Patent ID: 6891337

Claim:
A lighting system comprising: a d.c. voltage supply which is clocked at a converter frequency and supplies an operating voltage, an inverter which is fed by the operating voltage and has output terminals at which a lamp voltage is present, a high-pressure discharge lamp which is connected to the output terminals and has at least one acoustic resonant frequency, wherein: the converter frequency is an n-fold multiple of the at least one acoustic resonant frequency of the high-pressure discharge lamp, where n is a natural number other than zero, the inverter is designed as a half-bridge, in which case an upper and a lower half-bridge switch (S 2 , S 3 ) are switched alternately on and off at an inverter frequency, the inverter frequency is modulated, and the lighting system further comprises a saw-tooth voltage generator ( 2 ) that emits a saw-tooth voltage which is fed to a VCO ( 3 ) which generates an inverter frequency modulated by the characteristic of the saw-tooth voltage and by means of which the half-bridge switches (S 2 , S 3 ) are driven.