How to achieve higher PWM duty resolutions for a given PWM frequency?
I am trying to increase the PWM resolution in a dc-dc converter I've been working on. The PWM frequency is around 100KHz meaning that the PWM timer load value is 199 (up-down count mode) at 40MHz TCY. This gives me only a particular amount of PWM resolution and have found that it is not good enough for the converter. Is there a way I can create a 100KHz at higher count values? That is, a PWM timer load of 1000 instead of something as small as 199?
I understand that the FOSC of the primary PLL cannot be increased over 80MHz (FOSC = 40MHz), but I just realized that a dsPIC has an auxiliary PLL, is there a way I could direct the PWM module to use this source as the clock source instead of a Primary PLL that has a 40MHz limit?