Design Method of Vertical Lattice Loop Structure for Parasitic Inductance Reduction in a GaN HEMTs-based Converter

Abstract

Among the wide-bandgap devices, gallium nitride high electron mobility transistors (GaN HEMTs) are contributing to the high power density technology of power conversion systems due to their excellent physical properties. In contrast, the driving voltage and threshold voltage are relatively low compared to conventional power semiconductor devices, so a reliable circuit design is required. In this paper, a parasitic inductance reduction design method for the stable driving of GaN HEMTs is proposed. To reduce parasitic inductance, we propose a vertical lattice loop structure having multiple loops, and this method can be applied regardless of the package type and shape of GaN HEMT. For the design of the proposed vertical lattice loop structure, the reference loop is defined to minimize leakage inductance and the identical loop is vertically stacked. The proposed structure is applied 6-layer PCB design example and verified by experimental results. Furthermore, the proposed design method is applied at the buck converter, and improved efficiency is verified from 600 kHz to 1MHz switching frequency.