LT3760 Datasheet, PDF (1/32 Pages) Linear Technology – 8-Channel × 100mA LED Driver

LT3760
8-Channel × 100mA
LED Driver
Features
n _{Up to 45V of LEDs × 100mA, 8-Channel LED Driver}
n _{Wide Input Range : 6V to 40V}
n _{±2% LED Current Matching at 40mA (Typ ±0.7%)}
n _{Up to 3000:1 True Color PWM™ Dimming Range}
n _{Single Resistor Sets LED Current (20mA to 100mA)}
n _{LED Current Regulated Even for PVIN > VOUT}
n _{Output Adapts to LED VF for Optimum Efficiency}
n _{Fault Flag + Protection for Open LED Strings}
n _{Protection for LED Pin to VOUT Short}
n _{Parallel Channels for Higher LED Current}
n _{Programmable LED Current Derating vs Temperature}
n _{Accurate Undervoltage Lockout Threshold with}
Programmable Hysteresis
n _{Programmable Frequency (100kHz to 1MHz)}
n _{Synchronizable to an External Clock}
Applications
n _{Automotive, Notebook and TV Monitor Backlighting}
L, LT, LTC and LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. True Color PWM is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 7199560, 7321203.
Description
The LT^®3760 is an 8-channel LED driver with a step-up
DC/DC controller capable of driving up to 45V of LEDs.
Each channel contains an accurate current sink with ±2%
current matching. Channels follow a master programmable
current to allow between 20mA to 100mA of LED current
per string. Channels can be paralleled for higher LED
current. Output voltage adapts to variations in LED V_F for
optimum efficiency and open LED faults do not affect the
operation of connected LED strings.
The LT3760 allows a PWM dimming range up to 3000:1 and
an analog dimming range up to 25:1. Operating frequency
can be programmed from 100kHz up to 1MHz using a
single resistor or synchronized to an external clock.
Additional features include: programmable maximum V_OUT
for open LED protection, a fault flag for open LED, program-
mable LED current derating vs temperature, micropower
shutdown and internal soft-start. The LT3760 is available
in a thermally enhanced 28-pin TSSOP Package.
Typical Application
PV_IN
20V TO 36V
V_IN
8V TO 14V
92% Efficient, 36W Backlight LED Driver
4.7µF
10µH
UP TO 45V OF LEDs PER STRING
4.7µF
INTV_CC
V_IN
499k
4.7µF
GATE
SENSE
5s
2.2µF
••••
SHDN/UVLO
0.015Ω
40.2k
CTRL
PGND
V_OUT
•••
•••
•
•
•
•
20k
30.9k
PWM
REF
T_SET
LT3760
LED1
LED2
••••
LED7
LED8
11k
FAULT
OVP_SET
GND RT
I_SET
V_C SYNC
20k
39.2k
1MHz
5.76k
10k
2.2nF
•••• _{8 CHANNELS s 100mA}
100k
V_IN
3760 TA01
Worst-Case Channels LED Current Matching
(Normalized to 8-Channel Average)
0.8
0.4
0.0
– 0.4
R_ISET = 14.7k (I(LED) = 40mA)
– 0.8
–50 –25 0 25 50 75
100 125
JUNCTION TEMERATURE (°C)
3760 TA01
3760f