In some embodiments, a circuit for use in devices involving digital-to-analog conversion of signals includes: a capacitive digital-to-analog converter array and an amplifier. The capacitive digital-to-analog converter includes an input port for receiving a digital input signal and an output port. The amplifier includes capacitive feedback loops that include a first capacitor coupling the output of the amplifier with the input of the amplifier and a second capacitor coupled to the output port of the digital-to-analog converter array at the input of the amplifier. The circuit further includes a set of switches that include a first switch and a second switch coupled with opposed ends of the second capacitor at the input and at the output of the amplifier, respectively.

Applying positive and negative feedback voltages to an electromechanical sensor of a microphone utilizing a voltage-to-voltage converter to facilitate an improvement in sensitivity and reduction in distortion of the microphone is presented herein. A microphone comprises an electromechanical sensor comprising a capacitive sense element comprising a first sense node and a second sense node; and a voltage-to-voltage converter comprising an input, a first output, and a second output. The voltage-to-voltage converter forms, via a first capacitive coupling to the second sense node, a negative feedback loop between the first output of the voltage-to-voltage converter and the input of the voltage-to-voltage converter. The first sense node is electrically coupled to the input of the voltage-to-voltage converter, and the voltage-to-voltage converter forms, via a second capacitive coupling to the first sense node, a positive feedback loop between the second output of the voltage-to-voltage converter and the input of the voltage-to-voltage converter.

An operational amplifier based circuit has an operational amplifier, a feedback circuit, and a compensation circuit block. The feedback circuit is coupled between an output port and an input port of the operational amplifier. The compensation circuit block has circuits involved in stability compensation of the operational amplifier, wherein there is no stability compensation circuit driven at the output port of the operational amplifier.

An amplifying circuit includes a reference voltage generating circuit, a common-mode voltage conversion circuit, a common-mode negative feedback circuit, and an amplifying sub-circuit. The reference voltage generating circuit generates a first reference voltage, a second reference voltage, and a reference common-mode voltage according to a post-stage common-mode voltage. The common-mode voltage conversion circuit converts the pre-stage output differential signal into a differential input signal according to the reference common-mode voltage. The common-mode negative feedback circuit generates a control voltage to quickly establish a common-mode negative feedback of the amplifying sub-circuit, wherein the first reference voltage and the second reference voltage are used to cancel a baseline signal of the pre-stage output differential signal. The amplifying circuit can eliminate the baseline signal, convert the common-mode voltage and quickly establish the common-mode negative feedback.

A switched-capacitor circuit comprising a differential operational amplifier and a feedback circuit is described. In some embodiments, the feedback circuit may be configured to provide a reference voltage that is insensitive to temperature and/or process variations. In some embodiments, the feedback circuit may be configured to mitigate the time delay associated with one or more capacitors of the switched-capacitor circuit. The switched-capacitor circuit may be controlled by a pair of control signals. During a first phase, one or more capacitors may be charged, or discharged, through an input signal. During a second phase, the electric charge of the one or more capacitors may be retained.

A digital-to-analog converter (DAC) may include a conversion block providing a first analog value. The DAC may also include an amplification block for receiving the first analog value and providing a second analog value amplified by an amplification factor. The amplification block may include a first input terminal for receiving the first analog value, a second input terminal, and an output terminal for providing the second analog value. The amplification block may also include a first capacitive element and a second capacitive element. The first and second capacitive elements may determine the amplification factor. The amplification block may further include a control unit for recovering a charge at a first terminal of the second capacitive element, and based thereon, the second analog value.

A digital-to-analog converter (DAC) may include a conversion block providing a first analog value. The DAC may also include an amplification block for receiving the first analog value and providing a second analog value amplified by an amplification factor. The amplification block may include a first input terminal for receiving the first analog value, a second input terminal, and an output terminal for providing the second analog value. The amplification block may also include a first capacitive element and a second capacitive element. The first and second capacitive elements may determine the amplification factor. The amplification block may further include a control unit for recovering a charge at a first terminal of the second capacitive element, and based thereon, the second analog value.

A digital-to-analog converter (DAC) may include a conversion block providing a first analog value. The DAC may also include an amplification block for receiving the first analog value and providing a second analog value amplified by an amplification factor. The amplification block may include a first input terminal for receiving the first analog value, a second input terminal, and an output terminal for providing the second analog value. The amplification block may also include a first capacitive element and a second capacitive element. The first and second capacitive elements may determine the amplification factor. The amplification block may further include a control unit for recovering a charge at a first terminal of the second capacitive element, and based thereon, the second analog value.

A switched-capacitor circuit comprising a differential operational amplifier and a feedback circuit is described. In some embodiments, the feedback circuit may be configured to provide a reference voltage that is insensitive to temperature and/or process variations. In some embodiments, the feedback circuit may be configured to mitigate the time delay associated with one or more capacitors of the switched-capacitor circuit. The switched-capacitor circuit may be controlled by a pair of control signals. During a first phase, one or more capacitors may be charged, or discharged, through an input signal. During a second phase, the electric charge of the one or more capacitors may be retained.

An audio amplifier, including: at least a two stage amplifier configured to receive an input signal and output an amplified output signal, the at least a two stage amplifier including at least one stage amplifier and an output stage amplifier; and an auxiliary stage amplifier having an input coupled to an output of the at least one stage amplifier and an input of the output stage amplifier.