Self-Driven Synchronous Rectification Scheme Without Undesired Gate-Voltage Discharge for DC-DC Converters With Symmetrically Driven Transformers

This paper proposes a new self-driven synchronous rectification scheme for dc-dc converters with symmetrically driven transformers and wide input voltage range. The driving signals are obtained from the output inductor. Two auxiliary switches are utilized to turn off the main switches properly. Two extra auxiliary switches, which are controlled by a delayed signal from the inductor, are added to avoid the undesired gate discharge. This approach can achieve high efficiency and is suitable for practical applications. Experimental results based on a 36-75 V input, 2.5 V/30 A output prototype are shown to verify the proposed scheme.