Effects of Parasitic Components in High-Frequency Resonant Drivers for Synchronous Rectification MOSFETs

Resonant drivers are usually employed for driving synchronous rectifier (SR) metal oxide semiconductor field effect transistors in high-frequency applications mainly because of their ability to supply high total gate charge in a very short time, while maintaining a high efficiency. However, their practical performance are strongly affected by parasitic components, whose effect is enhanced in applications requiring very high switching frequencies. In this paper, the effects of parasitic components in three different nonisolated resonant driver topologies are analyzed by considering their impact on the driver losses and on the SR gate voltage. The analyses and the experimental verifications reported in this paper originally show that, due to the internal parasitic inductance as well as the parasitic output capacitance of the driver switches, some driver topologies, in principle promising optimum performance, are not always the best solution for very high frequency applications. The more performing resonant driver, was also tested on the voltage regulator module working at 1.8 MHz reported in [21].