下载
V
LED
+
Fault logics
to MCU
IOUT1
IOUT2
IOUT3
IOUT4
IOUT5
IOUT6
OTMb
FAULTb
VIN
AGND PGND
EN
DIM
ON
OFF
PWM for digital input/
DC voltage for analog input
LM3432/LM3432B
Connect to GND
for digital input/
Connect with
capacitor for
analog input
C
VIN
C
VDHC
R
DHC
C
DHC
To LM3430
VDHC pin
VCC
IREF
C
VCC
R
IREF
( 80V max. )
VDHC
CDHC
Adjust to the lowest possible
voltage level to maximize
efficiency
MODE
VIN
GND
LM3432, LM3432B
www.ti.com
SNVS498D –APRIL 2007–REVISED MAY 2013
6-Channel Current Regulator for LED Backlight Application
Check for Samples: LM3432, LM3432B
1
FEATURES
• Low profile, Thermally Enhanced WQFN-24
(5x4x0.8mm) and eHTSSOP-28
2
• Dynamic Headroom Control (DHC) Output to
(9.7x6.4x1.1mm) Packages (The LM3432B is
Maximize Efficiency when used in Conjunction
available in the WQFN-24 only)
with Texas Instruments Semiconductor's
LM3430 Boost Controller for LED Backlighting
APPLICATIONS
• Current Sinking Adjustable up to 40mA in
• LCD Display Backlight Applications
Each String
• General Lighting Solutions
• Fast Current Switching Slew Rate, t
r
= 60ns
Typical
DESCRIPTION
• Wide Dimming Ratio, up to 4000:1 with f
DIM
=
The LM3432/LM3432B are 6-channel high voltage
500Hz
current regulators which provide a simple solution for
• High LED Driving Voltage up to 80V
LED backlight applications. These devices
• ±2.0% Current Matching Between Strings
incorporate six individual current regulator channels
to give accurate driving current for each LED string.
• Accepts Both Digital and Analog Dimming
The string-to-string tolerance is kept within ±2.0%.
Control
Additionally, the Dynamic Headroom Control output
• LED Open/Short Fault Indication (For
can communicate with a LM3430 boost regulator to
LM3432B, no open fault indication)
adjust the LED supply voltage to the lowest level
needed to keep the string current in regulation,
• Over-Temperature Indication
yielding optimal overall system efficiency.
• Internal Thermal Shutdown with Hysteresis
TYPICAL APPLICATION CIRCUIT
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2007–2013, Texas Instruments Incorporated
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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