System for preventing oscillations in a fluorescent lamp ballast
First Claim
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1. A ballast for providing power to a fluorescent lamp from a substantially sinusoidal source of input power having variable conduction and non-conduction periods, the ballast comprising:
- a power stage for converting the input power to drive the fluorescent lamp;
a control circuit for controlling the power stage as a function of the variable conduction and non-conduction periods;
a control circuit power supply operable to draw power from the input power source and provide control power to the control circuit; and
a monitor and enabling circuit which permits the ballast to deliver power to the lamp only when characteristics of the input power source meet predetermined criteria.
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Abstract
A ballast adapted to power a fluorescent lamp as a function of a variable input signal, includes a power stage for providing power to a fluorescent lamp; a control circuit for controlling the power stage as a function of the variable input signal; a control circuit power supply for supplying control power to the control circuit; and a monitor and enabling circuit which permits the ballast to provide power to the lamp only when characteristics of the variable input signal meet predetermined criteria.
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Citations
60 Claims
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1. A ballast for providing power to a fluorescent lamp from a substantially sinusoidal source of input power having variable conduction and non-conduction periods, the ballast comprising:
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a power stage for converting the input power to drive the fluorescent lamp; a control circuit for controlling the power stage as a function of the variable conduction and non-conduction periods; a control circuit power supply operable to draw power from the input power source and provide control power to the control circuit; and a monitor and enabling circuit which permits the ballast to deliver power to the lamp only when characteristics of the input power source meet predetermined criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A ballast for providing power to a fluorescent lamp from a substantially sinusoidal source of input power having variable conduction and non-conduction periods, the ballast comprising:
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a power stage for converting the input power to drive the lamp; a control circuit for controlling the power stage; a control circuit power supply operable to draw power from the input power source and provide control power to the control circuit; the control circuit being operable to turn the power stage off when the power stage is not capable of delivering power to the lamp on a substantially uninterrupted basis in response to the input power source; and a monitor and enabling circuit operable to permit the control circuit power supply to draw current from the input power source only when characteristics of the input power source meet predetermined criteria. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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55. A ballast for providing power to a fluorescent lamp from a substantially sinusoidal source of input power having variable conduction and non-conduction periods, the ballast comprising:
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a power stage for converting the input power to drive the lamp; a control circuit for controlling the power stage; a control circuit power supply operable to draw power from the input power source and provide control power to the control circuit; and a monitor and enabling circuit including a monitoring stage and a switching stage, the switching stage permitting the ballast to deliver power to the lamp only when the monitoring stage indicates that the characteristics of the input power source meet predetermined criteria. - View Dependent Claims (56, 57, 58, 59, 60)
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Specification