Lighting system having photocontrol and fault monitoring capabilities
First Claim
1. A lighting circuit, comprising:
- a photosensor for detecting ambient light levels and for generating an ambient light signal comprising an indication of the level of ambient light;
a relay disposed between a power source and a light source to selectively allow the power source to provide power to the light source;
a photocontrol circuit electrically coupled to the relay and to the photosensor, the photocontrol circuit for;
receiving the ambient light signal from the photosensor;
determining whether the level of ambient light is below an activation threshold; and
in response to the level of ambient light being below the activation threshold, causing the relay to allow power from the power source to the light source; and
a fault detection circuit for monitoring for faults in the lighting circuit by comparing whether power should be provided to the light source based on the level of ambient light and whether power is actually being provided to the light source, whereinthe ambient light signal comprises a voltage level indicative of the level of ambient light and the photocontrol circuit determines whether the level of ambient light is below an activation threshold by comparing the voltage level to a threshold voltage.
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Accused Products
Abstract
A photocontroller operates one or more lamps, such as a GU24 compact fluorescent lamp, based on ambient light to provide dusk-to-dawn operation. The photocontroller includes a photosensor for detecting the level of ambient light. The photosensor provides a signal to a photocontrol circuit that controls a switching device to selectively provide power to the lamp based on the level of ambient light detected by the photosensor. A fault detection circuit monitors the level of ambient light and the status of the lamp to determine whether the photocontroller is operating properly. The fault detection circuit determines the status of the lamp based on current flow to the lamp as determined by a current sensor. In addition, the photocontroller can include a processor for performing certain photocontrol and fault monitoring functions.
23 Citations
30 Claims
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1. A lighting circuit, comprising:
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a photosensor for detecting ambient light levels and for generating an ambient light signal comprising an indication of the level of ambient light; a relay disposed between a power source and a light source to selectively allow the power source to provide power to the light source; a photocontrol circuit electrically coupled to the relay and to the photosensor, the photocontrol circuit for; receiving the ambient light signal from the photosensor; determining whether the level of ambient light is below an activation threshold; and in response to the level of ambient light being below the activation threshold, causing the relay to allow power from the power source to the light source; and a fault detection circuit for monitoring for faults in the lighting circuit by comparing whether power should be provided to the light source based on the level of ambient light and whether power is actually being provided to the light source, wherein the ambient light signal comprises a voltage level indicative of the level of ambient light and the photocontrol circuit determines whether the level of ambient light is below an activation threshold by comparing the voltage level to a threshold voltage. - View Dependent Claims (2, 3, 4, 5, 28)
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6. A lighting circuit, comprising:
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a photosensor for detecting ambient light levels and for generating an ambient light signal comprising an indication of the level of ambient light; a relay disposed between a power source and a light source to selectively allow the power source to provide power to the light source; a photocontrol circuit electrically coupled to the relay and to the photosensor, the photocontrol circuit for; receiving the ambient light signal from the photosensor; determining whether the level of ambient light is below an activation threshold; and in response to the level of ambient light being below the activation threshold, causing the relay to allow power from the power source to the light source; a fault detection circuit for monitoring for faults in the lighting circuit by comparing whether power should be provided to the light source based on the level of ambient light and whether power is actually being provided to the light source; and a current sensor for detecting electrical current flow to the light source and logically coupled to the fault detection circuit. - View Dependent Claims (7, 8)
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9. A lighting circuit, comprising:
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a photosensor for detecting ambient light levels and for generating an ambient light signal comprising an indication of the level of ambient light; a relay disposed between a power source and a light source to selectively allow the power source to provide power to the light source; a photocontrol circuit electrically coupled to the relay and to the photosensor, the photocontrol circuit for; receiving the ambient light signal from the photosensor; determining whether the level of ambient light is below an activation threshold; and in response to the level of ambient light being below the activation threshold, causing the relay to allow power from the power source to the light source; and a fault detection circuit for monitoring for faults in the lighting circuit by comparing whether power should be provided to the light source based on the level of ambient light and whether power is actually being provided to the light source, wherein the fault detection circuit comprises a processor logically coupled to a second photosensor and comprising information indicating the activation threshold, and the processor determines power should be provided to the light source by comparing a level of ambient light detected by the second photosensor to the activation threshold.
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10. A lighting circuit, comprising:
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a GU24 compact fluorescent lamp; a photocontroller for selectively providing power to the lamp from a power source, the photocontroller comprising; a relay comprising a set of relay contacts disposed between the power source and the lamp; a photosensor for detecting ambient light levels and for generating an ambient light signal comprising an indication of the level of ambient light; a processor for; receiving the ambient light signal from the photosensor; determining whether the level of ambient light exceeds a deactivation threshold; based on a determination that the level of ambient light exceeds the deactivation threshold, providing a signal to the relay to cause the relay contacts to open and block power from reaching the lamp; determining whether power is being provided to the lamp; and determining that a fault exists if power is being provided to the lamp when the level of ambient light exceeds the deactivation threshold; and one of a visual or an audible indicator logically coupled to the processor, wherein the processor activates the indicator upon determining that a fault exists. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 29)
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18. A lighting circuit, comprising:
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a light source; a switching mechanism disposed between the light source and a power source for allowing the power source to activate the light source upon receipt of a command signal; a photosensor for detecting ambient light levels and for adjusting a voltage level in response to the level of ambient light detected; a first voltage comparator having a first input for receiving the voltage level, a second input coupled to a reference voltage, and an output coupled to the switching mechanism, the first voltage comparator operable to provide the command signal to the switching mechanism in response to the voltage level indicating a low level of ambient light based on a comparison of the voltage level with the reference voltage; and a fault detection circuit for detecting a first fault condition in the lighting circuit when the command signal is not provided to the switching mechanism by the first voltage comparator and power is being provided to the light source, wherein the fault detection circuit further detects a second fault condition in the lighting circuit when the command signal is provided to the switching mechanism by the first voltage comparator and power is not being provided to the light source. - View Dependent Claims (21, 22, 30)
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19. A lighting circuit, comprising:
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a light source; a switching mechanism disposed between the light source and a power source for allowing the power source to activate the light source upon receipt of a command signal; a photosensor for detecting ambient light levels and for adjusting a voltage level in response to the level of ambient light detected; a first voltage comparator having a first input for receiving the voltage level, a second input coupled to a reference voltage, and an output coupled to the switching mechanism, the first voltage comparator operable to provide the command signal to the switching mechanism in response to the voltage level indicating a low level of ambient light based on a comparison of the voltage level with the reference voltage; and a fault detection circuit for detecting a first fault condition in the lighting circuit when the command signal is not provided to the switching mechanism by the first voltage comparator and power is being provided to the light source, wherein the fault detection circuit comprises a second voltage comparator for detecting an electrical short circuit fault condition in the photosensor by comparing the voltage level to a short circuit reference voltage level. - View Dependent Claims (25, 26, 27)
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20. A lighting circuit, comprising:
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a light source; a switching mechanism disposed between the light source and a power source for allowing the power source to activate the light source upon receipt of a command signal; a photosensor for detecting ambient light levels and for adjusting a voltage level in response to the level of ambient light detected; a first voltage comparator having a first input for receiving the voltage level, a second input coupled to a reference voltage, and an output coupled to the switching mechanism, the first voltage comparator operable to provide the command signal to the switching mechanism in response to the voltage level indicating a low level of ambient light based on a comparison of the voltage level with the reference voltage; and a fault detection circuit for detecting a first fault condition in the lighting circuit when the command signal is not provided to the switching mechanism by the first voltage comparator and power is being provided to the light source, wherein the fault detection circuit comprises a second voltage comparator for detecting an electrical open circuit fault condition in the photosensor by comparing the voltage level to an open circuit reference voltage level.
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23. A lighting circuit, comprising:
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a light source; a switching mechanism disposed between the light source and a power source for allowing the power source to activate the light source upon receipt of a command signal; a photosensor for detecting ambient light levels and for adjusting a voltage level in response to the level of ambient light detected; a first voltage comparator having a first input for receiving the voltage level, a second input coupled to a reference voltage, and an output coupled to the switching mechanism, the first voltage comparator operable to provide the command signal to the switching mechanism in response to the voltage level indicating a low level of ambient light based on a comparison of the voltage level with the reference voltage; and a fault detection circuit for detecting a first fault condition in the lighting circuit when the command signal is not provided to the switching mechanism by the first voltage comparator and power is being provided to the light source, wherein the fault detection circuit comprises a current sensor for detecting electrical current flow to the light source, and the fault detection circuit determines that power is being provided to the light source in response to the current sensor detecting current flow to the light source. - View Dependent Claims (24)
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Specification