Patent ID: 7974419

Claim:
A pop sound prevention module, for preventing a speaker apparatus generating a pop sound when a power shuts down, wherein the speaker apparatus comprises an audio processor coupled to a first operation voltage and an audio amplifier coupled to a second operation voltage, the pop sound prevention module comprising: a first resistor, being coupled in series with a second resistor between the first operation voltage and a ground end; a first transistor, a control end of the first transistor being coupled to a common node of the first resistor and the second resistor; a capacitor, being coupled between a second end of the first transistor and the ground end; a second transistor, a first end of the second transistor being coupled to a third resistor, the other end of the third resistor being coupled to the second operation voltage, and a second end of the second transistor being coupled to the ground end; a fourth resistor, being coupled between a first end of the first transistor and a control end of the second transistor; and a fifth resistor, being coupled between the second operation voltage and a second end of the first transistor, wherein the pop sound prevention module outputs a mute control signal to the speaker amplifier via a common node of the first end of the second transistor and the third resistor, and if the mute control signal is enabled, the output of the audio amplifier is a mute state.