Patent ID: 7734265

Claim:
An audio muting circuit muting an audio signal, comprising: a first sub mute signal generation circuit outputting, in a normal mode, a first sub mute signal at an inactivation level and outputting, in a mute mode, the first sub mute signal at an activation level; a second sub mute signal generation circuit outputting, in the normal mode, a second sub mute signal at the inactivation level and outputting, in the mute mode, the second sub mute signal at the activation level; an NPN bipolar transistor connected between an audio line where said audio signal is transmitted and a line of a reference potential; and a PNP bipolar transistor connected between a line of a power supply potential and a control electrode of said NPN bipolar transistor, rendered nonconductive when a mute signal generated by combining said first and second sub mute signals is at the inactivation level, and rendered conductive when said mute signal is at the activation level, wherein at start of muting, after a predetermined time from time when said first sub mute signal generation circuit changes said first sub mute signal from the inactivation level to the activation level, said second sub mute signal generation circuit changes said second sub mute signal from the inactivation level to the activation level.