A High-Performance 3:1 Conversion Ratio DC-DC Converter: Analysis Method and Modular Adoption

With the increasing demand for power supply in data centers, resonant switched-capacitor converters with high power density and high efficiency have been widely studied and applied. In this article, a 3-to-1 high-performance switched-capacitor converter is proposed, and optimizing methods are investigated to improve its performance. First, a detailed analysis of its working states under different modes is conducted. Second, the state-plane analysis is conducted to obtain the relationship between its state variables and various circuit parameters. By utilizing these relationships, the circuit parameters are optimized and designed, increasing the efficiency under zero voltage switching (ZVS) mode. Third, using the proposed 3-to-1 circuit structure, a cascaded switched-capacitor converter with a step-down ratio of 6-to-1 is constructed. In order to verify the theoretical analysis, a 48-to-8 V experimental prototype is built. The experimental prototype achieves 1078 W/in³ power density. Its peak efficiency reaches 97.4%, and full-load efficiency reaches 94.2%.