Load control device for a light-emitting diode light source
First Claim
1. A load control device for controlling an intensity of a lighting load, the load control device comprising:
- a regulation circuit configured to control a magnitude of a load current conducted through the lighting load, the regulation circuit including a regulation transistor adapted to be coupled in series with the lighting load, the regulation transistor having a gate configured to receive a gate voltage; and
a control circuit operatively coupled to the regulation transistor of the regulation circuit, the control circuit configured to adjust the magnitude of the load current to control the intensity of the lighting load to a target intensity, the control circuit configured to adjust a frequency and an on time of the gate voltage received by the gate of the regulation transistor to adjust the intensity of the lighting load;
wherein the control circuit is configured to control the intensity of the lighting load by maintaining the frequency of the gate voltage constant and adjusting the on time of the gate voltage when the target intensity is above a predetermined threshold, and adjusting the frequency of the gate voltage when the target intensity is below the predetermined threshold.
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Accused Products
Abstract
A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.
56 Citations
20 Claims
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1. A load control device for controlling an intensity of a lighting load, the load control device comprising:
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a regulation circuit configured to control a magnitude of a load current conducted through the lighting load, the regulation circuit including a regulation transistor adapted to be coupled in series with the lighting load, the regulation transistor having a gate configured to receive a gate voltage; and a control circuit operatively coupled to the regulation transistor of the regulation circuit, the control circuit configured to adjust the magnitude of the load current to control the intensity of the lighting load to a target intensity, the control circuit configured to adjust a frequency and an on time of the gate voltage received by the gate of the regulation transistor to adjust the intensity of the lighting load; wherein the control circuit is configured to control the intensity of the lighting load by maintaining the frequency of the gate voltage constant and adjusting the on time of the gate voltage when the target intensity is above a predetermined threshold, and adjusting the frequency of the gate voltage when the target intensity is below the predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A load control device for controlling power delivered from an AC power source to a lighting load, the load control device comprising:
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a flyback converter configured to receive a rectified AC voltage and to generate a DC bus voltage, the flyback converter configured to provide isolation between the AC power source and the lighting load; a buck converter configured to receive the DC bus voltage and control a magnitude of a load current conducted through the lighting load, the buck converter including a regulation transistor adapted to be coupled in series with the lighting load, the regulation transistor having a gate configured to receive a gate voltage; and a control circuit operatively coupled to the regulation transistor and configured to adjust the magnitude of the load current to control an intensity of the lighting load to a target intensity, the control circuit configured to adjust a frequency and an on time of the gate voltage received by the gate of the regulation transistor; wherein the control circuit is configured to control the intensity of the lighting load by maintaining the frequency of the gate voltage constant and adjusting the on time of the gate voltage when the target intensity is above a predetermined threshold, and adjusting the frequency of the gate voltage when the target intensity is below the predetermined threshold. - View Dependent Claims (12, 13, 14, 15)
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16. A method for controlling an intensity of a lighting load, the method comprising:
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receiving a target intensity for the lighting load; adjusting a magnitude of a load current conducted through the lighting load to control the intensity of the lighting load towards the target intensity by adjusting at least one of a frequency and an on time of a gate voltage received by a gate of a regulation transistor; when the target intensity is above a predetermined threshold, maintaining the frequency of a gate voltage constant and adjusting the on time of the gate voltage to control the intensity of the lighting load; and when the target intensity is below the predetermined threshold, adjusting the frequency of the gate voltage to control the intensity of the lighting load. - View Dependent Claims (17, 18, 19, 20)
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Specification