A display device comprising: a light emitting diode 'LED' module including a plurality of LEDs arranged in rows and columns as a passive matrix; a plurality of driving integrated chips 'ICs', each of the plurality of driving ICs being configured to apply a voltage to cathodes of a corresponding column of the plurality of LEDs, a timing controller configured to apply a voltage to anodes of a corresponding row of the plurality of LEDs so as to drive light emission when a difference in voltage between the anodes and cathodes is greater than a preset voltage; and a controller configured to: identify a first voltage to be applied across a first LED in operation, from among the plurality of LEDs, corresponding to an emission level of the first LED based on image data, compare the first voltage with a preset reference value, and control a first driving IC, from among the plurality of driving ICs, that corresponds to the first LED to supply a driving voltage to the cathode of the first LED, wherein when the first voltage is equal to or greater than the preset reference value, the driving voltage is the first voltage, and when the first voltage is less than the preset reference value, the driving voltage is a second voltage which is a preset voltage not changed depending on the image data and corresponding to a forward voltage of the first LED for preventing a reverse voltage across the first LED. a light emitting diode 'LED' module including a plurality of LEDs arranged in rows and columns as a passive matrix; a plurality of driving integrated chips 'ICs', each of the plurality of driving ICs being configured to apply a voltage to cathodes of a corresponding column of the plurality of LEDs, a timing controller configured to apply a voltage to anodes of a corresponding row of the plurality of LEDs so as to drive light emission when a difference in voltage between the anodes and cathodes is greater than a preset voltage; and a controller configured to: identify a first voltage to be applied across a first LED in operation, from among the plurality of LEDs, corresponding to an emission level of the first LED based on image data, compare the first voltage with a preset reference value, and control a first driving IC, from among the plurality of driving ICs, that corresponds to the first LED to supply a driving voltage to the cathode of the first LED, wherein when the first voltage is equal to or greater than the preset reference value, the driving voltage is the first voltage, and when the first voltage is less than the preset reference value, the driving voltage is a second voltage which is a preset voltage not changed depending on the image data and corresponding to a forward voltage of the first LED for preventing a reverse voltage across the first LED. identify a first voltage to be applied across a first LED in operation, from among the plurality of LEDs, corresponding to an emission level of the first LED based on image data, compare the first voltage with a preset reference value, and control a first driving IC, from among the plurality of driving ICs, that corresponds to the first LED to supply a driving voltage to the cathode of the first LED, wherein when the first voltage is equal to or greater than the preset reference value, the driving voltage is the first voltage, and when the first voltage is less than the preset reference value, the driving voltage is a second voltage which is a preset voltage not changed depending on the image data and corresponding to a forward voltage of the first LED for preventing a reverse voltage across the first LED.