I have a circuit that works from 3.8 to 5.2Vdc, some tests were done to
try to feed some extra micro or milliamps to the VDD via an input pin,
connected to another machine that supply its data lines with steady TTL
5V or zeroV. The idea was to "steal" this small current back into my
circuit VDD, when its battery was low. Primarily we used Schoktty
diodes from the data lines to VDD
I assume this was a PC or other parallel port. I was curious to find if the
circuit did work well with the Schoktty diodes in place. Were you able to
actually charge the internal battery? Did the circuit work until the data
lines were all low for enough time for the power caps to discharge? I've
tried a few things like this in the past with ...no.... success. For the
next project I am looking into the new complex battery management switching
power supply chips. Cost is less important that reliable operation. Any
input or experiences would be appreciated
James Newton, webmaster http://get.to/techref
jamesnewton@geocities.com
1-619-652-0593 phone