Patent ID: 8736196

Claim:
A backlight unit comprising: a light source; an inverter which provides the light source with an input voltage; and a printed circuit board connected to the light source, wherein the printed circuit board includes a protection circuit which detects an open-lamp-protection voltage which varies according to a change of the input voltage, and changes a reference voltage according to the change of the input voltage, and wherein the protection circuit turns off the inverter when the detected open-lamp-protection voltage is higher than the changed reference voltage by comparing the detected open-lamp-protection voltage with the changed reference voltage, and wherein the protection circuit includes; a voltage detection part which distributes the input voltage applied to the light source by using a capacitor to detect the open-lamp-protection voltage; a reference voltage changing part which distributes the input voltage by using the capacitor to change the reference voltage according to the change of the input voltage; and a protection-control signal generation part which compares the open-lamp-protection voltage with the reference voltage and generates a protection-control signal Which controls the operation of the inverter.