Load control device for a light-emitting diode light source
First Claim
1. A light-emitting diode (LED) driver for controlling an intensity of an LED light source, the LED driver comprising:
- an LED drive circuit configured to control a magnitude of a load current conducted through the LED light source, the LED drive circuit including a regulation transistor adapted to be coupled in series with the LED light source, the regulation transistor having a gate configured to receive a gate voltage; and
a control circuit operatively coupled to the regulation transistor of the LED drive circuit, the control circuit configured to adjust the magnitude of the load current to control the intensity of the LED light source 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 LED light source;
wherein the control circuit is configured to control the intensity of the LED light source by maintaining the frequency of the gate voltage constant and adjusting the on time of the gate voltage when the target intensity is greater than a predetermined threshold, and adjusting the frequency of the gate voltage when the target intensity is less than 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.
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Citations
20 Claims
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1. A light-emitting diode (LED) driver for controlling an intensity of an LED light source, the LED driver comprising:
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an LED drive circuit configured to control a magnitude of a load current conducted through the LED light source, the LED drive circuit including a regulation transistor adapted to be coupled in series with the LED light source, the regulation transistor having a gate configured to receive a gate voltage; and a control circuit operatively coupled to the regulation transistor of the LED drive circuit, the control circuit configured to adjust the magnitude of the load current to control the intensity of the LED light source 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 LED light source; wherein the control circuit is configured to control the intensity of the LED light source by maintaining the frequency of the gate voltage constant and adjusting the on time of the gate voltage when the target intensity is greater than a predetermined threshold, and adjusting the frequency of the gate voltage when the target intensity is less than the predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for controlling an intensity of a light-emitting diode (LED) light source, the method comprising:
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receiving a target intensity for the LED light source; generating a control signal for controlling a gate voltage received by a gate of a regulation transistor to adjust a magnitude of a load current conducted through the LED light source and control the intensity of the LED light source towards the target intensity; when the target intensity is greater than a predetermined threshold, maintaining a frequency of a gate voltage constant and adjusting an on time of the gate voltage to control the intensity of the LED light source; and when the target intensity is below the predetermined threshold, adjusting the frequency of the gate voltage to control the intensity of the LED light source. - View Dependent Claims (19, 20)
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Specification