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.