Circuit device

A circuit device for operating a discharge lamp by means of a high-frequency current, said circuit device comprising:

• a. input terminals for connecting said device to a low-frequency supply voltage source and rectifier means coupled to the input terminals for rectifying the low-frequency supply voltage;
• b. a first circuit coupled to a first output terminal N3 of the rectifier means and to a second output terminal N5 of the rectifier means, said first circuit comprising a series arrangement of first unidirectional means, second unidirectional means and first capacitive means;
• c. an inverter connected in parallel with the first capacitive means for generating the high-frequency current,
• d. a load circuit comprising a series arrangement of inductive means, second capacitive means and means for applying a voltage to the discharge lamp, said load circuit coupling a terminal N1 of the inverter to a terminal N2 between the first unidirectional means and the second unidirectional means;
• e. a second circuit coupling the terminal N2 to a terminal (N4) between the second unidirectional means and the first capacitive means and comprising third capacitive means;
• f. a third circuit coupling the first output terminal N3 of the rectifier means to the terminal N4, said third circuit comprising a series arrangement of third unidirectional means and fourth unidirectional means;
• g. a fourth circuit coupling the third circuit to a terminal N6, which forms part of the load circuit;
• h. a fifth circuit by means of which the fourth circuit couples the third circuit to the terminal N6, said fifth circuit comprising a transformer for coupling the terminal N4 to the fourth circuit, said transformer having a tap coupled to a terminal N7 between the third unidirectional means and the fourth unidirectional means.