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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.
| Top documentation | Type | Title | Format options | Date |
|---|---|---|---|---|
| * | Data sheet | LM3431/31A/31Q/31AQ 3-Chan Constant Current LED Driver w/Integrated Boost Cntr datasheet (Rev. G) | 02 May 2013 | |
| Selection guide | Power Management Guide 2018 (Rev. R) | 25 Jun 2018 | ||
| White paper | LED Drivers for Automotive Exterior Applications (Rev. B) | 27 Mar 2018 | ||
| Application note | AN-1656 Design Challenges of Switching LED Drivers (Rev. A) | 03 May 2013 | ||
| User guide | CCFL to LED Conversion Power Supply User Guide | 27 Jan 2012 |
For additional terms or required resources, click any title below to view the detail page where available.
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| HTSSOP (PWP) | 28 | Ultra Librarian |
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