A lighting device, such as a light-emitting diode (LED) light source, may operate in an interim operable state to avoid and/or prevent undesirable characteristics in the light emitted by the lighting device (e.g., strobing and/or flickering of a brightness of the light and/or shifting or change of a color of the light). When operating in a normal state, the control circuit may determine if a measured value of a first operational characteristic (e.g., a forward voltage of an emitter of the lighting device) is outside of a range and operate in the interim operable state if the measured value of the first operational characteristic is outside of the range. When operating in the interim operable state, the control circuit may adjust a drive current for the emitter in response to a measured value of a second operational characteristic (e.g., a forward voltage of a detector of the lighting device).

The present disclosure provides a light bulb apparatus for changing a color temperature of a luminaire using an encoded alternating current (AC) power signal transmitted from a lighting control system to the luminaire electrically coupled to the light bulb apparatus, wherein the color temperature is encoded with a cut phase of the AC power signal.

The present disclosure provides a light bulb apparatus for changing a color temperature of a luminaire using an encoded alternating current (AC) power signal transmitted from a lighting control system to the luminaire electrically coupled to the light bulb apparatus, wherein the color temperature is encoded with a cut phase of the AC power signal.

A method and illumination device are provided for interference-resistant compensation in light emitting diode (LED) illumination devices. In one embodiment, the method includes bringing to a level insufficient to produce illumination the respective drive current of all except one of multiple emission LED elements for the duration of a first measurement interval and a later-occurring second measurement interval. The first and second measurement intervals are within respective first and second series of measurement intervals interspersed with periods of illumination, and the first and second series of measurement intervals are separated by respective first and second offsets from a timing reference. An embodiment of an illumination device includes multiple emission LED elements, one or more photodetectors, and a lamp control circuit, where the lamp control circuit is adapted to perform steps of the method.

A method and light emitting diode (LED) illumination device comprising multiple emitter modules are provided. In one embodiment, the method includes bringing to a level insufficient to produce illumination the respective drive currents of all except one of multiple emission LED elements within respective first and second emitter modules for the duration of a measurement interval within respective first and second series of measurement intervals. The measurement intervals are interspersed with periods of illumination, and the first and second series of measurement intervals are separated by respective first and second offsets from a timing reference. An embodiment of an illumination device includes multiple emitter modules, where each emitter module includes multiple emission LED elements and one or more photodetectors. The illumination device further includes a lamp control circuit adapted to perform steps of the method.

A control circuit for a light emitting diode (LED) lighting system for achieving a dim-to-warm effect is provided. The control circuit includes an LED controller, a clamp circuit coupled to a set of warm correlated-color-temperature (“CCT”) LEDs, a switch coupled to a set of cool LEDs, and a feedback circuit coupled to the clamp and the switch. The LED controller is configured to control the clamp circuit to clamp current through the set of warm LEDs based on the input current, and control the switch to switch on the set of cool LEDs responsive to the input current being greater than a first threshold level and to switch off the set of cool LEDs responsive to the input current being lower than the first threshold level. The feedback circuit is configured to divert current from the set of warm LEDs to the set of cool LEDs.

A tunable lighting system includes a first LED having a first spectral output, a second LED having a second spectral output, and a correction circuit including a correction LED. The correction circuit in the tunable lighting system controls the correction LED to emit light that, when combined with light output from the first LED and light output from the second LED, produces a selected spectral characteristic.

A method of dimming an LED luminaire and a dimmable LED luminaire includes two pluralities of LEDs. The first plurality emits electromagnetic radiation at a first frequency to react with a remote phosphor and provide a phosphor illumination. The second plurality of LEDs are phosphor LEDs that emit phosphor electromagnetic radiation at a second frequency to react with the remote phosphor and provide double-phosphor illumination. The phosphors and LEDs are configured to produce specific color points when the LEDs are at full power and at full dim. When the luminaire receives a dimming signal, the first plurality of LEDs dim the phosphor illumination over a majority of the luminaire's illumination range, but the second plurality of LEDs continue to receive constant current and provide undimmed double-phosphor illumination over the majority of the luminaire's illumination range.

In an example embodiment, there is disclosed herein an apparatus with a transceiver coupled with a bus; and a plurality of interfaces coupled with a plurality of lighting devices, and lead through indicator (LTI) logic coupled with the transceiver and the plurality of interfaces. The LTI logic is operable to receive a signal via the bus with data for operating a selected one of the plurality of lighting devices. The LTI logic determines an interface and a channel for the selected one of the plurality of lighting devices. The LTI logic send a signal to the selected one of the plurality of lighting devices on the connector and channel corresponding to the selected one of the plurality of lighting devices to operate the selected lighting device in accordance with the data for operating the selected one of the plurality of lighting devices.

A switched-mode power supply and an associated television are disclosed. The switched-mode power supply includes a rectifier circuit, a transformer, a constant voltage control circuit, a power management circuit, and a constant current control circuit. An output terminal of the rectifier circuit is coupled both to a power detection terminal of the power management circuit and to a power input terminal of the transformer. A controlled terminal of the transformer is coupled to a control terminal of the power management circuit. A constant voltage output winding of the transformer is coupled through the constant voltage control circuit to a feedback input terminal of the power management circuit. A constant current output winding of the transformer is coupled to the constant current control circuit via an LED load. The solution of the present disclosure has the advantage of low cost.