公开(公告)号：JPH1139769A

公开(公告)日：1999-02-12

申请号：JP19280197

申请日：1997-07-17

Applicant: IBM

Inventor： FUJII KAZUO ,  ASAUMI TAKESHI ,  NAKAZAWA YUKIFUMI

IPC: G11B19/00 ,  G06F1/32 ,  H03G3/10 ,  H03G3/34 ,  H04R3/00

Abstract: PROBLEM TO BE SOLVED: To save the power of an audio amplifier by providing an audio amplifier amplifyingly processing audio signals from peripheral equipments and an AND gate which receives mute signals from peripheral equipments of one or more and which outputs a control signal reducing the power of the amplifier when all mute signal are in mute states while ANDing the mute signals. SOLUTION: Mute signals from, for example, five sets of peripheral equipments having mute signal outputs indicating mute states in which audio signals are not outputted are ANDed in an AND gate 52 and when all peripheral equipments are in mute states, the assert signal of the gate 52 indicates that an audio amplifier 51 is unused. The output of the AND gate 52 is inputted to the power saving control pin of the audio amplifier 51. When the input is in a negated state, the amplifier 51 performs an amplifying procession and when the input is in an asserted state, the amplifier is in a power saving state and it is made impossible to perform the amplifying processing of audio signals and, then, the lowering of power consumption is made possible.