I remenber a 20 year old electronics magazine with a design for this
     using only bipolar transistors, so MOSFETS are not necessarily
     required.

     Actually, the easiest way to do what you want is to charge a _single_
     capacitor to 12V across the input supply, then switch both capacitor
     poles so the -ve end is now connected to the +ve input supply, and the
     +ve end of the cap is now at 24V.  Dump this voltage to another cap
     and you have your 24V output.

     Note that because of various circuit losses, at 1A you are unlikely to
     get a full 24V output.


     CIAO - Martin.


______________________________ Reply Separator _________________________________
Subject: [OT] Doubling 12 volts...maybe use a 8-pin PIC!
Author:  pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> at
Internet
Date:    5/28/98 9:04 PM


I need to double a 12VDC input to get 24VDC at .5 - 1A.

This can be done, I'm sure, but how?
I think the basic concept is, you charge two capacitors in parallel,
then discharge in series.

What type of switches (MOSFETS?) do I need, and how many.
Any pointers to analog info would be much appreciated.