A Multiple-Modes Resonant Switched Capacitor DC/DC Converter With Variable Voltage Ratios

High step-down dc/dc converters with high efficiency and high power density are widely used in data centers, dc distribution grids and hybrid electric vehicles. In this article, a new resonant switched capacitor converter is proposed, which can not only realize high step-down conversion, but also operate in multiple-modes to achieve various voltage ratios. The duty cycle can be allocated to one-half and one-third, enabling the converter to operate in double-mode and triple-mode accordingly. In addition, the state of the basic resonant cell can be switched between series and parallel, which enriches the operating modes, and thus allowing the converter to achieve different voltage ratios. Furthermore, the principle and strategy of switching between operating modes with different voltage ratios and switching between operating modes with same voltage ratio are presented. With the mode switching strategy, this converter can operate in the optimal mode over the wide voltage range and the full load range, thus achieves high efficiency over the full operating range. Finally, five operating modes are selected to verify the feasibility and the correctness of the theoretical analysis