> >>I can't find it now. I'd like to avoid adding diode drops in front of
the
> >>regulator to get a bit more battery life. Anyone remember seeing such a
> >>regulator?

If you used a PFET in series with the battery you could get a very low
voltage drop. Bias it on with a resistor gate to ground and have the
wall-wart supply turn it off as it can provide a positive (off) gate bias.

A bipolar PNP transistor used in a  similar mode could have an on  forward
voltage drop far lower than a diode. Some of the small Zetex high gain low
saturation zline transistors would be ideal, but an eg BC327 would probably
be adequate for many purposes.


        RM

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads