A Capacitively-Isolated Dual Extended LC-tank Hybrid Switched-Capacitor Converter

Abstract

This work introduces a resonant Dickson-type converter topology whose flying capacitors provide dielectric isolation between input and output terminals. For even conversion ratios, it achieves complete soft-charging of all of its flying capacitors with a convenient 50% duty cycle. Additionally, switch count is reduced relative to prior work and no distributed bypass capacitor column is required. Moreover, this topology actively drives both of its inductors without the requirement for mutual coupling between magnetic elements. A discrete 4:1 hardware prototype designed for 48 V up to rectified US mains applications is demonstrated and achieves a high power density of 2,010 W/in3 with a 140 V input voltage and 941 kHz switching frequency.