A 1.5-MHz LLC Resonant Converter Employing Co-Packaged Gallium Nitride Power HEMTs with Integrated Gate Drivers

This paper investigates the circuit application of co-packaged Gallium Nitride (GaN) devices under high-frequency conditions, presenting a comparative analysis against discrete solutions. The co-packaging technology integrates two gate drivers and two GaN power high-electron-mobility transistors (HEMTs) into a single package. Unlike conventional discrete designs, which are susceptible to interconnect parasitics, this co-packaged approach significantly reduces inter-chip parasitic inductance and capacitance by minimizing interconnect lengths and optimizing the layout. This reduction in parasitic elements leads to faster switching transitions, lower ringing and overshoot, thereby enhancing switching performance and decreasing electromagnetic interference (EMI). To demonstrate these benefits, a 1.5 MHz, 330 W LLC converter with a 400 V DC input and a 20 V DC output was constructed and tested using diode rectification. Experimental measurements indicate that the co-packaged GaN solution reduces the total turn-on and turn-off energy losses by approximately 20% compared to the discrete implementation. The measurement results show a peak efficiency of 92.8%, validating the effectiveness and reliability of the co-packaged GaN solution for high-frequency resonant power conversion applications.