Patent ID: 7940502

Claim:
A backlight unit having a protection circuit using a center-tap, the backlight unit comprising: an inverter unit supplying lamp driving power; a lamp group including a plurality of lamps receiving the lamp driving power from the inverter unit and emitting light; a current balancing unit including a plurality of primary coils individually transmitting the lamp driving power from the inverter unit to the plurality of lamps, and a plurality of secondary coils each formed of one conductor having one end, the other end formed at an opposite side of the one side, and a center-tap between the one end and the other end, and each receiving an electromagnetically induced voltage from each of the plurality of primary coils, the one end and the center-tap of each of the plurality of secondary coils connected in series with the one end and the center-tap of the neighboring secondary coil to form at least one closed loop and maintain current transmitted to each of the lamps balanced; a sensing unit sensing a variation in current of the closed loop and a variation in current of the primary coil from the conductor ranging from the center-tap and the other end of the secondary coil of the current balancing unit; and a determination unit comparing a sensed voltage from the sensing unit with a predetermined reference voltage and determining whether each of the lamps performs an abnormal operation or not.