摘要:
A lighting apparatus includes a string of serially-connected light emitting devices and a bypass circuit coupled to first and second nodes of the string and configured to variably conduct a bypass current around at least one of the light-emitting devices responsive to a temperature and/or a total current in the string. In some embodiments, the bypass circuit includes a variable resistance circuit coupled to the first and second nodes of the string and configured to variably conduct the bypass current around the at least one of the light-emitting devices responsive to a control voltage applied to a control node and a compensation circuit coupled to the control node and configured to vary the control voltage responsive to a temperature and/or total string current.
摘要:
A lighting device comprising plural excitation sources configured to provide at least two excitation peak emissions of different wavelength and at least one phosphor material radiationally coupled to the plural light source, the lighting device having a plurality of operational states comprising a first operation state wherein excitation of the at least one phosphor material by a first peak emission from the plural excitation sources provides a first correlated color temperature (CCT) value, and at least one additional operational state wherein excitation of the at least one phosphor material by a second peak emission from the plural excitation sources provides at least one additional CCT value different from the first CCT value. Methods of varying the CCT value using the lighting device with controlled power distribution to the plural excitation sources.
摘要:
SSL lamps or luminaires are disclosed that combine blue, yellow (or green) and red photons or emissions to generate light with the desired characteristics. In different embodiments according to the present invention, the blue emission is not provided by an LED chip or package having a blue LED coated with a yellow phosphor, with blue light leaking through the yellow phosphor. Instead, the blue light component can be provided by other types of LED chips in the SSL luminaire such as one having a blue LED covered by a different colored conversion material, with blue light from the blue LED leaking through the different colored conversion material. In one embodiment, the blue component can be provided by an LED chip comprising a blue emitting LED covered by a conversion material that absorbs blue light and re-emits red light, with a portion of the blue light from the LED leaking through the red conversion material.
摘要:
A solid state lighting apparatus according to some embodiments includes a circuit including a plurality of light emitting devices, and a configurable shunt configured to bypass at least some current around at least one light emitting device of the plurality of light emitting devices. The configurable shunt may include, for example, a tunable resistor, a fuse, a switch, a thermistor, and/or a variable resistor.
摘要:
Some embodiments provide a lighting apparatus including a plurality of lighting circuits coupled in series. Each lighting circuit includes a control circuit configured to selectively provide current to at least one LED and at least one charge storage device coupled to the at least one LED. The control circuit may be configured to cause the at least one charge storage device to be selectively charged from a current source and to be discharged via the at least one LED responsive to a varying input. For example, the control circuit may be configured to limit current through the at least one LED to thereby divert current to the at least one charge storage device.
摘要:
A lighting apparatus includes a first substrate including a switching circuit, the switching circuit including a first port, a second port and a current control circuit configured to generate a current at the second port of the current control circuit responsive to a varying voltage at the first port. The apparatus further includes a second substrate mounted on the first substrate and including at least two LEDs electrically coupled to the second port of the current control circuit of the first substrate.
摘要:
Light emitting devices include a first string of LEDs that emit light having a color point that is within at least eight MacAdam ellipses of a first blue-shifted-yellow region on the 1931 CIE Chromaticity Diagram, a second string of LEDs that emit light having color point that is within at least eight MacAdam ellipses of a second blue-shifted-green region on the 1931 CIE Chromaticity Diagram, and a third light source that emits radiation having a dominant wavelength between 600 and 720 nm. A drive circuit supplies respective drive currents to the first string of LEDs, the second string of LEDs and the third light source, at least two of which are independently controllable.
摘要:
Semiconductor light emitting circuits include semiconductor light emitting diodes that are serially connected between a pair of input terminals. Four layer semiconductor devices, such as Shockley diodes and/or thyristors are also provided, a respective one of which is connected across a respective one of the semiconductor light emitting diodes. The four layer semiconductor devices can allow a string of light emitting diodes to continue to be lit if one light emitting diode fails.
摘要:
A solid state lighting apparatus includes a plurality of light emitting diodes, a sensor configured to output a sensor signal indicative of at least one operating condition of the solid state lighting apparatus, and a control circuit coupled to the sensor. The control circuit is configured to temporarily interrupt electrical current to ones of the plurality of light emitting diodes at respective intervals responsive to the sensor signal indicating that the operating condition does not meet a desired operating threshold to provide a visible indicator thereof in light emitted by the apparatus. Related devices and methods of operation are also discussed.
摘要:
SSL lamps or luminaires are disclosed that combine blue, yellow (or green) and red photons or emissions to generate light with the desired characteristics. In different embodiments according to the present invention, the blue emission is not provided by an LED chip or package having a blue LED coated with a yellow phosphor, with blue light leaking through the yellow phosphor. Instead, the blue light component can be provided by other types of LED chips in the SSL luminaire such as one having a blue LED covered by a different colored conversion material, with blue light from the blue LED leaking through the different colored conversion material. In one embodiment, the blue component can be provided by an LED chip comprising a blue emitting LED covered by a conversion material that absorbs blue light and re-emits red light, with a portion of the blue light from the LED leaking through the red conversion material.