A light emitting diode (LED) driver circuit is provided. The light emitting diode (LED) driver circuit includes an LED array; an LED driving circuit configured to provide a constant current to the LED array by a switching operation of a switch element; and a driving controller configured to control the switch element using a clock signal of a preset frequency so that the constant current corresponding to a dimming signal is provided to the LED array. The driving controller varies a frequency of the clock signal in response to a signal value indicating that the dimming signal is being transitioned.