6-Channel SMBus/I2C or PWM Dimming LED Driver with
Phase Shift Control
ISL97671A
Features
The ISL97671A 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 ISL97671A can drive six channels of LEDs
from input 4.5V~26.5V to output of up to 45V. It can also operate
from input as low as 3V to output of up to 26.5V in bootstrap
configuration (see Figure 40).
• 6 x 50mA Channels
• 4.5V to 26.5V Input with Max 45V Output
• 3V (see Figure 40) to 21V Input with Max 26.5V Output
• PWM Dimming with Phase Shift Control
• SMBus/I2C controlled PWM or DC Dimming
• Direct PWM Dimming
The ISL97671A 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.
• PWM Dimming Linearity
- PWM Dimming with Adjustable Dimming Freq and Duty
Cycle Linear from 0.4% to 100% <30kHz
The device can also be configured in Direct PWM Dimming with
minimum dimming duty cycle of 0.007% at 200Hz.
- Direct PWM Dimming Duty Cycle Linear from 0.007% to
100% at 200Hz
The ISL97671A can compensate for the non-uniformity of the forward
voltage drops in the LED strings and Its headroom control circuit
monitors the highest LED forward voltage string for output regulation,
to minimize the voltage headroom and power loss in a typical
multi-string operation.
• Current Matching ±0.7%
• 600kHz/1.2MHz selectable switching frequency
• Dynamic Headroom Control
• Fault Protection
The ISL97671A is offered in compact and thermally efficient
QFN-20 4mmx3mm package.
- String Open/Short Circuit, OVP, OTP, and Optional Output
Short Circuit Fault Protection
• 20 Ld 4mmx3mm QFN Package
Applications
• Tablet PC to Notebook Displays LED Backlighting
• LCD Monitor LED Backlighting
• RGB LEDs or Field Sequential LED Backlighting
Typical Application Circuits
45V*, 6 x 50mA
45V*, 6 x 50mA
45V*, 6 x 50mA
VIN = 4.5~26.5V
VIN = 4.5~26.5V
VIN = 4.5~26.5V
Q1 (optional)
Q1 (optional)
Q1 (optional)
ISL97671A
FAULT
1
ISL97671A
ISL97671A
1
2
4
FAULT
1
2
FAULT
VIN
LX 20
LX 20
2
LX 20
VIN
VIN
OVP
16
OVP
16
OVP
16
4
8
VDC
4
VDC
VDC
FPWM
PGND 19
PGND 19
PGND 19
7
6
SMBCLK/SCL
CH0
7
6
SMBCLK/SCL
7
6
SMBCLK/SCL
10
11
12
13
14
15
CH0 10
SMBDAT/SDA
CH1
SMBDAT/SDA
CH0 10
SMBDAT/SDA
CH1
CH2
CH3
CH4
CH5
11
12
13
14
15
5
3
PWM
CH1
CH2
CH3
CH4
CH5
11
12
13
14
15
5
3
PWM
EN
CH2
CH3
CH4
CH5
5
3
PWM
EN
EN
17
RSET
17
8
RSET
17
8
RSET
FPWM
*VIN > 12V
FPWM
COMP
9
18
AGND
COMP
*VIN > 12V
9
18
AGND
*VIN > 12V
COMP
9
18
AGND
FIGURE 1A. SMBus/I2C CONTROLLED
DIMMING
FIGURE 1C. DIRECT PWM DIMMING
FIGURE 1B. PWM DIMMING WITH
ADJUSTABLE DIMMING
FIGURE 1. ISL97671A TYPICAL APPLICATION DIAGRAMS
March 24, 2011
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 |Copyright Intersil Americas Inc. 2011. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
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