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

A method for starting and operating a high-pressure discharge lamp with a circuit arrangement, the circuit arrangement comprising:

• a half-bridge arrangement with a half-bridge center point, said half-bridge arrangement being connected to an intermediate circuit voltage with a reference potential and a feed voltage potential,
• a lamp inductor, which is connected at one end to the half-bridge center point, a starting stage, which is connected to the other end of the lamp inductor and to the intermediate circuit voltage,
• a first switch, which is connected between the reference potential of the intermediate circuit voltage and the starting stage,
• a series circuit of a first and a second capacitor, said series circuit being connected to the intermediate circuit voltage,
• terminals for connecting a high-pressure discharge lamp, wherein a first terminal is connected to the starting stage and a second terminal is connected to a node between the first and second capacitors,
• a two-port network, a first port of said two-port network being connected to the starting stage and a second port of said two-port network being connected to the node between the first and second capacitors, wherein
• the first switch can be activated in order to generate starting pulses for starting a high-pressure discharge lamp which is connected to the circuit arrangement and in order to discharge the second capacitor via the two-port network,
• the method comprising:
• generating a starting voltage,
• discharging the second capacitor to a predetermined first voltage by means of clocked activation of the first switch with a first frequency and a first pulse duty factor for a first time period,
• generating a starting voltage,
• charging of the second capacitor to a predetermined second voltage by means of clocked activation of the first switch with a second frequency and a second pulse duty factor for a second time period,
• generating a square-wave AC voltage for operating the high-pressure discharge lamp, and
• opening the first switch permanently.