A circuit arrangement for operating a high pressure discharge lamp comprises a down converter equipped with an output capacitor and a commutator equipped with an ignition choke. The amplitude of the DC current generated by the down converter is controlled by means of a control circuit. To suppress resonance of the ignition choke with the output capacitor caused by commutation of the DC current, the current reference signal of the current control is adjusted in dependency of the power consumed by the lamp and in dependency of the lamp voltage immediately before and after each commutation.