The LM3464 is a linear LED driver with Dynamic Headroom Control (DHC) technology designed to drive four serial high power / high brightness LED strings. Four individual linear current regulators with low-side N-channel MOSFETs realize regulations of LED currents. The DHC optimizes system efficiency automatically while maintaining stable and accurate LED currents. The LM3464 includes a voltage regulator for powering the internal circuits that operates over wide input range of 12V to 80V, eases the design of driver stage for different source voltage. The Thermal foldback feature is designed to prolong the lifetime of the LEDs by reducing the average LED current for applications with high ambient temperature. The LM3464 features a fault handling circuit that avoids system failure due to accidentally short or open circuit of LED strings. Two or more LM3464 can be cascaded to expand the number of output channels, enabling flexible system architectural design.
This evaluation board demonstrates the system efficiency and LED current regulation accuracy of the LM3464 LED driver typical application circuit as a 50W LED lighting system.