Highly Efficient Low-Voltage DC-DC Converter at 2-5 MHz with High Operating Current Using GaN Gate Injection Transistors

Highly efficient conversions from 12 V to 1.2 V are confirmed at 2-5 MHz with high output current by DC-DC converters using Gallium Nitride (GaN) Gate Injection Transistors (GITs). Reduction of the gate lengths of the GITs with optimized structure designs reduces the RonQg down to 19.1 mOmeganC, which is a figure-of-merit for high speed switching. The peak operating efficiency at 2 MHz reaches 90% together with high output current of 50 A by the single-phase operation. The operating frequency can be increased to 5 MHz by the GaN-based DC-DC converter with the peak efficiency as high as 81%, which cannot be achieved by existing Si-based converters.