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National Semiconductor has announced the industry’s first LED driver with dynamic headroom control and multiple outputs for high-power applications that drives up to four strings of LEDs.

The LM3464, part of National’s Powerwise energy-efficient product range, is said to maximise system efficiency and reduces system complexity and cost in LED-intensive applications, such as industrial, street and automotive lighting.

Unlike traditional high-brightness LED drivers that drive current to each string independently, the LM3464 LED driver includes four channels to drive up to 20 LEDs per channel, reducing system complexity and cost.

Its dynamic headroom control feature dynamically adjusts the LED supply voltage through the power supply feedback to the lowest level required to provide optimal system efficiency.

The LM3464 is a high-voltage current controller with four individual current regulator channels.

It works in conjunction with external N-channel MOSFETs and sense resistors to accurately drive current to each LED string.

The LM3464 features a wide input-voltage range up to 80V to drive multiple LEDs per string, making the LM3464 suitable for LED-intensive applications.

A thermal foldback feature protects the LEDs from unsafe temperatures.

During an over-temperature condition, the thermal foldback reduces the current through the LEDs until the LED junction temperature of the LEDs returns back to a safe operating temperature.

This user-programmable feature allows for a more robust and reliable thermal design, helping to ensure the lifetime and light output of the LEDs over time and through temperature variances due to environmental conditions of the fixture.

The dynamic headroom control feature monitors the forward voltages of the LED strings and dynamically adjusts the LED supply voltage through the power supply feedback to the lowest level required.

By directly controlling the output of the offline regulator, the LM3464 can eliminate the second stage switching regulator commonly required for offline LED power supplies.

The LM3464 features pulse-width modulation (PWM) and analogue dimming interfaces to allow the user to select between various dimming types for different applications.

Protection features include VIN under-voltage lock-out, LED open/short circuit and over-temperature fault signalling to the system controller.

National Semiconductor

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