Systems and methods for controlling solid state lighting during dimming and lighting apparatus incorporating such systems and/or methods
First Claim
Patent Images
1. A lighting apparatus comprising:
- a plurality of light-emitting devices (LEDs) comprising at least one first LED configured to emit first chromaticity light, at least one second LED configured to emit second chromaticity light, and at least one additional LED configured to emit third chromaticity light,wherein the at least one second LED comprises a Blue-Shifted-Yellow (BSY) LED, and the at least one additional LED comprises at least one amber LED;
a control circuit operatively coupled to the plurality of LEDs and configured to operate the at least one additional LED to cause a color temperature of light produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus responsive to a dimming control input provided to the plurality of LEDs; and
a bypass circuit, operatively coupled to the control circuit, the bypass circuit including a variable resistance circuit and the at least one amber LED coupled in series with the variable resistance circuit,wherein the variable resistance circuit is configured to continuously alter a resistance of the variable resistance circuit to increasingly bypass current around the at least one BSY LED through the at least one amber LED as the dimming control input decreases a brightness level of the light produced by the plurality of LEDs,wherein the variable resistance circuit comprises a transistor, andwherein the at least one amber LED is configured to provide biasing to the transistor to maintain the transistor in saturation mode during a dimming operation of the apparatus to provide an additional v′
component in a u′
-v′
coordinate system to the color temperature of the light produced by the plurality of LEDs.
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Accused Products
Abstract
A lighting apparatus having a plurality of light-emitting devices (LEDs) can include at least one first LED that is configured to emit first chromaticity light, at least one second LED that is configured to emit second chromaticity light, and at least one additional LED that is configured to emit third chromaticity light. A control circuit can be operatively coupled to the plurality of light-emitting devices and configured to cause a color temperature produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus in response to a dimming control input less than about 1800K.
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Citations
27 Claims
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1. A lighting apparatus comprising:
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a plurality of light-emitting devices (LEDs) comprising at least one first LED configured to emit first chromaticity light, at least one second LED configured to emit second chromaticity light, and at least one additional LED configured to emit third chromaticity light, wherein the at least one second LED comprises a Blue-Shifted-Yellow (BSY) LED, and the at least one additional LED comprises at least one amber LED; a control circuit operatively coupled to the plurality of LEDs and configured to operate the at least one additional LED to cause a color temperature of light produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus responsive to a dimming control input provided to the plurality of LEDs; and a bypass circuit, operatively coupled to the control circuit, the bypass circuit including a variable resistance circuit and the at least one amber LED coupled in series with the variable resistance circuit, wherein the variable resistance circuit is configured to continuously alter a resistance of the variable resistance circuit to increasingly bypass current around the at least one BSY LED through the at least one amber LED as the dimming control input decreases a brightness level of the light produced by the plurality of LEDs, wherein the variable resistance circuit comprises a transistor, and wherein the at least one amber LED is configured to provide biasing to the transistor to maintain the transistor in saturation mode during a dimming operation of the apparatus to provide an additional v′
component in a u′
-v′
coordinate system to the color temperature of the light produced by the plurality of LEDs. - View Dependent Claims (2, 3, 4, 5, 6, 9)
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7. A lighting apparatus comprising:
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a plurality of light-emitting devices (LEDs) comprising at least one first LED configured to emit first chromaticity light, at least one second LED configured to emit second chromaticity light, and at least one additional LED configured to emit third chromaticity light, wherein the at least one first LED comprises a red/orange LED, the at least one second LED comprises a Blue-Shifted-Yellow (BSY) LED, and the at least one additional LED comprises at least one amber LED; a control circuit operatively coupled to the plurality of light-emitting devices and configured to operate the at least one additional LED to cause a color temperature produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus responsive to a dimming control input provided to the plurality of LEDs; wherein the plurality of LEDs comprises; a first LED string including the at least one BSY LED coupled in series with the at least one red/orange LED; a second LED string, coupled in parallel with the first LED string, including the at least one amber LED; and an RC circuit coupled in series with the second LED string, and configured to discharge through the second LED string when the first string of LEDs is off. - View Dependent Claims (8)
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10. A lighting apparatus comprising:
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a control circuit operatively coupled to a plurality of light-emitting devices (LEDs) and configured to reduce current through at least one first chromaticity LED included in the plurality of LEDs by bypassing current from the at least one first chromaticity LED through at least one additional chromaticity LED included in the plurality to increase current through the at least one additional chromaticity LED and cause a color temperature of light produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus responsive to a dimming control input provided to the plurality of LEDs, wherein the at least one first chromaticity LED comprises at least one Blue-Shifted-Yellow (BSY) LED configured to emit BSY light and the at least one additional chromaticity LED comprises at least one additional LED configured to emit additional light; and a bypass circuit, operatively coupled to the control circuit, the bypass circuit including a variable resistance circuit and the at least one additional LED coupled in series with the variable resistance circuit, wherein the variable resistance circuit is configured to continuously alter a resistance of the variable resistance circuit to increasingly bypass current around the at least one BSY LED through the at least one additional LED as the dimming control input decreases a brightness level of the light produced by the plurality of LEDs, wherein the variable resistance circuit comprises a transistor, wherein the at least one additional LED is configured to provide biasing to the transistor, wherein the at least one additional LED comprises at least one amber LED configured to emit amber light, and wherein the at least one amber LED is configured to provide biasing to maintain the transistor in saturation mode during a dimming operation of the apparatus to provide an additional v′
component in a u′
-v′
coordinate system to the color temperature of the light produced by the plurality of LEDs. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of operating a lighting apparatus including a plurality of light-emitting devices (LEDs) comprising at least one first LED configured to emit first chromaticity light, at least one second LED configured to emit second chromaticity light, and at least one additional LED configured to emit additional chromaticity light, the method comprising:
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diverting current from the at least one second LED through the at least one additional LED to cause a color temperature of light produced by the plurality of LEDs to vary substantially in conformance with a Planckian locus responsive to a dimming control input, wherein the at least one first LED comprises a red/orange LED configured to emit red/orange chromaticity light, the at least one second LED comprises a Blue-Shifted-Yellow (BSY) LED configured to emit BSY chromaticity light, and the at least one additional LED comprises an amber LED configured to emit amber chromaticity light, wherein the plurality of LEDs comprises a first LED string including the at least one BSY LED coupled in series with the at least one red/orange LED, a second LED string, coupled in parallel with the first LED string, including the at least one additional LED, the method further comprising; discharging current through the second LED string when the first LED string switches off by an RC circuit coupled in series with the second LED string and not in series with the first LED string. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification