Patent ID: 7492106

Claim:
An inverter circuit comprising: an inverter transformer supplying an AC high voltage to a plurality of discharge tubes, one output terminal of the inverter transformer connected to first terminals of the discharge tubes; a plurality of balance transformers, wherein the balance transformers are arranged such that a primary coil and a secondary coil of each of the balance transformers have opposite polarities to each other; and a resistor, wherein first terminals of primary coils of the balance transformers are connected to second terminals of the discharge tubes, and second terminals of the primary coils of the balance transformers are connected to a ground; secondary coils of the balance transformers are connected in series to form a loop; a first terminal of the resistor is connected to the loop and a second terminal of the resistor is connected to the ground; and a voltage detection contact point is located on the loop where at least one secondary coil of the balance transformers is interposed between the voltage detection contact point and a point to which the first terminal of the resistor is connected.