cat3649主要特性:

high efficiency 1.33x charge pump

quad−mode charge pump: 1x, 1.33x, 1.5x, 2x

drives up to 6 leds at 25 ma each

pwm dimming 100 hz to 200 khz for cabc

1−wire ezdim_ 32 linear steps (adim)

power efficiency up to 92%

low noise input ripple in all modes

“zero” current shutdown mode

soft start and current limiting

short circuit protection

thermal shutdown protection

3 mm x 3 mm, 16−pad tqfn package

this device is pb−free, halogen free/bfr free and is rohs compliant

cat3649典型应用:

lcd display backlight

cellular phones

digital still cameras

handheld devices

图1。cat3649功能方框图

图2。cat3649典型应用电路

图3。cat3649驱动5夹led的应用电路on semi公司的cat3649是具有32种调光亮度的六路四模式led驱动器,提供4种电荷泵模式(1倍、1.33倍、1.5倍及2倍), 这种分数型电荷泵支持从2.4 v到5.5 v的宽输入电压范围。led电流可以通过单线(1-wire)接口以32个线性增量的模拟调光来调节，也可以通过pwm作进一步的调节,广泛用于最新的智能手机及其它消费类手持应用，如数码相机和便携式媒体播放器(pmp)。