Methods of Reducing the Intrinsic Loss for Continuously-Scalable-Conversion-Ratio SC Converters

This paper investigates the intrinsic loss in the continuously scalable conversion-ratio (CSCR) switched-capacitor (SC) converters and examines the relationship between the intrinsic loss and charge-sharing loss. Methods of reducing the intrinsic loss of CSCR SC converters are proposed. The study reveals that decreasing the size of the output decoupling capacitor improves efficiency but increases output voltage ripple. Design considerations for the output decoupling capacitor are also proposed to assist in the circuit design of the CSCR SC converter. Both calculation and simulation results validate the proposed methods. The simulation results show that 2% efficiency improvement is achieved by reducing the output decoupling capacitor from 500 nF to 0.5 nF with a 2 nF core flying capacitor and 2 A output current.