A General Method for Analyzing Single-Switch Step-Up DC-DC Converters With Switched-Capacitor Cells and an Output Inductor

Integration of the voltage multiplier cells (VMCs) with conventional step-up converters provides a higher voltage gain and lower voltage stress on the power switch. However, the output diode of the VMC cells usually withstands high voltage stress, which may cause reverse recovery power loss and electromagnetic interference issues. Also, the pulsating current of the output capacitor increases the required capacitance at the output. In this article, replacing the output diode of the basic VMCs with an inductor is investigated, and general forms of the voltage gain equations are derived. Moreover, the effects of the inductor value on the circuit operation are explored. Furthermore, the integration of the input and output inductors into one core has also been studied, showing that VMCs integrated into a conventional boost converter could achieve zero current ripple at input by using a coupled inductor. To validate the analysis, a 200 W, 40-200 V experimental setup is developed in the laboratory and the experimental results when using a diode and an inductor at the output of a VMC are presented.