1.5-A automotive constant current buck regulator for driving high power LEDs

The LM3406 family are monolithic switching regulators designed to deliver constant currents to high power LEDs. Ideal for automotive, industrial, and general lighting applications, they contain a high-side N-channel MOSFET switch with a current limit of 2.0A (typical) for step-down (Buck) regulators. Controlled on-time with true average current and an external current sense 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. LED dimming via pulse width modulation (PWM) is achieved using a dedicated logic pin or by PWM of the power input voltage. The product feature set is rounded out with low-power shutdown and thermal shutdown protection.