Patent ID: 7154228

Claim:
Circuit arrangement for operating a high pressure discharge lamp equipped with input terminals for connection to poles of a supply voltage source, a DC-DC-converter coupled to the input terminals and comprising an inductive element L 1 , a unidirectional element D 1 , a switching element S 1 , output terminals, a first control circuit coupled to a control electrode of the switching element S 1 for generating a control signal for rendering the switching element S 1 alternately conductive and non-conductive, a second control circuit, coupled with the first control circuit for controlling the level of an output voltage of the DC-DC converter that is present between the output terminals, a DC-AC-converter coupled to the output terminals and equipped with lamp connection terminals for generating an AC lamp current out of the output voltage, characterized in that the second control circuit is further equipped with a state control circuit for changing the level at which the output voltage is controlled from a first level associated with the starting of the high pressure discharge lamp to a second level associated with the stationary operation of the high pressure discharge lamp.