FN7953

Rev.1.00

Sep 19, 2017

ISL97686

4-Channel LED Driver with Independent Channel Control for Dynamic Dimming

DATASHEET

FN7953 Rev.1.00

Page 1 of 22

Sep 19, 2017

The ISL97686 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 ISL97686’s current sources achieve typical current

matching to ±1%, while dynamically maintaining the

scheme compensates for the non-uniformity of forward

voltage variance in the LED strings.

The ISL97686 dimming can be controlled by a high speed SPI

interface for independent channel control for dynamic

dimming function synthesized on chip at 10-bit resolution.

The ISL97686 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 ISL97686 incorporates

extensive protections of string open and short circuit

detections, OVP, and OTP.

Related Literature

• For a full list of related documents, visit our website

- ISL97686 product page

Features

• 4 x 160mA, 75V rated channels with integrated channel

regulation FETs

• Channels can be ganged for high current

- 2 x 350mA

- 1 x 700mA

• 9V~32V input voltage

•Dimming modes:

- Independent channel dimming control with SPI

- PWM dimming with adjustable output frequency

- 10-bit dimming resolution

-VSYNC mode

• Two 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 5x5mm TQFN and 28 Ld 300mil SOIC packages

available

Applications

• Monitor and TV LED backlighting

• General, industrial, and automotive lighting

FIGURE 1. ISL97686 APPLICATION DIAGRAM

FIGURE 2. PWM DIMMING LINEARITY

SDO

CLK

OSC

GD

PWM_SET/PLL

EN

OVP

VIN

VLOGIC

VDC

D1

CS

CH1

CH2

CH3

CH4

CSEL

ISET2

COMP

Fuse

SDI

PGND

SLEW

160mA MAX PER STRING

Q1

ISET1

/CS

EN_VSYNC

0

10

20

30

40

50

60

70

80

90

100

110

0

20

40

60

80

100

DIMMING DUTY CYCLE (%)

I_CH2

I_CH1

I_CH3

I_CH4