A Universal Adaptive Driving Scheme for Synchronous Rectification in LLC Resonant Converters
A universal adaptive driving scheme for a synchronous rectification (SR) is proposed as shown in Fig. 1. The drain to source voltage of the synchronous rectifier is sensed, so that the paralleled body diode conduction is detected. Using the proposed SR driving scheme, the SR turn-off time is tuned to eliminate the body diode conduction as illustrated in Fig. 2. The SR gate driving signal can be tuned within all operating frequency regions. Compared to analog ones, it enables more intelligent and precise SR control, improving converter efficiency.