Typical application circuit diagram LA4287 audio power amplifier circuit

Published:2014/1/13 0:31:00 Author: | Keyword: Typical application circuit diagram LA4287 audio power amplifier circuit, LA4287 | From:SeekIC

TV audio signal from ( 1 ) pin input N601 's , AV audio signal from ( 3 ) feet of the input N601 , CPU (40) pin output TV / AV switching signal via the base of R601 to V601 , V601 inverted by the after controlling N601 's ( 4 ) feet , after an internal selection ( 9 ) pin outputs an audio signal from the N601 , pushing the horn sound. V641, V642 audio squelch circuit consisting shutdown : normal boot , 12V voltage is applied through R641 base V641 , V641 has been added to the emitter VD642 , VD642 because of the presence of so than the base -emitter voltage V641 high voltage 0.7V, V641 deadline , V642 also cut , this circuit has no effect on the volume control , then, the C641 is near the 12V charging voltage . After the shutdown , 12V voltage disappears , since the case is filled with the C641 12V voltage , so the base voltage V641 is lower than the emitter voltage , V641 conduction , V642 is also on, the volume control voltage is shorted to ground , to achieve a static off noise .LA4287 pin functions and reference voltage: Pin 1 : 6.3V-- Signal Input 1 Pin 2 : 0V - ground Pin3 6.3V-- Signal Input 2 Pin 4: 2.1V-- signal switch Pin 5: 0.67V-- Volume control voltage input Pin 6: 9.8V-- Filter Pin 7: 9.8V-- Feedback Pin 8: 0V - ground Pin 9: 9.9V-- Output Pin 10: 21V - Power Diagram LA4287 typical audio amplifier circuit shown in Figure



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