42-V 1.0-A constant current buck LED driver

The LM3404 and LM3404HV devices are monolithic switching regulators designed to deliver constant currents to high power LEDs. Ideal for automotive, industrial, and general lighting applications, these devices contain a high-side N-channel MOSFET switch with a current limit of 1.5-A (typical) for step-down (Buck) regulators. Hysteretic controlled on-time and an external resistor allow the converter output voltage to adjust as needed to deliver a constant current to series and series-parallel connected LED arrays of varying number and type. Some features are: LED dimming using pulse width modulation (PWM), broken or open LED protection, low-power shutdown, and thermal shutdown.