Multiratio-Multiresonance Switched-Capacitor Step-Down Converter for DC Bus Voltage Conversion

For improving the voltage regulation capacity of resonant switched capacitor converters and satisfying the requirement for high power conversion efficiency and power density of emerging power electronic systems, a multiratio-multiresonance switched capacitor converter is proposed in this article. The studied topology can be divided into three switched capacitor submodules with a similar structure, and 21 effective combinations with different discrete voltage conversion ratios can be derived by combining the submodules with different operational modes. The voltage stress, the current stress (on the basis of charge balance method), the theoretical power conversion efficiency, and the number of switching actions are provided and compared comprehensively for the combinations with the same voltage conversion ratio. Moreover, for the selected combinations, the configuration of switching pulse signals is presented, and the studied topology can achieve various output voltages with no extra consumption of the controller resources. Finally, a prototype (with 48 V input voltage, 200 W output power, and 1/8, 1/7, 1/6, 1/5, 1/4, 1/3, 1/2 voltage conversion ratio) is built and tested to verify the principles and characteristics. The built prototype can achieve 98.96% peak efficiency with a small size.