LT3496
Triple Output LED Driver
FEATURES
DESCRIPTION
The LT®3496 is a triple output DC/DC converter designed
to operate as a constant-current source and is ideal for
driving LEDs. The LT3496 works in buck, boost or buck-
boost mode. The LT3496 uses a fixed frequency, current
mode architecture resulting in stable operation over a
wide range of supply and output voltages. A frequency
adjust pin allows the user to program switching frequency
between 330kHz and 2.1MHz to optimize efficiency and
external component size.
n
True Color PWM™ Dimming Delivers Up to 3000:1
Dimming Ratio
n
Built-In Gate Driver for PMOS LED Disconnect
n
Three Independent Driver Channels with 750mA,
45V Internal Switches
n
Operates in Buck, Boost, Buck-Boost Modes
n
CTRL Pin Accurately Sets LED Current Sense
Threshold Over a Range of 10mV to 100mV
n
Adjustable Frequency: 330kHz to 2.1MHz
n
Open LED Protection
Wide Input Voltage Range:
The LT3496 supports 3000:1 dimming control on each
channel. Each of the three regulators is independently
operated by that channel’s PWM signal. The PWM feature
allows precise adjustment of the color mixing or dimming
ratio of the LED source. Each of the three channels has
a built-in gate driver to drive an external LED-disconnect
P-channel MOSFET, allowing high dimming range. The
output current range of each channel of the LT3496 is
programmed with an external sense resistor.
n
Operation from 3V to 30V
Transient Protection to 40V
n
Surface Mount Components
n
28-Lead (4mm × 5mm) QFN and TSSOP Packages
APPLICATIONS
n
RGB Lighting
n
Billboards and Large Displays
The CTRL pin is used to adjust the LED current either for
analog dimming or overtemperature protection.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents, including
7199560, 7321203, and others pending.
n
Automotive and Avionic Lighting
Constant-Current Sources
n
TYPICAL APPLICATION
High Dimming Ratio Triple Output LED Power Supply
PV
IN
42V
1μF
s3
CAP1
200mΩ
LED1
CAP2
200mΩ
LED2
CAP3
200mΩ
LED3
3000:1 PWM Dimming at 120Hz
TG1
TG2
TG3
PWM
5V/DIV
7 LEDs
0.5A
0.5A
0.5A
0.47μF
I
L
0.47μF 0.47μF
0.5A/DIV
I
LED
0.5A/DIV
18μH
18μH
18μH
3496 TA01b
0.5μs/DIV
SW1
CAP1-3
LED1-3
SW2
SW3
TG1-3
VC1-3
V
REF
22k
470pF
LT3496
GND
V
IN
V
CTRL1-3
FADJ
OVP1-3
IN
3V TO 24V
PWM1-3
SHDN
PWM1-3
SHDN
1μF
3496 TA01a
3496fe
1