Load Control Device for a Light-Emitting Diode Light Source
First Claim
1. A load control device for controlling the intensity of an lighting load, the load control device comprising:
- a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage;
a load control circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, the load control circuit comprising a controllable-impedance circuit adapted to be coupled in series with the lighting load; and
a controller operatively coupled to the power converter circuit for adjusting the magnitude of the bus voltage to a target bus voltage, so as to control the magnitude of a controllable-impedance voltage generated across the controllable-impedance circuit, the controller operatively coupled to the load control circuit for generating a drive signal for controlling the controllable-impedance circuit to thus adjust the magnitude of the load current through the lighting load;
wherein the controller is operable to control both the magnitude of the load current and the magnitude of the controllable-impedance voltage to adjust the intensity of the lighting load, the controller operable to control the magnitude of the controllable-impedance voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage.
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Accused Products
Abstract
An LED driver for controlling the intensity of an LED light source includes a power converter circuit for generating a DC bus voltage, an LED drive circuit for receiving the bus voltage and controlling a load current through, and thus the intensity of, the LED light source, and a controller operatively coupled to the power converter circuit and the LED drive circuit. The LED drive circuit comprises a controllable-impedance circuit adapted to be coupled in series with the LED light source. The controller adjusts the magnitude of the bus voltage to a target bus voltage and generates a drive signal for controlling the controllable-impedance circuit. To adjust the intensity of the LED light source, the controller controls both the magnitude of the load current and the magnitude of the regulator voltage. The controller controls the magnitude of the regulator voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage.
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Citations
22 Claims
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1. A load control device for controlling the intensity of an lighting load, the load control device comprising:
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a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage; a load control circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, the load control circuit comprising a controllable-impedance circuit adapted to be coupled in series with the lighting load; and a controller operatively coupled to the power converter circuit for adjusting the magnitude of the bus voltage to a target bus voltage, so as to control the magnitude of a controllable-impedance voltage generated across the controllable-impedance circuit, the controller operatively coupled to the load control circuit for generating a drive signal for controlling the controllable-impedance circuit to thus adjust the magnitude of the load current through the lighting load; wherein the controller is operable to control both the magnitude of the load current and the magnitude of the controllable-impedance voltage to adjust the intensity of the lighting load, the controller operable to control the magnitude of the controllable-impedance voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An LED driver for controlling the intensity of an LED light source, the LED driver comprising:
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a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage; an LED drive circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the LED light source to thus control the intensity of the LED light source, the LED drive circuit comprising a controllable-impedance circuit adapted to be coupled in series with the LED light source; and a controller operatively coupled to the power converter circuit for adjusting the magnitude of the bus voltage to a target bus voltage, so as to control the magnitude of a regulator voltage generated across the controllable-impedance circuit, the controller operatively coupled to the LED drive circuit for generating a drive signal for controlling the controllable-impedance circuit to thus adjust the magnitude of the load current through the LED light source; wherein, if the magnitude of the load current is below a load current threshold and the magnitude of the regulator voltage is below a regulator voltage threshold, the controller maintains the magnitude of the drive signal constant, and increases the target bus voltage, so as to increase the magnitude of the regulator voltage.
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22. An LED driver for controlling the intensity of an LED light source, the LED driver comprising:
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a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage; an LED drive circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the LED light source to thus control the intensity of the LED light source, the LED drive circuit comprising a controllable-impedance circuit adapted to be coupled in series with the LED light source; and a controller operatively coupled to the power converter circuit for adjusting the magnitude of the bus voltage to a target bus voltage, so as to control the magnitude of a regulator voltage generated across the controllable-impedance circuit, the controller operatively coupled to the LED drive circuit for generating a drive signal for controlling the controllable-impedance circuit to thus adjust the magnitude of the load current through the LED light source; wherein, if the magnitude of the load current is above a load current threshold and the magnitude of the regulator voltage is above a regulator voltage threshold, the controller maintains the magnitude of the drive signal constant, and decreases the target bus voltage, so as to decrease the magnitude of the regulator voltage.
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Specification