| 摘要 |
A lamp driver circuit supplies an alternating current having an operating frequency to a lamp, e.g. a fluorescent lamp, for operating the lamp. To switch off the lamp, the frequency of the alternating current is changed to a non-operating frequency. Due to the frequency change, the impedance of an impedance element of the lamp driver circuit is changed. As a result, the lamp current decreases to zero and the lamp extinguishes. According to the invention, the current having the non-operating frequency is employed to generate a voltage to be supplied to a further circuit, such as a control circuit. Thus, the lamp driver circuit and an associated control circuit may operate in an operating mode or in a standby, i.e. non-operating, mode without requiring a separate voltage supply source. In the standby mode, the control circuit may be controlled to switch the lamp driver circuit from the non-operating mode into the operating mode, thereby switching the lamp on.
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