Quote Originally Posted by Melanie View Post
Here's a voltage doubler... 0-5v input (use 0-100% PWM from PIC), will produce 0-10v Output. To calibrate, output 5v from PIC (100% PWM) and adjust R2 for exactly 10v Output. For cheapness and to dispense with calibration, replace R1 and R2 with a single 1K5 Resistor, but all Reistor tollerances should in that case be 1% or better. Can't really get any cheaper than this... op-amp is about as low-cost as you can get at around 20 cents. You end up with a spare Op-Amp, configure it as your 5v Regulator to supply the PIC and dispense with the 78L05 or whatever you were planning to use.

Melanie
@Melanie,
Voltage Doubler working perfect for me, but i had to change R4(10k to 1k),PWM produces 3+ volts only from PIC if i use 10k as per your schematic..i dont know whats wrong with my circuit..
And would like to dim gradually a 5watt led x 2, could pls help me which power transistor needs to be used.
Thanks a lot.