A display apparatus including: a display; a driver including an amplifier configured to detect a current of the display and to generate a constant current control signal, and a transistor configured to adjust the current supplied to the display in accordance an output voltage of the amplifier; and a controller configured to monitor the current of the display and a dropout voltage of the transistor, and control the amplifier so that a pulse width modulation (PWM) duty ratio is decreased in response to the dropout voltage being equal to or higher than a reference voltage.