Semtech SC442高效120个白光LED驱动方案
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。本文介绍了SC442主要特性和典型应用电路。
SC442：10-Channel, Integrated, High Efficiency 120 White LED Driver
The SC442 is a 10-channel, high efficiency integrated step-up (boost) driver IC capable of powering up to 120 WLEDs. The device has a wide input voltage of 4.5V to 21V with no internal regulator or bypass capacitor required. The wide input range, up to 42V output voltage and flexible implementation make it the ideal LED backlight driver solution for medium to large LCD displays. The current sink channels are programmed with an external resistor up to 30mA each.
Channel-channel current matching is +/-1% . The device disables open or shorted LEDs by disabling only the affected LED channel; thus increasing LCD panel life. Channel-channel LED mismatch voltage is accomodated by adjusting the SCPSET resistor. The current sink channels may be operated in parallel for increased LED current. Unused channels are be disabled by connecting the pin to the input voltage.
..
