Single-turn Air-core Integrated Planar Inductor for GaN HEMT-based Zero-Voltage Switching Synchronous Buck Converter

摘要

Gallium nitride (GaN) high electron mobility transistor (HEMT) has a lateral device structure with a wafer-level packaging, which is advantageous in minimizing parasitic parameters and the overall device size. The wafer-level packaging also provides better thermal performance than the conventional packaging due to low junction-to-case and junction-to-bottom thermal resistances. When a printed circuit board layout is optimally designed, copper traces and pours in the vicinity of the switching devices can serve as effective heat dissipation channels. In this paper, a synchronous buck converter with a single-turn air-core integrated planar inductor is proposed to achieve both quasisquare wave zero-voltage switching (QSW ZVS) and high thermal performance of the GaN HEMTs in high-frequency operation. The integrated planar inductor which is directly connected to the GaN HEMTs serves as a heat dissipation channel to maintain the device temperature low enough without any additional heat sink. Three different inductor designs with two different copper thicknesses have been investigated and compared to verify the effective thermal performance of the proposed converters.