An Asynchronous Buck Converter by Using a Monolithic GaN IC Integrated by an Enhancement-Mode GaN-on-SOI Process

A three-level gate driver and a power GaN HEMT were integrated on a monolithic chip by an Enhancement-mode GaN-on-SOI process. The chip realises high speed switching and effective three-level gate driving without any external negative power supply. However it has a problem of low heat dissipaton in continuous operations because of the BOX layer and the deep trenches for isolating power devices. Then, the IC was implemented in a C-QFN package and evaluated the tolerance for continuous operation with measuring the case temperature. The measurement result shows that the GaN IC can safely operate continuously in condition of the storage temperature below 64 degrees C. We attempted to design a small and high power density converter using the fabrication chip.