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.