A backlight unit includes: a light source configured to emit light based on a driving current; a sensing resistor configured to generate a sensing voltage based on the driving current; a first comparator configured to compare the sensing voltage to a first reference voltage divided from a reference power to thereby produce a first comparison signal; a first switching element controlled by the first comparison signal applied from the first comparator to thereby switch the sensing voltage; a second comparator configured to compare the sensing voltage applied via the first switching element to a first ramp signal to thereby produce a second comparison signal; a current control switching element configured to control an amount of the driving current based on the reference power and a current control signal applied from a current controller; an abnormality detector configured to convert the second comparison signal applied from the second comparator into a DC voltage and to compare the DC voltage to a critical voltage to thereby generate a third comparison signal; and a cut-off controller configured to compare the third comparison signal applied from the abnormality detector to a cut-off voltage to control the reference power based on the comparison result.