一种新颖的单绕组自驱动同步整流方案的研究

A novel single-winding self-driving scheme for synchronous rectifiers

对低压 大电流输出DC DC变换器,提出了一种新颖的单绕组自驱动同步整流(SR)方案。该方案无需复杂的逻辑控制电路,即能实现同步整流管的自驱动。与传统自驱动方案相比,该方案解决了主变绕组电压为零时段副边同步整流管不能同时导通的问题,拓宽了自驱动同步整流的应用拓扑范围,特别适用于变压器对称工作的低压 大电流输出DC DC变换器。基于该方案制作的2 5V输出对称半桥变换器原理样机验证了分析和设计的正确性。

With the rapid development of information technology, low power DC/DC converter is widely used in computer and communication applications. SelfDriven Synchronous Rectification (SDSR) is an attractive means to provide high efficiency and circuitry simplification in these low power converters. But in traditional selfdriven approaches, it is necessary to add complex logical control circuits to maintain the SRs on when the voltage in the transformer winding is zero. In order to overcome this pitfall, a novel SingleWinding SelfDriven scheme for Synchronous Rectification (SWSDSR) is proposed in this paper. It works properly in topologies that drive the transformer symmetrically. A prototype of 2.5V output symmetrical halfbridge converter is built with the verification of the analysis and design given in this paper. 