| 摘要 |
Method for operating a ballast for discharge lamps. The ballast comprises a rectifier for rectifying and filtering an AC line voltage, with the rectified voltage being smoothed with a capacitor and fed to an inverter, wherein the inverter drives a resonant lamp circuit that includes a gas discharge lamp, with the frequency of the inverter being generated by a voltage controlled oscillator and a control circuit, so that during normal operation of the lamp, the inverter frequency is chosen according to the current value of the rectified voltage, and during start-up of the ballast, the inverter frequency is lowered from a high starting frequency, while being continuously monitored to ensure the latter does not fall below a minimum frequency, with the value of the minimum frequency depending on the value of the rectified voltage, thus decreasing the dependence of the light flux on the rectified voltage and assuring a safe start-up process.
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