Patent ID: 7339326

Claim:
An DC/AC converter for supplying two gas discharge lamps, comprising: a pair of input terminals for supplying a DC voltage; a first series circuit interconnecting the input terminals, comprising a first switching element and a second switching element; a second series circuit interconnecting the input terminals, comprising a third switching element and a fourth switching element; a third series circuit interconnecting the input terminals, comprising two compacitors with substantially equal capacitance; a first gas discharge lamp connected between a junction between the first and the second switching elements and the junction between the two capacitors; a second gas discharge lamp connected between the junction between the third and the fourth switching elements and the junction between the two capacitors; wherein an inductor is connected in series with each of the lamps; and control circuit for controlling the first to fourth switching elements, and which is adapted to avoid the simultaneously conducting of the first and second switching elements, the third and the fourth switching elements respectively, wherein the control circuit is adapted to control conducting periods of the switches with a duty cycle which is variable, wherein a series circuit of a further inductor and a diode is connected between one of the input terminals and the first switching element, and wherein a fifth switching element is connected between a junction of the diode and the further inductor and another of the input terminals, the fifth switching elements being controlled by the control circuit.