A PWM generator system provides improved duty cycle resolution using a sub-cycle generator for generating a sub-cycle with a period that is a small fraction of the maximum PWM period to be generated. An integral sub-cycle estimator is coupled to said sub-cycle generator for determining the integral number of said sub-cycles for on and off time of the PWM waveform. An additional sub-cycle estimator determines the additional fractional sub-cycle required to provide the on and off time. A timer coupled to the integral sub cycle estimator and the additional sub cycle estimator controls PWM output switching for the on and off time of the integral and additional fractional sub cycles.