Quad Driver for GaN transistors based Dual Active Bridge with capacitive coupling
Résumé
The four-transistor full bridge is an elementary building block of many converters. Besides Gallium-Nitride transistors are promoted for their capability of high switching frequency along with low losses. The transistors' fast operation enables a reduction in the size of the passive components in a converter. High switching frequency requires a dedicated gate driver to achieve the synchronous operation of the GaN transistors in a full bridge. In this perspective a quad gate driver is presented to achieve synchronicity over four GaN transistors switching in low voltage applications (40 V) like photovoltaic market. Moreover the driver enables diode-less operation with adequate gate voltage during free wheeling phase. The driver is fabricated using a high temperature silicon-on-insulator 0.18μm CMOS technology for 200° C ambient temperature. The driver architecture and operation are described as well as experiments up to 200° C. A good agreement is observed between simulation and experiment. Matching between the four gate channel operation is in the 100 ps range. The propagation delay is better than 18 ns for operation at 1 MHz and a consumption of 12 mW. A peak current of 1.33 A is available on all four gate channel outputs.