单级式两开关无电解电容LED驱动电路

Single stage two switch electrolytic capacitor-less LED driver

电解电容寿命是影响传统发光二极管(LED)驱动电源使用年限的主要原因。因此,本文提出了一种将反激变换电路与辅助储能电路高度集成的单级式两开关无电解电容LED驱动电路拓扑,并在此基础上提出了一种适应于该拓扑结构的控制策略,通过控制两个开关管同时关断时间与两个开关管同时导通时间,来控制储能电路充电和放电过程,进而平衡输入瞬时功率和输出恒定功率的脉动差,抑制了输出电流低频纹波。辅助储能电路吸收了引起电压尖峰的漏感能量,降低了开关管的电压应力。最后,本文通过30 W的实验样机验证了LED驱动电路的可行性和可靠性。

The life of electrolytic capacitor is the main reason that affects the service life of traditional LED driving power.Therefore,this paper presents a kind of LED driver circuit topology in a highly integrated circuits and auxiliary energy storage circuit of single stage type two switch with no electrolytic capacitor.Based on this,a control strategy is presented by controlling the two switch tubes to cut-off and to conduct at the same time so as to control the energy storage circuit.Then,the pulse difference between the input instantaneous power and the output constant power is balanced,and the low-frequency ripple of the output current is suppressed.The auxiliary energy storage circuit absorbs the leakage inductance energy which causes the voltage spike and reduces the voltage stress of the switch tube.Finally,this paper verifies the feasibility and reliability of LED driver circuit through 30W experimental prototype.