SN3910,pdf datasheet (Universa

The SN3910 is an open loop, current mode, control LED
driver IC. The SN3910 operates constant off-time mode. It
allows efficient operation of High Brightness (HB) LEDs
from voltage sources ranging from 8VDC up to 450VDC or
110VAC/220VAC. The SN3910 includes a PWM dimming
input that can accept an external control signal with a duty
ratio of 0 - 100% and a frequency of up to a few kilohertz.
It also includes a 0 - 250mV linear dimming input which
can be used both for linear dimming and temperature
compensation of the LED current.
The SN3910 is ideally suited for buck LED drivers. Since
the SN3910 operates in open loop current mode control, the
controller achieves good output current regulation without
the need for any loop compensation. PWM dimming
response is limited only by the rate of rise and fall of the
inductor current, enabling very fast rise and fall times.