A closed-loop scheme of 2-stage multiphase switched-capacitor (MPSC) converter is proposed by combining variable-phase control (VPC) and pulse-width-modulation (PWM) technique for low-power DC-DC step-up conversion and high-efficiency output regulation. In this MPSC, there are 2 voltage doublers in series for boosting voltage gain up to 4 at most. Here, VPC is suggested to improve power efficiency, especially for the lower output voltage. It realizes a variable multiphase operation by changing MPSC topological path for more suitable level of voltage gain (4x/3x/2x/1x) according to the desired output. Besides, PWM is adopted for better output regulation not only to compensate dynamic error, but also to reinforce robustness against source/loading variation. Further, the theoretical analysis and design include: MPSC model, steady-state analysis, power efficiency, conversion ratio, ripple percentage, capacitance selection, stability, and control design. Finally, the closed-loop MPSC is simulated, and the hardware implementation is realized and tested. All the results are illustrated to show the efficacy of the proposed scheme.
