LA4287 audio circuit diagram

Published:2011/10/17 22:05:00 Author:Rebekka | Keyword: audio circuit | From:SeekIC

TV sound signal isinput from the N601's pin 1, andAV audio signal is input from the N601's pin 3. The TV/AV switching signal output by CPU（40）feet bypassing the base ofR601 to V601. Thepin 4 isinverted by V601 chosen by the internal and output signal through N601 pin 9. Then itmakes the speaker sound. The shutdown audio squelch circuit is composed of V641 and V642. In the normal boot, 12V voltage passes R641, then it isadded to the base of V641 and the emitter VD642. Due to the existence of VD642, V641 base voltage is 0.7V, which ishigher than high-emitter voltage. V641 and V642 are stopped. The loop has no influence on volume control. 1 pin: 6.3V-- signal input 12 pin: 0V - to 3 pin: 6.3V-- signal input 24 pin: 2.1V-- signal switch 5 pin: 0.67V-- volume control voltage input6 pin: 9.8V-- Filter 7 pin: 9.8V-- Feedback 8 pin: 0V - to 9 pin: 9.9V-- output pin 10 pin: 21V - Power Supply



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