A Family of Zero Current Switching Switched-Capacitor DC-DC Converters

This paper presents a new zero current switching (ZCS) technique for a family of switched-capacitor dc-dc converters. Compared to the traditional ZCS switched-capacitor dc-dc converters by inserting a magnetic core in the circuit, these new ZCS switched-capacitor dc-dc converters employ the stray inductance present in the circuit as the resonant inductor and provide soft switching for the devices. These ZCS switched-capacitor dc-dc converters do not utilize any additional components to minimize switching loss and reduce the current and voltage spike, thus leading to high efficiency and reliable benefit over traditional switched-capacitor dc-dc converters. Moreover, the bulky capacitor bank existing in traditional switched-capacitor circuits for high power high current application to achieve high efficiency was reduced significantly. Small size, low capacitance, low ESR, high current rating and high temperature rating ceramic capacitors can be employed. Therefore, by using proposed ZCS technique, small size, high power density, high efficiency, high temperature rating, and high current rating switched-capacitor dc-dc converter could be built. Simulation and experimental results are given to demonstrate the validity and features of the soft switching switched-capacitor dc-dc converters.