Patent ID: 8193728

Claim:
A circuit arrangement for operating a high-pressure discharge lamp, comprising: at least one first electronic switch and one second electronic switch in a half-bridge arrangement; a supply voltage terminal for supplying the half-bridge arrangement with a DC voltage signal; a load circuit, which comprises a lamp inductor and is coupled firstly to the half-bridge center point and secondly to at least one terminal for connecting the high-pressure discharge lamp; a drive circuit for providing at least one first and one second drive signal for the at least one first electronic switch and the second electronic switch, the drive circuit being configured to provide the first and the second drive signal such that a clock thereof is firstly swept between a first and a second frequency; wherein the drive circuit is furthermore configured to modulate the first and the second drive signals with a predetermined third frequency, with the modulation with the predetermined third frequency being single-tone frequency modulation, selected so that, in an amplitude spectrum of the first and the second drive signals, at least one first, one second and one third spectral line appear, the first spectral line corresponding to an instantaneous frequency of the swept clock, and the second and the third spectral lines, in terms of absolute value, appearing at an interval with respect to the predetermined third frequency, symmetrically with respect to the first spectral line, and so that, in a power spectrum of the signal, at the at least one terminal for connecting the high-pressure discharge lamp, there is a spectral line at the predetermined third frequency.