Design and Implementation of a Digital PWM Controller for a High-Frequency Switching DC-DC Converter

This paper describes complete design and implementation of a digital controller for a high-frequency switching power supply. Guidelines for the minimum required resolution of the analog-to-digital converter, the pulse-width modulator, and the fixed-point computational unit are derived. A design example based on a buck converter operating at the switching frequency of 1MHz is presented. The controller design is based on direct digital design approach and standard root-locus techniques. Experimental results are shown to validate the design approach and the allocation of resources (resolution) in the implementation.