| 摘要 |
A fluorescent ballast and control circuit having a drive signal generator responsive to a drive frequency control signal, the drive signal generator providing a ballast drive signal having a drive signal frequency proportional to the drive frequency control signal. A fluorescent ballast is driven by the ballast drive signal and has an output voltage coupled to drive a fluorescent lamp load. The fluorescent ballast circuit provides a change in the output voltage applied to the lamp load in response to a change in the ballast drive signal frequency. A means for monitoring the brightness of the lamp load develops a brightness signal that characterizes the brightness of the lamp load. A signal conditioner responds to the brightness signal and to a reference signal and provides and adjusts a drive frequency control signal to keep the brightness signal substantially constant.
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