Thomas Walsh

Creating a high-frequency PWM from a low-frequency PWM

Discussion created by Thomas Walsh on Sep 15, 2010
Latest reply on Sep 16, 2010 by Thomas Walsh

This is more of a general EE question than an 8-bit MCU question, but one that folks here might have good insight on.


For many applications (eg. switching power supplies) it is useful to have a PWM in the >500 kHz range, with a duty cycle that can be finely tuned.  A typical MCU is not fast enough to provide this signal off of the main bus clock.


Is there a cost effective way to implement a PWM operating at 500 kHz, finely variable duty cycle, with an MCU?  Say, by converting (directly or indirectly) a 500 Hz PWM from the MCU into a 500 kHz signal using an external IC, or simply a crystal oscillator with some clever analog circuitry?


I have been googling around on this and have found some rather inelegant possible solutions, but I was wondering if anybody had quick advice here.