On 5/16/06, Harold Hallikainen wrote: > > We currently have several products running off an unregulated external > 12VDC power supply (wall wart). Inside our product, we run through a > 1N4001 for reverse polarity protection, then 1n LM7805 to regulate to +5V > (to run the PIC!). Upcoming California Energy Commission regulations > outlaw these external power supplies (due to lack of efficiency and > standby power). You're going to have to feed them at least 8-9V depending on the load, so that the regulators are in regulation. 12V would be a waste, but you won't get away with 5 unless you jump out the internal reg. We could replace these with 12V regulated switchers, but > that is pretty inefficient. What I'd like to do is replace them with > external 5V switchers, yet continue to allow the use of the old power > supplies. You'd have to have different plugs or something, so that the old supply into a new board dosen't end up in a barbecue. It would be great if there were an LDO equivalent of the TO-200 > LM7805 with reverse polarity protection (so I could get rid of the diode > and its drop). Anyone aware of a drop-in replacement? Having a series diode would pretty much kill the whole LDO thing. I've never seen one with internal RP protection like that. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist