Patent ID: 8098022

Claim:
A circuit arrangement for operating at least one discharge lamp, comprising: a first and a second input terminal for connecting a supply voltage; an inverter, which comprises at least one first switch and one second switch, which are coupled in series between the first and the second input terminal and between which a bridge center point is defined; a drive circuit for at least the first switch and the second switch with an input for receiving a control signal; an apparatus for generating an auxiliary voltage, the apparatus comprising: a first capacitor; a terminal for the provision of the auxiliary voltage, which terminal is coupled to a reference potential via the first capacitor; a two-state controller with a first input to which the control signal in inverted form is coupled, a second input, which is coupled to the terminal for the provision of the auxiliary voltage, and an output; a switch with a control electrode, a working electrode and a reference electrode, the control electrode being coupled to the output of the two-state controller, the working electrode being coupled to the terminal for the provision of the auxiliary voltage; and a nonreactive resistor; wherein the apparatus for generating the auxiliary voltage furthermore comprises a transformer with a primary winding and a secondary winding, the transformer being coupled to the first and the second input terminal, the terminal for the provision of the auxiliary voltage and the switch in such a way that a current through the switch results in a current through the primary winding, in a current through the secondary winding and therefore in charging of the first capacitor.