A novel high-frequency isolated resonant gate driver for LLC-DCX

The fixed-frequency unregulated LLC DC transformer (DCX) operates at MHz switching frequency, leading to high efficiency and high-power density. However, at this frequency, the LLC-DCX experiences substantial gate drive losses. To address this issue and achieve gate drive energy recovery, a new zero-voltage-switching high-frequency isolated resonant gate driver (RGD) for the LLC-DCX is proposed. The proposed RGD is capable of providing the drive signals for all MOSFETs in the LLC-DCX, resulting in an 85.5% reduction in drive losses compared to conventional drivers. The paper provides a detailed analysis of the operating principle, key parameter Lrd design, and loss analysis of the proposed RGD. Finally, a prototype that operates at 1.3MHz is constructed to validate the effectiveness of the proposed circuit.