Gallium Nitride (GaN) high-electron mobility transistors (HEMTs) are increasingly adopted in power converters due to their extremely fast switching, low capacitances, and negligible reverse recovery. To achieve higher power ratings, multiple GaN HEMTs are connected in parallel; however, their fast switching also makes them highly sensitive to propagation delay mismatches in the gate driver circuits. Even small delays can lead to asynchronous switching of the parallel devices, causing unequal current sharing, increased switching losses, and reliability concerns. This paper proposes a novel delay-compensation technique to enable synchronous switching of paralleled GaN HEMTs. The proposed method employs the device voltage slew rate (dv/dt) for pre-calibration of delay mismatches, while a time-to digital converter (TDC) compensates residual runtime delays. Experimental double-pulse tests and MATLAB simulations verify that the proposed method achieves balanced current sharing, reduces switching losses, and alleviates device stress, thereby improving the reliability of parallel GaN HEMTs.
