| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 381121000 | Feedback | 26 |
| 20090022339 | AMPLIFIER - An amplifier includes an amplifying block ( | 01-22-2009 |
| 20090028361 | SYSTEM FOR AMPLIFIERS WITH LOW DISTORTION AND LOW OUTPUT IMPEDANCE - System for pulse-width-modulated class D audio amplifiers. In one preferred embodiment an adder is described to generate a difference signal responsive to an input signal and a feedback signal, a pulse-width-modulator coupled to the adder to compare the difference signal to a reference signal and produce a pulse-width-modulated signal based on the comparing, a filter coupled to an output of the pulse-width-modulator, and a loop filter having a first input coupled to the output of the filter and a second input coupled to the input of the filter, the loop filter to generate a feedback signal by applying transfer functions to signals at its inputs. The loop transfer function of the amplifier is minimum aliasing error transfer function. The minimum aliasing error properties provide low distortion and taking the feedback from the output of the filter reduces high frequency output impedance. | 01-29-2009 |
| 20090232332 | CLASS-D TRANSCONDUCTANCE AMPLIFIER - The invention relates to a class-D audio amplifier. The class-D audio amplifier is configured in a current feedback mode as a voltage-controlled current source and a passive inductor/capacitor (LC) reconstruction filter. A portion of the passive LC reconstruction filter is situated in a feedback loop to an error amplifier. | 09-17-2009 |
| 20090245541 | Audio Power Amplifier with Feedback-Shifting Technology - A solid stage audio power amplifier comprises of two output stages with one generating the real output signal that drives the real loud speaker load and the other mimicking the real output stage and generating a dummy output signal that drives a dummy resistor load. A frequency dependent feedback selection network, denoted as Feedback-Shifting network hereafter, is implemented between the two outputs and the input of the amplifier to fulfill a unique global feedback loop. In a particular embodiment, the Feedback-Shifting network can be constructed so that it receives more feedback information from the real output node than from the dummy output node at low frequencies, but less feedback information from the real output node than from the dummy output node at mid to high frequency bands. Such a power amplifier performs as a traditional solid state feedback amplifier at low frequencies by generating a clear and tight bass, but it sounds similar to an open loop tube amplifier at higher frequencies by reproducing natural mid-band and treble with less listening fatigue. | 10-01-2009 |
| 20090290728 | DYNAMIC CONTOURED-SOUND/SUBWOOFER-SYNTHESIS AUDIO SYSTEM - A dynamic contoured-sound/subwoofer-synthesis system including an adjustable high pass filter coupled to the input terminal, the high pass filter being designed to provide a variety of frequency response shapes in response to adjustments thereof. A primary amplifier is coupled to receive one of the variety of frequency response shapes from the adjustable high pass filter and includes a main operational amplifier (op-amp) with the inverting input coupled to the adjustable high pass filter through a series connected input capacitor and input resistor. The primary amplifier provides low frequency signal gain and shaping of the received frequency response shape. A high frequency signal shaping circuit includes a feedback op-amp coupled to the inverting input of the main op-amp through a feedback resistor and a feedback capacitor. | 11-26-2009 |
| 20110044476 | SYSTEM TO GENERATE ELECTRICAL SIGNALS FOR A LOUDSPEAKER - The present disclosure describes an apparatus and a system for generating electrical signals for a loudspeaker. The loudspeaker may include one or more piezoelectric actuators configured to deflect a diaphragm of the loudspeaker in response to an input signal. The apparatus may be configured to receive the input signal and to drive the piezoelectric actuators to deflect the diaphragm based on the received input signal. | 02-24-2011 |
| 20110123049 | Systems and Methods for Offset Cancellation Method for DC-Coupled Audio Drivers - Direct current (DC) offset in and audio driver can cause a constant drain on power even when there is no sound. Furthermore it can cause an audible pop when the audio driver is enabled. A scaled replica output stage can be employed to perform DC offset cancellation offline during a sampling phase. Once DC offset cancellation is achieved, the audio driver uses a full scale output stage during the operation phase. | 05-26-2011 |
| 20110222712 | AUDIO OUTPUT DRIVER FOR REDUCING ELECTROMAGNETIC INTERFERENCE AND IMPROVING AUDIO CHANNEL PERFORMANCE - An audio output circuit includes an on-chip left channel amplifier module, an on-chip center channel amplifier module, and an on-chip right channel amplifier module. A left channel IC pin is operably coupled to an output of the on-chip left channel amplifier module. A right channel IC pin is operably coupled to an output of the on-chip right channel amplifier module. A center channel IC pin is operably coupled to an output of the on-chip center channel amplifier module. A center channel feedback IC pin is operably coupled to an input of the on-chip center channel amplifier module to provide a feedback loop. A left jack connection is operably coupled to the left channel IC pin. A right jack connection is operably coupled to the right channel IC pin. A jack return connection coupled to the center feedback IC pin. An inductor has a first node coupled to the jack return connection and a second node coupled to the center channel IC pin. | 09-15-2011 |
| 20110274296 | Ear Tip Method and Apparatus - An ear tip for a sound device. The ear tip has an asymmetrical arrangement which more closely aligns with a user's ear canal. The ear tip includes an ear tip base, ear tip shaft, and a first group of low-profile flanges. | 11-10-2011 |
| 20120230519 | Versatile Audio Power Amplifier - An audio power amplifier with a four-quadrant power supply having a synchronous output rectifier that includes a planar transformer. The amplifier includes a first amplification unit including a switching voltage amplifier with a command signal input and an amplified signal output. Control electronics provide a signal input to the first amplification unit. | 09-13-2012 |
| 20120237060 | METHOD AND APPARATUS FOR OUTPUTTING AUDIO SIGNAL - An apparatus for outputting audio signals. The apparatus for outputting audio signals includes a pulse density modulation (PDM) unit for PDM modulating an input audio signal to output a modulated audio signal, a driving signal generator for generating at least one driving signal to control switching amplification operations based on the modulated audio signal, and a power switching amplifier having at least one switch that is turned on or turned off in response to the driving signal and performs the switching amplification operations for using the at least one switch to output an amplified audio signal that corresponds to the modulated audio signal, wherein the at least one switch includes at least one from among a gallium nitride (GaN) transistor, gallium arsenide (GaAs) transistor, and a silicon carbide (SiC) transistor. | 09-20-2012 |
| 20130003995 | LOW-NOISE MICROPHONE PRE-AMPLIFIER WITH ACTIVE LOAD ELEMENT - A low-noise pre-amplifier with an active load element is integrated into a microphone. The microphone has an acoustic sensor coupled to the intrinsic pre-amplifier. A controllable current source is coupled to the intrinsic pre-amplifier and supplies a pre-amplifier bias current. A current source controller is coupled to the current source and controls the amplitude of the pre-amplifier bias current to maintain the intrinsic pre-amplifier at a bias point at which the intrinsic pre-amplifier amplifies microphone signals produced by the acoustic sensor. The intrinsic pre-amplifier may be actively regulated at the pre-determined bias point using negative feedback. Alternatively, the intrinsic pre-amplifier may be set to the pre-determined bias point by sweeping the pre-amplifier bias current for the intrinsic pre-amplifier over a range of currents. Use of an active load element with the intrinsic pre-amplifier results in lower noise, lower supply current, increased power supply suppression ratio and reduced signal post-processing. | 01-03-2013 |
| 20130044900 | AUDIO PLAYING DEVICE FOR ELECTRONIC DEVICES - An audio playing device for an electronic device includes an amplifier circuit, a voltage divider circuit, and a speaker. A south bridge of the electronic device is electrically connected to the amplifier circuit via the voltage divider circuit, and a sound card of the electronic device is electrically connected to the amplifier circuit. The south bridge generates electronic signals corresponding to startup prompt tones of the electronic device, and the electronic signals corresponding to startup prompt tones of the electronic device are transmitted to the speaker via the voltage divider circuit and the amplifier circuit to play. The sound card processes audio files, and electronic signals corresponding to the processed audio files are transmitted to the speaker via the amplifier circuit to play. | 02-21-2013 |
| 20130108081 | AMPLIFIER | 05-02-2013 |
| 20130121512 | AUDIO AMPLIFIER - An amplifier includes: a first operational signal path arranged to generate a first pre-output signal according to an input signal under a first operating mode of the amplifier; a second operational signal path arranged to generate a second pre-output signal according to the input signal under a second operating mode of the amplifier; and an output stage, coupled to the first operational signal path and the second operational signal path, for outputting a first output signal according to the first pre-output signal under the first operating mode and outputting a second output signal according to the second pre-output signal under the second operating mode, wherein the first operational signal path and the second operational signal path are arranged to share at least one common circuit element for generating the first pre-output signal and the second pre-output signal under the first operating mode and the second operating mode, respectively. | 05-16-2013 |
| 20130156232 | AMPLIFYING CIRCUIT CAPABLE OF SUPPRESSING SPIKES OF AN AUDIO SIGNAL - An amplifying circuit capable of suppressing spikes of an audio signal includes an integration module, a comparison module, an output module, a feedback module, and a limiting module. The integration module is used for receiving an input signal and generating a first voltage signal corresponding to the input signal. The comparison module is coupled to the integration module for receiving the first voltage signal and a reference signal, and generating a comparison signal. The output module is coupled to the comparison module for generating an audio signal according to the comparison signal. The feedback module is coupled between the output module and the integration module for feeding back an output signal to the integration module. The limiting module is coupled between the feedback module and the integration module for limiting the comparison signal to be within a predetermined range. | 06-20-2013 |
| 20130223652 | Digital Input Class-D Audio Amplifier - An audio amplifier receiving a digital input audio signal and generating an output audio signal for driving a speaker includes a digital input class D amplifier configured to receive the digital input audio signal and to generate the output audio signal. The digital input class D amplifier includes a first modulator configured to receive the digital input audio signal and to generate a quasi-digital signal in n-bit, and a class D modulator configured to receive the n-bit quasi-digital signal and to generate the output audio signal, the class D modulator implementing an analog feedback loop. In some embodiments, the class D modulator is implemented using a PWM modulator. In other embodiments, the PWM modulator incorporates enhanced features to improve the output noise characteristics. | 08-29-2013 |
| 20140003631 | AMPLIFICATION SYSTEMS AND METHODS WITH NOISE REDUCTIONS | 01-02-2014 |
| 20140112500 | DC OFFSET COMPENSATION - An apparatus and method for DC offset compensation. An amplifier receives an input signal (A | 04-24-2014 |
| 20140140542 | Configurable Audio Transmitter Circuitry - Audio transmitter circuitry is disclosed that is configurable into different modes by the user, and can output either a differential or single-ended audio signal on two signal wires. Depending on the mode, the transmitter deals with noise on the signal wires by adjusting the input resistance that such noise sees looking into the transmitter. If the transmitter is configured in a differential mode, the input resistance looking back into the transmitter from the perspective of the noise on both signal wires is relatively high. If the transmitter is configured in a single ended mode, the input resistance of noise looking back from the active signal wire into the transmitter is relatively low, to in effect ground such noise back into the transmitter, without significantly presenting such noise to the receiver. | 05-22-2014 |
| 20140369529 | Switched-Mode Audio Amplifier Employing Power-Supply Audio- Modulation - A device and method are disclosed for modulating a power converter based on an audio signal to directly drive a speaker with a differential audio output signal. A first modulation signal and a second modulation signal are generated based on an input audio signal so that the first and second modulation signals are complementary signals to each other. In one embodiment, a feedback signal, such as an acoustic feedback signal from the speaker, is also used to generate the first and second modulation signals. A power supply voltage is modulated with the first modulation signal to generate a first voltage signal. The power supply voltage is also modulated with the second modulation signal to generate a second voltage signal. The first and second voltage signals form a differential audio signal that is used to drive the speaker. Alternatively, the power converter can drive a speaker with a single-ended output signal. | 12-18-2014 |
| 20150016635 | Differential Microphone and Method for Driving a Differential Microphone - A differential microphone with improved biasing and a well defined common mode output voltage is connected to an amplifier that includes a differential amplifier stage and a common mode feedback circuit. The amplifier is in a feedback configuration. | 01-15-2015 |
| 20160065151 | AUDIO AMPLIFIER WITH RF INTERFERENCE SUPPRESSION FUNCTION - The present invention is related to an audio amplifier with RF interference suppression function, mainly comprising at least one amplifying unit and a speaker. The amplifying unit comprises a first input end, a second input end and an output end, in which a feedback circuit is presented between the first input end and the output end. The feedback circuit is provided therein with at least one resistor and at least one capacitor, in which the resistor is situated between the first input end and the output end, while one end of the capacitor is connected to the feedback circuit. RF signals entering from the speaker may be filtered out through the provision of the resistor and the capacitor in the feedback circuit. Thereby, interference generated on the audio amplifier due to RF signals is suppressed. | 03-03-2016 |
| 20160079937 | AMPLIFIER APPARATUS WITH CONTROLLED NEGATIVE OUTPUT IMPEDANCE - An audio amplifier apparatus includes an audio amplifier which receives a single audio signal and produces a plus phase audio signal and a minus phase audio signal, both dependent upon the single audio signal. The plus phase audio signal and minus phase audio signal are received by first and second inputs of a speaker, respectively. A current sensing circuit senses a level of current received by the first or second inputs of the speaker and outputs a current sensing signal dependent upon the sensed level of current. An amplifying circuit receives and amplifies the current sensing signal. A mixer circuit receives the amplified current sensing signal and an audio drive signal and produces the single audio signal dependent upon the amplified current sensing signal and the audio drive signal. The single audio signal is produced at a node in-between two resistors. | 03-17-2016 |
| 20160164477 | ELECTRIC AMPLIFIER CIRCUIT FOR AMPLIFYING AN OUTPUT SIGNAL OF A MICROPHONE - An electric amplifier circuit for amplifying an output signal of a microphone comprises a supply input terminal (V | 06-09-2016 |
| 20160191005 | METHOD OF OPERATING DIGITAL-TO-ANALOG PROCESSING CHAINS, CORRESPONDING DEVICE, APPARATUS AND COMPUTER PROGRAM PRODUCT - A signal processing chain, such as an audio chain, produces an analog output signal from a digital input signal. The signal processing chain is operated by generating a first flag signal for the analog output signal and one or more second flag signals for the digital input signal. Each flag signal assumes a first level or a second level and is set to the first level when a signal from which the flag is generated has a value within an amplitude window. An amount the first flag signal for the analog output signal and the second flag signal for the digital input signal match each other may be calculated for issuing an alert flag which indicates an impaired operation of the signal processing chain. | 06-30-2016 |
