A Novel ZVT Switched-Capacitor Converter for the Input-Stage of a Cascaded Two-Stage 48 V VRM

Switched-capacitor converters are being widely used in high conversion ratio applications due to their high power density and lower cost. This paper proposes a novel Zero-Voltage Transition switched-capacitor converter for the input-stage of a cascaded two-stage 48 V Voltage Regulator Module. The proposed converter adds a small inductor to the 6-to-1 Dickson switched-capacitor converter driving an inductive load and achieves soft switching for most of the switches, which allows it to efficiently operate at a high switching frequency. The proposed converter uses lower voltage and current rated switches which further increases the efficiency of the converter. The detailed operation of the proposed converter is presented. Thereafter, a 48 V to 8 V, 10 A laboratory prototype is implemented to experimentally verify the performance of the converter. The experimental results show that the converter can achieve a peak efficiency of 98.3% at 4 A and a full load efficiency of 94.4% at 10 A.