| 摘要 |
A backlight unit is provided to reduce a current difference between lamps by detecting current flowing on a first coil of a transformer and controlling output of an inverter through the detected current. A backlight unit(190) comprises a backlight(150) consisting of a plurality of lamps, and an inverter controlling tube current supplied to the backlight. The inverter includes a transformer(166) boosting the voltage of an alternating signal to supply the boosted alternating signal to the lamps, a feedback signal generator(168) detecting alternating current flowing on a first coil of the transformer to generate a feedback signal, a controller(162) generating a switching control signal in response to the feedback signal, a switching unit(164) converting a direct signal supplied from the outside into the alternating signal to supply the alternating signal to the transformer, and an overvoltage detector(169) detecting alternating voltage supplied to the lamps from a secondary coil of the transformer and returning the alternating voltage to the controller. The controller cuts off the alternating signal applied to the lamps by varying a duty rate of PWM(Pulse Width Modulation) to control the switching unit, when receiving an overvoltage detection signal. |
