Allegro - A6217 Automotive-Grade LED driver

The A6217 is a single IC switching regulator that provides
constant-current output to drive high-power LEDs. It integrates
a high-side N-channel DMOS switch for DC-to-DC step- down
(buck) conversion. A true average current is output using a
cycle-by-cycle, controlled on-time method.

Output current is user-selectable by an external current sense
resistor. Output voltage is automatically adjusted to drive
various numbers of LEDs in a single string. This ensures the
optimal system efficiency.

LED dimming is accomplished by a direct logic input pulse-width-modulation
(PWM) signal at the enable pin.