Systems and methods are provided for amplifying multiple input signals to generate multiple output signals. An example system includes a first channel, a second channel, and a third channel. The first channel is configured to receive one or more first input signals, process information associated with the one or more first input signals and a first ramp signal, and generate one or more first output signals. The second channel is configured to receive one or more second input signals, process information associated with the one or more second input signals and a second ramp signal, and generate one or more second output signals. The first ramp signal corresponds to a first phase. The second ramp signal corresponds to a second phase. The first phase and the second phase are different.

The present disclosure relates to Class D amplifier circuitry comprising a mode controller configured to dynamically adjust an operational switching mode of the Class D amplifier over a range between a Class AD mode and a Class BD mode.

A hearable has an audio amplifier circuit coupled to a speaker as a load. The amplifier circuit has current source drive, which attenuates electromagnetically coupled noise of the speaker. In other instances, the amplifier circuit has a first amplifier mode and a second amplifier mode, wherein in the first amplifier mode the amplifier circuit becomes configured to drive the speaker as a voltage source, and in the second amplifier mode the amplifier circuit becomes configured to drive the speaker as a current source. Control logic varies the amplifier circuit between i) the first amplifier mode for larger amplitudes of the audio signal, and ii) the second amplifier mode for smaller amplitudes of the audio signal. Other aspects are also described and claimed.

A switching amplifier comprises a controller, configured to receive an input signal and a reference signal, and to generate a control signal according to the input signal and the reference signal; a pulse-width modulation (PWM) modulator, coupled to the controller, configured to generate a PWM signal according to the input signal and the control signal; a power management unit, coupled to the controller, configured to receive a power supply and the control signal, and to provide an adaptive supply voltage according to the power supply and the control signal; and a switching power stage, coupled to the power management unit and the PWM modulator, configured to generate an output signal according to the PWM signal and the adaptive supply voltage.

A switched mode amplifier system may include a switched mode amplifier having an amplifier input coupled to an output of an analog integrator and an amplifier output, include a feedback network coupled between the amplifier output and an input of the analog integrator, include a loop filter configured to generate a digital loop filter output, include a quantizer configured to generate a pulse-width modulated representation of the digital loop filter output; and include a calibration system. The calibration system may be configured to force the input of the analog integrator to a fixed known input value, low-pass filter the pulse-width modulated representation of the digital loop filter output generated by the quantizer to generate a filtered quantizer output signal, determine an offset of the switched mode amplifier system based on the filtered quantizer output signal, and correct for the offset.

A switched mode amplifier system may include a switched mode amplifier having an amplifier input coupled to an output of an analog integrator and an amplifier output, include a feedback network coupled between the amplifier output and an input of the analog integrator, include a loop filter configured to generate a digital loop filter output, include a quantizer configured to generate a pulse-width modulated representation of the digital loop filter output; and include a calibration system. The calibration system may be configured to force the input of the analog integrator to a fixed known input value, low-pass filter the pulse-width modulated representation of the digital loop filter output generated by the quantizer to generate a filtered quantizer output signal, determine an offset of the switched mode amplifier system based on the filtered quantizer output signal, and correct for the offset.

The present invention relates generally to the field of electret capsule, and more particularly to a circuit configuration of an impedance converter integrated in an electret capsule such as for use in condenser microphones. The electret capsule of a microphone may include a gate biasing field effect transistor (FET) to facilitate biasing of a low noise FET. Advantageously, the use of low noise FET in the electret capsule of a microphone provides for a reduced cost, while achieving lower self-noise.

An amplifier system may include at least one input source, a converter configured to provide voltage rails to an amplifier, the voltage rails including a first voltage rail and a second voltage rail, a MOSFET arranged at a secondary side of the system at the first voltage rail, a second MOSFET arranged at the first voltage rail, a third MOSFET arranged at the second voltage rail, a fourth MOSFET arranged at the second voltage rail; and, a first capacitor arranged at the first voltage rail and a second capacitor arranged at the second voltage rail, the first and forth MOSFETS are configured to operate simultaneously with one another and the second and third MOSFETs are configured to operate simultaneously with one another and opposite of the first and fourth MOSFETs so as to allow synchronous rectification so that the first and second capacitors reciprocally and mutually exclusively charge and discharge.

A class-D driver circuit includes a feedback loop including an input integrator stage, a switched modulator, and an output driver stage. A feedback resistor connects an output terminal of the output driver stage with an input node of the input integrator stage to provide a feedback current. The class-D driver circuit also includes a compensation circuit configured to provide a compensation current to an output node of the input integrator stage to relieve a slew rate limitation of the feedback loop, the compensation current having a magnitude based on the magnitude of the feedback current.

The present disclosure relates to Class D amplifier circuitry comprising a mode controller configured to dynamically adjust an operational switching mode of the Class D amplifier over a range between a Class AD mode and a Class BD mode.