> If you have to use a PIC, you could make a simple voltage booster,
> again using a voltage divider to feed back and linearise the response.
> The PIC could be the oscillator and handle the ADC work etc and a
> bipolar or small FETs to drive the boost choke..

I think I'm more comfortable with a PIC rather than pure analogue.
What you describe is similar to the workings of a boost regulator IC,
which compares the output to an internal reference and adjusts the
switch duty cycle. Slightly different to my initial idea, good suggestion
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