LT3754_15 Datasheet, PDF (1/30 Pages) Linear Technology – 16-Channel 50mA LED Driver

Features
n _{Up to 45V of LEDs × 50mA, 16-Channel LED Driver}
n _{Wide Input Range : 6V to 40V (4.5V to 13V,}
V_IN Connected to INTV_CC)
n _{±2.8% LED Current Matching at 20mA (Typ ±0.7%)}
n _{Up to 3000:1 True Color PWM™ Dimming Range}
n _{Single Resistor Sets LED Current (10mA to 50mA)}
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.
LT3754
16-Channel × 50mA
LED Driver
Description
The LT^®3754 is a 16-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 ±2.8%
current matching. Channels follow a master programmable
current to allow between 10mA to 50mA 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 LT3754 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,
micropower shutdown and internal soft-start. The LT3754
is available in a thermally enhanced 5mm × 5mm 32-pin
QFN package.
Typical Application
92% Efficient, 36W Backlight LED Driver
PV_IN
24V
4.7µF
V_IN
10V
4.7µF
INTV_CC
V_IN
499k
4.7µF
SHDN/UVLO
40.2k
CTRL
10µH
GATE
SENSE
V_OUT
0.015Ω
UP TO 45V OF LEDs PER STRING
5×
2.2µF
••••
••
••
•
•
••
••
•
•
20k
30.9k
PWM
V_REF
T_SET
LT3754
LED1
LED2
••
••
LED15
LED16
11k
FAULT
OVP_SET
GND RT
I_SET
V_C SYNC
20k
39.2k 5.76k 10k
•• _{16 CHANNELS}
••
100k ^VIN
3754 TA01
2.2nF
Worst-Case Channels LED Current Matching
(Normalized to 16-Channel Average)
0.8
0.4
0.0
– 0.4
R_ISET = 14.7k (I(LED) = 20mA)
– 0.8
–50 –25 0 25 50 75
100 125
JUNCTION TEMERATURE (°C)
3754 TA01
3754fc
1