Monolithic Capacitive DC-DC Converter With Single Boundary–Multiphase Control and Voltage Domain Stacking in 90 nm CMOS

Abstract

Monolithic integration in CMOS has boosted the development of low cost, compact and portable consumer applications. But until now the monolithic integration of DC-DC converters is still omitted in commercial applications. Primarily due to the need for high-efficiency converters and appropriate techniques to control high-frequency capacitive DC-DC converters. This paper presents a fully integrated capacitive step-down DC-DC converter in 90 nm CMOS with an output power capability of 150 mW, a peak efficiency of 77% and a full load efficiency of 74%. The DC-DC converter is controlled by a Single Boundary-Multiphase Control (SB-MC). This control method provides a low power solution for controlling multiphase capacitive DC-DC converters without compromising the control loop bandwidth. This paper describes the design, implementation and measurements of the DC-DC converter.