新型LLC谐振变换器数字同步整流驱动方式

Digital synchronous rectification driving method for LLC resonant converter

提出了一种适用于LLC谐振变换器的数字同步整流驱动方式。该驱动方式基于检测同步整流MOS管的漏源极电压,进而判断体二极管的导通情况,通过电压比较器输出高低电平到数字处理器,算法程序捕获体二极管的导通时间,控制调节同步整流管驱动信号的占空比,从而使同步整流达到较理想的效果,提高变换器的效率。相比传统的同步整流驱动方式,所提的驱动方式具有电路结构与控制算法简单、驱动信号精确、动态性能好等优点。为了验证此方式的有效性,以一个72 W半桥LLC谐振变换器为样机进行了实验,样机效率达到97.5%。

A digital synchronous rectification driving metliod for LLC resonant converter was proposed. This driving method was based on detection of the drain-source voltage of the synchronous rectifier M0 S,and then conduction of tiie body diode was judged. Through the voltage comparator, the output level wastransferred to the digital processor, and algorit!im captures the turn-on time of tlates the duty cycle of t!ie driving signal of t!ie synchronous rectifier tube, so that t!ie scation achieves the ideal effect, and the efficiency of t!ie converter is improved. Compared wit!i the tradi-tional synchronous rectification driving met!iod, it has the advantages of simple cirtrol algorit!im, accurate driving signal, good dynamic performance and so on. In oness of the proposed method, a 72 W half bridge LLC resonant converter is used aefficiency is 97. 5% .