基于LM3421的大功率LED驱动电路的设计

Design of High Power LED Driver on Vehicle Lighting

对列车前照灯的工作要求，设计出一种大功率LED恒流源驱动电路。电路采用脉冲电流驱动的方式，可驱动多颗大功率LED，同时引入外部温控模块对LED结温进行闭环控制。通过调节PWM使能信号的占空比，从而控制LED的工作时间，保证结温不超过设定值，降低其热衰减，提高LED发光效率。整个驱动电路结构简单，电路性能可靠，能够适应轨道车辆的工作环境，满足了大功率LED照明的电压电流工作要求。

A constant current high-power LED driver according to the operational requirements of the train headlighted is designed.It can drive multiple high-power LEDs with high-frequency pulse current. The closed loop control of temperature is also used to ensure the junction temperature does not exceed the set value. It automatically adjust the PWM duty cycle according to the detected temperature thereby reducing LED thermal decay and improving luminous efficiency . This drive system is simple,reliable and able to adapt to the rail vehicle working environment, meeting the various requirements of the high power LED lighting.