PWM

This PWM came straight from the datasheet except Im using Pot inplace of a resistor. Pot attached to the capacitor controls the Pulse Width and Frequency. Some other changes as well to change thw frequency range. Adding a second Pot instead of the resistor allows control of the amplitude of the wave form and the duty cycle. It can be tedious to tune the frequency and duty cycle your looking for but it works well Frequency range 150 KHZ - 550 KHZ after about 85% on Pots Wiper Frequency Falls off to 5 KHZ not sure why this happens but the functional range of 150 KHZ to 550 KHZ i think is good. Larger Capacitor lower frequencies are possible the smaller the capacitor the higher the frequency as the capcitor charging and discharging has alot to do with your total frequency range Its frequency and response change when time of simulation changes which is a bug in software. I want someone to argue that this is wrong straight fro. Texas instruments datasheet. This bug has also been confirmed by my oscilloscope. Frequency does not change in different time situations but the waveform does. At 10uS time on oscope you get the square modulation higher timing you get the square wave but in a bigger wave that looks like the sqaure waves create a large sine wave.

published 8 years ago