An audio signal processing circuit includes an encoding circuit, a first audio conversion circuit, and a second audio conversion circuit. The encoding circuit receives pulse coded modulation signals and generates a first audio signal and a second audio signal accordingly. The first audio conversion circuit generates a first pulse width modulation (PWM) signal according to consecutive values of the first audio signal for configuring a first power stage circuit. The second audio conversion circuit generates a second PWM signal according to consecutive values of the second audio signal for configuring a second power stage circuit. The pulse width of the first PWM signal is configured to be substantially equal to the pulse width of the second PWM signal, and the pulse edges of the first PWM signal and the second PWM signal are configured to be separated by a predetermined time interval to mute the audio signal processing circuit.