| 摘要 |
A system and method for open loop bi-level ballast control providing multiple levels of illumination from a ballast-driven lamp. Power to a lamp is adjusted in response to a lamp control signal by adjusting the frequency driving the ballast powering the lamp. Line voltage feeds an AC/DC converter, which supplies DC voltage to a high frequency (HF) ballast. A frequency control circuit responds to a lamp control signal and supplies a ballast frequency signal to the HF ballast, which responds to the ballast frequency signal and adjusts the current supplied to the lamp accordingly. In one embodiment, the lamp control signal can be a bi-level signal providing bi-level illumination.
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