Patent ID: 7141935

Claim:
An inverter circuit for discharge lamps, comprising: a plurality of leakage flux step-up transformers each having a magnetically continuous central core, a primary winding, and a distributed-constant secondary winding, wherein a part of a resonance circuit is formed among a leakage inductance produced on the secondary winding side, a distributed capacitance of said secondary winding and a parasitic capacitance produced around a discharge lamp close to a proximity conductor, and as said resonance circuit resonates, said secondary winding has a close coupling portion in a vicinity of said primary winding which has a magnetic phase close to that of said primary winding and magnetically close couples with said primary winding and where a large portion of a magnetic flux produced under said primary winding penetrates, and a loose coupling portion distant from said primary winding which has a magnetic phase delayed form that of said primary winding and where a large portion of said magnetic flux produced under said primary winding leaks, wherein a first end of each of the secondary windings is connected to a first end of each of a plurality of discharge lamps, whereby the plurality of discharge lamps are lighted in parallel.