LT3003_15 Datasheet, PDF (1/16 Pages) Linear Technology – 3-Channel LED Ballaster with PWM

FEATURES
■ _{3% LED Current Matching}
■ _{Up to 350mA Continuous Current per LED String}
■ _{Up to 3000:1 True Color PWM}^TM _{Dimming Range}
■ _{PWM Input Disconnects LED Strings}
■ _{Can Operate in Buck, Boost and Buck-Boost Modes}
■ _{Wide Input Range: 3V to 40V}
■ _{Overtemperature Outputs}
■ _{Works with LT1618, LT3477, LT3474, LT3475,}
LT3476, LTC^®3783
■ _{Thermally Enhanced 10-Pin MSOP Package}
APPLICATIONS
■ _{High Power LED Ballaster}
■ _{Automotive Lighting}
■ _{Video Cameras}
■ _{TFT LCD Backlighting}
LT3003
3-Channel LED
Ballaster with PWM
DESCRIPTION
The LT^®3003 drives three separate strings of LEDs up
to 350mA/channel with 3% accurate current matching,
resulting in uniform LED brightness and intensity. This
approach is superior to conventional methods of running
three separate channels with external ballast resistors
requiring expensive factory calibration.
The LT3003 operates in boost, buck and buck-boost mode.
A True Color PWM Dimming ratio of up to 3000:1 is achiev-
able using a logic-level signal at the PWM pin for all modes
without the need for external level-shifting circuitry. For
applications with input supply above and below the output
voltage of the LED strings, the LT3003 allows the LEDs to
be returned to the input supply (buck-boost mode) instead
of being limited to only SEPIC solutions.
The LT3003 is ideal for high power LED driver applications
such as TFT LCD backlighting and heads-up displays. Ad-
ditional overtemperature outputs allow appropriate system
management for increased reliability.
The LT3003 is available in a small 10-pin MSE package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
True Color PWM is a trademark of Linear Technolology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Buck Mode LT3003 with the LT3476
PV_IN
32V
1µF
0.1Ω
8 × 3 = 24 LEDs
350mA PER STRING
V_IN
3V TO 16V
10µF
LED1 LED2 LED3
V_MAX
V_IN
SHDN _LT3003
1µF
PWM
DIMMING
PWM
GND OT1 OT2
V_EE
CAP LED
PWM
V_C
V_IN SIMPLIFIED LT3476
GND
SW
0.33µF
1nF ^10µH
3003 TA01a
Efficiency
90
85
80
75
70
65
PV_IN = 32V
NUMBER OF LEDS = 8 × 3 = 24
60
0 200 400 600 800
1000
TOTAL LED CURRENT (mA)
1200
3003 TA01b
3003fa
1