disclosure has power controllers and control methods used therein . a disclosed power controller is adapted for a power converter to power at least one light emitting diode . the power converter includes a power switch with a control gate to make an inductive energized or de - energized . the power converter receives a dimming signal to substantially control the lighting of the light emitting diode . the power controller has a gate - driving circuit , for driving the control gate according to a pulse - width signal and the dimming signal . when the dimming signal is asserted the gate - driving circuit has a first driving force . when the dimming signal is deasserted the gate - driving circuit has a second driving force less than the first driving force .