基于SC442設(shè)計(jì)的高效120個(gè)白光LED驅(qū)動(dòng)技術(shù)

SC442是10路高效120個(gè)白光LED驅(qū)動(dòng)器，輸入電壓4.5V-21V，高效的升壓轉(zhuǎn)換器可使輸出電壓高達(dá)42V，非常適合中到大型LCD顯示屏。電流沉可編程，每路高達(dá)30mA，路間的電流匹配在+/-1%，集成了3A開關(guān)，效率高達(dá)91%，可靈活進(jìn)行LED配置，高達(dá)50kHz調(diào)光頻率，大于500:1調(diào)光范圍，開關(guān)頻率500kHz - 1MHz，主要用在汽車LCD背光，臺(tái)式監(jiān)視器，筆記本電腦和手提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應(yīng)用：

Automotive LCD Backlighting

Desktop monitors

Notebook PCs

Portable TVs

圖1。SC442典型應(yīng)用電路