An integrated switched capacitor coupled inductor Buck-Boost DC-DC converter

Abstract

This paper focuses on the Buck-Boost converter and presents a new approach to improve its efficiency and voltage transformation capability. The approach involves introducing a coupled inductor structure and restructuring the quadric front-end unit to ensure continuous input inductor current. The converter also uses a diode-capacitor (D-C) double-branch structure of switched capacitors to expand the output range and reduce voltage stress on each device. In addition, the converter utilizes the leakage inductance energy to suppress the current surge in the switched capacitor, achieving soft switching. The paper provides a detailed theoretical analysis and compares various indicators horizontally in different converters. Moreover, an experimental prototype of 200W was built to verify the design expectations and theoretical analysis through experiments.