基于半桥LLC谐振变换器的LED驱动电源的研究

Research on LED Driver Based on Half-Bridge LLC Resonant Converter

针对LED驱动电源对高功率因数、高效率及高可靠性的要求,提出了改进型的固定关断时间模式。采用半桥LLC谐振变换器作为驱动电源DC/DC变换器的拓扑结构,给出了谐振参数优化设计的方法。对大电流输出整流二极管损耗较大的问题,采用外驱动同步整流方案取代传统输出整流方案,进一步提高电源效率。电源样机试验结果验证了所提方案的可行性和有效性。

For the requirements of high power factor,high efficiency,and reliability of LED driver power supply,this paper proposed an improved fixed off time( FOT) mode to improve the power factor of driving power supply. Half-bridge LLC resonant converter was used as DC / DC converter of high power LED driver,and the method of resonant parameters optimization was presented. For the large loss of output rectifier diode of LED driver with high output current,an external-driven synchronous rectification scheme was applied to replace the conventional output rectification program to further improve power efficiency. The experimental results of the prototype verify the feasibility and effectiveness of the scheme.