LM3432 Datasheet, PDF (1/27 Pages) National Semiconductor (TI) – 6-Channel Current Regulator for LED Backlight Application

LM3432, LM3432B
www.ti.com
SNVS498D – APRIL 2007 – REVISED MAY 2013
6-Channel Current Regulator for LED Backlight Application
Check for Samples: LM3432, LM3432B
FEATURES
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•2 Dynamic Headroom Control (DHC) Output to
Maximize Efficiency when used in Conjunction
with Texas Instruments Semiconductor's
LM3430 Boost Controller for LED Backlighting
• Current Sinking Adjustable up to 40mA in
Each String
• Fast Current Switching Slew Rate, t_r = 60ns
Typical
• Wide Dimming Ratio, up to 4000:1 with f_DIM =
500Hz
• High LED Driving Voltage up to 80V
• ±2.0% Current Matching Between Strings
• Accepts Both Digital and Analog Dimming
Control
• LED Open/Short Fault Indication (For
LM3432B, no open fault indication)
• Over-Temperature Indication
• Internal Thermal Shutdown with Hysteresis
• Low profile, Thermally Enhanced WQFN-24
(5x4x0.8mm) and eHTSSOP-28
(9.7x6.4x1.1mm) Packages (The LM3432B is
available in the WQFN-24 only)
APPLICATIONS
• LCD Display Backlight Applications
• General Lighting Solutions
DESCRIPTION
The LM3432/LM3432B are 6-channel high voltage
current regulators which provide a simple solution for
LED backlight applications. These devices
incorporate six individual current regulator channels
to give accurate driving current for each LED string.
The string-to-string tolerance is kept within ±2.0%.
Additionally, the Dynamic Headroom Control output
can communicate with a LM3430 boost regulator to
adjust the LED supply voltage to the lowest level
needed to keep the string current in regulation,
yielding optimal overall system efficiency.
TYPICAL APPLICATION CIRCUIT
Adjust to the lowest possible
voltage level to maximize
efficiency
VLED+ ^{( 80V max. )}
To LM3430
VDHC pin
Connect to GND
for digital input/
Connect with
capacitor for
analog input
RDHC
CDHC
CVDHC
MODE
VDHC
CDHC
VIN
CVIN
VIN
CVCC
RIREF
VCC
IREF
PWM for digital input/
DIM
DC voltage for analog input
EN
ON
OFF
LM3432/LM3432B
IOUT1
IOUT2
IOUT3
IOUT4
IOUT5
IOUT6
OTMb
FAULTb
AGND PGND
GND
Fault logics
to MCU
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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