Circuit arrangement and method for operating a high-pressure discharge lamp

• Main Author: KAESTLE HERBERT
• Format: Patent
• Language: English
• Published: 05.06.2012
• Subjects: ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY

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 first electronic switch and the second electronic switch, the drive circuit being adapted to provide the first and the second drive signal in such a way that the clock thereof is firstly swept between a first and a second frequency; wherein the drive circuit is furthermore adapted to modulate the first and the second drive signal with a predeterminable third frequency, with the modulation with the predeterminable third frequency being single-tone frequency modulation, with the result that, in the amplitude spectrum of the first and the second drive signal, at least one first, one second and one third spectral line appear, the first spectral line corresponding to the 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 predeterminable third frequency, symmetrically with respect to the first spectral line, and that, in the power spectrum of the signal, at the terminal for connecting the high-pressure discharge lamp, a spectral line at the predeterminable third frequency results.