Design Considerations and Dynamic Technique for Digitally Controlled Variable Frequency DC-DC Converter

A dynamic algorithm to avoid limit cycle oscillation problems and to improve stability in digitally controlled power converters with variable switching frequency operation is presented in this paper. Employing Variable switching frequency at light loads is one way to improve the efficiency of DC-DC converters. However, varying the switching frequency digitally introduces additional considerations that do not exist in variable frequency analog controllers. In this paper a dynamic algorithm to maintain system stability and dynamics at different switching frequencies and to avoid limit cycle oscillation problems is discussed and experimentally verified.