| 摘要 |
The invention relates to a method and a circuit arrangement for operating a discharge lamp. In the preheating phase, the actual value of the load current is registered, a first time-invariant setpoint value of the load current, which corresponds to a desired actual value of a load current in the preheating phase, is formed, and a clock generator is activated, which runs freely at a frequency which is less than the resonant frequency of the load circuit when the lamp is off and is greater than the resonant frequency of the load circuit when the lamp is on. The preheating phase is terminated after a first predeterminable time period has elapsed. In the striking phase, the actual value of the load current in the load circuit is registered, a time-varying setpoint value of the load current is formed, and the clock generator is synchronized with the frequency of an inverter. The striking phase is terminated as soon as the setpoint value of the load current reaches a value at which an on-time of a half-bridge switching element is greater than. the period of the free-running clock generator. In normal operation. the actual value of the load current is registered and a second time-invariant setpoint value of the load current is formed, which setpoint value corresponds to a desired actual value of the load current in normal operation. |
