ISL97674_10 Datasheet, PDF (1/28 Pages) Intersil Corporation – 6-Channel LED Driver with Phase Shift Control and Frame Rate to Dimming Frequency Synchronization

6-Channel LED Driver with Phase Shift Control and
Frame Rate to Dimming Frequency
Synchronization
ISL97674
The ISL97674 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 ISL97674 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 ISL97674 VIN pin.
The ISL97674 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.
The ISL97674 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. In addition, the
ISL97674 also has a unique V_SYNC function that accepts
30Hz ~ 120Hz frame signal and synchronizes it to the
dimming frequency to minimize panel to panel visual
interference variation. The dimming frequencies are
available from 200Hz to 30kHz and can be synchronized
from 140Hz to 1085Hz.
Features
• 6 Channels
• Frame Rate to Dimming Frequency Synchronization
• 4.5V to 26.5V Input
• 45V Output Max
• Up to 40mA LED Current per channel
• Extensive Dimming Control
- 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
• Protections with Flag Indication
- String Open/Short Circuit, V_OUT Short Circuit,
Overvoltage and Over-Temperature Protections
- Optional Master Fault Protection
• Current Matching ±0.7%
• 20 Ld 4mmx3mm QFN Package
Applications
• Notebook Displays WLED or RGB LED Backlighting
• LCD Monitor LED Backlighting
• Automotive Displays LED Backlighting
Typical Application Circuit
V_IN = 4.5~26.5V
V_OUT = 45V*, 40mA PER STRING
June 25, 2010
FN7634.0
ISL97674
1 FAULT
2 VIN
4 VDC
LX 20
OVP 16
18 COMP
7 SCL
PGND 19
6 SDA
3 EN/PWM
5 VSYNC
8 PLLC
17 RSET
CH0 10
CH1 11
CH2 12
CH3 13
CH4 14
CH5 15
AGND ⁹
*V_IN > 12V
FIGURE 1. ISL97674 TYPICAL APPLICATION DIAGRAM
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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