If the supply of power is interrupted, the capacitor 134 may have a capacity to measure the time that is the same as the predetermined cooling time of the display panel 150 or exceeds the cooling time thereof.

In FIGS. 2 and 3, it has been assumed that one capacitor 134 is used, but embodiments of the present disclosure are not limited thereto. The capacitor 134 may be configured by a plurality of capacitors.

The second switch 135 may be turned on according to the discharge of the capacitor 134. That is, the voltage discharged from the capacitor 134 is applied to a gate terminal of the second switch 135, and thus the second switch 135 may be turned on.

While the voltage is charged to the capacitor 134, no voltage is applied to the gate terminal of the second switch 135, and thus the second switch 135 may be turned off.

The second switch 135 may be turned off if the voltage charged in the capacitor 134 is completely discharged.

The discharge check terminal 136 may output a discharge uncompleted signal or a discharge completed signal based on a voltage at a reference point K1 connected to the second switch 135 and the power supply unit 131. The reference point K1 is a reference point for determining whether the voltage of the capacitor 134 has been completely discharged.

Referring to FIG. 3, the reference point K1 may be a point at which one end of the discharge check terminal 136, the drain terminal of the second switch (FET) 135, and one end of a third resistor R3 are met.