Analysis of Two-Stage Topologies with Buck and Switched-Capacitor Converters for Ultra-High Efficiency POL Applications

This paper presents a comparative study of the two-stage Point-of-Load (POL) converters combining Buck and Switched-Capacitor converters with switched-tank converter (STC) or cascaded resonant voltage divider (CVD) as the core. The operation principles of the STC and CVD are introduced, and several two-stage step-down DC-DC POL converters with different topologies are obtained. The power loss composition and system efficiency evaluation are provided for different POL converters(5V to 1V). The POL converter that BUCK cascading STC with 4 times input-to-output conversion ratio is more efficient at full load. The hardware prototype of BUCK cascading STC(4:1) is developed and tested, the experimental results show that the POL converter with the new topology proposed in this paper has a good performance and can achieve high efficiency.