A wide conversion ratio, 92.8% efficiency, 3-level buck converter with adaptive on/off-time control and shared charge pump intermediate voltage regulator

An efficient cascode 3-level buck converter with adaptive on/off-time (AOOT) control and shared charge pump (CP) intermediate voltage ( V mid ) regulator is proposed and demonstrated. The conversion ratio (CR) V out / V in is enhanced by using the proposed AOOT control scheme, where the control switches between adaptive on-time (AOnT) and adaptive off-time (AOffT) mode according to the target CR. The proposed CP shares flying capacitor C fly and power switches in the 3-level buck converter to generate V mid = V in /2 achieving both small size and low loss. The proposed 3-level buck converter is implemented in a standard 0.25μm CMOS process. 92.8% maximum efficiency and wide CR are obtained with the integrated V mid regulator.