A Clamped Interlocking Isolated Resonant Gate Driver for High-Frequency LLC-DCX

This article proposes a clamped interlocking isolated resonant gate driver (CIRGD) to provide multiple isolated complementary drive signals for the LLC dc transformer (LLC-DCX). The CIRGD clamps the gate voltage to 0-V-g using clamped mosfets, reducing conduction loss caused by the circulation current in the drive circuit and further improving system efficiency. With appropriate parameter design, the CIRGD generates gate drive signals with the necessary deadtime, enabling soft switching of the LLC-DCX. The working principle, parameter design, loss analysis, and comparative study of the CIRGD are presented in detail. Finally, a prototype with an operating frequency of 1.3 MHz, and a power output of 48 V-6 V/30 A was developed. The experimental results show that compared with the traditional voltage source drive circuit, the proposed CIRGD can significantly enhance efficiency and reduce gate drive power loss by nearly 85%.