倍流整流半桥变换器高效同步整流控制驱动

A High Efficiency Control-driven method for Synchronous Rectifier in the Symmetrical Half-bridge converter with Current-doubler

提出了一种新的基于UC3525芯片及其外围电路的电压控制驱动方法,保证倍流整流半桥式DC/DC变换器两个主开关管的驱动信号之间存有一定的死区,避免了出现连通短路现象,保证了在死区期间,两个同步整流管同时导通,因而减少了整流损耗。文中提供了实例控制电路的有关设计特点。理论分析和实验结果表明,该方法不仅能使变换器的整流损耗降到近乎最小,提高了效率,而且控制简单,易于实现。

A novel voltage control-driven method has been described in this paper,which was based on a micro-chip UC3525 and its peripheral circuitry,to control the synchronous rectifier of the symmetrical half-bridge DC/DC converter with current-doubler for low-voltage high-current output.The proposed control method guarantees the existence of the dead time between the driving signals of the two main switches to avoids the phenomenon of the short circuit caused by conducting of the main switches at the same time,and also guarantees two synchronous rectification switches to be turned on simultaneously during the dead time,so that the rectification losses were decreased.The relevant details about the design and calculation of the control circuit of the prototype for the experiment were also presented in the paper. The theoretical analysis and the experimental results showed that the proposed method can not only make the rectification losses lower to nearly the minimum and therefore improve the efficiency of the converter,but also it is simple in control procedure and easy in implementing.