LM3406/06HV,pdf datasheet (1.5

The LM3406/06HV 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 lowpower
shutdown and thermal shutdown protection.