Designing the Digital Compensator for a UCD91xx-Based Digital Power Supply

ABSTRACT This application report discusses a UCD91xx-based digital controller design for a high-frequency dc-dc switching power supply. Starting with a dc-dc buck converter power stage and a given set of performance specifications, different control blocks and parameters, used as in the analog control design approach, are reviewed prior to the digital controller design. The control loop is then analyzed and the digital controller is designed using the well-known PID controller template. Design examples are provided and validated with test results from prototype converters.