Abstract: A playback circuit including a digital-to-analog converter (DAC), an amplifying output circuit and a control circuit coupled to both is provided. The DAC is configured to convert an input playback audio signal into an input analog playback audio signal according to a first control signal for controlling an upper limit of power consumption of the DAC. The amplifying output circuit is coupled to the DAC and configured to generate an output playback audio signal according to the input analog playback audio signal and a second control signal for controlling an upper limit of power consumption of the amplifying output circuit. The control circuit is configured to generate the first control signal and second control signal according to a volume value of the input playback audio signal, thereby controlling the upper limit of power consumption of the DAC and the upper limit of power consumption of the amplifying output circuit.

Abstract: An amplifier includes a subtracting unit for generating an error signal according to an input signal and an output signal; a noise shaping unit for executing a noise shaping operation on the error signal to produce a noise-shaped signal; a pulse adjustment unit for generating a control signal according to the noise-shaped signal and the input signal; and a power stage for generating the output signal according to the control signal.

Abstract: An amplifier includes a subtracting unit for generating an error signal according to an input signal and an output signal; a noise shaping unit for executing a noise shaping operation on the error signal to produce a noise-shaped signal; a pulse adjustment unit for generating a control signal according to the noise-shaped signal and the input signal; and a power stage for generating the output signal according to the control signal.