National Semiconductor's New High-Brightness LED Driver Simplifies Area-lighting Design
LED drivers today often require multiple components to accurately drive a string of LEDs. In addition, maintaining equal currents among LED strings results in a complex design. National's LM3466 solves these problems by integrating a MOSFET and utilizing a unique control scheme. The high level of integration enables a basic design of just one LM3466 along with one resistor and one capacitor to drive a string of LEDs. A complete fixture can be constructed by repeating the strings in parallel.
A unique dynamic current equalizing control scheme enables communication between each LM3466 LED driver to divide current equally or ratiometrically amongst multiple active LED strings. No binning of the LEDs is required. During an open (inactive) string state, each LM3466 automatically equalizes current throughout remaining strings to maintain relatively constant output power.