Current feedback for improving performance and consistency of LED fixtures
First Claim
Patent Images
1. A lighting system comprising:
- a driver controller configured to output an independent control signal to each of a plurality of power controllers, the power controllers configured to control respective power converters;
the plurality of power converters connected to mains voltage and configured to provide a driving current responsive to each independent control signal, wherein each power converter is configured to output respective driving currents to a plurality of strings of LEDs;
a voltage measurement circuit configured to provide a voltage sense signal indicative of an amplitude of the mains voltage; and
a light-emitting diode (LED) module comprisingthe plurality of strings of LEDs that emit light responsive to the driving currents,a plurality of amplifiers, each amplifier connected to one of the plurality of strings of LEDs and configured to amplify an LED current through each corresponding string;
a multiplexer connected to the outputs of the plurality of amplifiers, configured to receive the amplified LED currents as detected LED currents of each string and selectively output the detected LED currents, andan analog to digital converter connected to the multiplexer configured to convert the detected LED currents as selected by the multiplexer into digital signals and output the digital signals as current feedback signals;
wherein the driver controller is configured to output the control signals responsive to the voltage sense signal and each respective current feedback signal.
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Abstract
A lighting system includes a power converter connected to mains voltage and configured to provide a driving current responsive to a control signal. A voltage measurement circuit is configured to provide a voltage sense signal indicative of an amplitude of the mains voltage. A light-emitting diode (LED) module includes at least one string of LEDs that emit light responsive to the driving current, and is configured to detect an LED current through the at least one string and output a current feedback signal indicative of the detected LED current. A driver controller is configured to output the control signal responsive to the voltage sense signal and the current feedback signal.
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Citations
17 Claims
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1. A lighting system comprising:
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a driver controller configured to output an independent control signal to each of a plurality of power controllers, the power controllers configured to control respective power converters; the plurality of power converters connected to mains voltage and configured to provide a driving current responsive to each independent control signal, wherein each power converter is configured to output respective driving currents to a plurality of strings of LEDs; a voltage measurement circuit configured to provide a voltage sense signal indicative of an amplitude of the mains voltage; and a light-emitting diode (LED) module comprising the plurality of strings of LEDs that emit light responsive to the driving currents, a plurality of amplifiers, each amplifier connected to one of the plurality of strings of LEDs and configured to amplify an LED current through each corresponding string; a multiplexer connected to the outputs of the plurality of amplifiers, configured to receive the amplified LED currents as detected LED currents of each string and selectively output the detected LED currents, and an analog to digital converter connected to the multiplexer configured to convert the detected LED currents as selected by the multiplexer into digital signals and output the digital signals as current feedback signals; wherein the driver controller is configured to output the control signals responsive to the voltage sense signal and each respective current feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A lighting driver comprising:
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a plurality of power converters connected to mains voltage and configured to provide driving currents to a solid state lighting load responsive to independent control signals; a voltage measurement circuit configured to provide a voltage sense signal indicative of an amplitude of the mains voltage; and a driver controller configured to output the independent control signals responsive to the voltage sense signal and respective current feedback signals indicative of a lighting current through the solid state lighting load, wherein the power converters provide the driving currents to maintain the lighting currents at a selected constant level regardless of the amplitude of the mains voltage, wherein the current feedback signals are received from an analog to digital converter, wherein a multiplexer is connected to outputs of a plurality of amplifiers configured to amplify the currents through the solid state lighting load, and wherein the analog to digital converter connected to the multiplexer output configured to convert the current outputs from the multiplexer into digital signals and output the digital signals as the current feedback signals. - View Dependent Claims (13, 14, 15, 16)
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17. A method of controlling a solid state lighting load comprising a plurality of strings of LEDs, the method comprising:
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converting mains voltage to provide independent driving currents to the plurality of strings via a plurality of power converters, wherein the power converters are configured to provide independent driving currents to each respective string; generating current feedback signals indicative of lighting currents through each string via a plurality of amplifiers, each amplifier configured to amplify the current through one of the strings, a multiplexer configured to receive the amplified currents and selectively output the selected amplified currents, and an analog to digital converter configured to receive the selected amplified currents and configured to convert the selected amplified currents into digital signals and output the digital signals as the current feedback signals; and detecting an amplitude of the mains voltage, wherein said converting comprises providing the independent driving currents to maintain light emitted from each of the strings at a selected constant brightness responsive to the detected amplitude of the mains voltage and the current feedback signals.
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Specification