>
> > > I built a nice little bench supply with a PIC running a P-Channel pass
> > > transistor, threw in an inductor and a capacitor and two pushbutton
> inputs
> > > to the PIC.  The PIC senses output voltage, and turns the pass
> transistor on
> > > and off.  The two pushbutton inputs run the setpoint up and down.  A
> little
> > > digital panel meter serves as the interface, you just push the UP
> button if
> > > you want the voltage higher, etc.  None of the part values seemed to
> be very
> > > critical, worked pretty good first time with junk parts off my bench.

I'm doing a NIMH battery charger with an AVR Tiny 15.
It has a 28 MHz clock for the PWM (no xtal, just internal osc), so I can
run quite fast.
Current design is for 6A output.

There is an AVR reference design for this, but the software isn't very
sophisticated.

Adding a 4066 lets me reprogram the AVR in system, from the main processor,
or change the charger's behaviour on the fly.

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