High-Gain Serial-Parallel Switched-Capacitor Step-Up DC-DC Converter

A closed-loop scheme of high-gain serial-parallel switched-capacitor step-up converter (SPSCC) is proposed by combining a phase generator and pulse-width-modulation (PWM) controller for step-up DC-DC conversion and regulation. The SC-based converter needs no magnetic element, e.g. inductor and transformer. In this SPSCC, there are two 3-stage SC cells in cascade between source Vs and output Vo, where each cell has 3 pumping capacitors. By using these capacitors charging in parallel and discharging in series, plus the front-stage voltage connected in series, each SC cell can be treated as a small step-up converter with a 4x voltage gain. Thus, this SPSCC is able to boost Vo to 4x4 times voltage of Vs at most just with the fewer number of pumping capacitors (6 totally). Further, the PWM technique is adopted not only to enhance the output regulation for the compensation of the dynamic error between the practical and desired outputs, but also to reinforce output robustness against source or loading variation. Finally, the closed-loop SPSCC is designed by OrCAD SPICE, and simulated for some cases as: (1) steady-state response, (2) dynamic response (source/loading variation).