8-Channel 45V 50mA LED Driver

The ISL97678 is an 8-channel PWM dimming LED driver for LCD backlight applications. The ISL97678 is capable of driving up to 96 pieces of 3.4V/50mA LEDs but larger numbers of LEDs is possible if the LED forward voltage combined is less than 45V. The ISL97678 has 8 channels of voltage controlled current sources with typical currents matching to ±1, which compensate for the non-uniformity effect of forward voltages variance in the LED strings. To minimize the voltage headroom and power loss in the typical multi-string operation, the ISL97678 features dynamic headroom control that monitors the highest LED forward voltage string and uses its feedback signal for output regulation.

Features

• 8 Channels

• 4.75V ~ 26V Input

• 45V Maximum Output

• Drive Typically 96 LEDs (3.4V/50mA each)

• External PWM Input up to 25kHz Dimming

• Dimming range 0.8~100 up to 30kHz

• Current Matching ±0.7

• Protections

- String Open Circuit and Short Circuit Detections, OVP, and OTP

• Adjustable Dimming Frequency

• Adjustable Switching Frequency

• 32 Ld (5mmx5mm) QFN Package

Applications

• Notebook Displays WLED or RGB LED Backlighting

• LCD Monitor LED Backlighting