Design and analysis of a generalised n-stage current-mode multiphase switched-capacitor converter

Abstract

A new closed-loop generalised scheme for an n-stage current-mode multiphase switched-capacitor converter (CMSC) is proposed by combining multiphase operation and pulse-width-modulation (PWM) control for step-up DC–DC conversion and output current regulation. The CMSC is composed of n-voltage doublers and one constant current source in series. The n-voltage doublers are in charge of boosting output voltage, and combined with multiphase operation to provide voltage gain of 2 n at most. The current source is adopted mainly for supplying a constant current at the output terminal, and combined with PWM to reinforce output regulation as well as robustness to source/loading variation. The relevant theoretical analysis and design include: an n-stage CMSC model, steady-state/dynamic analysis, power efficiency, source lower bound, voltage conversion ratio, output ripple, capacitance and current source selection, closed-loop control and stability. Finally, the closed-loop CMSC is simulated, and the hardware implementation is realised and tested. All the results are illustrated to show the efficacy of the proposed scheme.