Step up voltage for PIC.

[nath]

I was just wondering if anyone would know the simplest way to step up a 2.4v dc supply to around 4v dc (dosnt need to be exact) with the smallest ammount of compnents and cost. I have tried:

http://www.emanator.demon.co.uk/bigclive/joule.htm

Dosn't seem to do the job.

Any suggestions?

[Ttelmah]

Look at the MAX1674.
The circuit you post, is capabe of providing a supply, but stability will be poor, wih no regulation. If the load, or input voltage change, you risk applying too much voltage to the PIC and potential damage, or having the rail droop, lowering reliability.

Best Wishes

[treitmey]

I would try a charge pump. TC7662
http://ww1.microchip.com/downloads/en/DeviceDoc/21468b.pdf
see figure 4-6 voltage doubler.