San Diego, Calif.—National Semiconductor's two new high-brightness light-emitting diode (LED) drivers in its PowerWise product family, the LM3401 and LM3405A, are suited to industrial and automotive tasks and general lighting/signage. Each touts a wide input voltage range, constant-current operation for better regulating LED brightness, and low feedback voltage to minimize power dissipation.
The LM3401 switching controller, rated at a 4.5-to-35 volt input, drives an external PFET that can provide 1 amp at constant-current (within 6 percent) to a high-power LED string. The hysteretic window is adjustable for flexibility in component selection and overall design simplicity. No external compensation is required. Its design eliminates the need for an output capacitor. Offered in an 8-pin mini SOIC package, the LM3401 has programmable over-current voltage protection and a DIM input pin for PWM inputs to control dimming.
The LM3405A buck LED driver, with a 3-22 volt input, is a 1.6 MHz device that can regulate from a loosely coupled 12-volt AC rail that's typical of industrial and commercial lighting applications. Offered in a 6-pin SOT-23 package, the constant-current chip delivers up to 1 amp (drives up to five high-brightness LEDs). The LM3405A also includes an EN/DIM pin for pulse-width-modulation (PWM) dimming.
National Semiconductor , 1-800-272-9959, www.national.com