Circuit for operating at least one high-pressure discharge lamp

摘要

The circuit arrangement has four switches (Q 1-Q 4) in a full bridge arrangement (14). First and second switches form a first half bridge branch and third and fourth switches form a second half bridge branch. At least two connections couple the lamp (16) between the center point of the first and second half bridge branches, at least two connections supply the circuit arrangement with a d.c. voltage signal and a control circuit controls the four switches by providing control signals (z 1(t),..) whose clock is swept between first and second frequencies and whose pulse width and/or phase is/are modulated with a third frequency.