NS LM3421-3高压LED驱动方案

2009-07-15 14:37:00 NS, , ,

NS公司的LM3421/LM3423是多用途高压LED驱动,可以配置成降压,升压,降压-升压(反激)或SEPIC拓扑,输入电压从4.5V到高达75V,可调开关频率高达2MHz,具有快速(50kHz) PWM调光,关断电流小于1uA,可用在LED驱动器和多种恒流模式稳压器以及热电冷却驱动器.本文介绍了LM3421/LM3423的住要特性,方框图以及多种应用电路图,升压评估板主要特性和电路图和材料清单(BOM).

LM3421/ LM3423:N-Channel Controllers for Constant Current LED Drivers
The LM3421/LM3423 devices are versatile high voltage LED driver controllers. With the capability to be configured in a Buck, Boost, Buck-Boost (Flyback), or SEPIC topology, and an input operating voltage rating of 75V, these controllers are ideal for illuminating LEDs in a very diverse, large family of applications.

Adjustable high-side current sense with a typical sense voltage of 100mV allows for tight regulation of the LED current with the highest efficiency possible. Output LED current regulation is based on peak current-mode control with predictive Off-Time Control. This method of control eases the design of loop compensation while providing inherent input voltage feed-forward compensation.
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