LT3760
1
3760fc
Typical applicaTion
DescripTion
8-Channel
×
100mA
LED Driver
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,
programmable LED current derating vs temperature, mi-
cropower shutdown and internal soft-start. The LT3760 is
available in a thermally enhanced 28-pin TSSOP package.
L, LT , LT C and LT M , 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.
FeaTures
applicaTions
n
Automotive, Notebook and TV Monitor Backlighting
n
Up to 45V of LEDs × 100mA, 8-Channel LED Driver
n
Wide Input Range : 6V to 40V (4.5V to 13V,
V
IN
Connected to INTV
CC
)
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 PV
IN
> V
OUT
n
Output Adapts to LED V
F
for Optimum Efficiency
n
Fault Flag + Protection for Open LED Strings
n
Protection for LED Pin to V
OUT
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
Worst-Case Channels LED Current Matching
(Normalized to 8-Channel Average)
92% Efficient, 36W Backlight LED Driver
LT3760
GATE
5×
2.2µF
10µH
0.015Ω
V
OUT
SENSE
LED1
LED2
CTRL
PWM
REF
T
SET
OVP
SET
RTGND
I
SET
V
C
SYNC
V
IN
V
IN
8V TO 14V
IN
20V TO 36V
4.7µF
4.7µF
INTV
CC
40.2k
499k
PGND
•
•
•
•
•
•
•
•
•
•
11k30.9k
20k
39.2k
1MHz
5.76k 10k
100k
8 CHANNELS × 100mA
2.2nF
3760 TA01
SHDN/UVLO
FAULT
LED7
LED8
•
•
•
•
•
•
•
•
V
IN
4.7µF
• • • •
UP TO 45V OF LEDs PER STRING
20k
JUNCTION TEMERATURE (°C)
–50 –25
LED CURRENT MATCHING (%)
0.8
0.4
0.0
–0.4
–0.8
1000 25
3760 TA01
12550 75
R
ISET
= 14.7k (I(LED) = 40mA)