Switching Capacitor PWM DC/DC Converters and Its Variations

This paper proposes novel switching capacitor PWM converters. The converter is a combination of a switching capacitor converter and a PWM converter, and it has the following advantages: (1) Zero voltage switching of all the MOSFETs. (2) Using an auto transformer self-driven method to eliminate SR drivers and save driver loss. Therefore there is no need to adjust the synchronous rectifier (SR) control timing, and this reduces body diode conduction loss. (3) Its efficiency is not sensitive to leakage inductor, so that the discrete transformer can be used and it is suitable for both VRM and VRD application. (4) Single phase option makes it more flexible, and it can achieve higher efficiency in whole load range with phase shedding control strategy. A 700 kHz 1.2 V/35 A POL prototype and a four-phase 700 kHz 1.2 V/130 A output VRM prototype were built to verify the analysis.