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 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.

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.