The ISL97687 is a PWM controlled LED driver that supports

4 channels of LED current, for Monitor and TV LCD backlight

applications. It is capable of driving 160mA per channel from a

9V to 32V input supply, with current sources rated up to 75V

absolute maximum.

The ISL97687’s current sources achieve typical current

matching to ±1, while dynamically maintaining the

minimum required VOUT necessary for regulation. This adaptive

scheme compensates for the non-uniformity of forward

voltage variance in the LED strings.

The ISL97687 can decode both an incoming PWM signal and

an analog input voltage, for DC-to-PWM dimming applications.

Modes include direct PWM and several modes where the PWM

frequency is synthesized on chip at 10-bit resolution. This can

be either free running, or synchronized with the frame rate to

give both a frequency and a phase lock, minimizing panel to

panel variation and display flicker. Phase shift is supported,

reducing flicker and audio noise, as is multiplication of the

incoming decoded analog and PWM values.

The ISL97687 has an advanced dynamic headroom control

function, which monitors the highest LED forward voltage

string, and regulates the output to the correct level to minimize

power loss. This proprietary regulation scheme also allows for

extremely linear PWM dimming from 0.02 to 100. The LED

current can also be switched between two current levels, giving

support for 3D applications. The ISL97687 incorporates

extensive protections of string open and short circuit

detections, OVP, and OTP.

Features

• 4x160mA, 75V rated channels with integrated channel

regulation FETs

• Channels can be ganged for high current

- 2x350mA

- 1x700mA

• 9V~32V input voltage

• Dimming modes:

- Direct PWM dimming from 100Hz~30kHz

- PWM dimming with adjustable output frequency

- 10-bit dimming resolution

- VSYNC function to synchronize PWM signal to frame

rate

- Phase shift

- Analog to PWM dimming with 8-bit resolution

• 2 selectable current levels for 3D applications

• Current matching of ±1

• Integrated fault protection features such as string open

circuit protection, string short circuit protection, overvoltage

protection, and over-temperature protection

• 28 Ld 5mmx5mm TQFN and 28 Ld 300mil SOIC Packages

Available

Applications

• Monitor/TV LED Backlighting

• General/Industrial/Automotive Lighting