6-Channel SMBus/I2C or PWM Dimming LED Driver with
Phase Shift Control
ISL97671
Features
The ISL97671 is a 6-Channel 45V dual dimming capable LED
driver that can be used with either SMBus/I2C or PWM signal for
dimming control. The ISL97671 drives 6 channels of LED to
support 78 LEDs from 4.5V to 26V or 48 LEDs from a boost
supply of 2.7V to 26V and a separate 5V bias on the ISL97671
VIN pin.
• 6 Channels
• 4.5V to 26.5V Input
• 45V Output Max
• Up to 40mA LED Current per Channel
• Extensive Dimming Control
The ISL97671 compensates for non-uniformity of the forward voltage
drops in the LED strings with its 6 voltage controlled-current source
channels. Its headroom control monitors the highest LED forward
voltage string for output regulation, to minimize the voltage headroom
and power loss in a typical multi-string operation.
- PWM/DPST Dimming, I2C 8-bit with Equal Phase Shift, and
0.007% Direct PWM Dimming at 200Hz
• Optional Master Fault Protection
• PWM Dimming Linearity 0.4%~100% <30kHz
• 600kHz/1.2MHz Selectable Switching Frequency
• Dynamic Headroom Control
The ISL97671 features optional channel phase shift control to
minimize the input, output ripple characteristics and load
transients as well as spreading the light output to help reduce
the video and audio interference from the backlight driver
operation. The phase shift can be programmed with equal phase
angle or adjustable in 7-bit resolution.
• Protections with Flag Indication
- String Open/Short Circuit, VOUT Short Circuit, Overvoltage
and Over-Temperature Protections
- Optional Master Fault Protection
• Current Matching ±0.7%
The ISL97671 has a full range of dimming capabilities that
include SMBus/I2C controlled PWM dimming or DC dimming. It
can also do direct PWM dimming with as low as 350ns pulse on
PWM pin, which translates to a duty-cycle of 0.007% at a 200Hz
dimming frequency.
• 20 Ld 4mmx3mm QFN Package
Applications
• Notebook Displays WLED or RGB LED Backlighting
Related Literature
• See AN1581, “ISL97671/2/3/4IRZ-EVAL Quick Start Guide”
• LCD Monitor LED Backlighting
• Automotive Displays LED Backlighting
• Automotive or Traffic Lighting
V
= 45V*, 40mA PER STRING
OUT
V
= 4.5~26.5V
IN
ISL97671
FAULT
1
2
4
LX 20
VIN
OVP
16
VDC
PGND 19
CH0 10
SMBCLK/SCL
SMBDAT/SDA
7
6
CH1
CH2
CH3
CH4
CH5
11
12
13
14
15
5 PWM
3 EN
17
8
RSET
FPWM
AGND
*V > 12V
IN
COMP
9
18
FIGURE 1. ISL97671 TYPICAL APPLICATION DIAGRAM WITH SMBus/I2C CONTROL
August 14, 2012
FN7631.3
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1
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