In high-frequency (HF) power converters, precise dv/dt control is critical for ensuring system stability, efficiency, and electromagnetic compatibility. Conventional discrete capacitor-based closed-loop dv/dt sensors often face challenges related to limited gain, bandwidth, and reliability, particularly when controlling devices with low reverse transfer capacitance ( C RSS ). This paper proposes a discrete synchronous capacitive dv/dt sensor (syncFET dv/dt sensor) that enhances closed-loop dv/dt control performance in megahertz (MHz) power converter applications by integrating a syncFET with an active gate driver (AGD), leveraging GaN technology to improve feedback gain without the design complexities of integrated circuits. Experimental validation using a 10 MHz, 24 V buck converter demonstrates a reduction in the turn-on dv/dt of the low-side switch from -15 V/ns to -10 V/ns with a 0.1 pF sensor capacitor, achieving nanosecond-level response times for reliable dv/dt regulation during switching transients. Additionally, PSpice simulations confirm the syncFET dv/dt sensorโs capability to generate stronger feedback currents, and when coupled with the AGD, reduce the gate current for dv/dt control while maintaining system stability. By harnessing GaN technology, the proposed sensor supports the high switching frequency requirements of MHz power converters, improving both efficiency and control reliability.
