CIRRUS LOGIC, INC. Patent applications |
Patent application number | Title | Published |
20160056808 | SWITCHING POWER CONVERTER INPUT VOLTAGE APPROXIMATE ZERO CROSSING DETERMINATION - In at least one embodiment, the controller senses a leading edge, phase cut AC input voltage value to a switching power converter during a cycle of the AC input voltage. The controller senses the voltage value at a time prior to a zero crossing of the AC input voltage and utilizes the voltage value to determine the approximate zero crossing. In at least one embodiment, by determining an approximate zero crossing of the AC input voltage, the controller is unaffected by any disturbances of the dimmer that could otherwise make detecting the zero crossing problematic. The particular way of determining an approximate zero crossing is a matter of design choice. In at least one embodiment, the controller approximates the AC input voltage using a function that estimates a waveform of the AC input voltage and determines the approximate zero crossing of the AC input voltage from the approximation of the AC input voltage. | 02-25-2016 |
20150351178 | Adaptive Current Control Timing and Responsive Current Control for Interfacing with a Dimmer - In at least one embodiment, an electronic system adapts current control timing for half line cycle of a phase-cut input voltage and responsively controls a dimmer current in a power converter system. The adaptive current control time and responsive current control provides, for example, interfacing with a dimmer. The electronic system and method include a dimmer, a switching power converter, and a controller to control the switching power converter and controls a dimmer current. In at least one embodiment, the controller determines a predicted time period from a zero crossing until a leading edge of a phase-cut input voltage and then responsively controls the dimmer current to, for example, reduce current and voltage perturbations (referred to as “ringing”), improve efficiency, and reduce an average amount of power handled by various circuit components. | 12-03-2015 |
20150340956 | Utilizing Secondary-Side Conduction Time Parameters of a Switching Power Converter to Provide Energy to a Load - A power distribution system includes controller of a switching power converter to control the switching power converter and determine one or more switching power converter control parameters. In at least one embodiment, the switching power converter utilizes a transformer to transfer energy from a primary-side of the transformer to a secondary-side of the transformer. In at least one embodiment, the switching power converter control parameters includes a secondary-side conduction time delay that represents a time delay between when the primary-side ceases conducting a primary-side current and the secondary-side begins to conduct a secondary-side current. In at least one embodiment, determining and accounting for this secondary-side conduction time delay increases the prediction accuracy of the secondary-side current value and accurate delivery of energy to a load when the controller does not directly sense the secondary-side current provided to the load. | 11-26-2015 |
20150340955 | Switching Parameter Based Discontinuous Mode-Critical Conduction Mode Transition - An electronic system includes a controller to provide at least dual-mode conduction control of a switching power converter. In at least one embodiment, the controller is capable to control transitions between discontinuous conduction mode (DCM) and critical conduction mode (CRM) of the switching power converter using a measured switching time parameter having a value corresponding with an approximately peak voltage of a time-varying supply voltage supplied to the switching power converter. In at least one embodiment, the controller dynamically compensates for changing parameters of the electronic system by dynamically determining a minimum non-conductive time of the control switch of the switching power converter using the measured switching time parameter value at approximately the peak of the supply voltage of the supply voltage. | 11-26-2015 |
20150331656 | SYSTEMS AND METHODS FOR REDUCING DIGITAL INTERFERENCE OF EXTERNAL SIGNALS - A mobile device may include a digital data driver and digital data receiver for communication of digital signals within the mobile device at a selected clock rate. The mobile device may also have a device external for the digital data driver and digital data receiver for communication of external signals, such as radio-frequency signals, to and from the mobile device. To avoid interference of frequency harmonics of a digital signal with such external signals, the digital data driver may be configured to control the digital signal based on the frequency of the external signals, such that interference of the external signal by spectral content of the digital signal is minimized, while maintaining the selected clock rate. | 11-19-2015 |
20150318854 | PROPORTIONAL FEEDBACK FOR REDUCED OVERSHOOT AND UNDERSTOOT IN A SWITCHED OUTPUT - Embodiments of apparatuses and methods for proportional feedback for reduced overshoot and undershoot in a switched output are described. An embodiment of an apparatus includes a switching output stage configured to receive an input signal and provide a responsive output signal. The apparatus may also include a pulling circuit coupled to one of the first switching device and the second switching device. The pulling circuit may pull a control voltage of power transistors in the switching output stage to reduce impedance of at least one of the transistors in response to a determination that the output signal at the common output node is outside of a predetermined range of a threshold value. Pulling strength may increase as a voltage difference between the output signal and one of the first supply voltage and the second supply voltage increases. | 11-05-2015 |
20150318844 | SCHMITT TRIGGER WITH THRESHOLD VOLTAGE CLOSE TO RAIL VOLTAGE - Voltage level shifting in a switching output stage is presented. The circuit may include a switching output stage configured to receive an analog input signal and provide a responsive digital output signal, the switching output stage having a first switching device coupled to a first supply voltage and a second switching device coupled to a second supply voltage, the first switching device and the second switching device being coupled to a common output node. The apparatus may also include a voltage level shifter circuit coupled to a switching control node of the second switching device, the voltage level shifter configured to shift a voltage level at the switching control node of the second switching device relative to the analog input signal, wherein the digital output signal at the common output node transitions as the input signal reaches a predetermined threshold value. | 11-05-2015 |
20150312982 | LED Lighting System with Accurate Current Control - A light emitting diode (LED) lighting system and method are disclosed. The LED lighting system and method include an LED controller to accurately control a current in an LED system. The LED controller includes components to calculate, based on the current and an active time period of an LED current time period, an actual charge amount delivered to the LED system wherein the LED current time period is duty cycle modulated at a rate of greater than fifty (50) Hz and to utilize the actual charge amount to modify and provide a desired target charge amount to be delivered during a future active time period of the LED current time period. The LED system and method further involve components to compare the actual charge amount to a desired charge amount for the active time period and compensate for a difference between the actual charge amount and the desired charge amount during the future active time period. | 10-29-2015 |
20150303932 | COMPARATOR TRACKING CONTROL SCHEME WITH DYNAMIC WINDOW LENGTH - A comparator tracking scheme for an analog-to-digital converter (ADC) may implement a dynamic window size by varying, over time, a number of comparators powered up to convert an analog input signal to a digital output signal. A comparator-tracking scheme may be implemented, for example, in a controller coupled to a plurality of comparators in an ADC. For example, the controller may determine a window size for the ADC and determine a window position for the ADC. The controller may then activate comparators of the ADC within a window centered at the window position and having a width of the window size. The controller may determine a window size by analyzing an output of a filter. When the filter output indicates a rapidly changing analog input signal, the controller may dynamically increase a window size of the ADC, which may increase a number of comparators powered on. | 10-22-2015 |
20150296296 | FREQUENCY-SHAPED NOISE-BASED ADAPTATION OF SECONDARY PATH ADAPTIVE RESPONSE IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise is injected so that the adaptation of the secondary path estimating adaptive filter can be maintained, irrespective of the presence and amplitude of the source audio. The noise is shaped by a noise shaping filter that has a response controlled in conformity with at least one parameter of the secondary path response. | 10-15-2015 |
20150271882 | LED (LIGHT-EMITTING DIODE) STRING DERIVED CONTROLLER POWER SUPPLY - An LED lighting device includes an auxiliary power supply that supplies power to a control circuit of the LED lighting device that receives an input from a terminal of a light-emitting diode (LED) string of the lighting device that has a substantially lower voltage than the line voltage to which the lighting device is connected. The terminal may be within the LED string, or may be an end of the string. A linear regulator may be operated from the voltage drop across a number of the LEDs in the string so that the energy wasted by the auxiliary power supply is minimized. In other designs, the auxiliary power supply may be intermittently connected in series with the LED string only when needed. The intermittent connection can be used to forward bias a portion of the LED string when the voltage supplied to the LED string is low, increasing overall brightness. | 09-24-2015 |
20150264762 | Controlled Power Dissipation in a Switch Path in a Lighting System - A lighting system includes one or more methods and systems to control dissipation of excess power in the lighting system when the power into a switching power converter from a leading edge, phase-cut dimmer is greater than the power out of the switching power converter. In at least one embodiment, the lighting system includes a controller that controls dissipation of excess energy in the lighting system to prevent a premature disconnection of the phase-cut dimmer. In at least one embodiment, the controller actively controls power dissipation by generating one or more signals to actively and selectively control power dissipation in the lighting system. By actively and selectively controlling power dissipation in the lighting system, the controller intentionally dissipates power when the power into the lighting system should be greater than the power out to a lamp of the lighting system. In at least one embodiment, the controller creates one or more intermixed and/or interspersed power dissipation phases with one or more switching power converter charging and/or flyback phases. | 09-17-2015 |
20150256953 | SYSTEMS AND METHODS FOR ENHANCING PERFORMANCE OF AUDIO TRANSDUCER BASED ON DETECTION OF TRANSDUCER STATUS - Based on transducer status input signals indicative of whether headphones housing respective transducers are engaged with ears of a listener, a processing circuit may determine whether the headphones are engaged with respective ears of the listener. Responsive to determining that at least one of the headphones is not engaged with its respective ear, the processing circuit may modify at least one of a first output signal to the first transducer and a second output signal to the second transducer such that at least one of the first output signal and the second output signal is different than such signal would be if the headphones were engaged with their respective ears. | 09-10-2015 |
20150256660 | FREQUENCY-DEPENDENT SIDETONE CALIBRATION - A personal audio device includes a sidetone circuit with one or more adjustable coefficients that generates a sidetone signal from the output of a first microphone. The sidetone circuit has one or more adjustable coefficients for altering the relationship between the first microphone signal and the sidetone signal. The personal audio device also includes a transducer for reproducing playback audio and the sidetone signal at an ear of a listener and a second microphone for measuring the output of the transducer as delivered to the ear of the listener. The sidetone circuit includes a calibration circuit for estimating a response of the second microphone to the sidetone signal and adjusting the coefficient of the sidetone circuit according to the estimated response. | 09-10-2015 |
20150256091 | DIMMER OUTPUT EMULATION WITH NON-ZERO GLUE VOLTAGE - An apparatus may include a dimmer output voltage emulator for causing a power converter interface circuit to draw current from a capacitor in the power converter interface during a period of time when a dimmer coupled to the power converter interface circuit is non-conducting to generate an emulated dimmer output voltage. The emulated dimmer output voltage may emulate part of a cycle of a non-zero AC dimmer output voltage of the dimmer after a triac of the dimmer prematurely stops conducting that would occur if the triac continued conducting during the part of the cycle. The dimmer output voltage emulator may include a pull-down circuit to pull down current of the interface circuit and generally decrease the emulated dimmer output voltage during a first period of time and a hold circuit to maintain the emulated dimmer output voltage below a substantially non-zero threshold value during a second period of time. | 09-10-2015 |
20150216002 | LOW-COST LOW-POWER LIGHTING SYSTEM AND LAMP ASSEMBLY - In accordance with embodiments of the present disclosure, a method and apparatus may include receiving an input waveform from a dimmer, wherein the input waveform is periodic at a first frequency. The method and apparatus may also include generating an output waveform independent of a load coupled to the output waveform, wherein the output waveform is periodic at a second frequency substantially greater than the first frequency, wherein at least one of the second frequency and an amplitude of the output waveform is based on a phase-cut angle of the input waveform indicative of a control setting of the dimmer. | 07-30-2015 |
20150208484 | Lighting System with Lighting Dimmer Output Mapping - A system and method map dimming levels of a lighting dimmer to light source control signals using a predetermined lighting output function. The dimmer generates a dimmer output signal value. At any particular period of time, the dimmer output signal value represents one of multiple dimming levels. In at least one embodiment, the lighting output function maps the dimmer output signal value to a dimming value different than the dimming level represented by the dimmer output signal value. The lighting output function converts a dimmer output signal values corresponding to measured light levels to perception based light levels. A light source driver operates a light source in accordance with the predetermined lighting output function. The system and method can include a filter to modify at least a set of the dimmer output signal values prior to mapping the dimmer output signal values to a new dimming level. | 07-23-2015 |
20150180473 | TRANSISTOR DEVICES OPERATING WITH SWITCHING VOLTAGES HIGHER THAN A NOMINAL VOLTAGE OF THE TRANSISTOR - A voltage selector circuit may be coupled to transistors to protect one or more inputs of the transistor from exceeding a safe operating range. In one example, a cross-coupled pair of transistors may be coupled to a gate of a transistor to select between a first voltage and a cascoded voltage that is a safe bias voltage. Thus, the transistor may be protected from unsafe gate-to-source voltages. The voltage selector may be used to build circuits, such as invertors, level shifter, NAND gates, and NOR gates, that function with power supply voltages that may exceed the safe operating range of the transistors. | 06-25-2015 |
20150163592 | SYSTEMS AND METHODS FOR BANDLIMITING ANTI-NOISE IN PERSONAL AUDIO DEVICES HAVING ADAPTIVE NOISE CANCELLATION - A method may include adaptively generating an anti-noise signal from filtering a reference microphone signal with an adaptive filter in conformity with an error microphone signal and the reference microphone signal. The method may also include adjusting the response of the adaptive filter by combining injected noise with the reference microphone signal and receiving the injected noise by a copy of the adaptive filter so that the response of the copy is controlled by the adaptive filter adapting to cancel a combination of the ambient audio sounds and the injected noise and controlling the response of the adaptive filter with the coefficients adapted in the copy, whereby the injected noise is not present in the anti-noise signal and wherein each of a sample rate of the copy and a rate of adapting of the adaptive filter is significantly less than a sample rate of the adaptive filter. | 06-11-2015 |
20150162838 | COORDINATED DIMMER COMPATIBILITY FUNCTIONS - A system and method includes a controller that is configured to coordinate (i) a low impedance path for a dimmer current, (ii), control of switch mode power conversion and (iii) an inactive state to, for example, to allow a dimmer to function normally from cycle to cycle of an alternating current (AC) supply voltage. In at least one embodiment, the dimmer functions normally when the dimmer conducts at a correct phase angle indicated by a dimmer input setting and avoids prematurely resetting while conducting. In at least one embodiment, by coordinating functions (i), (ii), and (iii), the controller controls a power converter system that is compatible with a triac-based dimmer. In at least one embodiment, the controller coordinates functions (i), (ii), and (iii) in response to a particular dimming level indicated by a phase cut, rectified input voltage supplied to the power converter system. | 06-11-2015 |
20150161981 | SYSTEMS AND METHODS FOR SHARING SECONDARY PATH INFORMATION BETWEEN AUDIO CHANNELS IN AN ADAPTIVE NOISE CANCELLATION SYSTEM - Systems and methods of the present disclosure include analyzing and comparing transfer functions associated with a plurality of electro-acoustic paths for transducers of a personal audio device to determine proximity of the transducers to respective ears of a listener of the personal audio device, quality of acoustic seals associated with the transducers, and for one or more other purposes. | 06-11-2015 |
20150161980 | SYSTEMS AND METHODS FOR PROVIDING ADAPTIVE PLAYBACK EQUALIZATION IN AN AUDIO DEVICE - In accordance with systems and methods of the present disclosure, a method may include receiving an error microphone signal indicative of an acoustic output of a transducer and ambient audio sounds at the acoustic output of the transducer. The method may also include generating an anti-noise signal to reduce the presence of the ambient audio sounds at the acoustic output of the transducer based at least on the error microphone signal. The method may further include generating an equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal. The method may additionally include combining the anti-noise signal with the equalized source audio signal to generate an audio signal provided to the transducer. | 06-11-2015 |
20150145438 | VARIABLE RESISTANCE DEVICE FOR REDUCED POWER DISSIPATION IN DIMMER COMPATIBILITY CIRCUITS - A variable resistance device may be used in a dimmer compatibility circuit to reduce power dissipation in an integrated circuit of the dimmer compatibility circuit. For example, the integrated circuit may include switches coupled to resistors external to the integrated circuit. The integrated circuit may operate the switches to commutate among the external resistors and select a voltage drop that reduces a voltage at a drain voltage of the switches. The reduced drain voltage reduces power dissipation in the switches and instead dissipates the power in the external resistors. | 05-28-2015 |
20150145427 | BOOST AND LINEAR LED CONTROL - A light emitting diode (LED) lighting system includes a switching power converter having an input for coupling to an alternating current (AC) power source, an output, and a switch. The LED lighting system also includes an LED lighting subsystem coupled to receive power from the output of the switching power converter. The LED lighting subsystem includes a current source for one or more LEDs, and the current source has a control node and a sense node. The LED lighting system additionally includes a switch state controller coupled to the switching power converter and coupled to the LED lighting subsystem. The switch state controller controls switching of the switch and varies a control current provided to the control node of the current source based on at least a parameter sensed from the sense node. | 05-28-2015 |
20150086025 | SYSTEMS AND METHODS FOR PROTECTING A SPEAKER FROM OVEREXCURSION - In accordance with embodiments of the present disclosure, a system may include a controller configured to be coupled to an audio speaker. The controller may be configured to receive an audio input signal. The controller may also be configured to, based on a linear displacement transfer function associated with the audio speaker, process the audio input signal to generate a modeled linear displacement of the audio speaker, wherein the linear displacement transfer function has a response that models linear displacement of the audio speaker as a linear function of the audio input signal. The controller may further be configured to, based on an excursion linearity function associated with the audio speaker, process the modeled linear displacement to generate a predicted actual displacement of the audio speaker, wherein the excursion linearity function is a function of the modeled linear displacement and has a response modeling non-linearities of the displacement of the audio speaker as a function of the audio input signal. | 03-26-2015 |
20150078572 | SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION BY ADAPTIVELY SHAPING INTERNAL WHITE NOISE TO TRAIN A SECONDARY PATH - A processing circuit may include: (i) an adaptive filter having a response that generates an anti-noise signal from a reference microphone signal, wherein the response is shaped in conformity with the reference microphone signal and a playback corrected error, and wherein the playback corrected error is based on a difference between an error microphone signal and a secondary path estimate; (ii) a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and having a response that generates a secondary path estimate from the source audio signal; (iii) a secondary coefficient control block that shapes the response of the secondary path estimate filter in conformity with the source audio signal and the playback corrected error by adapting the response of the secondary path estimate filter to minimize the playback corrected error; and (iv) a noise injection portion for injecting a noise signal into the source audio signal, wherein the noise signal is shaped based on the playback corrected error. | 03-19-2015 |
20150078560 | SYSTEMS AND METHODS FOR DETECTION OF LOAD IMPEDANCE OF A TRANSDUCER DEVICE COUPLED TO AN AUDIO DEVICE - In accordance with systems and methods of the present disclosure, an audio device may include an electrical terminal, an audio circuit, and a transducer load detection circuit. The electrical terminal may couple a transducer device to the audio device. The audio circuit may generate an analog audio signal, wherein the analog audio signal is coupled to the electrical terminal The transducer load detection circuit may detect a load impedance of the transducer device when the transducer device is coupled to the audio device from characteristics measured at the electrical terminal. | 03-19-2015 |
20150078559 | SYSTEMS AND METHODS FOR DETECTION OF LOAD IMPEDANCE OF A TRANSDUCER DEVICE COUPLED TO AN AUDIO DEVICE - In accordance with systems and methods of the present disclosure, an audio device may include an electrical terminal, an audio circuit, and a transducer load detection circuit. The electrical terminal may couple a transducer device to the audio device. The audio circuit may generate an analog audio signal, wherein the analog audio signal is coupled to the electrical terminal The transducer load detection circuit may detect a load impedance of the transducer device when the transducer device is coupled to the audio device from characteristics measured at the electrical terminal. | 03-19-2015 |
20150078558 | SYSTEMS AND METHODS FOR DETECTION OF LOAD IMPEDANCE OF A TRANSDUCER DEVICE COUPLED TO AN AUDIO DEVICE - In accordance with systems and methods of the present disclosure, an audio device may include an electrical terminal, an audio circuit, and a transducer load detection circuit. The electrical terminal may couple a transducer device to the audio device. The audio circuit may generate an analog audio signal, wherein the analog audio signal is coupled to the electrical terminal. The transducer load detection circuit may detect a load impedance of the transducer device when the transducer device is coupled to the audio device from characteristics measured at the electrical terminal. | 03-19-2015 |
20150061536 | SYSTEMS AND METHODS FOR LOW-POWER LAMP COMPATIBILITY WITH A TRAILING-EDGE DIMMER AND AN ELECTRONIC TRANSFORMER - In accordance with embodiments of the present disclosure, an apparatus may comprise a controller to provide compatibility between a load and a secondary winding of an electronic transformer. The controller may be configured to operate a single-stage power converter in a first power mode for a first period of time, such that the single-stage power converter is enabled to transfer energy from the secondary winding to the load during the first power mode and operate the single-stage power converter in a second power mode for a second period of time prior to the first period of time, such that the single-stage power converter is enabled to transfer energy from the secondary winding to the load during the second power mode, wherein the first power mode and the second power mode occur within a half-line cycle of an electronic transformer secondary signal present on the secondary winding. | 03-05-2015 |
20150054418 | Multi-Mode Dimmer Interfacing Including Attach State Control - A system and method includes a controller that is configured to coordinate (i) a low impedance path for a dimmer current, (ii) attaching a dimmer to a power converter system at the leading edge of a phase-cut, rectified input voltage, (iii), control of switch mode power conversion, and (iv) an inactive state to, for example, reduce the dimmer current while allowing a dimmer to function normally from cycle to cycle of an alternating current (AC) supply voltage. In at least one embodiment, the dimmer functions normally when the dimmer conducts at a correct phase angle indicated by a dimmer input setting and avoids prematurely resetting while conducting. In at least one embodiment, by coordinating functions (i), (ii), (iii), and (iv) the controller controls a power converter system that is compatible with a triac-based dimmer. | 02-26-2015 |
20150032396 | BOOST CONVERTER CONTROLLER WITH INDUCTANCE VALUE DETERMINATION - A controller of a boost converter may be configured to dynamically adjust conditions within the boost converter by monitoring conditions in the boost converter. For example, the controller may determine an current inductance value for an inductor of the boost converter by monitoring a current through the inductor. When the inductance value of the inductor is known, a slope compensation value may be used in determining a transition time between charging the inductor of the boost converter and discharging the inductor. | 01-29-2015 |
20150030183 | BOOST CONVERTER VOLTAGE CONTROLLED BASED ON AUDIO SIGNAL - Audio amplification may be improved by controlling an audio amplifier based on the audio signal being amplified. For example, when the audio signal level increases or decreases, a boost voltage provided to an audio amplifier by a boost converter may also be increased or decreased. In another example, when the audio signal level decrease below a certain level, the audio amplifier may be switched from amplifying the audio signal with a boost converter input to amplifying the audio signal with a low voltage input. Control of the audio amplifier may be implemented in a digital boost converter controller coupled to the boost converter and/or the audio amplifier. | 01-29-2015 |
20140340158 | REDUCING KICKBACK CURRENT TO POWER SUPPLY DURING CHARGE PUMP MODE TRANSITIONS - Kickback current from a charge pump to a power management integrated circuit (PMIC) may be reduced by dissipating charge from fly and hold capacitors during mode transitions. A switch may be placed in series between the charge pump and the PMIC to disconnect the charge pump and prevent kickback current from reaching the PMIC. Further, additional loads, as switches, may be coupled to the charge pump outputs to dissipate charge from the fly and hold capacitors. Additionally, a closed feedback loop may be used to monitor and discharge excess charge from the fly and hold capacitors during mode transitions. Furthermore, charge may be redistributed between the fly and hold capacitors during mode transitions to reduce the time period of the transition. | 11-20-2014 |
20140339999 | CHARGE PUMP-BASED DRIVE CIRCUITRY FOR BIPOLAR JUNCTION TRANSISTOR (BJT)-BASED POWER SUPPLY - A bipolar junction transistor (BJT) may be used to generate a supply voltage for operating a controller, such as a lighting controller for a LED-based light bulb. A base of the BJT may receive current generated from the supply voltage to control operation of the BJT. Although the base of the BJT would be at a lower voltage than the emitter, a base drive circuit may be coupled between the emitter and the base of the BJT to increase the voltage. As one example, the base drive circuit may be a charge pump. In another example, the BJT may function as its own charge pump. In yet another example, a positive and a negative base current of the BJT may be independently controlled to regulate an output supply voltage V | 11-20-2014 |
20140339995 | SINGLE PIN CONTROL OF BIPOLAR JUNCTION TRANSISTOR (BJT)-BASED POWER STAGE - A power stage for light emitting diode (LED)-based light bulbs may include a bipolar junction transistor (BJT). The base of BJT switch may be biased externally and the operation of the BJT may be through a single pin to the emitter of the BJT. A controller integrated circuit (IC) may control the power stage through the main BJT's emitter pin in an emitter-controlled BJT-based power stage. The emitter-controlled BJT-based power stage may replace the conventional buck-boost power stage topology. For example, the controller may activate and deactivate a switch coupling the BJT's emitter to ground. A power supply for the controller IC may be charged from a reverse recovery of charge from the BJT, and the reverse recovery controlled by the controller IC. | 11-20-2014 |
20140333205 | STABILIZATION CIRCUIT FOR LOW-VOLTAGE LIGHTING - An electronic transformer stabilization circuit includes a detection circuit and a reactive load. The detection circuit may be configured to receive a transformer output or a transformer signal derived from the transformer output. The detection circuit may determine whether the transformer that generated the transformer output is an electronic transformer. The determination may be made based on the presence of absence of high frequency components in the transformer output. Responsive to determining that an electronic transformer generated the transformer output, the stabilization circuit may operate a switch to connect the reactive load across an output of the transformer. The reactive load may include an inductor and may be configured to draw a stabilization current from the transformer. The stabilization current may ensure that the total current drawn from the transformer exceeds an oscillation current required to maintain reliable operation of the electronic transformer. | 11-13-2014 |
20140312816 | Circuit and Method for Detecting Missed Commutation of a Brushless DC Motor - The system contains a controller unit comprising a memory device, a processing unit, and at least one analog-to-digital converter. A power stage has a plurality of switches, wherein the power stage receives a control signal from the control circuit and a power signal from a power source. The power stage drives two windings of the set of three stator windings to rotate a rotor and maintains one stator winding of the three stator windings undriven. The memory device stores a plurality of values for the driven current and a plurality of demodulated undriven winding voltages. The processing unit compares the plurality of values and periodically calculates a rotor sextant while the rotor rotates. The processing unit compares at least two demodulated undriven winding voltage values corresponding to at least two current values within the rotor sextant to calculate the rotor sextant parity and verify the calculation of the rotor sextant. | 10-23-2014 |
20140312797 | SELF-OSCILLATING RESONANT CONVERTER-BASED LIGHT EMITTING DIODE (LED) DRIVER - A self-oscillating resonator (SOR) may be used to control current through light emitting diodes (LEDs). The SOR may be started and stopped by a controller coupled to a transistor switch in the SOR. The controller may output a control signal that starts and stops the SOR by coupling a supply voltage or a ground to a base of the transistor switch in the SOR. Additional control over the current output to the LEDs may be gained through a resistive DAC coupled to the SOR and duty cycling the SOR. | 10-23-2014 |
20140307899 | SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION INCLUDING DYNAMIC BIAS OF COEFFICIENTS OF AN ADAPTIVE NOISE CANCELLATION SYSTEM - In accordance with method and systems of the present disclosure, a processing circuit may implement an adaptive filter having a response that generates the anti-noise signal from the reference microphone signal to reduce the presence of the ambient audio sounds heard by the listener, a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal and the reference microphone signal by adapting the response of the adaptive filter to minimize the ambient audio sounds in the error microphone signal, and a coefficient bias control block which biases coefficients of the coefficient control block towards zero in a range of frequencies outside of a frequency response of the source audio signal. | 10-16-2014 |
20140307890 | SYSTEMS AND METHODS FOR ADAPTIVE NOISE CANCELLATION INCLUDING SECONDARY PATH ESTIMATE MONITORING - In accordance with methods and systems of the present disclosure, a processing circuit may implement at least one of: a feedback filter having a response that generates at least a portion of an anti-noise component from a playback corrected error, the playback corrected error based on a difference between the error microphone signal and a secondary path estimate; and a feedforward filter having a response that generates at least a portion of the anti-noise signal from a reference microphone signal. The processing circuit may also implement a secondary path estimate filter configured to model an electro-acoustic path of a source audio signal and have a response that generates a secondary path estimate from the source audio signal and a secondary path estimate performance monitor for monitoring performance of the secondary path estimate filter in modeling the electro-acoustic path. | 10-16-2014 |
20140307888 | SYSTEMS AND METHODS FOR MULTI-MODE ADAPTIVE NOISE CANCELLATION FOR AUDIO HEADSETS - In accordance with the present disclosure, an integrated circuit for implementing at least a portion of a personal audio device may include an output and a processing circuit. The output may provide an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer. The processing circuit may implement an adaptive noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener by adapting, based on a presence of the source audio signal, a response of the adaptive noise cancellation system to minimize the ambient audio sounds at the acoustic output of the transducer, wherein the adaptive noise cancellation system is configured to adapt both in the presence and the absence of the source audio signal. | 10-16-2014 |
20140307887 | SYSTEMS AND METHODS FOR HYBRID ADAPTIVE NOISE CANCELLATION - In accordance with methods and systems of the present disclosure, a processing circuit may implement a feedback filter having a response that generates a feedback anti-noise signal component from a playback corrected error, the playback corrected error based on a difference between an error microphone signal and a secondary path estimate, and wherein the anti-noise signal comprises at least the feedback anti-noise signal component, a secondary path estimate filter configured to model an electro-acoustic path of the source audio signal and have a response that generates a secondary path estimate from the source audio signal, and a secondary coefficient control block that shapes the response of the secondary path estimate adaptive filter in conformity with a source audio signal and the playback corrected error by adapting the response of the secondary path estimate adaptive filter to minimize the playback corrected error. | 10-16-2014 |
20140301572 | SYSTEMS AND METHODS FOR COMPRESSING A DIGITAL SIGNAL IN A DIGITAL MICROPHONE SYSTEM - In accordance with embodiments of the present disclosure, a digital microphone system may include a microphone transducer and a digital processing system. The microphone transducer may be configured to generate an analog input signal indicative of audio sounds incident upon the microphone transducer. The digital processing system may be configured to convert the analog input signal into a first digital signal having a plurality (e.g., more than 3) of quantization levels, and in the digital domain, process the first digital signal to compress the first digital signal into a second digital signal having fewer quantization levels (e.g., +1, 0, −1) than that of the first digital signal. | 10-09-2014 |
20140301571 | SYSTEMS AND METHODS FOR GENERATING A DIGITAL OUTPUT SIGNAL IN A DIGITAL MICROPHONE SYSTEM - In accordance with embodiments of the present disclosure, a digital microphone system may include a microphone transducer and a digital processing system. The microphone transducer may be configured to generate an analog input signal indicative of audio sounds incident upon the microphone transducer. The digital processing system may be configured to convert the analog input signal into a first digital signal having three or more quantization levels, and in the digital domain, process the first digital signal to convert the first digital signal into a second digital signal having two quantization levels. | 10-09-2014 |
20140294206 | ASYMMETRICALLY-SWITCHED MODULATION SCHEME - An asymmetric modulation scheme may be used to drive two output nodes coupled to a load. The asymmetric modulation scheme may be one-sided such that the switching rate of a first output node is lower than the switching rate of a second output node. The first output node may be switched only to change a direction of current between the first output node and the second output node, while the second output node is switched to convey the information of an input signal. The asymmetric modulation scheme may be used to drive a speaker to reduce noise at the first output node to improve accuracy of current monitoring through the speaker by a current monitor coupled at the first output node. | 10-02-2014 |
20140274198 | REDUCING AN ACOUSTIC INTENSITY VECTOR WITH ADAPTIVE NOISE CANCELLATION WITH TWO ERROR MICROPHONES - A second error microphone may be incorporated in a mobile device to allow computation of additional parameters for modifying an adaptive noise cancellation (ANC) algorithm. For example, a first and second acoustic pressure may be calculated from a first and second error microphone of the mobile device. The first and second acoustic pressure may be input to an algorithm for determining an acoustic intensity vector. The ANC algorithm may receive the acoustic intensity vector as an input, and adapt an anti-noise signal to reduce the acoustic intensity vector. Additionally, an input impedance for the error microphones may be calculated from the acoustic pressure to determine coupling between a speaker and a user's ear. The anti-noise algorithm may be adjusted or disabled when the input impedance indicates the user has removed the phone from the user's ear. | 09-18-2014 |
20140270227 | WIRELESS EARPIECE WITH LOCAL AUDIO CACHE - A wireless earpiece may include a local memory for storing audio files that can be played back by the user. The wireless earpiece may fit entirely within the user's ear canal. Audio files, for example music files, may be loaded on the wireless earpiece by docking the wireless earpiece with a mobile device, which includes a larger memory storing the user's library of music files. The wireless earpiece may also be charged while docked with the mobile device by receiving power from the mobile device's larger battery. To provide stereo sound, two wireless earpieces may be worn by the user and docked separately with the mobile device. Each of the two wireless earpieces may store a single channel of an audio file, which is separated by the mobile device during synchronization. | 09-18-2014 |
20140270224 | AMBIENT NOISE-BASED ADAPTATION OF SECONDARY PATH ADAPTIVE RESPONSE IN NOISE-CANCELING PERSONAL AUDIO DEVICES - An adaptive noise canceller adapts a secondary path modeling response using ambient noise, rather than using another noise source or source audio as a training source. Anti-noise generated from a reference microphone signal using a first adaptive filter is used as the training signal for training the secondary path response. Ambient noise at the error microphone is removed from an error microphone signal, so that only anti-noise remains. A primary path modeling adaptive filter is used to modify the reference microphone signal to generate a source of ambient noise that is correlated with the ambient noise present at the error microphone, which is then subtracted from the error microphone signal to generate the error signal. The primary path modeling adaptive filter is previously adapted by minimizing components of the error microphone signal appearing in an output of the primary path adaptive filter while the anti-noise signal is muted. | 09-18-2014 |
20140270223 | ADAPTIVE-NOISE CANCELING (ANC) EFFECTIVENESS ESTIMATION AND CORRECTION IN A PERSONAL AUDIO DEVICE - Techniques for estimating adaptive noise canceling (ANC) performance in a personal audio device, such as a wireless telephone, provide robustness of operation by triggering corrective action when ANC performance is low, and/or by saving a state of the ANC system when ANC performance is high. An anti-noise signal is generated from a reference microphone signal and is provided to an output transducer along with program audio. A measure of ANC gain is determined by computing a ratio of a first indication of magnitude of an error microphone signal that provides a measure of the ambient sounds and program audio heard by the listener including the effects of the anti-noise, to a second indication of magnitude of the error microphone signal without the effects of the anti-noise. The ratio can be determined for different frequency bands in order to determine whether particular adaptive filters are trained properly. | 09-18-2014 |
20140270222 | LOW-LATENCY MULTI-DRIVER ADAPTIVE NOISE CANCELING (ANC) SYSTEM FOR A PERSONAL AUDIO DEVICE - A personal audio device including multiple output transducers for reproducing different frequency bands of a source audio signal, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each of the transducers from at least one microphone signal that measures the ambient audio to generate anti-noise signals. The anti-noise signals are generated by separate adaptive filters such that the anti-noise signals cause substantial cancellation of the ambient audio at their corresponding transducers. The use of separate adaptive filters provides low-latency operation, since a crossover is not needed to split the anti-noise into the appropriate frequency bands. The adaptive filters can be implemented or biased to generate anti-noise only in the frequency band corresponding to the particular adaptive filter. The anti-noise signals are combined with source audio of the appropriate frequency band to provide outputs for the corresponding transducers. | 09-18-2014 |
20140270208 | MONITORING OF SPEAKER IMPEDANCE TO DETECT PRESSURE APPLIED BETWEEN MOBILE DEVICE AND EAR - Coupling between a user's ear and a speaker of a mobile device may be determined by measuring an impedance of the speaker. When the user presses the mobile device against the user's ear, the speaker impedance changes as a result of loading in the speaker's acoustic radiation impedance. The speaker impedance change may be correlated with the force applied by the user to the mobile device. The measured speaker impedance may be provided as feedback to an adaptive noise cancellation (ANC) algorithm to adjust the output at the speaker. For example, when the mobile device is removed from the user's ear, the ANC algorithm may be muted. | 09-18-2014 |
20140266310 | SYSTEMS AND METHODS FOR EDGE CONTROL BASED ON DETECTING CURRENT DIRECTION IN A SWITCHED OUTPUT STAGE - In accordance with these and other embodiments of the present disclosure, an apparatus and a method may include receiving a first input configured to indicate an output voltage of an output node of a switched output stage comprising a pull-down driver device coupled at its non-gate terminals between a ground voltage and the output node and a pull-up driver device coupled at its non-gate terminals between a supply voltage and the output node. The method may also include receiving a second input configured to indicate a gate voltage of a gate terminal of a first one of the pull-up driver device and the pull-down driver device. The method may further include detecting direction of an output current flowing into or out of the output node based on the first input and the second input. | 09-18-2014 |
20140266126 | SYSTEMS AND METHODS FOR EDGE CONTROL IN A SWITCHED OUTPUT STAGE - In accordance with embodiments of the present disclosure, systems and methods may include a switch coupled at its gate terminal to an input signal voltage, the input signal voltage for controlling a gate voltage of a gate terminal of a driver device coupled at its non-gate terminals between a rail voltage and an output node. The systems and methods may also include a diode having a first terminal and a second terminal, the diode coupled to a non-gate terminal of the switch such that when the switch is enabled, the first terminal is electrically coupled to the gate terminal of the driver device and the second terminal is electrically coupled to the output node. | 09-18-2014 |
20140266109 | SYSTEMS AND METHODS FOR REDUCING VOLTAGE RINGING IN A POWER CONVERTER - In accordance with embodiments of the present disclosure, systems and methods may include an input configured to indicate a switching node voltage of a switching node of a power converter comprising a first switch device coupled at its non-gate terminals between a ground voltage and the switching node and a second switch device coupled at its non-gate terminals between an output supply node and the switching node. The systems and methods may also include a predriver circuit coupled to the input and a gate terminal of the first switch device, the predriver circuit configured to drive an input voltage signal to the gate terminal of the first switch device and configured to select an effective impedance of the gate terminal of the first switch device based on the input. | 09-18-2014 |
20140265968 | Motor Control Loop with Fast Response - A system and method of controlling a motor are disclosed. The system comprises a current observer for observing a motor current at a sampling rate and a proportionate-integral controller that provides a proportionate path and an integral path and at least forms part of a proportionate-integral control loop based on the motor current. The current observer observes a motor current of the motor at a sampling rate. The proportionate path calculates, for a present cycle of the sampling rate, a proportionate path term for the proportionate-integral control loop based on the motor current. The system outputs a respective motor output voltage to the motor in conformity with the proportionate path term calculated for the present cycle. In conformity with the motor current, the integral path calculates an integral path term for another respective motor output voltage to be used in a later cycle of the sampling rate. | 09-18-2014 |
20140265933 | SYSTEM AND METHOD FOR LEARNING DIMMER CHARACTERISTICS - Systems and methods for learning dimmer characteristics provide improved efficiency in operating lighting devices. In one embodiment, an apparatus includes a lamp controller that is configured to monitor voltage information associated with one or more lamps or a dimmer of a system, adjust one or more parameters of an attach current profile in conformity with the voltage information to arrive at a selected attach current profile, and apply within the system the selected attach current profile. | 09-18-2014 |
20140265916 | Controlled Electronic System Power Dissipation via an Auxiliary-Power Dissipation Circuit - An electronic system and method include a controller to actively control transfer of excess energy to an auxiliary-winding of an auxiliary power dissipation circuit. The excess energy is a transfer of energy from a primary winding of a switching power converter to the auxiliary-winding of the auxiliary power dissipation circuit. In at least one embodiment, the electronic system is a lighting system that includes a triac-based dimmer. The excess energy is energy drawn through the primary-side winding of the switching power converter to provide operational compatibility between a dimmer through which a power supply provides energy to the switching power converter and a load to which the switching power converter provides energy. | 09-18-2014 |
20140265893 | HIGH-EFFICIENCY LIGHTING DEVICES HAVING DIMMER AND/OR LOAD CONDITION MEASUREMENT - A circuit for powering high-efficiency lighting devices from a thyristor-controlled dimmer includes a power converter for powering the high-efficiency lighting devices from input terminals of the circuit. The circuit also includes a control circuit that controls the input current drawn by the input terminals at least while the power converter transfers energy to the lighting devices. The circuit also includes a sensing circuit that determines or measures at least one attach current characteristic at the input terminals and stores an indication of the characteristic for subsequent operation of the control circuit. | 09-18-2014 |
20140254805 | SYSTEMS AND METHODS FOR PROTECTING A SPEAKER - In accordance with these and other embodiments of the present disclosure, systems and methods may include a controller configured to be coupled to an audio speaker, wherein the controller receives an audio input signal, and based on a displacement transfer function associated with the audio speaker, processes the audio input signal to generate an output audio signal communicated to the audio speaker, wherein the displacement transfer function correlates an amplitude and a frequency of the audio input signal to an expected displacement of the audio speaker in response to the amplitude and the frequency of the audio input signal. | 09-11-2014 |
20140254804 | SYSTEMS AND METHODS FOR PROTECTING A SPEAKER - In accordance with embodiments of the present disclosure, systems and methods may include a controller configured to be coupled to an audio speaker, wherein the controller receives one or more signals indicative of one or more operating characteristics of the audio speaker and compares the one or more operating characteristics to one or more speaker protection thresholds, and based on the comparison, processes an audio input signal to generate an audio output signal communicated from the controller to the audio speaker, further wherein the one or more speaker protection thresholds are based on offline reliability testing of one or more audio speakers similar to the audio speaker and the controller generates one or more modeled parameters for the audio speaker and modifies the one or more speaker protection thresholds based on the one or more modeled parameters. | 09-11-2014 |
20140252990 | Quantization Error Reduction in Constant Output Current Control Drivers - An electronic system and method includes a controller to control a switching power converter in at least two different modes of operation, a normal mode and an error reduction mode. The controller controls an amount of charge pushed (i.e. delivered) by the switching power converter to a load to reduce a charge quantization error. The charge quantization error represents an amount of charge pushed to the load beyond a target charge amount. The controller determines an amount of charge to be pushed to the toad. Based on the amount of charge to be pushed to the load, the controller generates a current control signal that controls a current control switch in the switching power converter. Determination of the control signal depends on whether the controller is operating in normal mode or error reduction mode. The controller attempts to reduce the charge quantization error to avoid power fluctuations. | 09-11-2014 |
20140252981 | Utilizing Secondary-Side Conduction Time Parameters of a Switching Power Converter to Provide Energy to a Load - A power distribution system includes controller of a switching power converter to control the switching power converter and determine one or more switching power converter control parameters. In at least one embodiment, the switching power converter utilizes a transformer to transfer energy from a primary-side of the transformer to a secondary-side of the transformer. In at least one embodiment, the switching power converter control parameters includes a secondary-side conduction time delay that represents a time delay between when the primary-side ceases conducting a primary-side current and the secondary-side begins to conduct a secondary-side current. In at least one embodiment, determining and accounting for this secondary-side conduction time delay increases the prediction accuracy of the secondary-side current value and accurate delivery of energy to a load when the controller does not directly sense the secondary-side current provided to the load. | 09-11-2014 |
20140252975 | Reduction of Supply Current Variations Using Compensation Current Control - A power distribution system and method includes a controller that is configured to control a switching power converter. In at least one embodiment, the controller includes a compensation current control circuit to control a compensation current that reduces and, in at least one embodiment, approximately eliminates variations in current drawn by the controller during a particular operational time period. In at least one embodiment, the power distribution system is a lamp that includes the controller, a switching power converter, and one or more light sources, such as light emitting diodes. | 09-11-2014 |
20140239863 | Position Estimation System and Method for an Electric Motor - Systems and methods of estimating a motor position of a motor are disclosed. One exemplary system and method involve observing motor currents of the motor at two different times. Average motor voltages of the motor are determined between the two different times. Average back electro motive force (BEMF) values of the motor are calculated between the two different times. The BEMF values are in conformity with the observed motor currents and the average motor voltages. Another exemplary system and method for estimating a rotor position of a motor involve a motor position estimator that receives information from the motor and estimates a rotor position for a future time. The future time corresponds approximately to a desired target current, | 08-28-2014 |
20140211953 | BANDLIMITING ANTI-NOISE IN PERSONAL AUDIO DEVICES HAVING ADAPTIVE NOISE CANCELLATION (ANC) - A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit that performs the adaptive noise canceling (ANC) function also either adjusts the frequency response of the anti-noise signal with respect to the reference microphone signal, and/or by adjusting the response of the adaptive filter independent of the adaptation provided by the reference microphone signal. | 07-31-2014 |
20140167652 | SYSTEMS AND METHODS FOR CONTROLLING A POWER CONTROLLER - In accordance with systems and methods of the present disclosure, an apparatus may include a power converter and a controller. The controller may be configured to monitor a voltage at an input of the power converter, cause the power controller to transfer energy from the input to a load at a target current, decrease the target current responsive to determining that the voltage is less than or equal to an undervoltage threshold, and increase the target current responsive to determining that the voltage is greater than or equal to a maximum threshold voltage. | 06-19-2014 |
20140167639 | SYSTEMS AND METHODS FOR LOW-POWER LAMP COMPATIBILITY WITH A LEADING-EDGE DIMMER AND AN ELECTRONIC TRANSFORMER - Methods and systems to provide compatibility between a load and a secondary winding of an electronic transformer driven by a leading-edge dimmer may include: (a) responsive to determining that energy is available from the electronic transformer, drawing a requested amount of power from the electronic transformer thus transferring energy from the electronic transformer to an energy storage device in accordance with the requested amount of power; and (b) transferring energy from the energy storage device to the load at a rate such that a voltage of the energy storage device is regulated within a predetermined voltage range. | 06-19-2014 |
20140077721 | POWERING HIGH-EFFICIENCY LIGHTING DEVICES FROM A TRIAC-BASED DIMMER - A circuit for powering high-efficiency lighting devices from a thyristor-controlled dimmer operates a switching power circuit during active portions of half-cycles of the AC line voltage source that supplies the dimmer. A control circuit determines the durations of the active portions such that sufficient energy is transferred to operate the lighting devices until a next half-cycle of the AC line voltage, at which time the active portion of the half-cycle is terminated. A high impedance level is presented to the output of the dimmer until the next half-cycle commences. | 03-20-2014 |
20140042926 | Power Control System for Current Regulated Light Sources - A light emitting diode (LED) lighting system includes a PFC and output voltage controller and a LED lighting power system. The controller advantageously operates from an auxiliary voltage less than a link voltage generated by the LED lighting power system. The common reference voltage allows all the components of lighting system to work together. A power factor correction switch and an LED drive current switch are coupled to the common reference node and have control node-to-common node, absolute voltage that allows the controller to control the conductivity of the switches. The LED lighting system can utilize feed forward control to concurrently modify power demand by the LED lighting power system and power demand of one or more LEDs. The LED lighting system can utilize a common current sense device to provide a common feedback signal to the controller representing current in at least two of the LEDs. | 02-13-2014 |
20140028214 | SYSTEMS AND METHODS FOR LOW-POWER LAMP COMPATIBILITY WITH A TRAILING-EDGE DIMMER AND AN ELECTRONIC TRANSFORMER - A controller may be configured to: (i) predict based on an electronic transformer secondary signal an estimated occurrence of a high-resistance state of a trailing-edge dimmer coupled to a primary winding of an electronic transformer, wherein the high-resistance state occurs when the trailing-edge dimmer begins phase-cutting an alternating current voltage signal; (ii) operate a power converter in a trailing-edge exposure mode for a first period of time immediately prior to the estimated occurrence of the high-resistance state, such that the power converter is enabled to transfer energy from the secondary winding to the load during the trailing-edge exposure mode; and (iii) operate the power converter in a power mode for a second period of time prior to and non-contiguous with the first period of time, such that the power converter is enabled to transfer energy from the secondary winding to the load during the power mode. | 01-30-2014 |
20140019247 | SYSTEMS AND METHODS FOR DETERMINING LOCATION OF A MOBILE DEVICE BASED ON AN AUDIO SIGNAL - A mobile device includes a display, a microphone, and a controller all within an enclosure sized and shaped such that the enclosure is readily transported on a person of a user of the mobile device. The microphone is configured to receive an audio signal from an audio signal source. The controller is coupled to the microphone and the display, and configured to, based at least on information included in the audio signal, determine a delay between a transmission of the audio signal from the audio signal source to receipt of the audio signal by the microphone. The controller is further configured to, based at least on the delay, determine a geographical location of the mobile device. The controller is also configured to, based on the geographical location of the mobile device, display geographical information to the display indicative of the geographical location. | 01-16-2014 |
20140009082 | SYSTEMS AND METHODS FOR DETERMINING A TYPE OF TRANSFORMER TO WHICH A LOAD IS COUPLED - An apparatus may include a controller to provide compatibility between a load and a secondary winding of a transformer driven at its primary winding by a dimmer, wherein the controller is configured to: determine from a transformer secondary signal whether the transformer comprises a magnetic transformer or an electronic transformer; and select a compatibility mode of operation from a plurality of modes of operation based on the determination of whether the transformer comprises a magnetic transformer or an electronic transformer. A method for providing compatibility between a load and a secondary winding of a transformer driven at its primary winding by a dimmer may include determining from a transformer secondary signal whether the transformer comprises a magnetic transformer or an electronic transformer and selecting a compatibility mode of operation from a plurality of modes of operation based on the determination of whether the transformer comprises a magnetic transformer or an electronic transformer. | 01-09-2014 |
20140009079 | SYSTEMS AND METHODS FOR LOW-POWER LAMP COMPATIBILITY WITH A LEADING-EDGE DIMMER AND A MAGNETIC TRANSFORMER - A system and method for providing compatibility between a load and a secondary winding of a magnetic transformer driven at its primary winding by a trailing-edge dimmer may include determining from a magnetic transformer secondary signal a period of a half-line cycle of an output signal of the dimmer, determining from the magnetic transformer secondary signal an estimated occurrence of an end of a phase-cut angle of the dimmer, and generating a driving signal to the load based on the period and the estimated occurrence of the end of the phase-cut angle. A lamp assembly may include a lamp for generating light and a controller for controlling operation of the lamp, the controller comprising a timing control circuit for determining a period of a periodic signal received by the lamp assembly. | 01-09-2014 |
20140009078 | SYSTEMS AND METHODS FOR LOW-POWER LAMP COMPATIBILITY WITH A TRAILING-EDGE DIMMER AND AN ELECTRONIC TRANSFORMER - In accordance with these and other embodiments of the present disclosure, a system and method for providing compatibility between a load and a secondary winding of an electronic transformer driven by a trailing-edge dimmer may include predicting based on an electronic transformer secondary signal an estimated occurrence of a high-resistance state of the trailing-edge dimmer, wherein the high-resistance state occurs when the trailing-edge dimmer begins phase-cutting an alternating current voltage signal and operating the load in a high-current mode for a period of time immediately prior to the estimated occurrence of the high-resistance state. | 01-09-2014 |
20130342145 | SYSTEM AND METHOD FOR ISOLATING THE UNDRIVEN VOLTAGE OF A PERMANENT MAGNET BRUSHLESS MOTOR FOR DETECTION OF ROTOR POSITION - The system and method disclose for the controlling of sequential phase switching in driving a set of stator windings of a multi-phase sensorless brushless permanent magnet DC motor. A motor controller controls a power stage that drives two windings of a set of three windings in the motor with pulse width modulated signal. A plurality of voltage values on an undriven winding of the set of three windings are sampled within a window of time, wherein a period beginning when the driven windings are energized and ending when the driven windings are de-energized encompasses the window of time. The sampled voltage values are processed. When the processed voltage values exceed a threshold, the motor controller changes which two windings are driven. | 12-26-2013 |
20130342141 | DETERMINING COMMUTATION POSITION FOR A SENSORLESS PERMANENT MAGNET BRUSHLESS MOTOR AT LOW OR ZERO SPEED USING AN ASYMMETRIC DRIVE PATTERN - A system is disclosed for controlling motor switching in a sensorless BLDC motor having a set of three stator windings. A controller unit includes a control signal generator, a memory device, a processing unit, a signal acquisition device, and an analog-to-digital converter. A power stage having a plurality of switches receives a control signal from the control signal generator and a power signal from a power source. The power stage drives two windings of the set of three stator windings with an asymmetric pulse width modulation signal and leaves one stator of the three stator windings undriven. The processing unit acquires a demodulated measured voltage on the undriven winding. The processing unit also communicates with the power stage to change which two windings of the three stator windings are driven when the demodulated measured voltage surpasses a threshold. | 12-26-2013 |
20130342130 | LIGHTING SYSTEM WITH LIGHTING DIMMER OUTPUT MAPPING - A system and method map dimming levels of a lighting dimmer to light source control signals using a predetermined lighting output function. The dimmer generates a dimmer output signal value. At any particular period of time, the dimmer output signal value represents one of multiple dimming levels. In at least one embodiment, the lighting output function maps the dimmer output signal value to a dimming value different than the dimming level represented by the dimmer output signal value. The lighting output function converts a dimmer output signal values corresponding to measured light levels to perception based light levels. A light source driver operates a light source in accordance with the predetermined lighting output function. The system and method can include a filter to modify at least a set of the dimmer output signal values prior to mapping the dimmer output signal values to a new dimming level. | 12-26-2013 |
20130342123 | TRAILING EDGE DIMMER COMPATIBILITY WITH DIMMER HIGH RESISTANCE PREDICTION - In at least one embodiment, an electronic system includes a controller, and the controller provides compatibility between an electronic light source and a trailing edge dimmer. In at least one embodiment, the controller is capable of predicting an estimated occurrence of a trailing edge of a phase cut AC voltage and accelerating a transition of the phase cut AC voltage from the trailing edge to a predetermined voltage threshold. In at least one embodiment, the controller predicts an estimated occurrence of the trailing edge of the phase cut AC voltage on the basis of actual observations from one or more previous cycles of the phase cut AC voltage. | 12-26-2013 |
20130301849 | ERROR-SIGNAL CONTENT CONTROLLED ADAPTATION OF SECONDARY AND LEAKAGE PATH MODELS IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device, such as a wireless telephone, generates an anti-noise signal from a microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. The microphone measures the ambient environment, but also contains a component due to the transducer acoustic output. An adaptive filter is used to estimate the electro-acoustical path from the noise-canceling circuit through the transducer to the at least one microphone so that source audio can be removed from the microphone signal. A determination of the relative amount of the ambient sounds present in the microphone signal versus the amount of the transducer output of the source audio present in the microphone signal is made to determine whether to update the adaptive response. | 11-14-2013 |
20130301848 | DOWNLINK TONE DETECTION AND ADAPTATION OF A SECONDARY PATH RESPONSE MODEL IN AN ADAPTIVE NOISE CANCELING SYSTEM - An adaptive noise canceling (ANC) circuit adaptively generates an anti-noise signal from a reference microphone signal that is injected into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone proximate the speaker provides an error signal. A secondary path estimating adaptive filter estimates the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Tones in the source audio, such as remote ringtones, present in downlink audio during initiation of a telephone call, are detected by a tone detector using accumulated tone persistence and non-silence hangover counting, and adaptation of the secondary path estimating adaptive filter is halted to prevent adapting to the tones. Adaptation of the adaptive filters is then sequenced so any disruption of the secondary path adaptive filter response is removed before allowing the anti-noise generating filter to adapt. | 11-14-2013 |
20130301847 | SEQUENCED ADAPTATION OF ANTI-NOISE GENERATOR RESPONSE AND SECONDARY PATH RESPONSE IN AN ADAPTIVE NOISE CANCELING SYSTEM - A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate to the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Adaptation of adaptive filters is sequenced so that update of their coefficients does not cause instability or error in the update. A level of the source audio with respect to the ambient audio can be determined to determine whether the system may generate erroneous anti-noise and/or become unstable. | 11-14-2013 |
20130301846 | FREQUENCY AND DIRECTION-DEPENDENT AMBIENT SOUND HANDLING IN PERSONAL AUDIO DEVICES HAVING ADAPTIVE NOISE CANCELLATION (ANC) - A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to measure the output of the transducer in order to control the adaptation of the anti-noise signal and to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit that performs the adaptive noise canceling (ANC) function also detects frequency-dependent characteristics in and/or direction of the ambient sounds and alters adaptation of the noise canceling circuit in response to the detection. | 11-14-2013 |
20130301842 | NOISE BURST ADAPTATION OF SECONDARY PATH ADAPTIVE RESPONSE IN NOISE-CANCELING PERSONAL AUDIO DEVICES - A personal audio device, such as a wireless telephone, generates an anti-noise signal from an error microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. The error microphone is also provided proximate the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. Noise bursts are injected intermittently and the adaptation of the secondary path estimating adaptive filter controlled, so that the secondary path estimate can be maintained irrespective of the presence and amplitude of the source audio. | 11-14-2013 |
20130287219 | COORDINATED CONTROL OF ADAPTIVE NOISE CANCELLATION (ANC) AMONG EARSPEAKER CHANNELS - A personal audio device including earspeakers, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal for each earspeaker from at least one microphone signal that measures the ambient audio, and the anti-noise signals are combined with source audio to provide outputs for the earspeakers. The anti-noise signals cause cancellation of ambient audio sounds at the respective earspeakers. A processing circuit uses the microphone signal(s) to generate the anti-noise signals, which can be generated by adaptive filters. The processing circuit controls adaptation of the adaptive filters such that when an event requiring action on the adaptation of one of the adaptive filters is detected, action is taken on the other one of the adaptive filters. Another feature of the ANC system uses microphone signals provided at both of the earspeakers to perform processing on a voice microphone signal that receives speech of the user. | 10-31-2013 |
20130287218 | LEAKAGE-MODELING ADAPTIVE NOISE CANCELING FOR EARSPEAKERS - A personal audio device, such as a headphone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio, and the anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the reference microphone. A processing circuit uses the reference microphone to generate the anti-noise signal, which can be generated by an adaptive filter. The processing circuit also models an acoustic leakage path from the transducer to the reference microphone and removes elements of the source audio appearing at the reference microphone signal due to the acoustic output of the speaker. Another adaptive filter can be used to model the acoustic leakage path. | 10-31-2013 |
20130221871 | MIXED LOAD CURRENT COMPENSATION FOR LED LIGHTING - In at least one embodiment, a system and method provide current compensation in a lighting system by controlling a lamp current to prevent a current through a triac-based dimmer from undershooting a holding current value. In at least one embodiment, at least one of the lamps includes a controller that controls circuitry in the lamp to draw more lamp current for a period of time than needed to illuminate a brightness of the lamp at a level corresponding to particular phase-cut angle of the supply voltage. By drawing more current than needed, the controller increases the dimmer current during the period of time to prevent the dimmer current from falling below the holding current value. In at least one embodiment, the period of time corresponds to a compensating pulse of the lamp current at a time when the dimmer current would otherwise fall below the holding current value. | 08-29-2013 |
20130197839 | THREE PHASE POWER QUALITY MEASUREMENT USING ASYNCHRONOUS, ISOLATED SINGLE PHASE CIRCUITS - A system and method utilize multiple, asynchronous, voltage isolated integrated power data circuits (IPDCs) to respectively determine one or more power parameters of a multi-phase power distribution system. In at least one embodiment, the power parameters represent differences between voltage phases of a multi-phase power distribution system. In at least one embodiment, the IPDCs each sense a voltage or current from a single phase of a three-phase power distribution system. Additionally, the IPDCs are electrically isolated from each other and, thus, in at least one embodiment, can utilize voltage divider or shunt resistor sensing without being subject to high voltages representative of the difference between voltage phases. Additionally, in at least one embodiment, each of the IPDCs utilizes a separate clock signal to determine phase sequence and phase angle deltas of one or more three phase voltages of the three-phase power distribution system. | 08-01-2013 |
20130162307 | HIGH VOLTAGE LINEAR AMPLIFIER DRIVING HEAVY CAPACITIVE LOADS WITH REDUCED POWER DISSIPATION - A capacitive load drive circuit may comprise a high current drive amplifier configured to be coupled to a capacitive load during a high current ramp up of the voltage across the capacitive load to a cut off voltage; a low current drive amplifier configured to be connected to the capacitive load during a low current ramp up of the voltage across the capacitive load, from the cut off voltage to a maximum voltage across the capacitive load; and the high current drive amplifier configured to be connected to the capacitive load during a high current ramp down of the voltage across the capacitive load. The low current drive amplifier may be connected to the capacitive load during a period of steady state of the voltage across the capacitive load, intermediate the low current ramp up and the high current ramp down. | 06-27-2013 |
20130155728 | Isolation of Secondary Transformer Winding Current During Auxiliary Power Supply Generation - An electronic system and method include a controller to actively control power transfer from a primary winding of a switching power converter to an auxiliary-winding of an auxiliary power supply. The switching power converter is controlled and configured such that during transfer of power to the auxiliary-winding, the switching power converter does not transfer charge to one or more secondary-windings of the switching power converter. Thus, the switching power converter isolates one or more secondary transformer winding currents from an auxiliary-winding current. By isolating the charge delivered to the one or more secondary-windings from charge delivered to the auxiliary-winding, the controller can accurately determine an amount of charge delivered to the secondary-windings and, thus, to a load. | 06-20-2013 |
20130154496 | MULTI-MODE FLYBACK CONTROL FOR A SWITCHING POWER CONVERTER - In at least one embodiment, an electronic system and method includes a controller to control a switching power converter in at least two different modes of operation depending on whether the controller detects a dimmer or not and/or whether a load requests more power than either of the two operational modes can provide. In at least one embodiment, the controller detects whether a dimmer is phase cutting an input voltage to a switching power converter. The controller operates the switching power converter in a first mode if the dimmer is detected, and the controller operates the switching power converter in a second mode if the dimmer is not detected. The controller also transitions between operating the switching power converter in the first mode and the second mode if a status of detection of the dimmer changes. | 06-20-2013 |
20130154495 | Adaptive Current Control Timing and Responsive Current Control for Interfacing with a Dimmer - In at least one embodiment, an electronic system adapts current control timing for half line cycle of a phase-cut input voltage and responsively controls a dimmer current in a power converter system. The adaptive current control time and responsive current control provides, for example, interfacing with a dimmer. The electronic system and method include a dimmer, a switching power converter, and a controller to control the switching power converter and controls a dimmer current. In at least one embodiment, the controller determines a predicted time period from a zero crossing until a leading edge of a phase-cut input voltage and then responsively controls the dimmer current to, for example, reduce current and voltage perturbations (referred to as “ringing”), improve efficiency, and reduce an average amount of power handled by various circuit components. | 06-20-2013 |
20130069561 | COLOR MIXING OF ELECTRONIC LIGHT SOURCES WITH CORRELATION BETWEEN PHASE-CUT DIMMER ANGLE AND PREDETERMINED BLACK BODY RADIATION FUNCTION - A lighting system includes methods and systems to mix colors of light emitted from at least two LED emitters. In at least one embodiment, the lighting system includes a controller that responds to phase-cut angles of the dimming signal and correlates the phase-cut angles with a predetermined black body radiation function to dynamically adjust a color spectra of the mixed light in response to changes in phase cut angles of the phase-cut dimming level signal. In at least one embodiment, the controller utilizes the predetermined black body radiation function to dynamically adjust the color spectra of the mixed, emitted light in response to changes in phase cut angles of a phase-cut dimming level signal. In at least one embodiment, the predetermined black body radiation function specifies correlated color temperatures (CCTs) that model the CCTs of an actual non-LED based lamp, such as an incandescent lamp. | 03-21-2013 |
20110210674 | Multi-LED Control - A LED driver and controller system utilizes switches to parallel connect to respective sets of one or more LEDs and a current source to provide efficient control of the LEDs. In at least one embodiment, the LEDs are connected in series. An LED controller of the LED driver and controller system | 09-01-2011 |
20100013050 | Compensation Of Field Effect On Polycrystalline Resistors - A resistive circuit includes a first terminal and a second terminal and polycrystalline first and second resistive segments coupled between the first and second terminals. A third terminal A is coupled to the first resistive segment, and a third terminal B is coupled to the second resistive segment. The third terminal A has a first voltage with respect to the first terminal, and the third terminal B has a second voltage with respect to the second terminal. With this arrangement, the non-linearity of resistance of the first resistive segment at least partially compensates for non-linearity of resistance of the second resistive segment. | 01-21-2010 |