AMPLIFIER CIRCUIT, ACTIVATION METHOD THEREOF, AUDIO PLAYER USING THE SAME, AND ELECTRONIC APPARATUS

摘要

PROBLEM TO BE SOLVED: To suppress noise when muting is released. SOLUTION: An amplifier 10 amplifies an audio signal S1 input via a coupling capacitor C1. A charging circuit 20 charges one terminal of the coupling capacitor C1 connected to the input terminal 102 of the amplifier 10. A current detector 40 monitors a charging current Ic from the charging circuit 20 to the coupling capacitor C1. A bypass switch SW1 is provided between a first node N1 at the side of an output terminal of the amplifier 10 and a second node N2 at the side of the input terminal 102 of the amplifier 10. When it is detected by the current detector 40 that the charging current Ic becomes smaller than a predetermined threshold, the bypass switch SW1 is switched from ON to OFF. COPYRIGHT: (C)2010,JPO&INPIT