基于SC442设计的高效120个白光LED驱动技术

本文介绍了SC442主要特性和典型应用电路。
Semtech 公司的SC442是10路高效120个白光LED驱动器，输入电压4.5V-21V，高效的升压转换器可使输出电压高达42V，非常适合中到大型LCD显示屏。电流沉可编程，每路高达30mA，路间的电流匹配在+/-1%，集成了3A开关，效率高达91%，可灵活进行LED配置，高达50kHz调光频率，大于500:1调光范围，开关频率500kHz - 1MHz，主要用在汽车LCD背光，台式监视器，笔记本电脑和手提TV。

SC442主要特性：

Wide input voltage range from 4.5V to 21V

42V maximum operating output voltage

Programmable LED current up to 30mA per string

+/- 1% current matching

Integrated 3A switch

Low current sink voltage

Up to 91% efficiency

Flexible LED configurations

Mismatched LED channels

Disable individual channel(s)

Parallel channels for high LED current

PWM dimming capability

Up to 50kHz dimming frequency

>500:1 dimming range

Switching frequency: 500kHz - 1MHz

Parallel device operation with Sync Pin

Protection features:

Adjustable OVP

Cycle-by-cycle current limit

LED short channel with disable /Open channnel

Over-Temperature protection

MLPQ-28 lead-free package (WEEE and RoHS compliant), 4×4mm × 0.6mm

SC442应用：

Automotive LCD Backlighting

Desktop monitors

Notebook PCs

Portable TVs

图1。SC442典型应用电路