Circuit arrangement for operating at least one high-pressure discharge lamp

摘要

A circuit arrangement for operating at least one high-pressure discharge lamp ( 16 ), has four switches (Q₁ to Q₄) in a full-bridge arrangement ( 14 ), a first and a second switch (Q₁, Q₂) forming the first half-bridge arm, and a third and a fourth switch (Q₃, Q₄) forming the second half-bridge arm, at least two terminals for coupling the high-pressure discharge lamp ( 16 ) between the midpoint of the first and the second half-bridge arms, at least two terminals for supplying the circuit arrangement ( 10 ) with a dc voltage signal and a drive circuit ( 20 ) for driving the four switches (Q₁ to Q₄). The drive circuit ( 20 ) is designed to provide drive signals, (z₁(t), Z₂(t), {overscore (z₁(t), {overscore (z₂(t)) for the four switches (Q₁ to Q₄), whose clock pulse (ft) is swept between a first and a second frequency, and whose pulse width and/or phase is modulated with a prescribable third frequency (f_a).