Efficiency improvement of integrated synchronous buck converter using body biasing for ultra-low-voltage applications

This article presents an integrated synchronous DC-DC buck converter for ultra-low-voltage and low-power applications with 200 mV-1 V input and 100 mV-500mV output in 45 nm CMOS technology. The proposed design uses over & under driving (OUD) and adaptive body biasing (ABB) methods to enhance the efficiency. In the proposed design, a control circuit with the least possible number of transistors is proposed which changes power MOSFETs threshold voltages adaptively depending on their operating modes by applying voltage to the body of the MOSFETs. The proposed method improves the conduction and switching losses simultaneously which achieves peak efficiency of 93%. The proposed converter has an acceptable performance and efficiency in sub-threshold voltages and also in the wide output current range.