LM3431 - PowerWise 3-channel constant current LED driver with built-in boost controller

LM3431 - PowerWise 3-channel constant current LED driver with built-in boost controller

Working Principle The LM3431 is a 3-channel linear current controller with a built-in boost switch controller that can drive the LED backlight display of ultra-thin electronic products. The LM3431 controller can drive 3 external NPN transistors or MOSFET transistors to provide constant currents with very small deviations for the 3 LEDs. The output current of the LED driver can be adjusted to a maximum of more than 200 mA. The built-in boost controller is responsible for driving the external NFET switch to increase the input voltage between 5V and 36V to the specified level. The LM3431 also has an LED cathode feedback voltage to minimize the reserved redundant voltage to further improve efficiency. The chip's dimming signal control input pin can use analog or digital signals to control the brightness of the LED. The dimming control frequency can be as high as 25 kHz, and the contrast can be as high as 100:1. If the dimming frequency is adjusted, the contrast can even be as high as 1000:1. When dimming the LED, the LM3431 chip can ensure a constant output voltage through voltage regulation to suppress switching noise. This chip also has other features such as LED short circuit and open circuit protection, fault delay/fault marking, cycle-by-cycle current limiting, and shutdown protection to ensure that the chip and LED are not damaged by overheating.