LM3464 LED Driver
May 2010National SemiconductorRequest Info
SANTA CLARA, Calif., May 5, 2010 — National Semiconductor Corp. has announced the LM3464 LED driver with dynamic headroom control and multiple outputs for high-power applications such as industrial, street and automotive lighting.
It accurately and efficiently drives up to four strings of LEDs. The PowerWise controller maximizes system efficiency, simplifies design and reduces system cost.
The driver includes four channels and drives up to 20 LEDs per channel, and its dynamic headroom control feature adjusts the supply voltages of the LED strings through the power supply feedback to the lowest level required to provide optimal system efficiency. By directly controlling the output of the offline regulator, the driver can eliminate the second stage switching regulator commonly required for offline LED power supplies.
The high-voltage current controller works in conjunction with external N-channel metal-oxide semiconductor field-effect transistors and sense resistors to accurately drive current to each LED string. It features an input voltage range of up to 80 V. A thermal foldback feature protects the LEDs from unsafe temperatures that can degrade their light output or lifetime.
During an overtemperature condition, the thermal foldback reduces the current through the LEDs until the LED junction temperature returns 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 caused by environmental conditions.
Pulse-width modulation and analog dimming interfaces allow the user to select between various dimming types for different applications. Protection features include undervoltage lock-out, LED open/short circuit and over-temperature fault signaling to the system controller.
The driver is offered in a 28-pin thermally enhanced thin shrink small outline package.
For more information, visit: www.national.com