Zero-current switching switched-capacitor quasiresonant step-down converter

Current stress is usually high for conventional switched-capacitor converter circuits, because of short-circuiting when charging up the capacitors. In this paper, two zero-current switching switched-capacitor resonant step-down converter families are presented which can improve the current stress problem. They are able to provide 1/2 to 1/n, and -1 to -1/n conversion ratios respectively by using only two switches. Principles of operation, computer simulation and experimental results of the proposed converters are presented. The measured efficiency is high and all parts of the circuits are under zero-current switching conditions.