New PWM Control Method of Resonant Switched Capacitor DC-DC Converter

Resonant switched capacitor converter (RSCC) has the advantage of zero-current switching, however, the regulation of output voltage is poor. A new PWM control method for RSCC is presented in this paper. In the proposed method, the discharging time is fixed and the charging time is variable, good output voltage regulation for large changes in input voltage and/or load values can be obtained by adjusting the ratio of charging time. Almost all switching devices keep zero-current switching. The proposed PWM scheme has the advantages of low switching current and low EMI. A step-down RSCC is used as an example in this paper. The circuit operation principle and steady-state characteristics are described in detail. A 12V/5V/2A prototype based on the proposed method has been implemented, theoretical prediction of its regulation is verified experimentally.