Jinx wrote:
>> Why can't the PIC run from the 3V supply too ?
>
> IMHO 3V is just too low for that circuit. If the high- and low-side
> drivers each drop a volt (the 2003 at least has Darlington outputs),
> after the current-limiting resistor that leaves crumbs for the LEDs.
> And the LEDs are an important part of this project

I agree the LEDs need a reliable higher voltage, which is why I suggested to
use a step up converter for the LED supply.

Since most of the battery power will go into LEDs, I also think the LED
drive circuit should be designed for efficiency.  Dropping a volt in either
high or low side drivers is way too much, and totally unnecessary.  Off the
shelf darlington drivers are definitely not the way to go in this case.


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