LED driving circuit, LED device comprising the same, and driving method of LED

A light emitting diode (LED) driving circuit disclosed herein controls a switching operation of a power switch connected to an LED string and includes a reference voltage generator configured to generate a frequency modulation reference voltage according to a dimming signal that controls brightness of the LED string, and a switching controller configured to control a switching frequency of the power switch to be constant when a level of the dimming signal is higher than that of the frequency modulation reference voltage, and control the switching frequency of the power switch based on the dimming signal when a level of the dimming signal is lower than that of the frequency modulation reference voltage.