Ladder Multi-resonant Switched-capacitor Converters with Extended Voltage Gain Range

The traditional ladder switched-capacitor converter (SCC) has limited voltage gain range, sacrificing the overall efficiency severely to extend the voltage gain range. In this paper, Ladder multi-resonant switched-capacitor converters (MRSCC) with extended voltage gain range are proposed. By adding the multi resonance core and adopting the on-time fixed frequency modulation, a "charge balance" state with overlapped resonant currents is introduced. Consequently, the conversion ratio of the Ladder RSC can be regulated continuously, widely and efficiently even at light load condition. In addition, all transistors can be turned on with zero-current-switching (ZCS) operation and all diodes can be turned off with ZCS operation. Moreover, the complete soft-charging operation between capacitors is obtained, eliminating the charge-sharing loss effectively. A comprehensive analysis of the operation principle, voltage-gain curve and component stress is presented. An open loop prototype was built to verify the operation of the converter.