Title:
MUTING CIRCUIT FOR AUDIO AMPLIFIER
Document Type and Number:
Japanese Patent JPH02111110
Kind Code:
A
Abstract:
PURPOSE: To mute an audio amplifier(AA) over a prescribed periods immediately after turning on and before turning of by impressing feed voltage to 1st and 2nd input stages through current sources and connecting output to the inputs of an output stage in parallel with each other. CONSTITUTION: A current I from a current source A1 is supplied to corresponding in put stages 3, 4 of the AA through comparators 6, 7. When a muting circuit 1 is turned on, the current I is allowed to flow into transistors(TRs) T1, T3 so as to drive the 1st input stage 3 until the value of voltage Vd is held at a value less than the value of voltage VB. In the state, TRs T2, T4 are non-conductive and the 2nd input stage 4 is in an OFF state, so that a signal to be impressed to the input IN of the AA 2 is not transmitted to the output OUT. Thereby the AA 2 is held at a muted state.
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Inventors:
EDOARUDO BOTSUCHI
Application Number:
JP13940289A
Publication Date:
April 24, 1990
Filing Date:
June 02, 1989
Export Citation:
Assignee:
SGS THOMSON MICROELECTRONICS
International Classes:
H03G3/34; H03F1/00; (IPC1-7): H03F1/00
Attorney, Agent or Firm:
Hidekazu Miyoshi (1 outside)