Display device and control method therefor

A method of controlling a display device, the method comprising:

• acquiring brightness information of a display of the display device;
• identifying first power information required from the display based on the acquired brightness information;
• receiving third power information from an external device connected to an external input port of the display device, wherein the third power information includes information on voltage and current values required for charging the external device, and
• adjusting power supplied to the external input port based on the first power information, second power information supplied from a power supply of the display device, and the third power information,
• wherein, in the adjusting of the power supplied to the external input port, power is supplied to the external input port at the voltage and current values included in the third power information based on power required from the external device that is calculated based on the voltage and current values not exceeding the power available,
• wherein, in the adjusting of the power supplied to the external input port, power is supplied to the external input port at specified voltage and current values within a range of values that do not exceed the power available based on the power required from the external device that is calculated based on the voltage and current values exceeding the power available, and
• wherein the method further comprises:
• based on the display device being in a power saving mode, adjusting power supplied to the external input port based on default power information corresponding to the power saving mode of the display device and the second power information,
• adjusting the power supplied to the external input port to a threshold power based on the display device switching from the power saving mode to a normal mode, and
• controlling the display to display an image corresponding to the normal mode.