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.

The ISL97678 features PWM dimming up to 30kHz with

0.4~100 duty cycle and maintains ±1 current matching

across all ranges. The PWM dimming frequency can be

adjusted between 100Hz and 30kHz. The boost switching

frequency can also be adjusted between 600kHz and 1.5MHz.

The ISL97678 features extensive protection functions that

include string open and short circuit detections, OVP, and OTP.

ISL97678 is available in the 32 Leads QFN 5mmx5mm and

operate from -40°C to +85°C with input voltage ranges from

4.75V to 26V.

Features

• 8 Channels

• 4.75V ~ 26V Input

• 45V Maximum Output

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

• External PWM Input up to 20kHz Dimming

• Dimming range 0.4~100 up to 30kHz

• Current Matching ±0.7 Typical

• 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