Zero-current-switching multilevel modular switched-capacitor dc-dc converter

This paper presents a quasi-resonant technique for multilevel modular switched-capacitor circuit (MMSCC) to achieve zero-current-switching (ZCS) without increasing cost and sacrificing reliability. This zero-current-switching multilevel modular switched-capacitor circuit (ZCS-MMSCC) employs the stray inductance existing in the circuit as the resonant inductor to resonate with the capacitor and provide low dv/dt and low switching loss for the device. The ZCS-MMSCC does not utilize any additional components to achieve ZCS and solves the current and voltage spike problem during the switching transition, thus leading to reliable and high efficiency advantages over traditional MMSCC. Furthermore, the ZCS-MMSCC reduces the capacitance needed the circuit; in this case, the bulky capacitors present in traditional MMSCC to attain high efficiency is not necessary any more. A 150 W four-level ZCS-MMSCC prototype has been built. Simulation and experimental results are given to demonstrate the validity and features of the soft switching switched-capacitor circuit.