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