GENERAL 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. The 6-channel current sink can be adjusted from 15mA to 40mA by an external resistor. Their output drivers can withstand up to 80V. Digital PWM or analog voltage signal can be used to control the duty cycle of all the channels. With a fast current switching slew rate, tr = 60ns typical, accurate current control and wide dimming ratio during PWM dimming are ensured. The LM3432/LM3432B contain LED open/short circuit and over-temperature fault signaling to the system micro-controller (the LM3432B does not include open circuit fault signaling).
National Semiconductor
