【摘要】 随着大功率LED灯性价比的提高,LED刹车灯、方向灯等信号灯已被广泛应用,但LED车头灯、前雾灯等照明灯仍受电源驱动寿命与IC对温升要求的影响。用恒定关断时间控制(COFT)方法,不需要外部控制环路补偿就可实现精确恒流的LM3409芯片PWM控制LED亮度的恒流LED汽车驱动电路。对该电路进行了基于Webench软件的设计、仿真,在总体指标选定的基础上,对电路的各个器件参数进行优化,设计的电路具有输出电流稳定、精度高、驱动器效率高等优点。更多还原

【Abstract】 With the cost-effective improvement,the brake light and signal lights based on led have been widely used,but LED headlights and front fog lights are still affected by power-driven life and IC temperature rise requirements.In this paper,a constant current LED array driver used as automotive headlamp based on the LM3409 chip was designed by use of constant off-time control,considering the drive mode,topology and PWM dimming means.WEBENCH modeling of this circuit was built and optimized.The circuit based on system specifications was optimized for stable output current,high conversion efficiency and so on.更多还原