Patent ID: 7541744

Claim:
An electronic ballast for operating a high-pressure discharge lamp (L) having a converter having at least two switching transistors (S 1 , S 2 ) for the purpose of producing a supply power for the lamp (L) using a switching operation for the switching transistors (S 1 , S 2 ) having a first switching phase and a second switching phase, the first switching phase having only a first polarity, the second switching phase having only a second alternate polarity, characterized by a current-measuring device (R 1 , R 2 , C 6 ) having a measuring resistor (R 1 ), which is connected in series with at least one of the switching transistors (S 1 , S 2 ) and is designed to carry out current measurements only during a selected one of the first switching phase and the second switching phases of the converter.