Synaptics Corporation

Dan Shen

Lorenzo Crespi

Balakishan Challa

Ketan B Patel

Jae Won Choi

Davide Cartasegna

Yunfu Zhang

Ketankumar Balubhai Patel

Jinbao Lan

A circuit includes a controller circuit configured to receive an output voltage of a converter and adjust a switching frequency of the converter in response to a status of an output load and an output load sensing circuit configured to determine the status of the output load and provide the peak current to the controller circuit. The output load sensing circuit may include a first timer configured to provide a delayed first signal to a peak current control in response to the output load being a heavy load. A second timer may be configured to provide a delayed second signal to the peak current control in response to the output load being a light load. The peak current control may be configured to adjust a peak current based on the received first signal and the second signal and configured to provide the peak current to the controller circuit.

DC-DC converter output regulation systems and methods

Various techniques are provided to reduce common mode disturbance associated with an amplifier, such as a class D amplifier. In one example, an amplifier includes a power stage configured to generate first and second PWM signals. The amplifier further includes an integration stage comprising input nodes configured to receive an input differential analog signal. The integration stage is configured to generate an output differential analog signal in response to the PWM signals and the input differential analog signal. The amplifier further includes an active compensation circuit configured to provide a compensation signal to the integration stage to reduce disturbances at the input nodes associated with the PWM signals switching between a common mode and a differential mode. Additional devices, systems, and methods are also provided.

Active common mode compensation for improved amplifier performance

Systems and methods include a digital control module that receives and processes audio data for output through a loudspeaker. An analog block receives the audio data and the power control signal and amplifies the audio data for output. A first processing path includes a buffer to delay the audio data, a first component to combine the buffered audio data and anti-noise. A second processing path includes an absolute value block to receive the audio data and an envelope detector to receive the absolute value data and generate a maximum value for the envelope. An anti-noise path includes an absolute value block configured to determine an anti-noise absolute value which is combined with the absolute value anti-noise data. A power generator receives the output from the envelope detector and updates a power level to approximate a minimum powered needed to process the audio signal.

Class-G control system with low latency signal path

Systems and methods include a circuit having a plurality of integrator circuits arranged in series and configured to receive an input signal at a first of the plurality of integrators and generate an output signal at a last of the plurality of integrators, a filter arranged to receive a feedback signal comprising the output signal and generate a filtered feedback signal, which is applied to the input signal before input to the first of the plurality of integrators, and a feedback signal path configured to receive the feedback signal and apply the feedback signal to an input of a second of the plurality of integrators. The circuit may include a class-D amplifier and/or a delta-sigma modulator. The input signal may include an analog audio signal that is amplifier to drive an audio speaker.

Low delay, low power and high linearity class-D modulation loop

Embodiments described herein provide a zero-crossing detector (ZCD) for a direct current to direct current (DC-DC) converter. The ZCD includes a ZCD integrator configured to receive a switch voltage and an output voltage of a power stage of the DC-DC converter and to generate a zero-crossing detect signal based, at least in part, on the received switch voltage and output voltage, where the zero-crossing detect signal is configured to indicate an output current in an output inductor of the power stage of the DC-DC converter is approximately zero. The ZCD may also include a ZCD offset calibrator configured to receive the switch voltage and generate a ZCD calibration offset based, at least in part, on the received switch voltage, where the ZCD integrator is configured to generate the zero-crossing detect signal based, at least in part, on the ZCD calibration offset.

Zero-crossing detector for DC-DC converter systems and methods

Systems and methods are provided for improved stability of driver amplifiers. In one example, a system includes an NMOSFET power device operable to generate a current signal at a drain terminal. The system further includes a current comparison amplifier operable to amplify a difference signal comprising a difference between a replica current signal of the NMOSFET power device and a reference current signal to drive a current comparison amplifier voltage output signal. The system further includes a PMOSFET clamp device comprising a source terminal coupled to a gate terminal of the NMOSFET power device operable to limit a voltage at the gate terminal of the NMOSFET power device responsive to the current comparison amplifier voltage output signal.

Over current protection with improved stability systems and methods

Systems and methods according to one or more embodiments are provided for sensing a current at an output of a switching amplifier. In one example, a system includes a first transistor switch coupled to a load configured to conduct a current in the load responsive to a first pulse width modulated control signal coupled to a gate terminal of the first transistor switch. The system further includes a second transistor switch configured to conduct the current in the load responsive to a second pulse width modulated control signal coupled to a gate terminal of the second transistor switch. A shielding switch is coupled between the load and a current sensing circuit, wherein the shielding switch is configured to provide a small signal voltage to the current sensing circuit in response to the second pulse width modulated control signal, the current sensing circuit is configured to sense the current traveling through the load responsive to the small signal voltage.

Current measurement at a switching amplifier output

Systems and methods are provided for improved noise performance of audio amplifiers. In one example, a system includes a multistage amplifier comprising at least a first stage amplifier and a second stage amplifier. The system further includes a plurality of switches disposed within the multistage amplifier to configure the multistage amplifier. The system further includes a control signal configured to control the multistage amplifier to a normal amplification mode or a mute state, wherein the multistage amplifier is adapted to amplify an input signal in the normal amplification mode, the multistage amplifier is adapted to output a zero signal in the mute state, and internal amplification stages of the multistage amplifier are disabled in the mute state, and output stages of each of the at least first stage amplifier and the second stage amplifier are electrically shorted and/or shorted to a fixed bias voltage in the mute state.

Mute mechanism with reduced pop noise in audio amplifier systems and methods

Systems and methods according to one or more embodiments provide a low power current steering digital-to-analog converter. In one example, a device includes a current cell including a plurality of switches. The device further includes a current cell controller configured to selectively operate the plurality of switches. The plurality of switches is selectively operated to cause the current cell to generate a current signal in response to a first data signal. The plurality of switches is selectively operated to disable the current cell in an absence of the first data signal. The plurality of switches is selectively operated to transition the current cell to a common mode state before the current cell receives the first data signal. Related systems and methods are also provided.

Low power current steering digital-to-analog converter

Systems and methods according to one or more embodiments are provided for improved reliability and efficiency of high side power stage output drivers used in switching amplifiers. In one example, a system includes a power device structure comprising an nwell structure formed within a semiconductor p substrate and a pwell structure formed within the nwell structure. The system further includes one or more NMOS electronic power devices formed on the pwell structure and a pwell guardring formed on the pwell structure configured to surround the one or more NMOS electronic power devices. The system further includes an nwell guardring formed on the nwell structure configured to surround the pwell structure and a p+ guardring formed on the nwell structure configured to surround the nwell guardring.

Power device structure with improved reliability and efficiency

Systems and methods are provided for improved linearity of audio amplifiers. In one example, a system includes a first current source configured to provide a first current signal having a first current source output capacitance, and a second current source configured to provide a second current signal having a second current source output capacitance, where the first and second current source output capacitances are a different value. The system further includes a first capacitor compensation device coupled to an output of the first current source configured to provide a capacitance value to compensate for the second current source output capacitance, and a second capacitor compensation device coupled to an output of the second current source configured to provide a capacitance value to compensate for the first current source output capacitance. The system further includes a plurality of switches configured to switch the first and second current signals.

Current steering structure with improved linearity

Systems and methods according to one or more embodiments are provided for correcting a current measurement through a speaker in an audio system. In one example, a system for driving a speaker includes an output stage configured to drive a current through the speaker. The system further includes a first and second current sensor coupled to the output stage and configured to measure a positive current including a first measurement error and a negative current including a second measurement error through the speaker, respectively. The system further includes a processing block coupled to the first and second current sensors to receive the measured positive and negative current signals and configured to add a positive offset value to an input of each first and second current sensors, determine the first and second measurement errors, and correct a measured current using the positive and negative currents and the determined first and second measurement errors.

Correction of current measurement in an amplifier

Systems and methods according to one or more embodiments are provided for gate boosted drivers for integrated power stages. In one example, a gate driver includes an output stage comprising an n-channel metal-oxide-semiconductor (NMOS) pull-up transistor and an NMOS pull-down transistor, where the NMOS pull-up transistor and the NMOS pull-down transistor are coupled at an output node. The gate driver further includes a bootstrap circuit comprising a main bootstrap capacitor, where the bootstrap capacitor provides a supply voltage for driving the NMOS pull-up transistor. The gate driver further includes a high voltage generator coupled with the main bootstrap capacitor via a transistor switch and a replica bootstrap circuit comprising a replica bootstrap capacitor. The replica bootstrap circuit generates a reference voltage that regulates a drain current of the transistor switch, and the regulated drain current of the transistor switch charges the main bootstrap capacitor from the high voltage generator.

Gate boosting circuit and method for an integrated power stage

Systems and methods are provided for improved stability of audio amplifiers that incorporate external speaker connectivity. In one example, a system includes an audio amplifier circuit comprising two or more amplifier stages and a stability resistor and configured to receive an audio input signal, the audio amplifier circuit configured for at least two modes of operation, a first mode having a high input transconductance and the stability resistor is coupled to an output of the audio amplifier circuit, and a second mode having a lower input transconductance and the stability resistor is decoupled from the output of the audio amplifier circuit. The system further includes an amplitude detection circuit configured to provide a signal mode detection signal, an amplifier switching circuit configured to adjust a variable input transconductance of at least one of the amplifier stages, and a load switching circuit configured to couple and decouple the stability resistor at the output of the audio amplifier circuit.

Stabilizing high performance audio amplifiers

Systems and methods according to one or more embodiments are provided for improving noise performance in a delta sigma modulator comprising an adder, quantizer and nth order filter. The adder is operable to receive an input signal and a feedback signal, and output a modified input signal. The quantizer is operable to receive the modified input signal and output a quantized output signal, the quantized output signal having a corresponding quantization error. The nth order filter is operable to receive a quantization error value and generate the feedback signal, the nth order filter comprising a first memory element having a first error value, a second memory element having a second error value, and a gravity component operable to converge the first error value and the second error value when the input signal is approximately zero.

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Irvine, CA, United States of America

Dan Shen