Patent ID: 7312583

Claim:
An apparatus for driving a lamp unit, comprising: at least one lamp; an inverter to supply an alternating current signal; a transformer to boost the signal from the inverter and to supply the boosted signal to the lamp, wherein the transformer includes a primary winding wire connected to the inverter to generate the alternating current signal, a secondary winding wire induced by the primary winding wire to amplify the alternating current signal, and an auxiliary winding wire arranged between the primary winding wire and the secondary winding wire; and a safety circuit to detect the boosted signal flowing to the lamp and to compare the detected signal with a predetermined threshold to shut down the inverter based on the comparison, wherein the safety circuit includes a detector to detect the boosted signal, a rectifier to rectify the detected signal from the detector into a direct current level, a comparing part to compare the rectified signal from the rectifier with the predetermined threshold, and a switching part to switch the apparatus between a shut down state and an operating state in response to the resulting signal from the comparing part, wherein the detector is connected between the secondary winding wire and the lamp to detect the amplified signal and the detected signal is a current.