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    Resonant Converters

    T17.1 - A 1MHz GaN Synchronous Rectifier Controller with Adaptive Turn-Off Control and Ringing Suppression for High-Frequency LLC Converter in Data Center Applications

    Wednesday, March 25, 2026
    1:30 PM - 1:50 PM CT
    Location: 214A
    High-frequency LLC converters are widely used in data center. However, in high-frequency GaN operation, more severe switching ringing and induced voltage on power loop parasitic inductance is produced, presenting more challenges in gate drive timing and reliability controls. Traditional self-driven synchronous rectification (SR) controllers for Si power FETs are thus unsuitable for driving high-frequency GaN SR switches in LLC converters. This paper proposes a GaN SR controller with adaptive turn-off regulation which can adaptively adjust the turn-off delay by detecting the conduction time of the diode. Additionally, a ringing suppression gate driver, which provides tri-slope gate drive current, is proposed to modulate the slope of di/dt and dv/dt and suppress the switching ringing during turn-on transition. The controller is implemented using the 0.35µm high-voltage BCD process. In a 1MHz high-frequency LLC operation, the SR controller achieves a stable and efficient GaN turn-on/off under different load currents. Thanks to the adaptive turn-off time control, the efficiency of the LLC converter is improved by 2.5% at light load and by 1.7% at heavy load, with a peak value of 96.1%