I am scratching my head how to power an RTC chip (apr. 3uA) and I think I'll drop all these NiCd or NiMH rechargables and use a lithium battery which should last for 7 years (and costs 5-6 times less).
Now I began thinking what will happen if I use a Shottky diode, say, a BAT43 to draw power from the battery while the system is off. It will work this way, no doubt about that. But when the system is on - and if the diode gets hot - it may try to "charge" the battery with some microamps, perhaps tens of microamps (battery being some 20mm diamater lithium thikish button cell). The diode is specified at 100C and 25V reverse voltage at a max. of 100uA.... Will the battery endure this? Now it will clearly be less, the diode will be exposed to perhaps 1 or 2 volts max., but I don't know what the reverse current would be then and frankly I will be equally in the dark if it is 1 uA, I just don't know how the lithium button cells behave.
Thanks,
Didi
------------------------------------------------------ Dimiter Popoff Transgalactic Instruments
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