A novel LED driver controller, including: an auto-gain control unit, having an input end coupled to an input voltage signal which is derived from a line voltage, and an output end for providing a normalized signal; a comparator, used to perform voltage comparison on the normalized signal and a current sensing signal to generate a turn-off signal, wherein the turn-off signal will change state from inactive to active when the current sensing signal reaches the normalized signal; and a driving circuit, having a set input end, a reset input end, and an output end, the set input end being coupled to a turn-on signal, the reset input end being coupled to the turn-off signal, the output end being used for providing a gating signal.