier. The differential amplifier amplifies a difference between an output of the first low pass filter and an output of the second low pass filter, which is then supplied to an analog to digital converter. The analog to digital converter converts an output from the differential amplifier to digital data, which is then supplied to the compensation circuit. By doing so, a compensation value based on an output from the analog to digital converter is added to the following PCM sound data that is applied to the input terminal. | 04-23-2009 |
20090108932 | Signal generating apparatus and class-d amplifying apparatus - A signal generating apparatus includes: a data generator which generates a data series in which first, second, third and fourth data are arranged at a sampling period; a first signal generator which generates a first pulse-width modulation signal in which a pulse is arranged in a pulse period longer than the sampling period, time points of front and rear edges of the pulse being set in response to the first and second data; and a second signal generator which generates a second pulse-width modulation signal in which a pulse is arranged between the adjacent pulses of the first pulse-width modulation signal, time points of front and rear edges of the pulse of the second pulse-width modulation signal been set in response to the third and fourth data, respectively. | 04-30-2009 |
20090115514 | Class D amplifier - A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state. | 05-07-2009 |
20090128237 | SWITCHING AMPLIFIERS - Systems and methods implemented in a switching amplifier for providing consistent, matching switching between top and bottom switching devices in a switching amplifier. One embodiment includes a half-bridge circuit output stage, a driver stage and a transformer. The driver stage, which drives the switches of the output stage, is very fast, has a low propagation delay, and has minimal input capacitance. The transformer drives the drive paths from the transformer inputs to the switches. The transformer avoids resonances within the audio band and at the amplifier switching frequencies, has low and spread free leakage inductance, has enough magnetizing inductance to keep transformer currents low in proportion to the total driver stage current drain, has low core losses at the switching frequency, has minimal inductance change and operates well below its saturation point. The amplifier stage provides a substantially constant amplitude drive signal to the output power switching devices. | 05-21-2009 |
20090146737 | CLASS-D AMPLIFIER AND MULTI-LEVEL OUTPUT SIGNAL GENERATED METHOD THEREOF - A class-D amplifier and a method of generating a multi-level output signal thereof are provided. The class-D amplifier includes a controlling logic circuit and an output module. The controlling logic circuit analyzes the amplitude of an input signal to generate a voltage modifying signal. A power supply provides a voltage according to the voltage modifying signal. The controlling logic circuit generates controlling signals according to the input signal. The output module generates an output signal to drive a load according to the voltage and the controlling signals. In other words, the resolution of the amplitude of the output signal is increased by modifying the voltage, and a signal to noise ratio is then increased. | 06-11-2009 |
20090153243 | CLASS D AMPLIFIER - A single-end-output class D amplifier is provided that handles a load such as stereo headphones without using an expensive part such as a crystal resonator or transformer. Class D amplifier | 06-18-2009 |
20090160551 | Switching Amplifier - A switching amplifier includes an input end for receiving an input signal, a reference signal reception end for receiving a reference signal, a feedback end for receiving a feedback signal, an output end for outputting an output signal, an integration circuit for performing integration operation on the input signal according to the output signal and the feedback signal, so as to generate an integration result, a comparison circuit coupled to the integration circuit, the reference signal end, and the output end, for comparing the integration result and the reference signal, so as to generate the output signal for the output end, and a feedback circuit coupled between an output end of the integration circuit and the feedback end, for generating the feedback signal for the feedback end to clamp the integration result to a predetermined value when the integration result reaches the predetermined value. | 06-25-2009 |
20090160552 | APPARATUS AND METHOD FOR CLASS D AMPLIFIER WITH SAMPLING RATE CONVERSION - A class D amplifier is provided. The class D amplifier includes an interpolator, a sampling rate converter, a pulse width modulator, a sigma-delta modulator, and a pulse width modulation (PWM) pulse generator (PPG). The sampling rate converter interpolates the output of the interpolator such that the sampling rate converter up-samples the interpolator output by a factor that is greater than one and less than two. The pulse width modulator outputs a multi-bit digital signal. The sigma-delta modulator performs sigma-delta modulation on the pulse width modulator output, the order of the sigma-delta modulation is programmable, and the output of the sigma-delta modulator is a multi-bit, digital signal. At least one of the orders to which the sigma-delta modulator can be programmed is greater than two. The PPG provides a pulse signal such that the width of each pulse is based on the value of the sigma-delta modulator output. | 06-25-2009 |
20090160553 | DISTORTION SUPPRESSION CIRCUIT FOR DIGITAL CLASS-D AUDIO AMPLIFIER - A digital Class-D amplifier distortion suppression circuit design is disclosed. A distortion suppression feedback loop is described to improve audio performance by suppressing output stage non-linearity and improving power supply noise rejection achieving reduced THD+N. The feedback loop is placed around the power stage. It forces tracking between the audio band signals at the input and output of the power stage by automatically adjusting the gating signal timing based on sensed effective duty ratio error. Error sensing and compensation are performed using techniques that lend to simple circuit implementation. | 06-25-2009 |
20090167436 | HIGH-EFFICIENCY SWITCHING POWER AMPLIFIERS WITH LOW HARMONIC DISTORTION - In one embodiment, a switching power amplifier is provided that includes: a power switch coupled between a power supply node and ground, wherein the power switch is configured to be cycled on and off responsive to an input signal voltage; and a matching network coupled between a terminal of the power switch and an output node, wherein the matching network includes: a first capacitor coupled between the terminal of the power switch and ground; a second capacitor having a first terminal and an opposing second terminal, the second terminal being coupled to ground, the second capacitor having a greater capacitance than the first capacitor; and a second switch coupled between the first terminal of the second capacitor and the terminal of the power switch, the second switch being configured to be cycled on and off responsive to a switching signal voltage such that the second switch is turned on before the power switch is turned off and such that the second switch is turned off after a current through the power switch is substantially zero responsive to the turning off of the power switch. | 07-02-2009 |
20090174478 | Circuit and method for generating a PWM control signal for a class-D amplifier - In a class-D amplifier, the input signal is compared with a carrier signal to generate a basic PWM signal, the PWM signal is then sent to a pulse processing unit, and by comparing with a basic periodic signal, half-width of the output PWM signal is extracted. Then, in the pulse processing unit, the half-width PWM pulse signal is used to generate a complete pulse whose width equals to the output PWM signal. The output power of the class-D amplifier can be kept as large as that by using differential input signals although the input signal is single-end and the entire signal processing path is kept single-ended. | 07-09-2009 |
20090184765 | CLASS-D AMPLIFIER AND METHOD THEREFOR - In one embodiment, a class-D amplifier ( | 07-23-2009 |
20090219090 | OUTPUT DC OFFSET PROTECTION FOR CLASS D AMPLIFIERS - A class D amplifier with output DC offset protection is disclosed. The DC offset protection receives a PWM input signals from the outputs and investigates the PWM output signals whether there is a large DC voltage difference is being reflected on the speaker load. If so, shutdown signal SD will be sent by the DC offset protection to the PWM control logic and gate driver, thus, shutting down the output of the class D system and preventing disastrous condition from being develop across the speaker. | 09-03-2009 |
20090231035 | CLASS D AUDIO AMPLIFIER - A class D audio amplifier includes an error amplifier, a comparator, a bridge circuit, a feedback circuit and a silent start circuit. The error amplifier generates an error signal by amplifying a difference between a feedback signal and an audio input signal. The comparator generates a first pulse width modulation (PWM) signal by comparing a first triangular-wave signal and the error signal. The bridge circuit has switches alternately conducting a current flowing into and from a load. The feedback circuit generates the feedback signal indicating a condition of the load. The silent start circuit performs AND operation of the first PWM signal and a second PWM signal having a gradually increased duty ratio to generate a third PWM signal for control of the switches of the bridge circuit. | 09-17-2009 |
20090237159 | OUTPUT STAGE CIRCUIT - A PWM signal drives a pair of output transistors connected in series between a supply line and ground so that a push-pull current is output toward a speaker via a coil from a point connecting both output transistors. A current limiting resistor has one end connected to the supply line and between the other end and ground is provided a control transistor. Furthermore, a comparator compares the supply line voltage and a reference voltage and turns on the control transistor when the supply line voltage is higher than the reference voltage in the comparison result thereof. | 09-24-2009 |
20090237160 | Switch Mode Power Amplifier Using MIS-HEMT with Field Plate Extension - Disclosed are a switch mode power amplifier and a field effect transistor especially suitable for use in a switch mode power amplifier. The transistor is preferably a compound high electron mobility transistor (HEMT) having a source terminal and a drain terminal with a gate terminal therebetween and positioned on a dielectric material. A field plate extends from the gate terminal over at least two layers of dielectric material towards the drain. The dielectric layers preferably comprise silicon oxide and silicon nitride. A third layer of silicon oxide can be provided with the layer of silicon nitride being positioned between layers of silicon oxide. Etch selectivity is utilized in etching recesses for the gate terminal. | 09-24-2009 |
20090243722 | Reduction of power consumption and EMI of a switching amplifier - A switching amplifier has a network including current sources and resistors connected to the two output terminals of the H-bridge of the switching amplifier, to provide a small current to the load connected between the two output terminals at zero input, whereby the common mode voltage bouncing is reduced and the switching amplifier has less power consumption and reduced electro-magnetic interference. | 10-01-2009 |
20090251212 | SWITCHING AMPLIFIER - An amplifier having at least one switch controlled by an output voltage of a hysteresis block, wherein the hysteresis block is adapted to receive an input voltage signal based on an integration of an error signal, a low threshold voltage and a high threshold voltage, and is arranged to change the output voltage from a first value to a second value when the input voltage signal is higher than the high threshold voltage and to change the output voltage from the second value to the first value when the input voltage signal is lower than the low threshold voltage, and wherein the low threshold voltage is equal to V | 10-08-2009 |
20090261902 | Asynchronous Error Correction Circuit for Switching Amplifier - A circuit ( | 10-22-2009 |
20090289709 | Closed loop timing feedback for PWM switching amplifiers using predictive feedback compensation - Methods and systems are disclosed for closed loop feedback for pulse width modulated (PWM) switching amplifiers using predictive feedback compensation (PFC) for suppressing distortions caused by supply voltage variations and output amplitude switching non-idealities in pulse width modulated (PWM) switching amplifiers by pre-compensating the PWM input based upon the supply voltage or output pulse amplitude and using closed loop timing feedback. Output amplitude errors associated with previous PWM output signals are used to predict output amplitude errors expected for future PWM output signals. These predicted output amplitude errors are then used to adjust the pulse widths for the future PWM output signals. Timing differences between pulse widths for the uncompensated PWM input signal and the pre-compensated PWM signal are used as feedback to provide closed loop width adjustment. | 11-26-2009 |
20090289710 | AMPLIFIER PROVIDING POWER RECOVERY FROM A NARROW-BAND ANTENNA - A method, amplifier and system are provided for enabling power recovery from a narrow-band antenna when a signal having bandwidth exceeding that of the antenna is utilized. The amplifier provides amplification of a source signal to the antenna and recovery of power stored in the antenna during periods when the impedance of the antenna is negative to enable reverse current through the amplifier to a direct current (DC) power source. | 11-26-2009 |
20090302942 | D-CLASS AMPLIFIER - A D-class amplifier that can suppress noise generated when a D-class amplification operation is started/stopped. When a D-class amplification operation is started/stopped, the pulse widths and pulse interval of output signals Pout | 12-10-2009 |
20090302943 | CLASS D AMPLIFIER - A class D amplifier including a PWM circuit, a buffer amplifying circuit, a low-pass filter, and two current sources is provided. The PWM circuit transfers an analog signal into a PWM signal. The buffer amplifying circuit amplifies the PMW signal and generates an amplified signal. The low-pass filter will filter high frequency components out from the amplified signal and then transmit the filtered signal to a loading of the class D amplifier. The two current sources provide currents flowing into and out from a feedback node in the PWM circuit, respectively. The charging and discharging provided by the two current sources can generate a triangular signal for the PWM circuit. | 12-10-2009 |
20090309658 | METHOD AND APPARATUS FOR POWER CONVERTER FOR CLASS D AUDIO POWER AMPLIFIERS - A method and apparatus for power conversion in a class D amplifier is provided. The power conversion is achieved using synchronous rectifiers in a regulated half bridge power supply, taking the sum of the positive and negative rails as feedback, in order facilitate energy transfer between positive and negative output rails. This minimizes the effects of off side charging and rail sag, as well as achieving good line regulation, while allowing use of very small, low value output capacitors. | 12-17-2009 |
20090315623 | CLASS D AUDIO AMPLIFIER - A class D amplifier ( | 12-24-2009 |
20090322426 | Output Short Circuit and Load Detection - One embodiment of an apparatus for testing an amplifier includes an amplifier having a driver and a filter, the filter being connected between an output of the driver and an output of the amplifier. The filter is operable to produce a demodulated output signal from a higher frequency modulated signal at the driver output. The apparatus also includes a voltage level detector connected to the driver output and a control circuit operable to detect at least one fault based on a voltage level measured at the driver output by the voltage level detector. | 12-31-2009 |
20100001796 | Radio Frequency (RF) Envelope Pulsing Using Phase Switching of Switch-Mode Power Amplifiers - A radio frequency (RF) power generator includes a first switch-mode amplifier that generates a first RF signal in accordance with a first control signal and a second switch-mode amplifier that generates a second RF signal in accordance with a second control signal. The first and second control signals determine a phase difference between the first and second RF signals. An output signal envelope is based on the first and second RF signals and the phase difference. The first control and second control signals alternate phases of the first and second RF signals. | 01-07-2010 |
20100013555 | POWER AMPLIFIER - A driver (Highside Driver, Lowside Driver) adapted to drive each of final transistors (M | 01-21-2010 |
20100019846 | AMPLIFIER EMPLOYING INTERLEAVED SIGNALS FOR PWM RIPPLE SUPRESSION - An amplifier having improved distortion characteristics is set forth. The amplifier includes an interleaved PWM amplifier that generates interleaved PWM pulses in response to a modified input signal and one or more carrier signals. The interleaved PWM pulses of the amplifier are used to drive a power stage, such as an opposed current power stage. The amplifier also includes an interleaved PWM generator that provides interleaved PWM pulses in response to the modified input signal and one or more further carrier signals. The carrier signals used by the PWM generator may differ in phase from the carrier signals used by the interleaved PWM amplifier to generate its interleaved PWM pulses. One or more feedback circuits are employed in the generation of the modified input signal. More particularly, the feedback circuit(s) generates the modified input signal based on an input signal that is to be amplified and the interleaved PWM pulses of the interleaved PWM generator. | 01-28-2010 |
20100019847 | AMPLIFIER EMPLOYING INTERLEAVED SIGNALS FOR PWM RIPPLE SUPPRESSION - An amplifier having improved distortion characteristics is set forth. The amplifier includes an interleaved PWM amplifier that generates interleaved PWM pulses in response to a modified input signal and one or more carrier signals. The interleaved PWM pulses of the amplifier are used to drive a power stage, such as an opposed current power stage. The amplifier also includes an interleaved PWM generator that provides interleaved PWM pulses in response to the modified input signal and one or more further carrier signals. The carrier signals used by the PWM generator may differ in phase from the carrier signals used by the interleaved PWM amplifier to generate its interleaved PWM pulses. One or more feedback circuits are employed in the generation of the modified input signal. More particularly, the feedback circuit(s) generates the modified input signal based on an input signal that is to be amplified and the interleaved PWM pulses of the interleaved PWM generator. | 01-28-2010 |
20100033247 | TRUE CURRENT LIMITING - The invention relates to a current limiting method, e. g. for Class D amplifiers comprising a unique detection- and control method. The current detection circuit can be implemented as a voltage measurement where the measured voltage corresponds to the current flowing through the power-switching device. The device can be switched OFF when a set limit is reached. By forcing certain OFF time, the associated control system behaves as a self-oscillating current limiting circuit. This can be implemented locally close to the switching device and be independent of other local or global control systems. | 02-11-2010 |
20100033248 | Power Amplifier and Common Mode Choke Coil Apparatus - Common mode choke coil device includes four coils wound on a core in a same direction. Hot-side outputs of first and second class-D amplifiers are connected to respective ones of first ends of two of the four coils, and first and second hot-side output terminals are connected to respective ones of second ends of the two coils. Ground-side outputs of the first and second class-D amplifiers are connected to respective ones of the first ends of remaining two of the four coils, and first and second ground-side output terminals are connected to respective ones of the second ends of the remaining two coils. Single-end connection is realized by connecting a separate load to each of the class-D amplifiers via the corresponding first (or second) hot-side and ground-side output terminals. BTL connection is realized by connecting a single load to the class-D amplifiers via the first and second hot-side output terminals. | 02-11-2010 |
20100045376 | CLASS D AMPLIFIER CONTROL CIRCUIT AND METHOD - Circuit and method for a Class D amplifier. In one exemplary embodiment, an audio amplifier is disclosed. A closed loop configuration for driving high and low side driver transistors is provided, each circuit is compatible with advanced sub micron semiconductor processes. The analog time varying input is coupled to one input of a sigma delta analog to digital converter. A feedback signal from the output is also input to the analog to digital converter. A bit stream is output by the analog to digital converter. A decimator receives this bit stream and downconverts the samples to digital values at a lower frequency. A digital filter with adaptable coefficients is used to filter that signal and a digital pulse width modulator then develops an analog differential PWM signal. A predriver inputs the PWM signal and derives the output gating signals to control the high and low side drivers of a Class D amplifier. | 02-25-2010 |
20100045377 | Switching Amplifier - A switching amplifier includes a modulator, which includes a pulse generator. The pulse generator generates positive and negative pulses, in response to an input signal, and the frequency of the negative pulses can be controlled independently of the frequency of the positive pulses. The positive pulses and negative pulses are combined to form a composite pulse stream, which can be low-pass filtered such that the filter output is an amplified version of the input signal. | 02-25-2010 |
20100052783 | CLASS-D AMPLIFIER - An amplifier that receives an input signal and outputs an amplified output signal includes an integration stage, a comparison stage, and a full bridge circuit. The integration stage is be used for receiving a constant common mode voltage, for receiving a first signal representing the input signal of the amplifier, and for generating a ramp signal. The comparison stage coupled to the integration stage is used for generating a pulse width modulation signal according to the ramp signal and according to a hysteretic signal. The full bridge circuit coupled to the comparison stage is used for receiving a power supply and the pulse width modulation signal, and for generating the output of the amplifier. | 03-04-2010 |
20100066446 | CLASS-D AMPLIFIER - The invention describes a power amplifier comprising a first transistor (M | 03-18-2010 |
20100066447 | FILTER COMPENSATION FOR SWITCHING AMPLIFIERS - Embodiments of the present invention provide methods and systems for limiting bipolar current flow in a switching amplifier. Embodiments of the present invention are directed to a multi-referenced switching amplifier. In some embodiment, the switching amplifier is a dual referenced switching amplifier comprising a regulator between the two references, where the first reference provides coarse modulation to a load and the second reference provides fine modulation to the load. The dual referenced switching amplifiers comprise the output filters made up of an inductor and a capacitor. In some embodiments, fine modulation is not applied to the load, thus limiting bipolar current flow induced by the filter inductors. | 03-18-2010 |
20100079207 | STAGED LINEAR CONVERSION METHOD - The present invention discloses a staged linear conversion method, which comprises steps: receiving a staged linear triangular-wave signal and a reference signal with a comparator, wherein the staged linear triangular-wave signal has a waveform having at least three different slopes; and performing a conversion on the reference signal to output a PWM signal according to the voltages of the intersections of the staged linear triangular-wave signal and the reference signal and the slope variation of the staged linear triangular-wave signal. The present invention can reduce the distortion of saturation signals when a Class D amplifier performs signal conversion. | 04-01-2010 |
20100079208 | Minimum pulse generation in a class-D amplifier - For minimum pulse generation in a class-D amplifier, a trapezoid switching waveform shape is used to replace the tradition triangle type to generate PWM pulses. Two voltages are compared with a sawtooth wave signal to generate the trapezoid waveform signal and a constant pulse width signal. An audio input signal is compared with the trapezoid waveform signal to generate a pulse width modulation signal, and either the pulse width modulation signal or the constant pulse width signal is used for driving a load at an output of the class-D amplifier. Flexible minimum pulse width could be obtained by offsetting one of the two voltages in generation of the constant pulse width signal. | 04-01-2010 |
20100085118 | Dead-time locking circuit - The dead-time locking circuit includes phase detector and a delay-comparator. The delay-comparator includes two input ends for receiving phase adjusting signal and the input-exchanging signal received by the class D amplifier. After comparing, the delay-comparator outputs a gate driving signal. The phase detector detects the phase difference between the output signal of the class D amplifier and the gate driving signal of the power transistor of the class D amplifier, and accordingly adjusts the rising/falling edges of the gate driving signal outputted from and the comparator via the charge-pump. In this way, the dead-time can be locked at the predetermined value. | 04-08-2010 |
20100090764 | CLASS D AMPLIFIER - The invention refers to an amplifier ( | 04-15-2010 |
20100097139 | ERROR CORRECTION SYSTEM FOR A CLASS-D POWER STAGE - The present invention relates to a method for correcting for a source of non-linearity and noise introduced in a switching power amplification stage during power amplification of a pulse-modulated reference signal from a pulse modulator, where the method comprises the following steps: —providing an output stage embedded in an analogue self-oscillating control loop able to receive a pulse-referenced input signal; —generating a feedback signal from the switching power amplification stage or after a demodulation filter; —deriving an error signal by comparing the feedback signal with the reference signal; —filtering the error signal by a low pass filter for reducing the higher harmonics of the carrier; —adding a compensator for generating high loop gain in the audio band; —feeding the compensator output to a zero cross detector or comparator, thus providing a carrier for re-modulation or re-timing by feeding the filtered signal to a zero cross detector or comparator, which controls the output stage. The invention furthermore relates to various systems for implementing the above method. | 04-22-2010 |
20100102881 | SAMPLING FREQUENCY REDUCTION FOR SWITCHING AMPLIFIERS - The present invention is directed toward providing a system and method of reducing RF interference in switching amplifiers without degrading performance. In one embodiment, the sampling rate of coarse high voltage modulated pulsewidths are decreased relative to the sampling rate of fine lower voltage modulated pulsewidths. This reduction in the sampling rate of coarse high voltage modulated pulsewidths results in a reduction in EMI. In addition, the higher sampling rate of the fine lower voltage modulated pulsewidths mitigates the distortion caused by the reduced sampling rate of the coarse pulsewidths. | 04-29-2010 |
20100102882 | ELECTRIC LOAD DRIVING CIRCUIT - An electric load driving circuit for driving an electric load having a capacity component includes a plurality of power sources generating different voltages, capacitors provided parallel to the plurality of power sources, a switch control unit that switches connections between the capacitors and the electric load and thereby switching a voltage applied to the electric load, discharge paths that enable discharging electric charge stored in the capacitor, and a discharge control unit that controls a quantity of electric charge discharged from the discharge paths. | 04-29-2010 |
20100102883 | PWM SIGNAL GENERATION CIRCUIT, CLASS-D AMPLIFIER AND METHOD FOR DRIVING THE SAME - A first situation indicating that the system is in a power-on situation or an un-mute situation, or a second situation indicating that the system is in a power-off situation or in a mute situation, is detected. When the first situation is detected, a differential PWM signal including a plurality of pulses each having a gradually increased or reduced width and the subsequent pulse train of 50% duty cycle pulses is generated and, if the output of an audio processor is in a stable situation, sent to the amplifier via a multiplexer. When the second situation is detected, the differential PWM signal including a plurality of pulses each having a gradually reduced width and the subsequent pulse train of no signal is generated and, at the same time, the generated pulses are sent to the amplifier via the multiplexer. | 04-29-2010 |
20100109772 | SIGMA DELTA CLASS D POWER AMPLIFIER AND METHOD THEREOF - A sigma delta class D power amplifier includes a loop filter, a quantizer, and an output stage. The quantizer is coupled to the loop filter and quantifies an error signal according to levels of two reference signals to output a pair of mean signals, wherein different logic combinations of the mean signals belong to one of three quantum states. The output stage is coupled to the quantizer and outputs a corresponding output signal according to the different quantum states to drive a load, wherein a driving current of the output signal belongs to one of the three driving states which include at least a steady state with no current of a power amplifier. | 05-06-2010 |
20100109773 | Class-D Amplifier - A class-D power amplifier according to the present invention includes: a pulse width modulation circuit which modulates an analog signal into low-level and high-level binary signals; and a detection circuit which turns off operation of a circuit connected with a back stage of the pulse modulation circuit if the high level or the low level of the binary signal output from the pulse width modulation circuit is maintained for a predetermined time. | 05-06-2010 |
20100117730 | D/A converter circuit and digital input class-D amplifier - The present invention provides a D/A converter circuit which enables D/A conversion with a high precision and can prevent occurrence of a limit cycle component in the case where an input signal is low, and can also prevent the effect of dither signal from occurring in an analog signal which is a D/A conversion result. | 05-13-2010 |
20100117731 | Thermal regulation of a class-D audio amplifier - A class-D audio amplifier is protected by thermal regulation which decreases the gain of the class-D audio amplifier by asserting an over-temperature signal when the temperature of the class-D audio amplifier is detected to be higher than a threshold. The output of the class-D audio amplifier is therefore reduced by the smaller gain, and the chance for the class-D audio amplifier to stop working due to overheating is greatly reduced. | 05-13-2010 |
20100117732 | POWER AMPLIFIER AND LIQUID JET PRINTING APPARATUS - A power amplifier includes: a modulator pulse-modulating a drive waveform signal serving as a reference of a drive signal applied to actuators and outputting a modulated signal; a digital power amplifier amplifying the power of the modulated signal and outputting an amplified digital signal; a low pass filter smoothing the amplified digital signal and outputting the drive signal; and an inverse filter circuit being disposed at a front stage of the modulator and capable of obtaining a desired waveform precision of the drive signal even when a frequency characteristic of a filter including the low pass filter and an electrostatic capacitor of the actuators varies depending on the number of driven actuators, wherein the inverse filter circuits include a plurality of inverse filters connected in series. | 05-13-2010 |
20100176881 | PULSE WIDTH MODULATION CIRCUIT AND CLASS-D AMPLIFIER COMPRISING THE PWM CIRCUIT - A pulse width modulation (PWM) circuit comprises a first integrator (g m | 07-15-2010 |
20100182083 | AMPLIFIER CIRCUITRY - A class D amplification device that prevents beats caused by switching operations of a switching power supply and a class D amplifier from causing noise within a voice band, enables easy control over power supply operations, and offers low power loss is provided. The amplification device includes a unit that generates a reference clock, a switching power supply that operates at a first frequency at which the frequency of the reference clock is divided, and a triangular wave generation unit that operates at a second frequency higher than the first frequency at which the frequency of the reference clock is divided. The amplification device further includes a class D amplifier that performs a switching operation with a pulse whose width has been modulated according to the input signal. | 07-22-2010 |
20100182084 | LOW RF INTERFERENCE SWITCHING AMPLIFIER AND METHOD - A switching amplifier includes first and second output terminals that may be connected to a load. A pulse-width modulator receiving an input signal to obtain respective positive and negative values of the input signal. The modulator is connected to first and second switching circuits. The first switching circuit applies a plurality of pulses to the first output terminal that, in response to the positive samples, have a constant frequency and are pulse-width modulated, and, in response to the negative samples, have a varying frequency and a constant width. Similarly, the second switching circuit applies a plurality of pulses to the second output terminal that, in response to the negative samples, have a constant frequency and are pulse-width modulated, and, in response to the positive samples, have a varying frequency and a constant width. The varying phase of the constant width pulses disperses RF interference across a wider spectrum. | 07-22-2010 |
20100188150 | Switching Amplifier - A switching amplifier is disclosed and comprises: a power supply (Vcc); input circuits (Va, Vb); switch transistors (M | 07-29-2010 |
20100201443 | REDUCTION OF DEAD-TIME DISTORTION IN CLASS D AMPLIFIERS - Pulse-width-modulating class D amplifier with an H-bridge output stage, and method of operating the same. in which output stage dead-time is compensated. Offset logic circuitry detects various dead-time-related conditions at push-pull output drivers, and generates an offset signal applied to the amplified differential input signal, to adjust the time at which the voltage at differential signal lines crosses a ramp reference waveform. The offset signal can correspond to the duration of a disturbance (dead-time at one driver in combination with an active signal at the active driver), or the sum of that disturbance duration with a dead-time at the active driver. The offset signal is generated by charging a capacitor for the duration of this disturbance, or disturbance plus dead-time. According to another approach, error is reduced by charging a capacitor for each transition of the signal for a duration of the dead-time of the active driver. Total harmonic distortion is reduced without requiring increased circuit complexity and without shortening the dead-time to unsafe margins. | 08-12-2010 |
20100201444 | Signal Modulation for Switched Mode Power Amplifiers - In a device ( | 08-12-2010 |
20100201445 | Class D Amplifier Having PWM Circuit With Look-Up Table - A class D amplifier includes a noise-shaping modulator, a pulse width modulator, and a pulse amplifier. The noise-shaping modulator receive a pulse code modulated (PCM) signal and produces an oversampled PCM signal. The pulse width modulator produce a pulse width modulated (PWM) signal from the oversampled PCM signal. The pulse amplifier amplifies the PWM signal to produce an amplified PWM signal. The PWM uses a lookup table to convert from PCM to PWM. A compensation circuit optimizes amplifier performance. An optional demodulator filter converts the amplified PWM signal to an analog signal. The amplifier is ideal for integrated audio applications. | 08-12-2010 |
20100219891 | Class-D amplifier - A class-D amplifier includes a differential integrator that integrates a difference between an input signal and a feedback signal to output an integration value signal, a pulse width modulation circuit that outputs a digital signal having a pulse width corresponding to a level of the integration value signal, an output buffer that drives a load based on the digital signal, a feedback section that feeds an output signal of the output buffer into the differential integrator as the feedback signal, a clamp section that performs a clamping of limiting the level of the integration value signal within a specified level range, an attenuation section that attenuates the level of the input signal to be input to the differential integrator in response to an attenuation command, and an attenuation control section that outputs the attenuation command to the attenuation section in response to the clamping performed by the clamp section. | 09-02-2010 |
20100225391 | Three-level half-bridge pulse-width modulation amplifier and method of driving the same - A three-level half-bridge PWM amplifier includes a PWM generator and an output stage. The PWM generator changes a width of a pulse at a first level or a second level according to amplitude of an input signal and outputs a three-level PWM output signal having the first level, the second level, and a reference level. The output stage drives an output node connected to a terminal of a load to a first power supply voltage, a second power supply voltage, or a third power supply voltage based on the three-level PWM output signal. Accordingly, unnecessary static current consumption is reduced, thereby increasing efficiency. | 09-09-2010 |
20100231297 | ELECTRONIC DEVICE FOR SELF OSCILLATING CLASS D SYSTEM - The present invention relates to an electronic device that includes an integrated power comparator circuit ( | 09-16-2010 |
20100231298 | Class D amplifier circuit - A class D amplifier circuit for generating a pulse signal whose pulse width is modulated in response to an input signal, the class D amplifier circuit includes first to fifth switching elements, a first capacitance element and a control section. The control section controls transition between a conduction state and a non-conduction state of each of the first to fifth switching elements to control a current direction flowing into a load having a first end electrically connected to the output end and a second end set to the reference potential, so that the current flows from the first end of the load to the second end of the load at a first timing and the current flows from the second end of the load to the first end of the load at a second timing. | 09-16-2010 |
20100244958 | Class D amplifier circuit - A class D amplifier circuit includes a signal generation section that generates a first pulse width modulation signal and a second pulse width modulation signal based on an input signal. When a level of the input signal is zero, the signal generation section generates: the first pulse width modulation signal having a repeated first wide-width pulse signal portion, which has a wide width and a repeated first narrow-width pulse signal portion, which has a narrow width which is narrower than the wide width of the first wide-width pulse signal; and the second pulse width modulation signal having a repeated second narrow-width pulse signal portion, which has a narrow width and a repeated second wide-width pulse signal portion, which has a wide width which is wider than the narrow width of the second narrow-width pulse signal portion. A rising point in time of the second narrow-width pulse signal portion occurs after a rising point in time of the first wide-width pulse signal portion and a falling point in time of the second narrow-width pulse signal portion occurs before a falling point in time of the first wide-width pulse signal portion. A rising point in time of the first narrow-width pulse signal portion occurs after a rising point in time of the second wide-width pulse signal portion and a falling point in time of the first narrow-width pulse signal portion occurs before a falling point in time of the second wide-width pulse signal portion. | 09-30-2010 |
20100253427 | CLASS-D AMPLIFIER - The invention discloses a class-D amplifier, which is used for driving a two-terminal load according to a set of analog signals. The D-class amplifier includes a pulse-width modulation (PWM) circuit, a signal processing circuit and a driving amplifier circuit. The PWM circuit receives the set of analog signals and converts them into a set of PWM signals with identical phase. The signal processing circuit generates a set of pulse signals which are attached to the set of PWM signals respectively. The driving amplifier circuit is coupled between the signal processing circuit and the two-terminal load. The driving amplifier circuit receives and amplifies the set of PWM signals. According to the set of PWM signals, the driving amplification circuit drives the two-terminal in a filterless way. | 10-07-2010 |
20100253428 | PWM AMPLIFIER - Amplifier device of the pulse width modulation amplifier type (PWM amplifier), which comprises a switch according to a micro-electromechanical system (MEMS-switch) for a signal to be amplified (V | 10-07-2010 |
20100253429 | METHOD FOR MEASURING THE SATURATION RATE OF AN AUDIO AMPLIFIER - A method and corresponding circuit that adjusts the gain of an audio output stage having a class D amplifier, this method including the steps of setting the gain to a nominal value, analyzing an output signal during successive clock periods, counting the number of clock periods during which the signal is in a state corresponding to a saturation, decreasing the gain if the number reaches, before the end of a first time interval, a value corresponding to a first percentage, maintaining the gain constant if, at the end of a second time interval, different from the first interval, the number corresponds to a second percentage being comprised between the first percentage and a third percentage, and increasing the gain if, at the end of the second time interval, the number corresponds to a fourth percentage, lower than the third percentage. | 10-07-2010 |
20100264985 | CLOSE-LOOP CLASS-D AUDIO AMPLIFIER AND CONTROL METHOD THEREOF - The present invention discloses a Class-D power amplifier and control method thereof. In one embodiment, the amplifier feeds back the signal at the output node to the inverting input of the comparator, and provides a high frequency triangular wave signal to the non-inverting input of the comparator. In addition, the non-inverting input of the comparator may be coupled to an offset voltage, while the inverting input of the comparator may be coupled to a fixed-frequency rectangular wave signal, a feedback signal which is derived from the output stage and an input signal. In use, the switching frequency may be at least substantially fixed, so as to reduce the influence on the system caused by electromagnetic interruption (EMI). Further, the control circuit is simple, and some devices can be integrated. | 10-21-2010 |
20100277238 | Hybrid Feedback Controlled Oscillation Modulator and Switching Power Amplifier System - A Hybrid feedback Controlled Oscillation Modulator (HCOM) is disclosed, having a 1 | 11-04-2010 |
20100289578 | MULTI-BIT CLASS-D POWER AMPLIFIER SYSTEM - Techniques for designing an efficient power amplifier are described. In one aspect, multiple single unit instance class-D power amplifiers with coupled outputs are utilized to increase efficiency and reduce quantization noise. In another aspect, multiple groups of single unit instance class-D power amplifiers are coupled at the outputs thereof with each group of power amplifiers configured to resonate at unique frequency. This results in increased efficiency and reduction of quantization noise at multiple frequencies bands. | 11-18-2010 |
20100289579 | SWITCHABLE INPUT PAIR OPERATIONAL AMPLIFIERS - Techniques for designing a switchable amplifier are described. In one aspect, a switchable amplifier including a core amplifier circuit configured to selectively enable one or more parallel input transistor pairs is described. The core amplifier circuit comprises a permanently enabled input transistor pair. In another aspect, a device operable between a first mode of operation and a second mode of operation comprising a receiver logic circuit for selectably enabling and disabling a plurality of input transistor pairs within a switchable amplifier is described where the switchable amplifier also includes a core amplifier circuit coupled to the receiver logic circuit for selectably enabling and disabling a transistor pair therein. The described switchable amplifiers result in the ability to provide varying amplifier performance characteristics based upon the current mode of operation of the device. | 11-18-2010 |
20100321111 | POWER AMPLIFIER - The invention refers to a power amplifier comprising a first transistor (M | 12-23-2010 |
20100327972 | Time Delay Compensation and Pulse Width Correction - A system, method and apparatus is provided for pulse width correction in a power driver. In an embodiment, an apparatus includes an operational amplifier having an input and an output. The input of the operational amplifier is coupled to receive an input pulse signal. The apparatus further includes an output stage having an input coupled to the output of the operational amplifier. The output stage also includes a current output configured to couple to a load and to a voltage sense output. The apparatus also includes a comparator having an inverting input coupled to the voltage sense output of the output stage, a non-inverting input configured to couple to an input signal, and an output. Also, the apparatus includes a timing circuit with an input coupled to the output of the comparator and an input coupled to the input signal. The timing circuit also has an output to supply the input pulse signal. The timing circuit measures a delay from a change in the input signal to a change in the output of the comparator. The timing circuit replicates the measured delay as a delay in a change to the input pulse signal. | 12-30-2010 |
20100327973 | AMPLIFIER CIRCUIT COMPRISING CHARGE PUMP AND LOW-PASS FILTER - According to one embodiment, an amplifier circuit includes a clock generation circuit, a switching amplifier circuit, and a smoothing circuit. The clock generation circuit generates a pseudo random period pattern signal whose period varies. The switching amplifier circuit samples an input signal based on the pseudo random period pattern signal used as a sampling clock. The smoothing circuit smoothes an output signal of the switching amplifier circuit. | 12-30-2010 |
20110006843 | Offset voltage correction circuit and class D amplifier - A class D amplifier includes an input unit that inputs an input signal and an integrator which includes a differential operational amplifier having an offset voltage correction function. The integrator integrates the input signal input. A pulse-width modulator modulates the integration result of the integrator to generate a pulse signal having a pulse width reflective of the integration result. An output unit outputs the pulse signal. A feedback unit superimposes a signal output from the output unit on the input signal and feeds back the superimposed signal to the integrator. An input controller selectively set the input unit to a state where no signal is input. An output controller sets a voltage of an output from the feedback unit to a constant voltage. | 01-13-2011 |
20110006844 | Class D Amplifier Control Circuit and Method - Circuit and method for a Class D amplifier. In one exemplary embodiment, an audio amplifier is disclosed. A closed loop configuration for driving high and low side driver transistors is provided, each circuit is compatible with advanced sub micron semiconductor processes. The analog time varying input is coupled to one input of a sigma delta analog to digital converter. A feedback signal from the output is also input to the analog to digital converter. A bit stream is output by the analog to digital converter. A decimator receives this bit stream and downconverts the samples to digital values at a lower frequency. A digital filter with adaptable coefficients is used to filter that signal and a digital pulse width modulator then develops an analog differential PWM signal. A predriver inputs the PWM signal and derives the output gating signals to control the high and low side drivers of a Class D amplifier. | 01-13-2011 |
20110012676 | SYSTEMS AND METHODS OF REDUCED DISTORTION IN A CLASS D AMPLIFIER - Systems and methods for reduced distortion in a class D amplifier are provided. An “ideal” digital output signal is produced. The “ideal” digital output signal is then compared to the actual output signal in an error amplifier. The integrator input is the difference between the output stage waveform and the ideal output stage waveform. The net input to the integrator now comprises the imperfections of the power stage, and the feedback loop drives their average to zero. This error is then amplified and integrated. The integrated signal is than applied to a summer where it is added to the analog input. Then as in the typical Class D amplifier, the integrated signal is compared in an error amplifier to a ramp signal generated from the ramp generator. | 01-20-2011 |
20110012677 | CURRENT SENSING - A switching amplifier comprising: an output driving circuit ( | 01-20-2011 |
20110025415 | Digital Modulated RF Power Amplifier with Impedance Compensation Circuit - A digital modulated power amplifier unit includes a differential radio frequency (RF) amplifier circuit having differential output nodes, a digital modulation signal input and complimentary clock signal inputs. The differential RF amplifier circuit includes a first pair of transistors operable to receive a digital modulation signal and a second pair of transistors operable to receive complimentary clock signals. The digital modulated power amplifier unit further includes an impedance compensation circuit connected between the differential output nodes of the differential RF amplifier circuit. The impedance compensation circuit includes a transistor connected in series between first and second RC circuits. The transistor is operable to electrically connect and disconnect the first RC circuit and the second RC circuit responsive to the digital modulation signal. | 02-03-2011 |
20110032034 | SWITCHED MODE AMPLIFIER - A switched mode amplifier includes a voltage source, a switched amplifier, a controller and a feedback unit. The switched amplifier sources or sinks a current to or from a load. The load and the current define a voltage over the load. The controller generates control signals for the switched amplifier in response to an input signal and a feedback signal. The feedback unit is connected to the controller and the load, and generates the feedback signal from the voltage over the load. | 02-10-2011 |
20110037517 | Concept, method and apparatus of improved distortion switched-mode amplifier - Systems and methods for switched-mode amplifiers having improved harmonic distortion are disclosed. High order in-band filtering is enabled without undue trade-off of distortion due to intermodulation/aliasing. A pre-modulation block is introduced, deployed between a loop filter block and a pulse-width modulation block, performing uniform pulse-width modulation. The pre-modulation block attenuates/removes amplitude dependent high frequency ripples before pulse-width modulation. The pre-modulation block in conjunction with the pulse-width modulation block performs double sampling of the input signals. | 02-17-2011 |
20110057726 | SWITCHING AMPLIFIER - A switching amplifier ( | 03-10-2011 |
20110063027 | Class-D amplifier - A class-D amplifier for generating from an input signal a digital signal for driving a load, includes an output limit instruction generating section that detects that the digital signal falls outside a limit range and that outputs an output limit instruction signal, an attenuation instruction pulse generating section that includes an integrator for integrating the output limit instruction signal and that outputs a periodical attenuation instruction pulse having pulse width corresponding to an integrated value in the integrator, an attenuating section provided in an input path for the input signal and that attenuates the input signal based on the attenuation instruction pulse, and a mute control section that controls the integrated value in the integrator independently of the output limit instruction signal to control an amount of the attenuation of the attenuating section applied to the input signal. | 03-17-2011 |
20110068869 | SINGLE-ENDED CLASS-D AMPLIFIER WITH DUAL FEEDBACK LOOP SCHEME - A single-ended class-D amplifier with dual feedback loop scheme has a gain adjusting circuit, a second-order integrator, two comparators, a logic circuit, an output driver and an inverter. The output driver cooperates with the inverter to produce a differential signal. The differential signal is input to the second-order integrator to construct a dual feedback differential loop to eliminate noise of output signals of the class-D amplifier, and offer enhanced signal to noise and distortion ratio (SNDR). | 03-24-2011 |
20110068870 | CLASS-D AMPLIFIER WITH DUAL FEEDBACK LOOP - A class-D amplifier with dual feedback loop scheme has a gain adjusting circuit, a second-order integrator, two comparators, a logic circuit and an output driver. Two differential output terminals of the class-D amplifier are connected to two differential amplifiers of the second-order integrator to construct a second-order feedback loop for offering second order noise shaping, eliminating non-linear components in the class-D amplifier, and also enhancing signal to noise and distortion ratio (SNDR). Further, distortion component existing in the differential signal output from the differential output terminals is amplified by the two differential amplifiers so as to improve the loop gain of the class-D amplifier. The differential signal processed by the two differential amplifiers also can be precisely adjusted. | 03-24-2011 |
20110109386 | CLASS D AMPLIFIER CAPABLE OF SETTING RESTRAINT POWER - A Class D amplifier capable of setting restraint power is provided, which comprises: an audio amplification unit, a pulse width modulation (PWM) unit, a first pre-drive unit, a second pre-drive unit, a first power transistor set, a second power transistor set and a power restraint unit. The power restraint unit has a comparator circuit and a power restraint circuit. The comparator circuit is configured to compare the level of first/second amplified audio signals against the level of a first reference voltage that is externally settable. When the high level of the first/second amplified audio signals is higher than the level of the first reference voltage, the comparator circuit outputs a first comparison signal and a second comparison signal to the power restraint circuit to restrain the power. | 05-12-2011 |
20110109387 | Power amplification apparatus for envelope modulation of highfrequency signal and method for controlling the same - A power amplification apparatus and method provide for controlling envelope modulation of a Radio Frequency (RF) signal. The power amplification apparatus includes a linear amplifier configured to receive an input signal to be amplified, and generate a linear output signal for compensating for a current ripple of an amplified signal and a switch control signal having a current obtained by dividing the linear output signal by a predetermined ratio. The power amplification apparatus also includes a switching amplifier configured to receive the switch control signal through a multi-mode resistor having a variable resistance, and generate the amplified signal. The variable resistance of the multi-mode resistor determines a switching frequency representing an operating speed of the switching amplifier, and is adjusted according to a communication mode of the input signal. | 05-12-2011 |
20110133836 | CLASS-D AMPLIFIER - Class D amplifier is provided. The class D amplifier includes at least a block; each block includes an input circuit, an integrator, a comparator, a driving circuit and two feedback circuits. The input circuit receives a digital input to provide a differential pair of a positive and a negative input signals. The integrator receives the positive and negative input signals and a pair of positive and negative feedback signals for providing a positive error signal according to the positive input signal and the negative feedback signal, and providing a negative error signal according to the negative input signal and the positive feedback signal. The comparator compares between the positive and the negative error signals such that the driving circuit generates a driving output signal according to comparison result. The two feedback circuits respectively providing said positive and negative feedback signals according to the driving output signal. | 06-09-2011 |
20110148521 | DYNAMIC CONSTANT POWER AMPLIFIER - A switching amplifier including a voltage sensor circuit connected to a high voltage supply rail for measuring the power supply voltage. A current sensor circuit is connected to the high voltage supply rail for measuring the power supply current. An error amplifier is connected to the switching amplifier and receives one or more values based on the measurements taken by the voltage sensor and current sensor, and the error amplifier produces an error signal when a predetermined power limit is exceeded. A signal limiting circuit is connected to the error amplifier and the switching amplifier and limits the output power to rated power at any rated load impedance when the error amplifier produces the error signal. This switching amplifier is capable of automatically limiting output power at rated power into all rated load impedances, and dynamically reacts to the frequency-dependant impedance of a typical audio system. | 06-23-2011 |
20110181356 | SWITCHING DEVICE OF DIGITAL AMPLIFIER AND METHOD FOR DRIVING THE SAME - A switching device of a digital amplifier and a method for controlling the same are disclosed. In accordance with the present invention, a linearity is maintain even for a short pulse width since a data signal having a pulse width shorter than a predetermined length. Moreover, when an MLP signal is located at both sides of a compensating signal without overlapping with each other, a problem due to a common mode may be prevented. | 07-28-2011 |
20110210790 | FILTER COMPENSATION FOR SWITCHING AMPLIFIERS - Embodiments of the present invention provide methods and systems for limiting bipolar current flow in a switching amplifier. Embodiments of the present invention are directed to a multi-referenced switching amplifier. In some embodiment, the switching amplifier is a dual referenced switching amplifier comprising a regulator between the two references, where the first reference provides coarse modulation to a load and the second reference provides fine modulation to the load. The dual referenced switching amplifiers comprise the output filters made up of an inductor and a capacitor. In some embodiments, fine modulation is not applied to the load, thus limiting bipolar current flow induced by the filter inductors. | 09-01-2011 |
20110215867 | REDUCING PULSE ERROR DISTORTION - A class D amplifier that includes circuitry to apply a non-linear correction to pulse error distortion. The amplifier includes an output voltage controlling circuit, comprising at least two switches, controlled by a modulator; an output inductor, coupling the switching circuit to an output terminal; and correction circuitry to provide to the modulator a correction signal characterized by a non-linearity. The correction circuitry includes a current sensor that senses the current from the output inductor to the output terminal. | 09-08-2011 |
20110227645 | CLASS-D POWER AMPLIFIER - A class-D power amplifier includes a switching power source section, a synchronization signal generation section and a class-D power amplifying section. The synchronization signal generation section takes out of the switching power source section a clock signal having a second frequency which is “n” times of a first frequency. The class-D power amplifying section includes a comparator which compares an input signal with a feedback signal, a second switching section which switches a power source fed from the synchronization signal generation section, a filter section which smoothes an output signal from the second switching section, and a combining section which combines a delayed output signal with a clock signal from the synchronization signal generation section to generate the feedback signal. The class-D power amplifying section is adjusted so as to cause self-oscillating operation at a frequency substantially identical with the second frequency, when a level of the output signal from the filter section is low. | 09-22-2011 |
20110248781 | Duplicate feedback network in class D amplifiers - A circuit and a method are provided for suppressing the pop and click noise during the power on and power off of Class D amplifiers. The technique also suppresses pops and clicks when the Class D amplifier enters or exits standby mode. A duplicate feedback network is used to establish the stable operating points, including offsets in the Class D circuit without turning on the outputs. The technique works by gradually propagating or dissipating the offset through the signal path of a Class D amplifier by swapping the differential outputs using switches to suppress pops and clicks when starting up and shutting down the amplifier. | 10-13-2011 |
20110254625 | CIRCUIT AND METHOD FOR REDUCING NOISE IN CLASS D AMPLIFIERS - A circuit for reducing noise in Class D amplifiers has a power stage voltage control means ( | 10-20-2011 |
20110260793 | Ground-referenced common-mode amplifier circuit and related method - Disclosed is an amplifier circuit configured to amplify a pulse stream. The amplifier circuit comprises a switching block including a first switch operable to couple an output node of the switching block to a positive reference voltage, a second switch operable to couple the output node to a ground reference voltage and a third switch operable to couple the output node to a negative reference voltage. The amplifier circuit is configured to amplify the pulse stream into an amplified signal detectable at the output node such that the amplified signal has a common-mode voltage level substantially equal to zero volts. In one embodiment, the amplifier circuit is configured to amplify the pulse stream in accordance with a Class-D amplification scheme. In one embodiment, the output node can be directly connected to a load device without a DC blocking capacitor being interposed between the output node and the load device. | 10-27-2011 |
20110260794 | HIGH FREQUENCY POWER AMPLIFIER - A high frequency power amplifier includes first and second transistors connected in parallel and amplifying a high frequency signal; a first switch connected to outputs of the first and second transistors and which connects an input terminal selectively to first and second output terminals; a third transistor amplifying a signal output from the first output terminal of the first switch; and a second switch having a first input terminal connected to the third transistor, a second input terminal connected to the second output terminal of the first switch, and which selectively connects the first and the second input terminals to an output terminal of the second switch. | 10-27-2011 |
20110285463 | OUTPUT CIRCUITS WITH CLASS D AMPLIFIER - Output circuits using pulse width modulation (PWM) and/or pulse density modulation (PDM) are described. In one aspect, a PWM output circuit includes a PWM modulator that operates based on a square wave signal instead of a sawtooth or triangular wave signal. In another aspect, a PDM output circuit includes a PDM modulator that uses variable reference voltages to reduce variations in switching frequency. In yet another aspect, a dual-mode output circuit supports both PWM and PDM and includes a pulse modulator and a class D amplifier. The pulse modulator performs PWM on an input signal if a PWM mode is selected and performs PDM on the input signal if a PDM mode is selected. The class D amplifier receives a driver signal from the pulse modulator and generates an output signal. | 11-24-2011 |
20110316627 | DYNAMIC CONSTANT POWER AMPLIFIER - A switching amplifier including a voltage sensor circuit connected to a high voltage supply rail for measuring the power supply voltage. A current sensor circuit is connected to the high voltage supply rail for measuring the power supply current. An error amplifier is connected to the switching amplifier and receives one or more values based on the measurements taken by the voltage sensor and current sensor, and the error amplifier produces an error signal when a predetermined power limit is exceeded. A signal limiting circuit is connected to the error amplifier and the switching amplifier and limits the output power to rated power at any rated load impedance when the error amplifier produces the error signal. This switching amplifier is capable of automatically limiting output power at rated power into all rated load impedances, and dynamically reacts to the frequency-dependant impedance of a typical audio system. | 12-29-2011 |
20120025910 | Switching amplifier with enhanced supply rejection and related method - Disclosed is a switching amplifier having an enhanced supply rejection. The switching amplifier comprises a digital modulator that provides a modulated signal. The switching amplifier further comprises a closed-loop analog driver that is coupled to the digital modulator. As disclosed, the closed-loop analog driver is configured to re-modulate a modulation signal that corresponds to the modulated signal. An output stage of the switching amplifier is driven by the re-modulated signal, thereby providing enhanced supply rejection. In one embodiment, the modulated signal is produced by a digital pulse-width modulator (PWM) circuit of a Class-D amplifier, and has a pulse rate substantially less than a clock rate of the digital PWM circuit. In one embodiment, the switching amplifier is implemented as an audio amplifier in a mobile communication device such as a cellular telephone. | 02-02-2012 |
20120044020 | METHOD AND APPARATUS FOR SENSING A CURREN FOR VARYING IMPEDANCE LOADS - Recently, there has been an increased desire to measure load currents of class-D amplifiers to improve performance. The traditional solution has been to include one or more discrete components in series with the load, but this degrades performance. Here, however, circuit is provided (which includes sample-and-hold circuit) that accurately measures load currents without inhibiting performance and that is not inhibited by the phase differences between the load voltage and load current. | 02-23-2012 |
20120056670 | CROSS CURRENT MINIMIZATION - A method of optimising cross current in class D amplifiers and simultaneously minimizing the harmonic distortion is provided. The method overcomes the problem of using the limited speed voltage comparators often used in cross current preventing circuits. Method embodiments are based on introducing a replica amplifier with a current sensor matched to a main amplifier. The duration of a sensed cross current within the replica amplifier is compared by a current comparator with a small enough reference current. The comparator output generates a pulse with a duration equal to the duration of the cross current event in the replica amplifier. The duration of that pulse is measured and used to generate a dead time pulse for blanking amplifier pre-driver inputs. | 03-08-2012 |
20120081179 | DUTYCYCLE ADJUSTMENT TO IMPROVE EFFICIENCY OF A DIGITAL RF-PA - An amplification unit reduces a duty cycle of a digital signal at a carrier radio frequency to optimize the efficiency of the RF power amplifier that amplifies the reduced duty cycle signal. An exemplary amplification unit includes a duty cycle controller and a digital power amplifier. A delay unit in the duty cycle controller applies a delay to an input digital signal at the carrier radio frequency to generate a delayed signal at the carrier radio frequency. A logic gate in the duty cycle controller logically combines the input digital signal with the delayed signal to generate a modified digital signal at the carrier radio frequency, where the modified input digital signal has a reduced duty cycle relative to that of the input digital signal. Amplifying the modified digital signal in the digital RF power amplifier generates an amplified analog signal at the carrier radio frequency while improving amplifier efficiency. | 04-05-2012 |
20120154043 | HIGH-FREQUENCY POWER AMPLIFIER DEVICE - Disclosed is a high-frequency power amplifier device capable of reducing a talk current. For example, the high-frequency power amplifier device has first and second power amplifier circuits, first and second transmission lines, and a region in which the first and second transmission lines are disposed close to each other. Either the first or second power amplifier circuit becomes activated in accordance with an output level. When the second power amplifier circuit is activated, currents flowing in the first and second transmission lines are transmitted in the same direction so that magnetic coupling occurs to strengthen each transmission line's magnetic force. When, on the other hand, the first power amplifier circuit is activated, currents flowing in the first and second transmission lines are transmitted in the opposite directions so that magnetic coupling occurs to weaken each transmission line's magnetic force. | 06-21-2012 |
20120154044 | Class-D Amplifier Circuit - A class-D amplifier circuit includes an amplifier that generates pulse-width modulated output signals according to input signals which have phases reverse to each other and are supplied to a first input end and a second input end, a first transistor interposed between a first input path extending from the first input end to the amplifier and a second input path extending from the second input end to the amplifier, and a voltage applying circuit that applies a control voltage corresponding to a predetermined value to a control terminal of the first transistor so that a current flowing between both ends of the first transistor increases in accordance with increase of levels of the input signals within a range in which the levels of the input signals are higher than the predetermined value. | 06-21-2012 |
20120169420 | CIRCUIT AND METHOD FOR AMPLIFYING A DIGITAL SIGNAL - An amplifier circuit includes an amplifier unit that is configured to receive an input signal and generate a switching output signal. A level shifter is configured to shift the amplitude of the input signal to have a shifted amplitude that is proportional to a peak-to-peak amplitude of the switching output signal. | 07-05-2012 |
20120182069 | AMPLIFIER SYSTEM FOR A POWER CONVERTER - An amplifier system for a power converter includes at least a first switching device and a second switching device formed in an integrated circuit in a substrate of a semiconductor. The first and second switching devices may be formed in a half bridge configuration and may be cooperatively switchable to generate an amplified output signal on an output node of the semiconductor. A resistor and a capacitor may be coupled in parallel between a power supply input node and a substrate node included in the semiconductor. The capacitor may be selectively charged to a de-biasing voltage during a switching cycle of the first and second switching devices to reverse bias a parasitic switching device appearing in the integrated circuit. | 07-19-2012 |
20120229211 | AMPLIFIER USING FAST DISCHARGING REFERENCE - Techniques are disclosed relating to charging and discharging a gate of transistor. In one embodiment, an apparatus is disclosed that includes a driver configured to discharge a gate of a transistor. The driver is configured to discharge the gate at a first rate until reaching a Miller plateau for the transistor, and to discharge the gate at a second rate after reaching the Miller plateau. In such an embodiment, the first rate is greater than the second rate. In some embodiments, the driver is also configured to charge the gate of the transistor at a third rate until reaching a Miller plateau for the transistor, and to charge the gate at a fourth rate after reaching the Miller plateau, the third rate being greater than the fourth rate. In some embodiments, the apparatus is a class D amplifier. | 09-13-2012 |
20120229212 | AMPLIFIER USING MASTER-SLAVE CONTROL SCHEME - Techniques are disclosed relating to charging and discharging gates of transistors. In one embodiment, an apparatus includes first and second drivers. The first driver is configured to discharge a gate of a first transistor, and to send a charge indication to the second driver in response to reaching a Miller plateau for the first transistor. The second driver is configured to charge a gate of a second transistor above a threshold voltage in response to receiving the charge indication. In some embodiments, the second driver is configured to begin charging the gate of the second transistor to a voltage below the threshold voltage when the first driver begins discharging the gate of the first transistor begins, and to wait to charge the gate of the second transistor above the threshold voltage until the charge indication has been received. | 09-13-2012 |
20120235743 | APPARATUS FOR OUTPUTTING SYMMETRICAL SIGNAL AND AMPLIFIER CIRCUIT - A symmetrical signal generator that includes a first signal part configured to produce a first output pulse signal using a first input pulse signal and a second input pulse signal asymmetrical to each other, and a second signal part configured to produce a second output pulse signal using the first input pulse signal and the second input pulse signal. The second output pulse signal is one inverted to be symmetrical to the first output pulse signal. | 09-20-2012 |
20120242407 | Switched Amplifier Circuit Arrangement and Method for Switched Amplification - A switched amplifier circuit arrangement comprises a main amplifier (Amp) having an input terminal (In) and an output terminal (Out) and a regulating amplifier (rAmp) to set an input and an output operating point of the main amplifier (Amp). The regulating amplifier (rAmp) exhibits an auxiliary amplifier (A) having a first input terminal coupled to a reference level (Vref), a second input terminal (Ain) coupled to the output terminal (Out), and an output terminal (Aout) which is connected via a first switch (S | 09-27-2012 |
20120286868 | CLASS D POWER AMPLIFIER - A class D power amplifier (PA) is provided. The PA generally comprises a driver, output capacitor, a matching network, and a cancellation circuit. The driver has an input, an output, and a parasitic capacitance, and the input of the driver is configured to receive complementary first and second radio frequency (RF) signals, where there is a free-fly interval between consecutive pulses from the first and second RF signals. The output capacitor and cancellation circuit are each coupled to the output of the driver such that the cancellation circuit provides harmonic restoration at least during the free-fly interval, and the matching network is coupled to the output capacitor. | 11-15-2012 |
20120293256 | SWITCHING AMPLIFIER - When a switching amplifier transitions into a power-off state, a switch is turned off and a power supply controller forcibly discharges a capacitor and forcibly reduces a reference potential with respect to a second power supply voltage. Since a logic power supply voltage reduces by the same amount as the reference potential, the logic power supply voltage from a viewpoint of the reference potential is fixed. A constant current circuit reduces a constant current according to the reduction in the reference potential with respect to the second power supply voltage, and reduces a first electric current and a second electric current. Before the logic power supply voltage from the viewpoint of the reference potential reduces, the first electric current and the second electric current are reduced, and an operation of a pulse generating unit can be ended in a normal state. | 11-22-2012 |
20120293257 | HIGH FREQUENCY POWER AMPLIFIER - A high frequency power amplifier includes: a first transistor for amplifying an input high-frequency signal; a second transistor for amplifying an output signal of the first transistor; a third transistor connected in parallel with the first transistor and for amplifying the input high-frequency signal; a first switching element connected between an output of the first transistor and an input of the second transistor; a second switching element connected between an output of the third transistor and the first switching element; third and fourth switching elements connected in series between the output of the first transistor and an output of the second transistor, and between the second switching element and the output of the second transistor; and a first capacitor connected between the third switching element and the fourth switching element. | 11-22-2012 |
20120299652 | MULTI-AUTONOMOUS ELECTRONIC AMPLIFIER - An electronic amplifier includes a configurable integrated circuit device structured to synthesize at least a first signal and a second signal, scale the first signal to create a scaled first signal and scale the second signal to create a scaled second signal, create a discrete time composite signal which comprises a summation of at least the scaled first signal and the scaled second signal, create a discrete time pulse width modulated signal based on the discrete time composite signal, and generate a number of control signals based on the discrete time pulse width modulated signal. The electronic amplifier also includes a power switching stage receiving the number of control signals from the configurable integrated circuit device, wherein the number of control signals are configured to control the power switching stage, and a low pass filter coupled to an output of the power switching stage. | 11-29-2012 |
20120326783 | LOW-VOLTAGE POWER-EFFICIENT ENVELOPE TRACKER - Techniques for efficiently generating a power supply are described. In one design, an apparatus includes an envelope amplifier and a boost converter. The boost converter generates a boosted supply voltage having a higher voltage than a first supply voltage (e.g., a battery voltage). The envelope amplifier generates a second supply voltage based on an envelope signal and the boosted supply voltage (and also possibly the first supply voltage). A power amplifier operates based on the second supply voltage. In another design, an apparatus includes a switcher, an envelope amplifier, and a power amplifier. The switcher receives a first supply voltage and provides a first supply current. The envelope amplifier provides a second supply current based on an envelope signal. The power amplifier receives a total supply current including the first and second supply currents. In one design, the switcher detects the second supply current and adds an offset to generate a larger first supply current than without the offset. | 12-27-2012 |
20120326784 | POWER AMPLIFIER - A power amplifier includes: an input terminal at which an input signal is input; a first amplifier element amplifying the input signal; a second amplifier element amplifying an output signal of the first amplifier element; an output terminal from which an output signal of the second amplifier element is output; a matching circuit connected between an output of the second amplifier element and the output terminal; a first switch connected between an output of the first amplifier element and an input of the second amplifier element; and a second switch having a first end connected to the output of the first amplifier element, and a second end. The matching circuit includes a first inductor and a first capacitor connected in series between the output of the second amplifier element and a grounding point. The second end of the second switch is connected to a connecting point of the first inductor to the first capacitor. | 12-27-2012 |
20130021096 | DIGITAL AMPLIFIER - A digital amplifier comprises: a switching unit that amplifies a signal input to the digital amplifier by performing a switching operation; a driving unit that turns the switching unit on and off; an input signal detection unit that detects an input signal to the digital amplifier; and a first control unit that performs control such that the switching unit starts a switching operation by starting driving of the driving unit, when the digital amplifier is changed to a signal input state and the input signal detection unit detects an input signal, and performs control such that the switching unit stops the switching operation by stopping the driving of the driving unit, when the digital amplifier is changed to a no signal input state and the input signal detection unit does not detect an input signal. This configuration enables to reduce power consumption when no signal is input. | 01-24-2013 |
20130033318 | SWITCHING AMPLIFIER AND AUDIO DEVICE - A switching amplifier is provided. The switching amplifier includes an input unit which receives an audio signal; a first switching device and a second switching device which switch and output the audio signal; a first snubber circuit which is commonly connected to the first and second switching devices and which reduces overshoot of the audio signal that is output by the first and second switching devices via switching; and a second snubber circuit which is commonly connected to the first and second switching devices, which is connected in parallel to the first snubber circuit and which reduces the overshoot of the audio signal, wherein the first and second snubber circuits alternately reduce the overshoot of the audio signal. | 02-07-2013 |
20130033319 | AMPLIFIER CIRCUITS AND MODULATION SIGNAL GENERATING CIRCUITS THEREIN - An amplifier circuit includes a modulation signal generating circuit, a driving stage circuit and an output stage circuit. The modulation signal generating circuit generates a pair of modulation signals according to a pair of differential input signals and a pair of clock signals. The pair of clock signals includes a first clock signal and a second clock signal having a phase difference therebetween. The driving stage circuit generates a pair of driving signals according to the pair of modulation signals. The output stage circuit generates a pair of amplified output signals according to the pair of driving signals. | 02-07-2013 |
20130038391 | METHOD AND APPARATUS FOR REDUCING DISTORTION IN CLASS D AMPLIFIER - Provided are apparatuses and methods for reducing nonlinear distortions in Class D amplifiers by dynamically changing first and second threshold voltages in a pulse width modulator. A Class D amplifier apparatus is disclosed, comprising a pulse width modulator whose operation relies on a first and second threshold value, and a threshold controller which varies the thresholds in response to internal signals in the amplifier. Further, a method of processing Class D amplifier internal signals is disclosed, comprising steps involving measuring internal signals in a Class D amplifier and varying threshold signals in response to those measurements within the amplifier. | 02-14-2013 |
20130038392 | POWER SUPPLY METHOD AND APPARATUS - A method and apparatus for providing a power supply for an amplifier is provided. The power conversion is achieved using synchronous rectifiers in a regulated half bridge power supply, taking the sum of the positive and negative rails as feedback, in order facilitate energy transfer between positive and negative output rails. This minimizes the effects of off side charging and rail sag, as well as achieving good line regulation, while allowing use of very small, low value output capacitors. | 02-14-2013 |
20130049862 | SWITCHING CIRCUIT AND ENVELOPE SIGNAL AMPLIFIER - A switching circuit according to one embodiment has: N switching elements; a connection circuit including N−1 first inductance elements that are connected in series; a second inductance element; and N third inductance elements. Control terminals of the N switching elements are connected to ends of the connection circuit and connection contacts, respectively. One end of the second inductance element is connected to a power supply. The N third inductance elements electrically connects one ends of the N switching elements and the other end of the second inductance element with each other, respectively. | 02-28-2013 |
20130063209 | SWITCHING AMPLIFIER WITH AN INDUCTOR - A switching amplifying method or a switching amplifier for obtaining a linearly amplified replica of an input signal, is highly efficient, and does not have the disadvantage of “dead time” problem related to the class D amplifiers. Another aspect of the present invention provides a switching amplifier that is completely off when there is no input signal. Yet another aspect of the present invention further comprises an act of comparing an input signal with an output feedback signal for detection and correction of overall system signal processes therefore does not require a power supply regulator and is substantially immune to power supply and load perturbations. | 03-14-2013 |
20130088296 | Attenuating Noise and Cross-Talk in an Audio System by Offsetting Outputs In Phase - An amplifier may include two or more pulse-width modulators (PWMs) controlling respective sets of switches to produce an amplified version of a source signal. The clocking for the amplifier may be controlled to delay signal processing within the PWMs relative to one another in time, thereby providing an effective time offset between the respective edge transitions of the controlling signals provided to the respective sets of switches. The PWMs may count down to zero from the next PWM duty-cycle value when a new data sample is detected, beginning a new count for each new sample, with the PWM outputting a pulse when the counter value is nonzero. A “data-sample-ready” signal may be decoded from a master counter, which may be clocked based on the high speed PWM clock, and the decode value may be adjusted to determine when the PWM should initialize to the next data sample. | 04-11-2013 |
20130088297 | PWM Re-Clocking Scheme To Reject Accumulated Asynchronous Jitter - An amplifier may use pulse-width modulators controlling respective sets of switches to produce an amplified version of a source signal. A phase locked loop in the amplifier may generate a differential clock signal. A first processing element operating according to a first supply voltage may generate a PWM signal representative of the source signal, and also generate a clock enable signal corresponding to the differential clock signal. A second processing element (PE2) may receive the differential clock signal, the PWM signal, and the clock enable signal, and level shift the PWM signal and the clock enable signal to operate according to a second supply voltage, and may generate a resampling clock signal from the differential clock signal according to the level shifted clock enable signal. The PE2 may provide a PWM output signal representative of the source signal by resampling the level shifted PWM signal with the resampling clock signal. | 04-11-2013 |
20130093515 | PWM COMPARATOR AND CLASS D AMPLIFIER - The present disclosure generally relates to a PWM comparator and a class D. The PWM comparator described above introduces current feedback mechanism, basing the waveform state of received high frequency triangle signal and the level state of output signal of the PWM comparator, the hysteresis is changing dynamically. In the same resolution, the noise resistance ability of the PWM comparator described above is much better than that of the conventional PWM comparators which has a fixed hysteresis, thus the PWM comparator can work stably even if the duty cycle of output signal is nearly 100%. | 04-18-2013 |
20130113561 | OUTPUT MODE SWITCHING AMPLIFIER - An output mode switching amplifier, including: a transistor for signal amplification connected between a first node on an input side and a second node on an output side; a bypass path for bypassing the transistor between the first node and the second node; a voltage control circuit for switching whether to apply a bias voltage to the transistor so that a transmission signal is amplified by the transistor or to output a transmission signal via the bypass path without amplifying the transmission signal by the transistor; and a second-harmonic reflection circuit connected to the bypass path, for reflecting a second harmonic of the transmission signal. | 05-09-2013 |
20130120063 | AMPLIFIER CIRCUIT - Class D amplifier circuits for amplifying an input signal. The amplifier has an H-bridge output stage and thus has switches for switchably connecting a first output to a first voltage, e.g. Vdd, or a second voltage (e.g. ground) and for switchably connecting a second output to the first or second voltages. A switch controller is configured to control the H-bridge stage so as to vary between a plurality of states including at least a first state in which the outputs are both connected to the first voltage and a second state in which the outputs are both connected to said second voltage. The switch controller is configured to vary the proportion of time spent in the first state relative to the second state based on an indication of the amplitude of the input signal. The amplifier may therefore have first circuitry for deriving a proportion value (α) based on the input signal (Din) and second circuitry for generating control signals for selecting the first state or said second state based on the proportion value (α). | 05-16-2013 |
20130127530 | MULTI-LEVEL BOOSTED CLASS D AMPLIFIER - Techniques to generate boosted multi-level switched output voltages from a boosted multi-level Class D amplifier. The amplifier may include a multi-level H-bridge, which may include pairs of transistor switches coupled to a first, second, and third supply potential. The second supply potential may be a boosted representation of the first supply potential. The amplifier may receive an input signal, and from the input signal may generate pulse-modulated control signals to control the switching for the transistor switches of the multi-level H-bridge. The amplifier may generate the boosted multi-level switched output voltages from output nodes of the multi-level H-bridge. | 05-23-2013 |
20130127531 | AMPLIFIER CIRCUIT WITH OFFSET CONTROL - Methods and apparatus for Class-D amplifier circuits with D.C. offset control/correction. A Class-D amplifier is described having an output stage, such as a full H-bridge or half bridge, with a plurality of switches operable to provide a plurality of output states comprising at least a positive output state and a negative output state. Control circuitry is configured to receive a first signal based on the input signal and produce a digital control signal, which is used to determine the switch state of the output stage. A digital integrator is configured to receive a feedback signal indicative of the output state of the output stage and to sample the feedback signal at a sample rate and produce an integrated output signal (INT, IVC) indicating the difference in number of instances of the positive output state and the negative output state. Correction circuitry subtracts the integrated output signal from the input signal to produce a D.C. offset corrected signal. | 05-23-2013 |
20130127532 | SWITCHED-MODE POWER SUPPLY APPARATUS AND METHOD - The present invention relates to a switched-mode power supply apparatus and a corresponding method. For an effective compensation of non-linearities caused by dead-time and voltage drops in the switching power amplifier of the apparatus, an apparatus is proposed comprising a switching power amplifier ( | 05-23-2013 |
20130135046 | SWITCHING CIRCUIT AND ENVELOPE SIGNAL AMPLIFIER - A switching circuit | 05-30-2013 |
20130141162 | SWITCHING AMPLIFIER WITH INDUCTANCE MEANS FOR TRANSMITTING ENERGY - A switching amplifying method or a switching amplifier for obtaining one or more linearly amplified replicas of an input signal, is highly efficient, and does not have the disadvantage of “dead time” problem related to the class D amplifiers. Said switching amplifier comprises: an inductance means; a switching unit for switching a current from a DC voltage to the inductance means; a switching power transmitting unit for blocking a current when the switching unit switches on, and conducting the current from the inductance means to a filter unit positively or negatively according to the polarity of the input signal when the current from the DC voltage to the inductance means is switched off; an amplifier control unit to control the switching unit and the switching power transmitting unit according to the input signal; said filter unit filtering the current from the switching power transmitting unit to get an output signal. | 06-06-2013 |
20130147551 | AMPLIFYING APPARATUS - There is provided an amplifying apparatus which can prevent characteristic deterioration while reducing costs. The amplifying apparatus includes a first amplifier connected between an input terminal to which a high-frequency signal is input and an output terminal through which the high-frequency signal is output, including a bipolar transistor, and amplifying the high-frequency signal input from the input terminal; a second amplifier including a bipolar transistor, amplifying the high-frequency signal input from the input terminal, and having a lower maximum output power than that of the first amplifier; and a switching unit connected between the second amplifier and the output terminal, and selectively outputting the high-frequency signal amplified by the second amplifier through the output terminal. | 06-13-2013 |
20130147552 | CLASS-D AMPLIFIER - A class-D amplifier includes a quantized amplifier, having no quantization error feedback circuit, coupled to receive a digital input signal, according to which an output signal is generated to be switched between power rails. The digital input signal is pre-compensated to correct an error. A low-pass filter is configured to operate on the output signal to generate a filtered output signal. | 06-13-2013 |
20130154736 | Transient Signal Suppression for a Class-D Audio Amplifier Arrangement - A Class-D amplifier arrangement is disclosed that implements an auxiliary feedback loop and a primary feedback loop. The auxiliary feedback loop operates upon an input signal when the Class-D amplifier arrangement is operating under a power-up condition and a power-down condition so that a modulated signal is confined within the auxiliary feedback loop during the power-up condition and the power-down condition. The confinement of the modulated signal within the auxiliary feedback loop during the power-up condition and the power-down condition diverts transient signals coupled onto the modulated signal from an output device. The primary feedback loop operates upon the input signal when the Class-D amplifier arrangement is operating under a normal condition so that the modulated signal is introduced to the output device during the normal condition. | 06-20-2013 |
20130162351 | POWER AMPLIFIER AND LIQUID JET PRINTING APPARATUS - A power amplifier includes: a modulator pulse-modulating a drive waveform signal serving as a reference of a drive signal applied to an actuator and outputting a plurality of modulated signals; a digital power amplifier having a plurality of digital power amplifier stages each including a pair of push-pull switching elements, amplifying the power of the plurality of modulated signals, and outputting multi-value amplified digital signals; and a low pass filter smoothing the amplified digital signals and outputting the drive signal, wherein the modulator includes a control section switching one of a state where the same modulated signal is connected to two or more of the digital power amplifier stages and a state where different modulated signals are connected to different digital power amplifier stages to the other. | 06-27-2013 |
20130187713 | POWER AMPLIFIER CIRCUIT AND CONTROL METHOD - A power amplifier circuit uses an output transistor and a cascode transistor. First and second drive circuits apply gate control signals to the two transistors, which rise and fall in synchronism, and this is such that the voltage drop across the cascode transistor is reduced (compared to a constant gate voltage being applied to the output transistor). | 07-25-2013 |
20130200952 | POWER MOSFETS WITH IMPROVED EFFICIENCY FOR MULTI-CHANNEL CLASS D AUDIO AMPLIFIERS AND PACKAGING THEREFOR - A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (Vcc) and at least one ground contact for connecting the drains of the low-side devices to ground, the electrical contacts also including respective contacts for each source of the high and low-side devices allowing the source of each high-side device to be connected to the source of a respective low-side device to form two H-bridge circuits. | 08-08-2013 |
20130222062 | EFFICIENCY IMPROVED ENVELOPE AMPLIFIER USING DUAL SWITCHING AMPLIFIERS - Provided is a hybrid envelope amplifier having improved efficiency, and more particularly, to an envelope amplifier using a dual switching amplifier and having improved efficiency in which power consumption is reduced by controlling a switching current of a switching region according to a magnitude of an envelope input signal, thereby improving efficiency compared to a conventional hybrid envelope amplifier. The envelope amplifier using a dual switching amplifier and having improved efficiency comprises a linear amplifier and a switching amplifier, wherein the switching amplifier includes two or more switching stages that are selectively operated according to a magnitude of an input signal. | 08-29-2013 |
20130222063 | Method and Apparatus for Efficient and Distortion Compensated Digital Class-D Amplifier Ternary Modulation Scheme - The present disclosure generally relates to the field of digital Class-D amplifiers and more specifically to a technique for reducing output waveforms distortion of a digital class-D amplifier implementing a ternary modulation scheme. An apparatus embodiment comprises an enlarging component for enlarging at least one pulse of a first output waveform PWM_P_TERN′ of the amplifier | 08-29-2013 |
20130229230 | CASCADED CLASS D AMPLIFIER WITH IMPROVED LINEARITY - An amplifier includes first and second stages. The first stage includes an input node for receiving an analog input signal, an analog digital converter for converting the analog input signal to a digital input signal, and a first switching circuit for outputting a first analog intermediate output signal in response to receiving a digital pulse width modulated signal that is based on the digital input signal. The second stage is configured to receive a pulse width modulation quantization error of the first stage, scale the pulse width modulation quantization error of the first stage by a gain factor to produce a scaled pulse width modulation quantization error of the first stage, and output a second analog intermediate output signal based on the scaled pulse width modulation quantization error of the first stage. A summation circuit combines the first and second analog intermediate output signals to generate an amplified output signal. | 09-05-2013 |
20130234795 | FREE-FLY CLASS D POWER AMPLIFIER - A method is provided. A first enable signal is asserted so as to enable a first driver, where the first driver has a first output and a first parasitic capacitance. A second enable signal is asserted so as to enable a second driver, where the second driver has a second output and a second parasitic capacitance. The first and second outputs are coupled together by a switching network when the second driver is enabled. Pulses from complementary first and second radio frequency (RF) signals are applied to the first driver, where there is a first set of free-fly intervals between consecutive pulses from the first and second RF signals, and pulses from complementary third and fourth RF signals are applied to the second driver, wherein there is a second set of free-fly interval between consecutive pulses from the third and fourth RF signals. | 09-12-2013 |
20130241647 | Distortion Correction in Class-D Amplifiers - The present application describes an apparatus and method for reducing distortion in a class-D amplifier. The power output section of the amplifier is driven by an adjusted PWM signal, rather than by a PWM signal created directly from the input analog signal. A reference output, designed to closely track the input analog signal, is compared to the amplifier output. The resulting difference is an error signal which is inverted and summed with a second analog signal corresponding to the directly created PWM signal and changes the timing of the voltage transitions of the second analog signal. The changed voltage transitions are used to create the adjusted PWM signal. The inversion of the error signal causes negative feedback which results in the adjustment of the PWM signal being in a direction which reduces the error signal and thus the distortion of the amplifier. | 09-19-2013 |
20130257533 | SWITCHED-MODE POWER SUPPLY AND METHOD OF OPERATION - A method of operating a switched-mode power supply (SMPS) for supplying power to a load circuit, which draws a supply current that varies with an input signal to the load circuit is disclosed. The method comprises monitoring the input signal and controlling the amount of accumulated energy transferred for consumption by the load circuit, in use, in accordance with the input signal. | 10-03-2013 |
20130271214 | CLASS D AMPLIFIERS - A 3-level class D amplifier circuit comprises a first comparator for comparing an input with a first triangular reference and a second comparator for comparing the input with a second triangular reference. A phase relationship between the signals to the first comparator is 180 degrees shifted relative to a phase relationship between the signals to the second comparator. An amplifier stage generates a three-level PWM output signal using the outputs of the first and second comparators. A shared feedback path is used from the three-level PWM output signal. | 10-17-2013 |
20130271215 | CLASS D AUDIO AMPLIFIER WITH NOISE SUPPRESSION AND THE METHOD THEREOF - A class D audio amplifier having: an audio control circuit configured to provide a switching signal based on an input signal and a reference signal; an input capacitor coupled between the input signal and the first input terminal of the audio control circuit; an inductor having a first terminal coupled to the switching terminal of the audio control circuit, and a second terminal; an output capacitor having a first terminal coupled to second terminal of the inductor and a second terminal coupled to a load; and a noise suppression circuit having a first terminal coupled to the first input terminal of the audio control circuit, and a second terminal coupled to the switching terminal of the audio control circuit, wherein the noise suppression circuit charges the input capacitor and the output capacitor to reach a preset value. | 10-17-2013 |
20130285744 | Overcurrent Protection for Class D Power Amplifier - In an aspect of the disclosure, a class D power amplifier with an overcurrent protection (OCP) circuit is provided. The class D power amplifier includes a plurality of output transistors, and the OCP circuit is mirrored to at least one output transistor of the plurality of output transistors in a closed-loop feedback configuration for precisely controlling a sensing current of the OCP circuit with respect to an output current of the at least one output transistor. The class D power amplifier with the OCP circuit in the closed-loop feedback configuration mitigates a variation in a current threshold value for triggering interruption of the class D power amplifier. | 10-31-2013 |
20130285745 | POP-NOISE REDUCTION - A method of adjusting the frequency or phase of operation of a Class-D amplifier is disclosed. The method comprises making a series of step changes in the frequency or phase to adjust the frequency or phase from a start value to a desired end value, each step change in frequency or phase causing a corresponding disturbance of an output of the Class-D amplifier to produce a series of disturbances, each of which varies from an initial magnitude in first and second senses to exhibit a first peak and then in the first sense to exhibit a second peak. The time between the step changes is selected so that the second peak of each disturbance other than a final disturbance in the series overlaps the first peak of an immediately succeeding disturbance. | 10-31-2013 |
20130293298 | Split Capacitors Scheme for Suppressing Overshoot Voltage Glitches in Class D Amplifier Output Stage - A class D power amplifier is provided. The class D power amplifier includes a class D driver circuit having a plurality of output transistors, at least one active clamp circuit coupled to at least one output transistor of the plurality of output transistors, and at least one filter bank circuit coupled to the at least one active clamp circuit for controlling a voltage of the at least one output transistor. Accordingly, a voltage across a drain node and source node (VDS), a voltage across a gate node and source node (VGS), and a voltage across the gate node and drain node (VGD) of the output transistors is reduced to increase reliability of the power amplifier while consuming less power and utilizing less die area. | 11-07-2013 |
20130293299 | VOLTAGE VARIABLE TYPE DIGITAL AUDIO AMPLIFYING DEVICE FOR NOISE COMPENSATION AND METHOD THEREOF - The present invention relates to a voltage variable type digital audio amplifying device for noise compensation and a method therefore, and more specifically, varies the power according to an audio input signal, and compensates for the noise generated when varying the power, thereby enhancing audio output efficiency and easily removing noise. | 11-07-2013 |
20130300500 | METHOD AND APPARATUS FOR FILTER-LESS CLASS D AUDIO AMPLIFIER EMI REDUCTION - An audio system includes a speaker and a class D amplifier with a class-D PWM (pulse width modulation) modulator configured for generating first and second PWM signals, each with three differential output levels. The class-D amplifier also has a differential output driver configured for driving a first and a second output signals onto a first and a second output terminals in response to the first and the second PWM signals, wherein each of the first and the second output signals has three differential output levels. An inverse common-mode signal generator is coupled to first and second output signals for providing an inverse common-mode signal. The audio system also includes one or more output terminals for providing the inverse common mode signal, and further includes a wire or a trace on a PCB (printed circuit board) inverse common mode signal. | 11-14-2013 |
20130321079 | SWITCHING AMPLIFIER WITH EMBEDDED HARMONIC REJECTION FILTER - A switching amplifier with an embedded harmonic rejection filter is disclosed. In an exemplary design, the switching amplifier includes a generator circuit and a plurality of output circuits. The generator circuit receives an input signal and a carrier signal at a carrier frequency and generates a plurality of versions of a drive signal associated with different delays. The drive signal may be a pulse width modulation (PWM) signal. The plurality of versions of the drive signal may be generated by delaying the carrier signal, or the input signal, or the drive signal. The output circuits receive the plurality of versions of the drive signal and provide an output signal. The output circuits have outputs that are coupled together and implement a finite impulse response (FIR) filter based on the plurality of versions of the drive signal. The FIR filter has a frequency response with zeros at harmonics of the carrier frequency. | 12-05-2013 |
20130328628 | AMPLIFIER CIRCUITS AND MODULATION SIGNAL GENERATING CIRCUITS THEREIN - An amplifier circuit includes a modulation signal generating circuit, a driving stage circuit and an output stage circuit. The modulation signal generating circuit generates a pair of modulation signals according to a pair of differential input signals and a plurality of clock signals. The driving stage circuit generates a pair of driving signals according to the pair of modulation signals. The output stage circuit generates a pair of amplified output signals according to the pair of driving signals. | 12-12-2013 |
20130335143 | CLASS-D POWER AMPLIFIER CAPABLE OF REDUCING ELECTROMAGNETIC INTERFERENCE AND TRIANGULAR WAVE GENERATOR THEREOF - A class-D power amplifier capable of reducing electromagnetic interference includes an integrator, a triangular wave generator, a comparator, a gate driver, a feedback circuit, and an output stage circuit. The integrator is used for receiving an input signal and potential of ground, and outputting a first voltage. The comparator is used for comparing the first voltage with a triangular wave generated by the triangular wave generator to output a pulse-width modulation signal. The gate driver is used for driving the output stage circuit to output an output voltage according to the pulse-width modulation signal. Therefore, the class-D power amplifier reduces the electromagnetic interference by the triangular wave. | 12-19-2013 |
20140002189 | SWITCHING AMPLIFIER WITH PULSED CURRENT SOURCE AND SINK | 01-02-2014 |
20140002190 | SYSTEMS AND METHODS FOR PROVIDING HIGH AND LOW ENABLE MODES FOR CONTROLLING RADIO-FREQUENCY AMPLIFIERS | 01-02-2014 |
20140009230 | Versatile Audio Power Amplifier - An audio power amplifier includes a first and a second amplification unit, each including a switching voltage amplifier, an output filter, a current compensator, an inner current feedback loop feeding a measurement of current measured at the output inductor back to a summing input of the current compensator, a voltage compensator coupled to the summing input of the current compensator, and an outer voltage feedback loop. A controlled signal path provides the output of the voltage compensator of the first amplification unit to the current compensator of the second amplification unit. The first and second amplification units are operable with separate loads, in parallel driving a common load, or across a bridge-tied-load. A second pair of amplification units may be added and operated together with the first pair to drive a single speaker with a parallel pair of amplifiers on each side of a bridge-tied-load. | 01-09-2014 |
20140009231 | APPARATUS FOR AMPLIFYING AN INPUT-SIGNAL - Embodiments of the present invention provide an apparatus for amplifying an input-signal. The apparatus includes a switch-mode amplifier for amplifying a digital input-signal. The apparatus is characterized by a generator for generating the digital input-signal based on the input-signal, wherein the generator is configured to generate the digital input-signal such that the digital input-signal is located at a predefined frequency band and such that distortions are located at a frequency higher than the predefined frequency band. | 01-09-2014 |
20140022013 | ANTENNA DRIVE APPARATUS - An antenna drive apparatus applying an antenna drive voltage to an antenna from an H-bridge circuit including four switching elements to drive the antenna, includes: a switching mechanism to switch between a full-bridge state in which a differential voltage between a pulse voltage and a reverse pulse voltage reversed from the pulse voltage is applied to the antenna as the antenna drive voltage, and a half-bridge state in which the pulse voltage or the reverse pulse voltage is applied to the antenna as the antenna drive voltage; and a control mechanism to control the switching mechanism so that the frequency of the full-bridge state per unit time during an initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna becomes higher than that during the subsequent period in the transmission period. | 01-23-2014 |
20140028393 | CIRCUITS FOR PROVIDING CLASS-E POWER AMPLIFIERS - In some embodiments, circuits for providing Class-E power amplifiers are provided, the circuits comprising: a first switch having a first side and a second side; a first Class-E load network coupled to the first side of the first switch; a second Class-E load network: and a second switch having a first side and a second side, the first side of the second switch being coupled the second side of the first switch and the second Class-E load network. In some embodiments, the circuits further comprise: a third switch having a first side and a second side; a third Class-E load network coupled to the first side of the third switch; a fourth Class-E load network; and a fourth switch having a first side and a second side, the first side of the fourth switch being coupled the second side of the third switch and the fourth Class-E load network. | 01-30-2014 |
20140035668 | CASCADED CLASS D AMPLIFIER WITH IMPROVED LINEARITY - An amplifier includes a first stage, a second stage coupled to the first stage, and a summation circuit. The first stage is configured to receive an analog input signal, convert the analog input signal to a digital signal, and output an intermediate analog output signal in response to the digital signal. The second stage is configured to output a second analog intermediate output signal based on a scaled pulse width modulation quantization error of the first stage. The summation circuit is configured to combine the first and second analog intermediate output signals to generate an amplified output signal. | 02-06-2014 |
20140062592 | POP-FREE SINGLE-ENDED OUTPUT CLASS-D AMPLIFIER - A pop-free single-ended output class-D amplifier includes: an input signal generator for generating an input signal; a power supply for supplying input power; a reference voltage generator for generating a reference voltage; a gain-adjustable stage for generating an amplified signal according to the reference voltage and adjusting a gain of the single-ended output class-D amplifier; a pulse width modulation module for outputting a pulse width modulation signal according to the reference voltage, the amplified signal, and the input power; a low-pass filter for low-pass filtering the pulse width modulation signal to generate an output voltage; and a logic controller for generating at least one control signal to control the reference voltage generator, the gain-adjustable stage, and the pulse width modulation module according to the input power, the reference voltage, and the pulse width modulation signal. | 03-06-2014 |
20140062593 | CLASS RESONANT-H ELECTROSURGICAL GENERATORS - A generator for use with an electrosurgical device is provided. The generator has a gain stage electrically disposed between a first voltage rail and a second voltage rail, wherein the gain stage includes an input and an output. A voltage source operably coupled to the gain stage input and configured to provide an input signal thereto responsive to a drive control signal is also provided. The generator also has one or more sensors configured to sense an operational parameter of the amplifier and to provide a sensor signal corresponding thereto and a controller adapted to receive the sensor signal(s) and in response thereto provide a drive control signal to the voltage source. The generator has an amplifier output configured to supply an output voltage corresponding to the first voltage rail and the second voltage rail when the output of the gain stage falls between a voltage of the first voltage rail and a voltage of the second voltage rail and is configured to supply a peak voltage output when the voltage output is falls greater than the voltage of the first voltage rail or less than the voltage of the second voltage rail. | 03-06-2014 |
20140070885 | POWER SUPPLY ARRANGEMENT FOR SINGLE ENDED CLASS D AMPLIFIER - A power supply arrangement for a single ended class D amplifier, including a first primary winding connected in series with a first switch between the positive supply rail and ground, a second primary winding in phase with said first primary winding and connected in series with a second switch between the negative supply rail and ground, and a controller adapted to apply a control signal to said first and second switches, said control signal (Q) having ON-pulses of a predefined pulse time separated by a dead time. In use, the primary winding connected to the supply rail with the highest numerical voltage will transform the rail voltage difference to the supply rail with the lowest numerical voltage through the opposite primary winding thus reducing any voltage unbalance between the windings. | 03-13-2014 |
20140077877 | AMPLIFIER CIRCUIT - An amplifier circuit comprising a driver ( | 03-20-2014 |
20140097895 | PSEUDO-ENVELOPE FOLLOWING FEEDBACK DELAY COMPENSATION - A switch mode power supply converter and a feedback delay compensation circuit are disclosed. The switch mode power supply converter has a switching voltage output and provides a switching voltage at the switching voltage output, such that a target voltage for a power amplifier supply voltage at a power amplifier supply output is based on the switching voltage. Further, the switching voltage is based on an early indication of a change of the target voltage. The feedback delay compensation circuit provides the early indication of the change of the target voltage. | 04-10-2014 |
20140111277 | APPARATUS AND METHOD FOR EXPANDING OPERATION REGION OF POWER AMPLIFIER - An apparatus for amplifying power is provided. The apparatus includes a supply modulator for generating a supply voltage based on an amplitude component of a transmission signal, and a power amplify module for amplifying power of the transmission signal using the supply voltage, wherein the power amplify module includes a first power amplifier and a second power amplifier, and when an output power of the transmission signal is greater than a reference power, the first power amplifier amplifies the power of the transmission signal using the supply voltage, and when the output power of the transmission signal is equal to or less than the reference power, the second power amplifier amplifies the power of the transmission signal using the supply voltage. | 04-24-2014 |
20140125411 | METHOD AND APPARATUS FOR FILTER-LESS ANALOG INPUT CLASS D AUDIO AMPLIFIER CLIPPING - An integrated circuit (IC) chip has a class D PWM (pulse width modulation) amplifier configured for generating first and second PWM signals. The class-D PWM modulator includes a differential output driver configured for driving a first and a second output signals in response to the first and the second PWM signals. A clipping detection circuit is configured to turn on a clipping indication signal when one or both of the first PWM signal and the second PWM signal maintain the same state between two consecutive edges of the oscillator clock signal. The clipping detection circuit is also configured to turn off the clipping indication signal when both the first PWM signal and the second PWM signal change states between two consecutive edges of the oscillator clock signal. | 05-08-2014 |
20140125412 | Asymmetric Multilevel Outphasing Architecture For RF Amplifiers - A radio frequency (RF) circuit includes a power supply configured to generate a plurality of voltages, a plurality of power amplifiers, each having an RF output port and a power supply input port, a switch network having a plurality of input ports coupled to the power supply and a plurality of switch network output ports coupled to the power supply input ports of the plurality of power amplifiers, wherein the switch network is configured to output selected ones of the plurality of voltages from the plurality of switch network output ports, at least two of the switch network output port voltages capable of being different ones of the plurality of voltages, and an RF power combiner circuit having a plurality of input ports coupled to RF output ports of the plurality of power amplifiers and an output port at which is provided an output signal of the RF circuit. | 05-08-2014 |
20140159811 | SUPER-EFFICIENT SINGLE-STAGE ISOLATED SWITCHING POWER AMPLIFIER - A super-efficient single-stage switching power amplifier is realized by not incorporating a rectification process in its power conversion loop while incorporating a bidirectional active clamping circuit to not only remove or maximally reduce otherwise occurring disruptive ringing and spikes but also convert the energy otherwise associated with the ringing and spikes to return energy that goes back to the DC power supply. | 06-12-2014 |
20140184328 | CASCODE BIAS OF POWER MOS TRANSISTORS - There is disclosed a driver circuit for a power amplifier of class D type having a segmented architecture with at least one current branch which can be powered down in a low power mode of operation of the circuit. The branch comprising a switch with a cascode MOS transistor, the circuit further comprises a bias circuitry adapted for dynamically generating a dynamic bias control signal so as to cause the cascode MOS transistor of the switch to be ‘Off’ in the low power mode. | 07-03-2014 |
20140191801 | BICMOS GATE DRIVER FOR CLASS-S RADIO FREQUENCY POWER AMPLIFIER - The invention may be embodied in a resynchronizing, push-pull drive circuit for driving the gate electrodes of a digital Class-S Radio Frequency Power Amplifier (RF-PA). A binary bitstream received from a bitstream generator, such as a sigma-delta modulator, Viterbi-based optimal-bit-pattern modulator sigma-delta, or other suitable modulator, is resynchronized to a low-jitter master clock, then converted to fast-rise, high-swing complementary digital signals to drive the gates of the Class-S RF-PA. The drive circuit provides a high slew-rate, large-swing, quasi-digital gate drive circuit to drive the significant gate capacitance of the RF-PA with sufficient rise times. A combination of bipolar transistor current switches and cascoded CMOS devices is employed to attain requisite performance. For example, the driving circuit is well suited for use with Class-S RF-PAs used in wireless communication systems. | 07-10-2014 |
20140191802 | NARROW VOLTAGE RANGE MULTI-LEVEL OUTPUT PULSE MODULATED AMPLIFIER WITH ONE-BIT HYSTERESIS QUANTIZER - An amplifier system may include a power stage having inputs for three different supply voltages and an output for coupling to a load, a controller to generate control signals to the power stage that cause the power stage to vary an output voltage applied to the load among more than three distinct voltage levels, a monitor to provide a first control signal to the controller based on an input voltage signal, and a feedback system to provide a second control signal to the controller based on comparison of the output voltage and the input signal. | 07-10-2014 |
20140197886 | AMPLIFIER WITH SWITCHABLE COMMON GATE GAIN BUFFER - An amplifier having a switchable common gate gain buffer is disclosed. In an exemplary embodiment, an apparatus includes a plurality of selectable gain channels that provide constant input impedance at a common input to receive an input signal and generate an output signal having at least one of selected gain and current characteristics. At least two gain channels utilize transistors having different transconductance values. The apparatus also includes at least one impedance network coupled to at least one gain channel to provide the constant input impedance. | 07-17-2014 |
20140203870 | POWER MOSFETS WITH IMPROVED EFFICIENCY FOR MULTI-CHANNEL CLASS D AUDIO AMPLIFIERS AND PACKAGING THEREFOR - A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including, four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (Vcc) and at least one ground contact for connecting the drains of the low-side devices to ground, the electrical contacts also including respective contacts for each source of the high and low-side devices allowing the source of each high-side device to be connected to the source of a respective low-side device to form two H-bridge circuits. | 07-24-2014 |
20140203871 | ZERO-VOLTAGE-SWITCHING CONTOUR BASED OUTPHASING POWER AMPLIFIER - A zero-voltage-switching contour based outphasing power amplifier having two class-E power amplifiers connected in an out-phasing architecture coupled on opposite sides of a load being driven. The pair of class-E power amplifiers receive separate digital drive signals with an amount of phase difference that is adjusted based on the load. Variable capacitor arrays are coupled in parallel on the class-E power amplifiers and controlled in response to system parameters including duty cycle of the input signal. Efficiency of the power amplifier is maintained despite variation in output loading. | 07-24-2014 |
20140218109 | 2G SUPPORT FOR 2G AND 3G/4G ENVELOPE TRACKING MODULATOR - There is provided an amplification stage including an envelope tracking modulated supply for tracking a reference signal, comprising a low frequency path for tracking low frequency variations in the reference signal and for providing a first output voltage, and a high frequency path for tracking high frequency variations in the reference signal and for providing a second output voltage, and a combiner for combining the first and second output voltages to provide a third output voltage, the amplification stage further comprising a first amplifier arranged to receive the first output voltage as a supply voltage, and a second amplifier arranged to receive the third output voltage as a supply voltage, wherein the first and second amplifiers are enabled in different modes of operation. | 08-07-2014 |
20140292408 | Radio-Frequency Power Amplifier - A device for radio-frequency power amplification having a switching arrangement is provided. The switching arrangement is configured to amplify, during operation, a radio-frequency input signal that is present at a signal input and has a low input power, and to provide, during continuous wave (CW) operation, a continuous output signal at an output. The switching arrangement includes at least two amplifier devices. A respective output of the at least two amplifier devices is connected to the output of the switching arrangement. Each of the amplifier devices includes at least one switching transistor. The switching transistors are not operable during CW operation without being destroyed. The at least two amplifier devices are drivable as pulse amplifiers with a temporal offset by a control device such that the pulses generated in temporal succession at the outputs of the at least two amplifier devices produce a CW signal at the output. | 10-02-2014 |
20140300413 | POWER TRANSISTOR GATE DRIVER - The present invention relates to a gate driver for a power transistor comprising a first charging path operatively connected between a first voltage supply and a gate terminal of the power transistor for charging the gate terminal to a first gate voltage. A second charging path is connectable between the gate terminal of the power transistor and a second supply voltage to charge the gate terminal from the first gate voltage to a second gate voltage larger or higher than the first gate voltage. A voltage of the second voltage supply is higher than a voltage of the first voltage supply. | 10-09-2014 |
20140306758 | Versatile Audio Power Amplifier - An audio power amplifier includes a first and a second amplification unit, each including a switching voltage amplifier, an output filter, a current compensator, an inner current feedback loop feeding a measurement of current measured at the output inductor back to a summing input of the current compensator, a voltage compensator coupled to the summing input of the current compensator, and an outer voltage feedback loop. A controlled signal path provides the output of the voltage compensator of the first amplification unit to the current compensator of the second amplification unit. The first and second amplification units are operable with separate loads, in parallel driving a common load, or across a bridge-tied-load. A second pair of amplification units may be added and operated together with the first pair to drive a single speaker with a parallel pair of amplifiers on each side of a bridge-tied-load. | 10-16-2014 |
20140312969 | POWER CONTROL - A Class E amplifier having a FET with a transistor (T | 10-23-2014 |
20140312970 | POWER SUPPLY CIRCUIT - A power supply circuit includes: a push-pull amplifier unit which amplifies an input signal with a push-pull amplification protocol; a variable power supply unit which varies, with a control signal, the voltage level of a power supply voltage which is supplied to the push-pull amplifier; a switch control unit which, on the basis of the input signal, outputs the control signal which controls the voltage level of the power supply voltage; and a timing control unit which applies a specified time delay to the input signal. When the control signal rises, the switch control unit causes the control signal to rise at a faster timing, according to the voltage level switch transition timing, than a delay time upon the timing control unit, and when the control signal falls, the switch control unit causes the control signal to fall at the timing of the delay time. | 10-23-2014 |
20140333378 | Circuit arrangement for generating a radio frequency signal - A circuit arrangement for generating a radio frequency signal is described. The circuit arrangement comprises an RF output port, a shunt capacitor connected to the RF output port, at least two switch-mode amplifiers, each switch-mode amplifier comprising a switch-mode amplifier output port and a series inductive circuit element connected between the switch-mode amplifier output port and the RF output port. | 11-13-2014 |
20140333379 | BROADBAND POWER AMPLIFIER HAVING HIGH EFFICIENCY - A wideband power amplifier module includes a plurality of switch mode amplifiers and a plurality of impedance amplifier modules. Each switch mode amplifier includes an input to receive an input signal, and an RF output to output an RF power signal. The switch mode amplifier includes at least one semiconductor switch formed from gallium nitride (GaN). Each impedance amplifier module includes an output electrically connected to the RF output of a respective switch mode amplifier. The impedance amplifier module is configured to inject at least one impedance control signal to each RF output. | 11-13-2014 |
20140347127 | SWITCHING POWER AMPLIFIER AND METHOD FOR CONTROLLING THE SWITCHING POWER AMPLIFIER - A switching power amplifier includes: a first transistor controlled by a first digital signal to selectively output a first output signal; a second transistor controlled by a second digital signal to selectively output a second output signal; and a control circuit arranged to generate the second digital signal according to the first digital signal and a third digital signal; wherein the first output signal and the second output signal are outputted on a common connected node of the first transistor and the second transistor. | 11-27-2014 |
20140347128 | Digital Class-D Amplifier and Digital Signal Processing Method - A digital class D amplifier ( | 11-27-2014 |
20140354356 | CIRCUITS AND METHODS RELATED TO POWER AMPLIFIER EFFICIENCY BASED ON MULTI-HARMONIC APPROXIMATION - Circuits and methods related to power amplifier efficiency based on multi-harmonic approximation. In some embodiments, an output network circuit can be provided for multi-harmonic control of a radio-frequency (RF) power amplifier. The output network circuit can include an impedance matching network configured for a fundamental frequency of the power amplifier. The output network circuit can further include a broadband harmonic trap in communication with the impedance matching network. The broadband harmonic trap can be configured to substantially trap a plurality of harmonics associated with the fundamental frequency. The output network circuit can further include a dipole network in communication with the broadband harmonic trap. The dipole network can be configured to tune reactances resulting from the operation of the broadband harmonic trap. | 12-04-2014 |
20140361831 | AMPLIFIER DEVICE AND METHOD FOR ACTIVATING AN AMPLIFIER DEVICE OR THE AMPLIFIER UNIT - Known types of amplifiers include so-called class D amplifiers, which first use a pulse-width modulator to convert an analogue signal into a pulse-width modulated switching signal, which is then amplified and subsequently converted back into a continuously variable voltage via a filter. This type of amplifier is particularly energy-efficient and is therefore preferably used for high-power amplifiers. The invention relates to an amplifier device | 12-11-2014 |
20140375384 | SLEW-ENHANCED OPERATIONAL TRANSCONDUCTANCE AMPLIFIER - Embodiments of the invention are generally directed to improving the slew rate of an amplifier as the amplifier charges or discharges a capacitive load. In one embodiment, the amplifier is coupled to a slew-enhancing circuit which uses a control signal from the amplifier to aid the amplifier when charging or discharging the load. For example, the control signal may be an internal voltage used by the amplifier to control circuit elements within the amplifier. By routing the control signal to the slew-enhancing circuit, the control signal biases the circuit elements within the slew-enhancing circuit to source a boost current when charging the capacitive load or sink the boost current when discharging the capacitive load. | 12-25-2014 |
20150015329 | RADIO FREQUENCY COMPOSITE CLASS-S POWER AMPLIFIER HAVING DISCRETE POWER CONTROL - A composite amplifier providing digitally selectable amplification includes a plurality of channels and a combiner. Each of the channels includes a digitally controllable selector, a Class-S power amplifier, and bandpass filter. The digitally controllable selector selectively couples a digital bitstream to the amplifier. The amplifier receives the digital bitstream and provides an amplified signal. The bandpass filter generates a filtered signal as a function of the amplified signal. The combiner couples filtered signals provided by the channels to form a composite output signal. A method of providing digitally selectable amplification includes steps of: selectively coupling a digital bitstream to a plurality of channels in the amplifier; amplifying the digital bitstream to provide an amplified signal associated with a corresponding one of the channels; filtering amplified signals associated with the channels to provide corresponding filtered signals; and combining the filtered signals to generate a composite output signal. | 01-15-2015 |
20150022265 | ADAPTIVE BOOST SUPPLY WITH SLOPE CONTROL - An apparatus includes a first circuit configured to generate a boost voltage, and a second circuit to control a slope of a magnitude of the boost voltage when the magnitude of the boost voltage is reduced. The first circuit is configured to generate the boost voltage having the magnitude equal to a first voltage when a control signal is in a first state, and reduce the magnitude of the boost voltage when the control signal is in a second state and the magnitude of the boost voltage is greater than a second voltage which is less than the first voltage. A method of providing a boost voltage includes controlling a slope of a magnitude of the boost voltage when the magnitude of the boost voltage is decreased. | 01-22-2015 |
20150028948 | SWITCH-MODE AMPLIFIER - A device includes a Doherty amplifier. The Doherty amplifier has a carrier path and a peaking path. The Doherty amplifier includes a carrier amplifier configured to amplify a signal received from the carrier path and a peaking amplifier configured to amplify a signal received from the peaking path. The device includes a resistive switch having a first terminal connected to the peaking path and a second terminal connected to a voltage reference, and a controller configured to set the resistive switch to a first resistance value when a power input of the Doherty amplifier is below a threshold and to a second resistance value when the power input of the Doherty amplifier is above the threshold. | 01-29-2015 |
20150035596 | Versatile Audio Power Amplifier - An audio power amplifier includes a first and a second amplification unit, each including a switching voltage amplifier, an output filter, a current compensator, an inner current feedback loop feeding a measurement of current measured at the output inductor back to a summing input of the current compensator, a voltage compensator coupled to the summing input of the current compensator, and an outer voltage feedback loop. A controlled signal path provides the output of the voltage compensator of the first amplification unit to the current compensator of the second amplification unit. The first and second amplification units are operable with separate loads, in parallel driving a common load, or across a bridge-tied-load. A second pair of amplification units may be added and operated together with the first pair to drive a single speaker with a parallel pair of amplifiers on each side of a bridge-tied-load. | 02-05-2015 |
20150042403 | High-Voltage Voltage-Switched Class-S Amplifier - A voltage-switched class-S amplifier circuit includes an output stage configured to receive at least one control signal and operative to generate an output signal as a function of the at least one control signal. The amplifier circuit further includes a driver circuit coupled with the output stage. The driver circuit is configured to receive an input bit stream signal and is operative to generate the control signal as a function of the input bit stream signal in such a manner that a common mode component is eliminated from the control signal. | 02-12-2015 |
20150070090 | SUSPEND MODE IN CHARGE PUMP - A device may be associated with a power source. The device may include a charge pump configured to output a pulse-width modulated voltage based upon an input voltage from the power source, with the pulse-width modulated voltage varying between a first voltage and a second voltage. The device may also include a low-pass filter comprising an output capacitor, with the output capacitor being configured to average the pulsed-width modulated voltage and to output a filtered voltage having a value different than that of the input voltage. The device may further include a controller configured to selectively decouple the charge pump from the power source when a load imposed on the low-pass filter is below a threshold load. | 03-12-2015 |
20150077181 | SWITCHED MODE HIGH LINEARITY POWER AMPLIFIER - A switched mode, high linearity power amplifier can include a dynamic quantizer, a pulse width modulator and an output driver. In one embodiment, the dynamic quantizer can include a sigma-delta modulator configured to provide a multi-level digital signal. The pulse width modulator can receive the multi-level digital signal and provide a variable pulse width signal based, at least in part, on the multi-level digital signal. The output driver can include a class D output driver. The output driver can receive the variable pulse width signal to operate the class D output driver and provide an amplified signal. In one embodiment, the output driver can adjust the amplified signal to compensate for output errors. | 03-19-2015 |
20150084690 | Gain Invariant Impedance Feedback Amplifier - A system includes a weighting element, a transconductance circuit, a feedback loop, and an auxiliary loop. In some implementations, the transconductance circuit may accept an input and provide a first portion of an output for amplification at a variable amplification level to generate an amplifier output. The feedback loop may provide a portion of the amplifier output as a first feedback to the input. The first feedback may be associated with an impedance that may vary with the amplification level. The auxiliary loop may provide a second feedback to the input to reduce the dependence of the impedance on the amplification level. | 03-26-2015 |
20150084691 | SWITCHING AMPLIFIER AND TRANSMITTER USING SAME - The present invention is applied to a switching amplifier that includes a first high-side gate and a first low-side gate having output terminals connected together, and a high-side driver and a low-side driver that drive the first high-side gate and the first low-side gate, respectively. In the switching amplifier of the present invention, the high-side driver includes an input switching amplifier that uses the output terminal of the first high-side gate as a power source. | 03-26-2015 |
20150084692 | CMOS RF SWITCH DEVICE AND METHOD FOR BIASING THE SAME - According to certain aspects, a method includes determining whether to amplify a radio frequency (RF) signal by a first gain achievable by a first circuit or a second gain achievable by a second circuit, amplification of the first and second circuits respectively configured to be turned on or off by first and second switches, the first switch in the on state and the second switch in the off state resulting in the RF signal being amplified by the first gain, and the first switch in the off state and the second switch in the on state resulting in the RF signal being amplified by the second gain; and applying or inducing application of a first bias voltage or a second bias voltage to an isolated well of the first switch upon determination that the RF signal is to be amplified by the first gain or the second gain, respectively. | 03-26-2015 |
20150091644 | CLASS HD POWER AMPLIFIER - A multi-level amplifier including a converter circuit being supplied with a supply voltage and operable to generate at least two output voltages, a voltage comparator circuit adapted to compare each of the output voltages with the supply voltage to generate a driving signal, and an amplifier circuit being supplied with an analog input signal, the amplifier circuit including an analog-to-digital converter coupled to a power stage driver and power stage, wherein the power stage driver receives the driving signal from the voltage comparator. | 04-02-2015 |
20150091645 | ENVELOPE TRACKING POWER TRANSMITTER USING COMMON-GATE VOLTAGE MODULATION LINEARIZER - An envelope tracking power transmitter includes an envelope amplifier, a common-gate power modulation linearizer and a power amplifier. The envelope amplifier may receive a first envelope voltage to generate a power supply voltage that is amplified in proportion to change of the first envelope voltage. The common-gate power modulation linearizer may receive a second envelope voltage to amplify the second envelope voltage according to change of the second envelop voltage. The power amplifier may receive a first output of the envelope amplifier as a power supply voltage and a drain bias voltage, may receive a second output of the common-gate power modulation linearizer as a common gate bias voltage, and may amplify a radio frequency (RF) input signal to provide a RF output signal by maintaining an output capacitance according to an envelope of the RF input signal. | 04-02-2015 |
20150097620 | Resonant Pre-Driver for Switching Amplifier - An arrangement and a method for improving the efficiency of a multistage switching amplifier using a resonant circuit element is presented. The multistage amplifier comprises a pre-diver amplifier, a final stage amplifier and a series L-C arrangement coupled between the pre-driver amplifier and the final stage amplifier. The series L-C arrangement forms a parallel L-C resonant circuit with a gate to source capacitor of an input transistor of the final stage amplifier. An oscillation of energy takes place between the gate to source capacitor of the input transistor of the final stage amplifier and the series L-C arrangement. This oscillation of energy provides the final stage amplifier with driving current and improves efficiency of the overall multistage amplifier arrangement. | 04-09-2015 |
20150109055 | METHOD OF REDUCING POWER DISSIPATION IN A SWITCHING AMPLIFIER AND CIRCUIT IMPLEMENTING SUCH METHOD - A method is for reducing power dissipation in a switching amplifier. The method may include comparing a load current with a ripple current and, if the load current is greater than the ripple current, then detecting a first potential value at a first output terminal of the switching amplifier, detecting a second potential value at a second output terminal of the switching amplifier, detecting a third potential value between first and the second terminals of a first capacitor, and coupling the first terminal of the first capacitor to one of the first output terminal and the second output terminal. The second terminal of the first capacitor may be coupled to a reference voltage, the first output terminal, or the second output terminal based upon whether the first potential value or the second potential value is equal to the third potential value. | 04-23-2015 |
20150109056 | CLASS-D AMPLIFIER CIRCUITS - Methods and apparatus for Class-D amplifier circuits with improved power efficiency. The circuit has an output stage with at least first and second switches and a modulator that receives an input signal to be amplified, S | 04-23-2015 |
20150137886 | POWER SUPPLY DEVICE, TRANSMISSION DEVICE USING SAME, AND METHOD FOR OPERATING POWER SUPPLY DEVICE - A power supply device includes a switching amplification unit that supplies power to a load, a linear amplification unit that corrects an output voltage applied to the load according to an input signal, and a power supply control unit that controls the power supply of the linear amplification unit according to the input signal. | 05-21-2015 |
20150303885 | CLASS-D AMPLIFIER HAVING MIXED SIGNAL FEEDBACK CONTROL - A Class-D amplifier includes an analog-to-digital converter (ADC), a digital filter, a digital pulse width modulation (PWM) unit, a pre-driver unit, and an output driver. The ADC is configured to receive an input signal and one or more feedback signals, and to generate a first digital signal. The digital filter, the digital PWM unit, and the pre-driver unit are configured to generate control signals based on the first digital signal. The output driver is configured to generate an output signal based on the control signals. A first feedback path is defined as from a first output node of the output driver to a first input node of the ADC; and a second feedback path is defined as from a second output node of the output driver to a second input node of the ADC. The first and second feedback paths are free from a low-pass filtering device. | 10-22-2015 |
20150311865 | Flyback Amplifier with Direct Feedback - In at least one embodiment, the invention provides a bidirectional amplifier and method of control that enables immediate feedback directly from the output for fast response and low distortion. Mechanisms responsive to instantaneous feedback eliminate undershoot, overshoot, and sub-harmonic behavior. One embodiment comprises two switches and a single two-terminal inductor. Another embodiment produces a bipolar output from a single unregulated supply rail. The use of Predictive Energy Balancing controls yield high efficiency and low total harmonic distortion. These amplifiers are suited for audio application, and can drive piezo or dynamic speakers. | 10-29-2015 |
20150311866 | DEVICE AND METHOD FOR CONTROLLING POWER AMPLIFIER - A control device provides a supply voltage to an output transistor of a power amplifier. The control device includes a detector encoder, a switch sequencer and a power switch. The detector encoder receives a detection signal indicating a negative peak voltage level of an output signal of the power amplifier, receives a reference signal indicating a critical voltage of the detection signal at which the negative peak voltage level of the output transistor is deemed to be out of voltage with reference to saturation voltage of the output transistor, compares the detection and reference signals, and outputs Boost Request and Recovery Request signals in response. The switch sequencer translates the Boost Request and Recovery Request signals into multiple control bits. The power switch coordinates switching among a no boost voltage and multiple boost voltages based on the control bits, and outputs one of these voltages as the supply voltage. | 10-29-2015 |
20150311867 | HIGH-FREQUENCY AMPLIFIER CIRCUIT - A high-frequency amplifier circuit ( | 10-29-2015 |
20150318828 | A QUASI-BROADBAND AMPLIFIER ACCORDING TO THE DOHERTY PRINCIPLE - An amplifier comprises a first amplifier circuit, a second amplifier circuit, a hybrid-coupler circuit and a termination. The hybrid-coupler circuit comprises an output port and an isolation port. The termination in this context is connected to the isolation port of the hybrid-coupler circuit. The termination comprises a first switch, a first capacitor and a first inductance. | 11-05-2015 |
20150333708 | CLASS-D AMPLIFIER - In a class-D amplifier, oscillation phenomenon is suppressed in a high RF range and surge voltage is reduced. An oscillation absorption circuit is connected on the power supply side of the class-D amplifier circuit, and the class-D amplifier circuit and thus connected oscillation absorption circuit equivalently configure an oscillation circuit. Resistance provided in the oscillation absorption circuit is assumed as damping resistance of the oscillation circuit, thereby suppressing the oscillation phenomenon and reducing the surge voltage. The oscillation absorption circuit is made up of the RL parallel circuit of resistance and inductance. The oscillation absorption circuit and the class-D amplifier circuit constitute the oscillation circuit, and the resistance of the oscillation absorption circuit constitutes the damping resistance of the oscillation circuit in the high RF range. | 11-19-2015 |
20150357976 | DRIVER AMPLIFIER SYSTEMS AND METHODS OF THEIR OPERATION - The embodiments described herein provide a radio frequency (RF) driver amplifier and method of operation. In general, the driver amplifier facilitates high performance operation in RF devices while being implemented with only n-type transistors. Using only n-type transistors in the driver amplifier can increase the operating bandwidth of the driver amplifier. | 12-10-2015 |
20150365051 | SYSTEM AND METHOD FOR LEAKAGE CURRENT CONTROL FOR PROGRAMMABLE GAIN AMPLIFIERS - A system that utilizes an amplified signal is disclosed that includes a plurality of first switches coupled to a plurality of first impedances. A plurality of second switches coupled to a plurality of second impedances. An amplifier having a first input coupled to the plurality of first switches and a second input coupled to the plurality of second switches. A leakage current offset source coupled to the first input of the amplifier, wherein the leakage current offset source cancels a leakage current component of a first current provided from the plurality of first switches to the first input. | 12-17-2015 |
20150372645 | CLASS-E OUTPHASING POWER AMPLIFIER WITH EFFICIENCY AND OUTPUT POWER ENHANCEMENT CIRCUITS AND METHOD - An outphasing amplifier includes a first class-E power amplifier ( | 12-24-2015 |
20150381119 | AUDIO SWITCHING AMPLIFIER - A switching amplifier includes a compensation circuit to compensate for DC offset in the amplifier, to enhance operation of the switching amplifier. The compensation circuit may comprise a SAR ADC, where the DAC element can be used to provide a compensation voltage. The switching amplifier may further include a PWM modulator configured to avoid cross-talk to further enhance operation of the switching amplifier. | 12-31-2015 |
20160006402 | EDGE CORRECTION TO MITIGATE TOTAL HARMONIC DISTORTION IN CLASS D AMPLIFIER - A circuit includes an amplifier output stage that includes a high switch and a low switch that generates a pulse width modulated (PWM) output signal to provide a load current to a load in response to a PWM input signal. The circuit includes a high gate drive that drives the high switch with a PWM high drive signal derived from the PWM input signal. This includes a low gate drive that drives the low switch with a PWM low drive signal derived from the PWM input signal. The circuit includes an edge corrector that adjusts at least one of a leading edge and a trailing edge of the PWM input signal to compensate for response time differences with respect to a direction of the load current to the load. | 01-07-2016 |
20160013767 | MODE LINEARIZATION SWITCH CIRCUIT | 01-14-2016 |
20160020732 | SYSTEMS AND METHODS RELATED TO SWITCHABLE OUTPUT STAGES IN POWER AMPLIFIERS - Systems and method related to switchable output stages in power amplifiers. In some embodiments, a power amplifier (PA) circuit can include a driver stage configured to amplify a radio-frequency (RF) signal. The PA circuit can further include a plurality of output stages, with each output stage being configured to be capable of further amplification the RF signal. The PA circuit can further include a switch implemented to route the amplified RF signal from the driver stage to a selected one of the plurality of output stages, such that the selected output stage further amplifies the amplified RF signal. | 01-21-2016 |
20160020735 | Power Amplifier - A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section. | 01-21-2016 |
20160028353 | SYSTEMS, CIRCUITS AND METHODS RELATED TO LOW POWER EFFICIENCY IMPROVEMENT IN MULTI-MODE MULTI-BAND POWER AMPLIFIERS - Systems, circuits and methods related to low power efficiency improvement in multi-mode multi-band power amplifiers. In some embodiments, a power-amplifier (PA) system can include a first amplification path having one or more PAs configured to generate a high power radio-frequency (RF) signal from an input RF signal when in a high power mode. The PA system can further include a second amplification path having one or more PAs configured to generate a low power RF signal from the input RF signal when in a low power mode. The PA system can further include a switching circuit coupled to the first amplification path and the second amplification path. The switching circuit can be configured to allow amplification of the input RF signal through the first amplification path in the high power mode or the second amplification path in the low power mode. | 01-28-2016 |
20160049911 | LIMITING DRIVER FOR SWITCH-MODE POWER AMPLIFIER - A switch-mode RFPA driver includes first and second field-effect transistors (FETs) arranged in a totem-pole-like configuration. The switch-mode RFPA driver operates to generate a switch-mode RFPA drive signal having a generally square-wave-like waveform from an input RF signal having a generally sinusoidal-like waveform. According to one embodiment of the invention, to maximize high-frequency operation and avoid distorting the switch-mode RFPA drive signal, the switch-mode RFPA driver is designed so that its output can be connected directly to the input of the switch-mode RFPA to be driven, i.e., without using or requiring the use of an AC coupling capacitor. The first and second FETs of the switch-mode RFPA driver are designed and configured to limit and control the upper and lower magnitude levels of the switch-mode RFPA drive signal to levels suitable for switching the switch-mode RFPA directly, obviating any need for DC biasing at the input of the switch-mode RFPA. | 02-18-2016 |
20160056767 | ENERGY-EFFICIENT MODE-SWITCH POWER AMPLIFIER SET - An amplifier device comprises two modes of operation. In a first mode, the amplifier device operates in a wideband mode, whereas in a second mode the amplifier operates in a narrowband mode. Switching in the amplifier device provides antenna selection, in either mode. Control of mode and antenna selection is carried out with reference to a probability based optimisation, as to whether changing mode and/or antenna selection will improve efficiency. By that, the energy consumption associated with switching can be accommodated in the optimisation, thereby offering an improvement to efficiency. | 02-25-2016 |
20160056774 | System and Method for a Low Noise Amplifier - In accordance with an embodiment, a circuit includes a first signal path coupled between an input port and an output port, and a second coupled between the input port and the output port in parallel with the first signal path. The first signal path includes a low noise amplifier (LNA) having an input node coupled to the input port, and the second signal path includes a switch coupled between the input port and the output port. | 02-25-2016 |
20160056777 | ENERGY-EFFICIENT PERSONAL AUDIO DEVICE OUTPUT STAGE WITH SIGNAL POLARITY-DEPENDENT POWER SUPPLY UPDATE RATE - A charge pump power supply may comprise a plurality of capacitors and a switching circuit for switching the capacitors to provide a first voltage or a second voltage in accordance with the select input. The charge pump power supply may have a signal polarity input for indicating a polarity of an output audio signal. Switches for switching one or more capacitors providing a first polarity voltage in a then-current operating mode may be configured to switch at a greater frequency than switches for switching one or more capacitors providing a second polarity voltage responsive to the signal polarity input indicating a positive polarity of the output audio signal. Switches for switching one or more capacitors providing the first polarity voltage in a then-current operating mode are configured to switch at a lesser frequency than switches for switching one or more capacitors providing the second polarity voltage responsive to the signal polarity input indicating a negative polarity of the output audio signal. | 02-25-2016 |
20160065134 | ASYMMETRIC H-BRIDGE IN A CLASS D POWER AMPLIFIER - Disclosed is an amplifier circuit having an output stage that includes an H-bridge circuit. The H-bridge circuit includes sense resistors on one side of the circuit. A current detection circuit can produce an output indicative of current flow through a load based on voltages across the sense resistors. | 03-03-2016 |
20160065140 | CLASS D AMPLIFIER AND ELECTRONIC DEVICES INCLUDING THE SAME - An electronic device includes a waveform generator, a comparator, and an amplifier. The waveform generator receives a voltage from a power supply to the electronic device and outputs a voltage waveform signal. The comparator compares an input signal and the voltage waveform signal to output a first pulse-width-modulated signal. The amplifier receives the first pulse-width-modulated signal and outputs a second pulse-width-modulated signal. | 03-03-2016 |
20160065148 | ADVANCED CURRENT LIMIT FUNCTION FOR AUDIO AMPLIFIER - A class-D audio amplifier incorporates an overcurrent protection scheme implementing two overcurrent thresholds to avoid a dynamic impedance drop. When output current reaches the first threshold as a result of an impedance drop across the speaker, the overcurrent protection circuitry limits the output current to the value of the first threshold, but does not shut down the circuit. The second threshold is used to detect an overcurrent condition to shut down the circuit. Current limiting logic of a first channel monitors the overcurrent condition of a second channel and controls the first channel output in response thereto. This permits the second channel output current to reach the second threshold if the circuit is experiencing a short-circuit condition. This scheme also allows the output current to drop below the first threshold if the overcurrent condition of the second channel is caused by an impedance drop across the output speaker. | 03-03-2016 |
20160065158 | CLASS D AMPLIFIER CIRCUIT - This application relates to Class D amplifier circuits ( | 03-03-2016 |
20160072454 | PULSE-WIDTH MODULATION GENERATOR - The present application relates to a pulse-width modulation generator for generating a pulse-width modulated signal, the PWM generator comprising: a PWM modulator; and a loop filter, wherein the loop filter is configured to receive an input signal and to output a filtered signal to the PWM modulator, and the PWM modulator is configured to receive the filtered signal from the loop filter and to output a pulse-width modulated signal, the PWM generator further comprising: a feedback loop coupling an output of the PWM modulator to an input of the loop filter, wherein the feedback loop includes a comb filter. | 03-10-2016 |
20160079926 | AMPLIFYING CIRCUIT - An amplifying circuit includes a first differential amplifier (first differential pair) and a second differential amplifier (second differential pair) having an input capacitance smaller than the first differential amplifier. The amplifying circuit switches between the first differential amplifier (first differential pair) and the second differential amplifier (second differential pair) in response to an amplification mode setting signal to perform amplification processing of an input signal. | 03-17-2016 |
20160079934 | World Band Radio Frequency Front End Module, System and Method Thereof - The present disclosure relates to a World Band Radio Frequency Power Amplifier and a World Band Radio Frequency Front End Module. The World Band Power Amplifier can contain at least one broadband power amplifier connected to a switch which can direct an RF input signal to a plurality of transmission paths, each transmission path configured for a different frequency. The World Band RFFE Module is more integrated version of the World Band Power Amplifier that can contain broadband RF PA(s), switches, logic controls, filters, duplexers and other active and passive components. | 03-17-2016 |
20160079938 | MODULATION METHOD FOR SWITCHING MODULATOR - An exemplary embodiment of the present disclosure illustrates a modulation method for a switching modulator. Firstly, a data signal is received. Then, a first output signal at a first output side of the switching modulator and a second output signal at a second output side of the switching modulator are generated according to the data signal received, wherein the first output signal is an addition signal of a first pulse signal and the data signal, the second output signal is a second pulse signal, the first pulse signal and the second pulse signal are aligned to a same pulse width, and the pulse width equals to a minimum resolution of the switching modulator. | 03-17-2016 |
20160079939 | Resonant Pre-Driver for Switching Amplifier - An arrangement and a method for improving the efficiency of a multistage switching amplifier using a resonant circuit element is presented. The multistage amplifier comprises a pre-driver amplifier, a final stage amplifier and a series L-C arrangement coupled between the pre-driver amplifier and the final stage amplifier. The series L-C arrangement forms a parallel L-C resonant circuit with a gate to source capacitor of an input transistor of the final stage amplifier. An oscillation of energy takes place between the gate to source capacitor of the input transistor of the final stage amplifier and the series L-C arrangement. This oscillation of energy provides the final stage amplifier with driving current and improves efficiency of the overall multistage amplifier arrangement. | 03-17-2016 |
20160099685 | 60 GHz Wideband Class E/F2 Power Amplifier - A novel and useful fully integrated switched-mode wideband 60 GHz power amplifier architecture. Using an appropriate second-harmonic termination of its output matching network, the required systematic peak current of the final stage is reduced such that the PA functions as a class-E/F | 04-07-2016 |
20160099691 | Transformer Based Impedance Matching Network And Related Power Amplifier, ADPLL And Transmitter Based Thereon - A novel and useful transmitter (TX) architecture for ultra-low power (ULP) radios. An all-digital PLL employs a digitally controlled oscillator (DCO) having switching current sources to reduce supply voltage and power consumption without sacrificing phase noise and startup margins. It also reduces 1/f noise allowing the ADPLL after settling to reduce its sampling rate or shut it off entirely during direct DCO data modulation. A switching power amplifier integrates its matching network while operating in class-E/F | 04-07-2016 |
20160099693 | SWITCHING AMPLIFIER AND CONTROL METHOD THEREFOR - A fault-tolerant switching amplifier includes an inverter unit including N inverters, where N is a natural number, each of the N inverters including a plurality of switching elements and configured to perform switching ON or OFF of the switching elements based on a PWM signal inputted to the switching elements, thus switching an applied direct-current (DC) voltage, and to generate an output signal based on the switching and a switch unit including N switches respectively connected to output terminals of the N inverters, each of the N switches being configured to be short-circuited or open-circuited based on whether or not the corresponding one of the N inverters is in a normal operation condition. The output terminals of the N inverters are connected in series, such that output signals outputted from the inverters are combined to generate an amplified signal. | 04-07-2016 |
20160099695 | SEMICONDUCTOR INTEGRATED CIRCUIT, VARIABLE GAIN AMPLIFIER, AND SENSING SYSTEM - Provided is a semiconductor integrated circuit including a pad Pd | 04-07-2016 |
20160105152 | Reconfigurable Power Amplification Device and an Integrated Circuit Including Such a Device - This reconfigurable power amplification device ( | 04-14-2016 |
20160105154 | HIGH-FREQUENCY GENERATOR - The power stage at the output of a high-frequency generates operates in class D and comprises a voltage supply and a common earth, a first and a second switch linked to the common earth and periodically switched on at a high frequency F; these switches are linked to two common-mode inductors connected in a Guanella balun. Each common-mode inductor comprises two inductive lines with strong mutual coupling. The first switch is linked to the input of the first inductive line but not to the second, third and fourth lines and the second switch is linked to the input of the fourth inductive line but not to the first, second and third lines, the output of the first inductive line is linked to an output of the generator, the output of the fourth inductive line is linked to an internal resistor, the inputs of the second and third inductive lines are linked to the supply voltage source, the output of the third inductive line is linked to the output of the first inductive line and the output of the second inductive line is linked to the output of the fourth inductive line. | 04-14-2016 |
20160118948 | SYSTEMS AND METHODS FOR DYNAMIC RANGE ENHANCEMENT USING AN OPEN-LOOP MODULATOR IN PARALLEL WITH A CLOSED-LOOP MODULATOR - An integrated circuit may have two signal paths: an open-loop modulator (which may comprise a digital-input Class-D amplifier) and a closed-loop modulator (which may comprise an analog-input Class-D amplifier). A control subsystem may be capable of selecting either of the open-loop modulator or the closed-loop modulator as a selected path based on one or more characteristics (e.g., signal magnitude) of an input audio signal. For example, for higher-magnitude signals, the closed-loop modulator may be selected while the open-loop modulator may be selected for lower-magnitude signals. In some instances, when the open-loop modulator is selected as the selected path, the closed-loop modulator may power off, which may reduce power consumption. In addition, one or more techniques may be applied to reduce or eliminate user-perceptible audio artifacts caused by switching between the open-loop modulator and the closed-loop modulator, and vice versa. | 04-28-2016 |
20160118949 | AMPLIFIER WITH ADJUSTABLE RAMP UP/DOWN GAIN FOR MINIMIZING OR ELIMINATING POP NOISE - A variable ramp up/down gain in a pre-power stage block of an audio amplifier may be used to reduce audible pops and clicks output by the audio amplifier. A controller may adjust the variable ramp up/down gain during operation of the audio amplifier. The variable ramp up/down gain may be implemented as a pulse width modulation (PWM) modulator/generator with a ramp-up and ramp-down gain under control of the controller. The variable ramp up/down gain smooths transitions of the offset between a pre-power stage block and a feedback loop and thus can reduce audible pops and clicks by reducing the offset that is amplified in the power stage block of the audio amplifier. | 04-28-2016 |
20160126895 | SWITCHED MODE POWER AMPLIFIER WITH IDEAL IQ COMBINING - An I converter outputs I sign data and I magnitude data based on received I data. A Q converter outputs Q sign data and Q magnitude data based on received Q data. An I clock generates an I phase based ort the I sign data. A Q clock generates a Q phase based on the Q sign data. An I modulator generates an I magnitude pulse stream based on the I magnitude data. A Q modulator generates a Q magnitude pulse stream based on the Q magnitude data. A digital logic component generates an output signal based on the I phase, the I magnitude pulse stream, the Q phase and the Q magnitude pulse stream. A power amplifier generates an amplified signal based on the output signal. | 05-05-2016 |
20160126898 | APPARATUS AND METHODS FOR REDUCING INPUT BIAS CURRENT OF AN ELECTRONIC CIRCUIT - Apparatus and methods for reducing input bias current of electronic circuits are provided herein. In certain implementations, an electronic circuit includes a first input terminal, a second input terminal, an input circuit, and a plurality of input switches including at least a first input switch and a second input switch. The first input switch is electrically connected between the first input terminal and a first input of the input circuit, the second input switch is electrically connected between the second input terminal and a second input of the input circuit, and the first and second input switches can be opened and closed using a clock signal. The electronic circuit further includes a charge compensation circuit for compensating for charge injection through the first and second input switches during transitions of the clock signal. | 05-05-2016 |
20160126907 | AMPLIFIER CONTROL APPARATUS - An apparatus for controlling a pulse width modulation (PWM) amplifier is disclosed. In one aspect, the apparatus includes a delay circuit configured to delay an input signal and provide the delayed input signal to the PWM amplifier. The apparatus also includes a controller configured to generate and provide a supply voltage to the PWM amplifier based at least in part on the input signal such that the PWM amplifier generates an output signal based at least partially on the delayed input signal and the supply voltage. | 05-05-2016 |
20160126908 | POWER STAGE WITH SWITCHED MODE AMPLIFIER AND LINEAR AMPLIFIER - A method for producing an output voltage to a load may include, in a power stage comprising power converter having a power inductor, a plurality of switches arranged to sequentially operate in a plurality of switch configurations, and an output for producing the output voltage comprising a first output terminal and a second output terminal, controlling the linear amplifier to transfer electrical energy from the input source of the power stage to the load in accordance with one or more least significant bits of a digital input signal, and controlling the power converter in accordance with bits of the digital input signal other than the one or more least significant bits to sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from the input source of the power stage to the load. | 05-05-2016 |
20160134246 | APPARATUS AND METHOD FOR HIGH-EFFICIENCY ENVELOPE AMPLIFIER USING ADJUSTMENT OF SWITCH CURRENT - The present invention provides an apparatus and method for an envelope amplifier using adjustment of a switch current, in order to maximize the efficiency of the envelope amplifier at the entire sections of envelope output power. The apparatus and method can extend the battery lifetime of portable wireless devices such as smart phones or mobile phones or application devices such as notebook computers, which use a battery as a power supply. | 05-12-2016 |
20160142018 | POWER MOSFETS WITH IMPROVED EFFICIENCY FOR MULTI-CHANNEL CLASS D AUDIO AMPLIFIERS AND PACKAGING THEREFOR - A stereo class-D audio system includes a first die including four monolithically integrated NMOS high-side devices and a second a second die including four monolithically integrated PMOS low-side devices. The audio system also includes a set of electrical contacts for connecting the high and low-side devices to components within the a stereo class-D audio system, the set of electrical contacts including at least one supply contact for connecting the drains of the high-side devices to a supply voltage (Vcc) and at least one ground contact for connecting the drains of the low-side devices to ground, the electrical contacts also including respective contacts for each source of the high and low-side devices allowing the source of each high-side device to be connected to the source of a respective low-side device to form two H-bridge circuits. | 05-19-2016 |
20160142019 | AMPLIFYING DEVICE AND OFFSET VOLTAGE CORRECTION METHOD - An output voltage delay time caused by the relationship between offset voltage and input voltage is shortened. A single power supply amplifying device includes first and second amplifying units, a state detecting unit, and an offset voltage correcting unit. The first amplifying unit has differential pair transistors and amplifies the difference between input voltages. The second amplifying unit amplifies a first output voltage of the first amplifying unit. The state detecting unit detects a state where a negative offset voltage that causes a second output voltage of the second amplifying unit to be lower than the input voltage occurs, and a potential of the input voltage is lower than the absolute value of the negative offset voltage. The offset voltage correcting unit then corrects the negative offset voltage to a positive offset voltage that causes the second output voltage to be higher than the input voltage. | 05-19-2016 |
20160142024 | ADVANCED CURRENT LIMIT FUNCTION FOR AUDIO AMPLIFIER - A class-D audio amplifier incorporates an overcurrent protection scheme implementing two overcurrent thresholds to avoid a dynamic impedance drop. When output current reaches the first threshold as a result of an impedance drop across the speaker, the overcurrent protection circuitry limits the output current to the value of the first threshold, but does not shut down the circuit. The second threshold is used to detect an overcurrent condition to shut down the circuit. Current limiting logic of a first channel monitors the overcurrent condition of a second channel and controls the first channel output in response thereto. This permits the second channel output current to reach the second threshold if the circuit is experiencing a short-circuit condition. This scheme also allows the output current to drop below the first threshold if the overcurrent condition of the second channel is caused by an impedance drop across the output speaker. | 05-19-2016 |
20160156313 | OPERATIONAL AMPLIFIER AND METHOD OF OPERATING THE OPERATIONAL AMPLIFIER | 06-02-2016 |
20160173039 | AMPLIFIERS WITH A SHORT PHASE PATH, PACKAGED RF DEVICES FOR USE THEREIN, AND METHODS OF MANUFACTURE THEREOF | 06-16-2016 |
20160181984 | QUASI-SWITCHED, MULTI-BAND, HIGH-POWER AMPLIFIER AND METHOD | 06-23-2016 |
20160181986 | TUNABLE MATCHING NETWORK WITH PHASE-SWITCHED ELEMENTS | 06-23-2016 |
20160181987 | Phase-Switched Impedance Modulation Amplifier | 06-23-2016 |
20160197589 | INVERSE CLASS F AMPLIFIERS WITH INTRINSIC CAPACITANCE COMPENSATION | 07-07-2016 |
20160204751 | CLASS-D AMPLIFIERS AND METHODS | 07-14-2016 |
20160254786 | POWER SUPPLY CIRCUIT, HIGH-FREQUENCY POWER AMPLIFICATION CIRCUIT, AND POWER SUPPLY CONTROL METHOD | 09-01-2016 |
20160254792 | A DOHERTY AMPLIFIER WITH ADDITIONAL DELAY ELEMENT | 09-01-2016 |
20160380600 | BOOSTRAP CLASS-D WIDEBAND RF POWER AMPLIFIER - A high-power, high-frequency radio frequency power amplifier includes an output stage and a single-phase driver. The output stage is arranged in a Class-D amplifier configuration and includes a first depletion mode field effect transistor (FET), a second depletion mode FET, and a bootstrap path that couples the output of the output stage to the gate of the second FET. The first and second depletion mode FETs are switched out-of-phase and between fully-ON and fully-OFF states, under the direction of the single-phase driver. The single-phase driver directly controls the ON/OFF state of the first depletion mode FET and provides a discharge path through which the input gate capacitor of the second depletion mode FET in the output stage can discharge to turn OFF the second depletion mode FET. The bootstrap path provides a current path through which the input gate capacitor of the second depletion mode FET can charge to turn the second depletion mode FET ON. | 12-29-2016 |
20190149101 | CLASS-D AMPLIFIER WITH MULTIPLE INDEPENDENT OUTPUT STAGES | 05-16-2019 |
20190149107 | LOW POWER DISSIPATION HIGH PERFORMANCE CLASS-D AMPLIFIER | 05-16-2019 |
20190149113 | LOW-RADIATION INTERFERENCE, HIGH-EFFICIENCY, HIGH-LINEARITY, AND HIGH-ROBUSTNESS POWER TUBE DRIVER OF CLASS-D AUDIO AMPLIFIER | 05-16-2019 |