A light emitting diode, LED, filament lamp (100), comprising a light emitting diode light source (110), comprising at least one first filament (120a), arranged to emit light having a first color temperature, at least one second filament (120b), arranged to emit light having a second color temperature, different from the first color temperature, wherein each of the first and second filaments comprises a substrate (130a, 130b) of elongated shape, wherein at least one light emitting diode (140a, 140b) is arranged on the substrate. The LED filament lamp further comprises a control unit (150) configured to control a first intensity of the light emitted from the first filament(s) and to control a second intensity of the light emitted from the second filament(s) according to at least one predetermined setting, in order to control the total color temperature of the light emitted from the LED filament lamp as a function of the predetermined setting(s).

A lighting system and a circuit for a solid state lighting apparatus are provided. The circuit includes an AC power source, an AC TRIAC dimmer, a plurality of light emitting diodes (LEDs), a bridge rectifier for providing a rectified AC waveform, and at least one capacitor for reducing flicker in the LEDs, and a plurality of LEDs with lower forward voltage connected to a static dimming bleeder or bleeder circuit for providing holding current to the triac of a dimmer circuit to increase the overall efficiency of the lighting system without dynamic control of the bleeder circuit. In some embodiments, the circuit includes a plurality of current sinks used for setting and maintaining a current to the main LEDs and to establish a stable bleeder current.

A lighting apparatus includes a rectifier, a 0-10 V dimmer converter, a power circuit and a light source. The rectifier for receives an AC power from an AC input to generate a DC current. The TRIAC wall switch is selectively coupled to the AC input. The TRIAC wall switch is operated by a user with an first manual operation to suppress a portion of the AC power from the AC input corresponding to the first manual operation. The 0-10 V dimmer converter is selectively coupled to a 0-10 V dimmer. The 0-10 V dimmer converts a dimmer voltage of the 0-10 V dimmer to a dimmer signal corresponding to a second manual operation of the user. The power circuit is coupled to the 0-10 V dimmer converter and the rectifier to convert the DC current to a set of driving current. The light source includes multiple LED modules.

An LED light bulb includes a lamp housing, an LED filament in the lamp housing and a power module. The LED filament includes a first and a second LED sections, a conductive section, a first and a second conductive electrodes and a light conversion layer. Each LED section includes LED chips connected in serial to from a LED string. The conductive section connects one end of the LED string of the first LED section with one end of the LED string of the second sections. The polarities of the ends of the LED strings are the same. The other ends of the LED strings are respectively connected to the first and the second conductive electrodes. The light conversion layer is coated on at least two sides of the LED chips. The power module's terminals are connected to the conductive section and the conductive electrodes.

A multi-channel power supply system including a power supply circuit configured to generate a drive signal for powering a plurality of color channels based on an input power signal, a first current control circuit coupled to a first color channel of the plurality of color channels and configured to adjust a first channel current of the first color channel based on the drive signal and a first reference signal, and a channel controller configured generate the first reference signal based on a color temperature according to a black body curve.

An LED light bulb comprising a lamp housing, a bulb base, connected to the lamp housing, a stem connected to the bulb base and located in the lamp housing; an LED filament, disposed in the lamp housing, where points of the LED filament in an xyz coordinates are defined as x, y, and z, an x-y plane of the xyz coordinates is perpendicular to the height direction of the LED light bulb, an z-axis of xyz coordinates is parallel with the stem, and the projection of the LED filament on the x-y plane, y-z plane and x-z plane respectively has a length L1, L2 and L3, and the length L1, the length L2, and the length L3 are substantially in a ratio of 1:(0.5 to 1):(0.6 to 0.9).

The disclosed invention is embodied in an improved LED-based lighting fixture for projecting a beam of light having a substantially uniform intensity, rotationally, and a selectable, substantially uniform chromaticity. The lighting fixture includes (1) a concave reflector having circumferential facets, a focal region, an aperture, and a central opening; and (2) a light source assembly including two or more groups of LEDs mounted at the forward end of an elongated, thermally conductive support. The light source assembly is mounted relative to the reflector with the elongated support's longitudinal axis aligned with the reflector's longitudinal axis and with the groups of LEDs located at or near the reflector's focal region. Each of the two or more groups of LEDs includes a plurality of LEDs arranged in two or more columns substantially parallel with the light source axis, with each column including only LEDs configured to emit light in a limited range of the visible spectrum and having the same distinct dominant wavelength, and with each group of LEDs including LEDs configured to emit light in two or more dominant wavelengths. The two or more groups of LEDs are configured to cooperate with the faceted concave reflector to project a beam of light having a selectable, substantially uniform chromaticity.

The disclosed invention is embodied in an improved LED-based lighting fixture for projecting a beam of light having a substantially uniform intensity, rotationally, and a selectable, substantially uniform chromaticity. The lighting fixture includes (1) a concave reflector having circumferential facets, a focal region, an aperture, and a central opening; and (2) a light source assembly including two or more groups of LEDs mounted at the forward end of an elongated, thermally conductive support. The light source assembly is mounted relative to the reflector with the elongated support's longitudinal axis aligned with the reflector's longitudinal axis and with the groups of LEDs located at or near the reflector's focal region. Each of the two or more groups of LEDs includes a plurality of LEDs arranged in two or more columns substantially parallel with the light source axis, with each column including only LEDs configured to emit light in a limited range of the visible spectrum and having the same distinct dominant wavelength, and with each group of LEDs including LEDs configured to emit light in two or more dominant wavelengths. The two or more groups of LEDs are configured to cooperate with the faceted concave reflector to project a beam of light having a selectable, substantially uniform chromaticity.

An LED light bulb comprising a lamp housing, a bulb base, connected to the lamp housing, a spectral distribution of the light bulb is generally between a wavelength range of about 400 nm to 800 nm, and three peak wavelengths P1, P2, and P3 appear in wavelength ranges corresponding to light emitted by the light bulb, wherein a wavelength of the peak P1 is between 430 nm and 480 nm, a wavelength of the peak P2 is between 480 nm and 530 nm, a wavelength of the peak P3 is between 630 nm and 680 nm.

In one embodiment, an LED filament lamp for warm dimming is presented that includes a dimmable LED driver circuit; a first channel LED filament having a first forward voltage drop which emits a first white light of a first correlated color temperature; and a second channel LED filament having a second forward voltage drop and which emits a second white light of a second correlated color temperature warmer than the first correlated color temperature. In another embodiment, an LED filament for warm dimming lamps is presented that includes a light-transmissive substrate; at least one LED die and one non-light-emitting current regulator mounted thereon and connected in series; and an adhesive bead with fluorescent particles suspended therein affixed to the light-transmissive substrate, wherein illuminating the fluorescent particles with the at least one LED die causes the LED filament to emit white light of a predetermined correlated color temperature.