LM3431_14 Datasheet, PDF (1/36 Pages) Texas Instruments – 3-Channel Constant Current LED Driver with Integrated Boost Controller

LM3431
www.ti.com
SNVS547F – NOVEMBER 2007 – REVISED MARCH 2009
LM3431/LM3431A/LM3431Q/LM3431AQ 3-Channel Constant Current LED Driver with
Integrated Boost Controller
Check for Samples: LM3431
FEATURES
1
•2 LM3431Q/LM3431AQ are Automotive Grade
Products that are AEC-Q100 Grade 1 Qualified
(–40°C to 125°C operating junction
temperature)
• 3-Channel Programmable LED Current
• High Accuracy Linear Current Regulation
• Analog and Digital PWM Dimming Control
• Up to 25kHz Dimming Frequency
• >100:1 Contrast Ratio
• Integrated Boost Controller
• 5V-36V Input Voltage Range
• Adjustable Switching Frequency up to 1MHz
• LED Short and Open Protection
• Selectable Fault Shutdown or Automatic
Restart
• Programmable Fault Delay
• Programmable Cycle by Cycle Current Limit
• Output Over Voltage Protection
• No Audible Noise
• Enable Pin
• LED Over-Temperature Shutdown Input
• Thermal Shutdown
• TSSOP-28 Exposed Pad Package
DESCRIPTION
The LM3431 is a 3-channel linear current controller
combined with a boost switching controller ideal for
driving LED backlight panels in space critical
applications. The LM3431 drives 3 external NPN
transistors or MOSFETs to deliver high accuracy
constant current to 3 LED strings. Output current is
adjustable to drive strings in excess of 200 mA. The
LM3431 can be expanded to drive as many as 6 LED
strings.
The boost controller drives an external NFET switch
for step-up regulation from input voltages between 5V
and 36V. The LM3431 features LED cathode
feedback to minimize regulator headroom and
optimize efficiency.
A DIM input pin controls LED brightness from analog
or digital control signals. Dimming frequencies up to
25 kHz are possible with a contrast ratio of 100:1.
Contrast ratios greater than 1000:1 are possible at
lower dimming frequencies.
The LM3431 eliminates audible noise problems by
maintaining constant output voltage regulation during
LED dimming. Additional features include LED short
and open protection, fault delay/error flag, cycle by
cycle current limit, and thermal shutdown for both the
IC and LED array. The enhanced LM3431A features
reduced offset voltage for higher accuracy LED
current.
APPLICATIONS
• Automotive Infotainment Displays
• Small to Medium Format Displays
1
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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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