An Integration Method of Resonant Switched-Capacitor Converters Based on Parasitic Inductance

The parasitic inductor can be used as resonant component to increase the power density in resonant converters. However, the parasitic inductance value of PCB copper traces is not large enough to achieve zero current switching in low and medium switching frequency conditions. To tackle this problem, a novel integration method to increase parasitic inductance value is proposed in this letter. The proposed method is based on direct coupling, which utilizes lateral structure and vertical structure to increase equivalent inductance between two parasitic inductors. The proposed method not only can achieve high efficiency, high power density, and very low profile design, but also can save the cost and space of discrete inductors for the designed prototype in low and medium frequency range. The comparison and design procedure of both lateral and vertical structures of the parasitic inductor are presented in details. Two 100-W prototypes employing gallium nitride devices are built to compare the discrete inductor solution with the proposed parasitic inductor integration method. The power density of the prototype using parasitic inductor is 62.5% higher than discrete inductance and has achieved a peak efficiency of 93.4%.