A Step-up Series-parallel Resonant Switched-capacitor Converter with Extended Line Regulation Range

In this paper, a step-up series-parallel resonant switched-capacitor converter is proposed featuring two resonant inductors with two resonant path. A series-parallel switched-capacitor cell is applied to extend the conversion ratio for high voltage gain applications. The modified Cuk dual resonance core provides a unique merit of resonant operation for all flying capacitors. Due to ZCS turn-on of switches and ZCS turn-off of diodes, the high transient current spikes are eliminated and switching loss is reduced. Moreover, the small capacitance of flying resonant capacitors is implemented with reduced volume and high power density. By adopting the on-time fixed frequency modulation, a wide and continuous line regulation is achieved with high efficiency. A comprehensive analysis of operation principle, voltage-gain curve, voltage and current stress are given. A 50V~145.9V prototype with maximum 150W was built to verify the converter feasibility and voltage regulation capability.