| 摘要 |
A three light level electronic ballast, and methods of operating lamps at three light levels, are provided. The ballast includes a rectifier, a power factor correction circuit, an inverter circuit, a first circuit, a second circuit, and a control circuit. The rectifier receives an AC voltage signal and produces a rectified voltage signal, which the power factor correction circuit receives and uses to provide a corrected voltage signal. The inverter circuit receives the corrected voltage signal and provides an energizing signal to power at least two lamps. The first circuit selectively reduces the current applied to the lamps by the energizing signal. The second circuit selectively prevents the second lamp from being energized by the energizing signal. The control circuit controls the first circuit and the second circuit. |
