ISL97686_14 Datasheet, PDF (1/23 Pages) Intersil Corporation – 4-Channel LED Driver with Independent Channel Control for Dynamic Dimming

4-Channel LED Driver with Independent Channel
Control for Dynamic Dimming
ISL97686
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 minimum required
V_OUT necessary for regulation. This adaptive 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
• See Application note for “ISL97686IBZ_EVALZ” for SOIC
Application
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
• 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 5x5mm TQFN and 28 Ld 300mil SOIC Packages Available
Applications
• Monitor/TV LED Backlighting
• General/Industrial/Automotive Lighting
VIN: 9V~32V
Fuse
VIN
VDC
VLOGIC
EN
CLK
SDI
SDO
/CS
EN_VSYNC
CSEL
ISET1
ISET2
OSC
PWM_SET/PLL
SLEW
GD
CS
PGND
COMP
OVP
CH1
CH2
CH3
CH4
D1
Q1
RSENSE
160mA MAX PER STRING
FIGURE 1. ISL97686 APPLICATION DIAGRAM
110
100
90
80
70
60
50
40
30
20
10
0
0
I_CH2
I_CH3
I_CH1
I_CH4
20
40
60
80
100
DIMMING DUTY CYCLE (%)
FIGURE 2. PWM DIMMING LINEARITY
April 23, 2012
1
FN7953.0
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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