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 load regulation circuit configured to control a magnitude of a load current conducted through the lighting load, the load regulation circuit including a regulation transistor adapted to be coupled in series with the lighting load; and
a control circuit operatively coupled to the regulation transistor of the load regulation circuit for adjusting the magnitude of the load current to control the intensity of the lighting load to a target intensity, the control circuit configured to generate a control signal for rendering the regulation transistor conductive and non-conductive;
wherein the control circuit is configured to control the intensity of the lighting load by maintaining a frequency of the control signal constant and adjusting an on time of the control signal when the target intensity is above a predetermined threshold, and adjusting the frequency of the control signal 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.
54 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 load regulation circuit configured to control a magnitude of a load current conducted through the lighting load, the load regulation circuit including a regulation transistor adapted to be coupled in series with the lighting load; and a control circuit operatively coupled to the regulation transistor of the load regulation circuit for adjusting the magnitude of the load current to control the intensity of the lighting load to a target intensity, the control circuit configured to generate a control signal for rendering the regulation transistor conductive and non-conductive; wherein the control circuit is configured to control the intensity of the lighting load by maintaining a frequency of the control signal constant and adjusting an on time of the control signal when the target intensity is above a predetermined threshold, and adjusting the frequency of the control signal when the target intensity is below the predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. 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; and a control circuit operatively coupled to the regulation transistor for adjusting the magnitude of the load current to control an intensity of the lighting load to a target intensity, the control circuit configured to generate a control signal for rendering the regulation transistor conductive and non-conductive; wherein the control circuit is configured to control the intensity of the lighting load by maintaining a frequency of the control signal constant and adjusting an on time of the control signal when the target intensity is above a predetermined threshold, and adjusting the frequency of the control signal when the target intensity is below the predetermined threshold. - View Dependent Claims (15, 16, 17)
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18. A method for controlling an intensity of a lighting load, the method comprising:
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generating a control signal for rendering a regulation transistor conductive and non-conductive to adjust a magnitude of a load current conducted through the lighting load; receiving a target intensity for the lighting load; when the target intensity is above a predetermined threshold, maintaining a frequency of the control signal constant and adjusting an on time of the control signal to control the intensity of the lighting load; and when the target intensity is below the predetermined threshold, adjusting the frequency of the control signal to control the intensity of the lighting load. - View Dependent Claims (19, 20)
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Specification