Efficiency Optimization of Phase-Shift Full-Bridge through Adaptive Dead-Time and Burst-Mode at Very Light Load

In the traditional phase-shift full-bridge converter, the dead-time is calculated under a pre-set load condition, which leads to more body diodes conduction loss of the switches when the load is heavy and the loss of ZVS when the load is light. Therefore, an adaptive dead-time strategy of efficiency improvement for PSFB converter is proposed in this paper, which can adaptively adjust dead-time based on the relationship between the load current and dead-time. By the proposed strategy, the efficiency of the PSFB converter can be improved at both light and heavy load conditions without additional power devices. In addition, the efficiency can be significantly improved by burst-mode at very light load.