At 03:36 AM 7/9/2004, Russell McMahon wrote: >1. Produce hardware PWM variable from 0 to 100% at at least 20 kHz. > >2. Input to be an analog voltage SOMEWHERE in the 0 to 5 volt range. eg >may be 0 - 3 or 2.3 - 4.2 or whatever. I have some very old single-sided board layouts that do this for 8 channels. Its all analog using LM339 comparitors (I think) fed by a ramp. The original application was for phase control lamp dimming but I recall using it at several KHz for at least one project. I don't know how well it works at supersonic frequencies and the output stages would need to be re-worked for FET drive (add 1 transistor, diode, resistor for each output). But it may be a starting point. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 20 years of Engineering Innovation (1984 - 2004) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu