LM3432SQE

• Dynamic Headroom Control (DHC) to maximize efficiency, output LED backlight when used with National Semiconductor's LM3430 boost controller
• Adjustable sink current up to 40mA per string
• Fast current switching slew rate, typical of T R = 60ns
• Wide dimming ratio up to 4000:1 f DIM = 500Hz
• High-power LEDs can be driven up to 80V
• ± Current matching between 2.0% strings
• Receives digital and analog dimming control
• LED open/short circuit fault indication (for LM3432B, no open fault indication)
• Over temperature indication
• With lagging internal thermal shutdown
• Low-profile, heat-resistant enhanced LLP-24 (5x4x0.8mm) and eTSSOP-28 (9.7x6.4x1.1mm) packages (LM3432B in LLP-24pcs)

illustrate

The LM3432/LM3432B 6-channel high-voltage current regulator for LED backlight applications offers a simple solution. These devices include six independent channels of current regulators that give each LED string the exact drive current. String-to-string tolerance is kept within 2.0% of ±. In addition, the headroom control output can be combined with an LM3430 step-up regulator to adjust the LED supply voltage to maintain the minimum level required for string current regulation, resulting in optimal overall system efficiency.

The 6-channel sink current can be adjusted from 15 mA to 40 mA via an external resistor. Their output drivers can withstand up to 80V. Digital PWM or analog voltage signals can be used to control the duty cycle of all channels. With a fast current switching slew rate, typical, precise current control of T R = 60ns and a wide dimming ratio during PWM dimming are guaranteed.

The LM3432/LM3432B contains an LED open/short circuit and an over-temperature fault signal system microcontroller (excluding the LM3432B for open-circuit fault signals). These devices are available in a low-profile, thermally enhanced 24-pin LLP package. The LM3432 is also available in 28-pin eTSSOP.

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• LCD Backlight Applications
• General lighting solutions