Hi John


>I have a PIC controlled circuit that also includes an LM386 audio
>amplifier. When I put the PIC into sleep mode, I'd like to eliminate the
>power drain of the amp. I can use a relay to do this but I figure that
>there is probably some very clean solid state way to accomplish this.
>Any ideas?


    Sure!! Use a TIP31 or some other medium to high power bipolar PNP
transistor as a saturated common emmiter. Then tie the base to one of the
PIC's output! Don't forget the biasing! You should not use the divider
configuration; use a single resistor instead. The Vce(sat) commonly is
around 0.4V so the voltage drop will be small. The base current may get a
little high. If it occurs, use a 2N2222 to drive the base (you may use the
Darlington configuration for this).

    The collector will be tied to the Vee pin of the LM386; the emmiter to
the Vdd pin of the PIC. When there is a logical 0 at the base, the collector
will cut the power!


    I'll send some drawings of the  circuit for you... The analisys is quite
straightforward, but if you need help I can explain...



    Rafael Pinto