| 摘要 |
An electronic ballast (60) for providing electrical energy to one or more fluorescent lamps (22, 32) having electrical discharge filaments (24, 26; 34, 36). The ballast includes a pre-heating circuit (40) having a first resonant frequency (F1), coupled to pre-heat the filaments. An ignition driver circuit (52) having a second resonant frequency (F2) is coupled to ignite an electrical discharge through a gas between the filaments. Power controller circuitry (58, 64, 66, 68) provides power to the pre-heating and ignition driver circuits in succession, so as to ignite the one or more lamps. The power controller circuitry first provides power to the pre-heating circuit substantially at the first resonant frequency and subsequently provides power to the ignition driver circuit substantially at the second resonant frequency, by a smooth operating frequency transition from pre-heating to ignition. The ballast also features a voltage-controlled pre-heating circuit, and circuit configuration capable of igniting the lamps even in the case where one or both of the filaments are broken.
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