125 W multiphase GaN/Si hybrid point of load converter for improved high load efficiency

This work presents experimental results of an optimized five-phase GaN/Si hybrid synchronous buck converter designed to improve low voltage point of load (POL) converter efficiency while meeting increasing load demands typical in high performance computing. The best enhancement-mode GaN HEMTs have very low gate charge, switch much faster than Si, and enable higher frequency operation which can reduce size. However, GaN HEMTs are not yet available with extremely low R_DS(ON), like comparable Si MOSFETs. For this reason, GaN-based systems are susceptible to poor efficiency at high loads. To mitigate this consequence, the appropriate combination of GaN and Si is utilized in a 12 to 1 V POL converter with peak efficiency above 95% and 125 W rated load. The results of this work submit that optimal performance can be achieved by combining two semiconductor technologies, and the design is a novel approach to improve upon current state-of-the-art POL converters.