A display apparatus comprising a light source, comprising: an image processor which is configured to process an image comprising a plurality of frames; a display which is configured to display the image in a screen mode of a plurality of screen modes based on an image signal and in which a quantity of light provided by the light source is controlled by dimming; a driver which is configured to drive the light source, the driver comprising a multiplexer and a constant current controller; a storage unit; and a controller which is configured to: set a plurality of current levels for supply to the light source corresponding to each of the respective plurality of screen modes for display of the image by the display, and to store the plurality of current levels in the storage unit, control the multiplexer to select a reference current having a stored current level corresponding to the screen mode among the plurality of screen modes, and to output the selected reference current to the constant current controller, and control the constant current controller to supply the light source with a driving current having the current level corresponding to the screen mode based on the selected reference current output from the multiplexer, by changing an on/off ratio of the driving current to perform the dimming for each of the plurality of frames. an image processor which is configured to process an image comprising a plurality of frames; a display which is configured to display the image in a screen mode of a plurality of screen modes based on an image signal and in which a quantity of light provided by the light source is controlled by dimming; a driver which is configured to drive the light source, the driver comprising a multiplexer and a constant current controller; a storage unit; and a controller which is configured to: set a plurality of current levels for supply to the light source corresponding to each of the respective plurality of screen modes for display of the image by the display, and to store the plurality of current levels in the storage unit, control the multiplexer to select a reference current having a stored current level corresponding to the screen mode among the plurality of screen modes, and to output the selected reference current to the constant current controller, and control the constant current controller to supply the light source with a driving current having the current level corresponding to the screen mode based on the selected reference current output from the multiplexer, by changing an on/off ratio of the driving current to perform the dimming for each of the plurality of frames. set a plurality of current levels for supply to the light source corresponding to each of the respective plurality of screen modes for display of the image by the display, and to store the plurality of current levels in the storage unit, control the multiplexer to select a reference current having a stored current level corresponding to the screen mode among the plurality of screen modes, and to output the selected reference current to the constant current controller, and control the constant current controller to supply the light source with a driving current having the current level corresponding to the screen mode based on the selected reference current output from the multiplexer, by changing an on/off ratio of the driving current to perform the dimming for each of the plurality of frames.