andrew whyte wrote: > I know that this isn't very sporting, but I honestly can't remember... > > Rather than spending a long time on worrying about supercaps why not > stack two coin cells in series and have a little LDO from 6V to 3V3, > the LDO wouldn't be efficient when your running 100mA, but for 1s that > wouldn't be much of a problem, the rest of the time your PIC could run > efficiently. Better still, you could run the motor straight off the > batteries (with PWM) so that they droop, but the LDO & PIC isn't > affected. Run the LDO at the lowest possible voltage (2.7V) to > minimise the chance of brown out. > > There are plenty of tiny LDOs in SOT23-5 footprints etc. if space is > a problem. You should really still have bulk capacitance (or at very > least put the footprints down for it) >
I tried stacking coin cells when I first started this whole she-bang. The problem I ran into were the physical constraints. I only have enough height above board for a single 2032, or two 2016's. The increase in voltage was good, but the drop in capacity killed me (220mAh down to 70 mAh). thx, Jason. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
