发明名称 |
Sensing and control for dimmable electronic ballast |
摘要 |
A sensing circuit for a triac dimmable gas discharge lamp ballast uses the duty cycle of the output waveform of a conventional triac dimmer as the parameter representing a set point for controlling the degree of clamping applied to the ballast circuit, and thus the amount of light produced by a fluorescent lamp. The sensing circuit may include a comparator that receives a rectified output waveform of a triac dimmer and produces output pulses corresponding in width to the duty cycle of the waveform, and a capacitor averaging the values of the pulses produced by the comparator to produce a set point signal representing a dimming level of the lamp. A triac dimmable ballast circuit using this sensing circuit has reduced sensitivity to line voltage and a wide mechanical range over which the light level of the fluorescent lamp is controlled by the user. The sensing circuit also enables a preheat timing circuit that eliminates the timing capacitor of prior art preheating circuits. A gas discharge lamp ballast and a method for its operation are also disclosed.
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申请公布号 |
US2002101193(A1) |
申请公布日期 |
2002.08.01 |
申请号 |
US20000731000 |
申请日期 |
2000.12.07 |
申请人 |
GENERAL ELECTRIC COMPANY |
发明人 |
FARKAS THOMAS;RAO NARESH KESAVAN |
分类号 |
H05B41/392;(IPC1-7):H05B37/02 |
主分类号 |
H05B41/392 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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