Best way to generate +5V from +15V?

[dar303]

If I were to incorporate a small PIC into an existing analog design, what would be the most power effective way to do it? The processor and associated circuitry shouldn't draw more than 20-50 mA. A standard 7805 isn't the most effective I guess, any better ways?

[blue hell]

Most power efficient would be to have a little switcher, but that might send some HF into your analog circuits when its not done correctly. When you're not up to that it probably would be best to allow for 200 ... 500 mW to go up into heat in the 7805.

20 .. 50 mA seems a bit much for a PIC BTW, typically they do around 4 mA @ 10 MHz I think?

[dar303]

Thanks!
Most microcontrollers are very power efficient and i'm just allowing for some more current draw for analog switches and other possible ic's on the +5V line.