Re: gEDA-user: CR2032 with supercap, was Re: [SOT] suggestion for a SMT switch

[andrew whyte <ajwhyte@xxxxxxxxx>]

 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)


-- 
╒═════════════════════════════════════════════╕
     Andrew Whyte MEng CEng
               paramita ltd
╘═════════════════════════════════════════════╛


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