Patent ID: 6956335

Claim:
A circuit arrangement for operating a discharge lamp, the circuit arrangement having reduced power loss, comprising: a first circuit for generating a second DC voltage from a first DC voltage, including input terminals for connection to a voltage source having a cathode and an anode for supplying the first circuit with the first DC voltage, a switching element, a control circuit coupled to the switching element for changing the conductive state of the switching element, a unidirectional element, and a transformer having a primary and a secondary winding; and a second circuit coupled to the secondary winding for supplying current to the discharge lamp; wherein the secondary winding, the input terminals, and the second circuit are coupled together such that the second circuit is supplied by a voltage whose amplitude is equal to the sum of the first DC voltage and the second DC voltage in order to transfer some power from the voltage source directly to the second circuit without passing through the transformer, thereby avoiding power loss that would result if the power directly transferred from the voltage source to the second circuit were instead transferred to the second circuit through the transformer.