Cree Gmbh

Shawn Hill

Mark Cash

Everett Bradford

A solid state lighting apparatus can include a plurality of light-emitting devices (LEDs) that are electrically coupled together in at least one string. The apparatus can further include a first LED segment that is configured to emit a first chromaticity light coupled across a first bypass circuit, a second LED segment that is configured to emit a second chromaticity light coupled across a second bypass circuit, and at least one additional LED segment that is configured to emit an additional chromaticity light coupled across a respective at least one additional bypass circuit. A control circuit can be configured to modulate the at least one additional bypass circuit, to cause the lighting apparatus to emit an additional v' shift in a chromaticity value of light emitted by the string to vary substantially in conformance with a Planckian locus in response to a dimming input to the control circuit.

Circuits and methods for controlling solid state lighting

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.

Systems and methods for controlling solid state lighting during dimming and lighting apparatus incorporating such systems and/or methods

An apparatus includes a bus configured to be coupled to a controlled current source and at least one light emitting device coupled to the bus. The apparatus further includes a voltage regulator circuit configured to regulate a voltage at the bus and a current regulator circuit configured to control a current through the at least one light emitting device. In some embodiments, the current regulator circuit is used to control a color output of the apparatus.

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Raleigh, NC, United States of America

Shawn Hill