ISL97675 Datasheet, PDF (1/20 Pages) Intersil Corporation – 4-Channel LED Driver with Phase Shift Control

4-Channel LED Driver with Phase Shift Control
ISL97675
The ISL97675 is an LED driver that drives 4 channels of
low power LEDs from 4.5V to 26V input and up to 45V
output.
The ISL97675 compensates for non-uniformity of the
forward voltage drops in the LED strings with its 4 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 the typical multi-string operation.
The ISL97675 offers two PWM Dimming modes: The part
digitizes the incoming 100Hz to 30kHz PWM signal and
provides 8-bit PWM dimming with phase shift function.
Another mode is direct PWM mode without phase shift,
where the dimming frequency follows the input PWM
signal and the minimum on time can be as short as 350ns.
The ISL97675 features channel phase shift control to
minimize the input, output ripple characteristics and load
transients as well as spreading the light output to help
eliminate or reduce the video and audio noise interference
from the backlight driver operation.
Features
• 4 x 30mA Channels
• 45V Output Max
• 4.5V to 26V Input
• Channel Phase Shift PWM Dimming with 8-bit
resolution
• 0.007% Direct PWM dimming at 200Hz
• Current Matching of ±1.5% from 1% ~ 100% Dimming
• Dynamic Headroom Control
• Protections
- String Open/Short Circuit, V_OUT Short Circuit
Overvoltage, and Over-temperature Protections
- Optional Master Fault Protection
• Selectable 600kHz or 1.2MHz Switching Frequency
• 20 Ld QFN 4mmx4mm Package
Applications*(see page 19)
• Netbook Displays LED Backlighting
• Notebook Displays LED Backlighting
Typical Application Circuit
V_IN* = 4.5V~26V
V_OUT = 45V max*
I_LED = 30mA PER STRING
ISL97675
17 FAULT
19 _VIN
1 _VDDIO
SW 16
OVP 14
PGND ¹⁵
3 _{FSW/Phase Shift}
2 EN
20 _PWM
18 _COMP
FB1 ¹²
FB2 ¹¹
13 _{RFPWM/DirectPWM}
FB3 7
4 _ISET
FB4 6
8 AGND
9 AGND
* V_IN ≥ 6V
May 19, 2010
FN7630.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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