Alternative topologies for the low-voltage buck converter

Abstract

In this thesis, investigative work on and development of alternative topologies for the buck converter for low voltage dc dc conversion was performed. The three level buck, Resonant Switch Capacitor (ResSC), and Cuk-Buck2 were selected to be studied further based on the fact that they contain few components and were discovered in this work to have the possibility of operating at fixed frequency while smoothly regulating output voltage over the entire conversion ratio of 0 to 1. All three use a capacitive storage element in addition to a small inductance/s, so it was believed this may allow for efficiency or density improvements due to the excellent energy storage capability of MLCCs. New control methods were developed in order to operate the ResSC and Cuk-Buck2 at fixed frequency over the entire output range. New work was done to in order to achieve flying capacitor balancing in the ResSC and Cuk-Buck2, practical for future implementation in a monolithic converter. Simulated efficiency and other characteristics of the three converters are compared. Prototypes were built and used to confirm functionality of the new control schemes and balancing methods..