Energy Focus, Inc. | Date: 2012-06-20
An elongated LED lighting arrangement comprises an elongated fiberoptic light pipe having an exteriorly facing sidewall between its ends. The light pipe is constructed to promote TIR of light between the ends. A first LED light source is tuned to efficiently provide light within a wavelength range to the pipe. Light-extracting means are applied along the light pipe along the main path of TIR light propagation, and comprise down-converting means tuned to efficiently convert light rays from the LED light source within the wavelength range to lower-energy light rays at respectively longer wavelengths and light-scattering means for extracting from the pipe some light rays within the wavelength range without changing the wavelengths of the foregoing light. The light emitted by the down-converting means and the light-scattering means intermix to produce light, the majority of which has a composite color determined by the foregoing light emitted and the foregoing light extracted.
Energy Focus, Inc. | Date: 2011-10-11
A switching power supply circuit has a control circuit for current-mode on-off control of a primary switch connected to an inductor in a voltage boost topology for operation in boundary-conduction mode. The time at which the primary switch is opened is determined by magnitude of current flowing through the primary switch together with the instantaneous voltage present on an AC input to the power supply circuit. The time at which the primary switch is closed is determined by demagnetization of the inductor. An improvement to the foregoing switching power supply circuit comprises a maximum-on-time enforcement circuit to limit the maximum possible primary switch on-time to a predetermined maximum period of time. The enforcement circuit provides a signal to the control circuit to cause termination of the primary switch on-state if and only if the primary switch has been turned on for more than the predetermined maximum period of time.
Energy Focus, Inc. | Date: 2011-12-22
An elongated LED lighting arrangement comprises an elongated light pipe with homogeneous optical material between first and second ends. In an exemplary embodiment, an LED provides blue light to the light pipe via a first dichroic mirror tuned to pass blue light. Down-converting means on sidewall of the light pipe, tuned to receive blue light, absorbs blue light from the LED and to emit lower-energy light outside of the light pipe at respectively higher wavelengths. Light-extracting means on the sidewall extract from the light pipe some blue light without changing the wavelengths of the foregoing light. Light from the down-converting means and the light-extracting means are combined to provide a composite color. The first dichroic mirror receives some light emitted by the down-converting means and reflects back into the light pipe more than 80 percent of the light received by the mirror.
Energy Focus, Inc. | Date: 2015-05-01
An LED lamp has dual modes of operation from fluorescent lamp fixtures. A first circuit powers at least one LED in a first mode of operation when first and second power pins at a first end of the lamp are inserted into power contacts of the fixture that are directly connected to power mains. A second circuit powers at least one LED in a second mode of operation when the second power pin at the first end of the lamp and a third power pin at a second end of the lamp are inserted into power contacts of a fixture powered from an electronic ballast. First and second conduction control means permit the second circuit to power at least one LED during the second mode of operation.
Energy Focus, Inc. | Date: 2012-09-17
Disclosed is an LED lamp system designed to fit into a fluorescent lamp fixture and to utilize a fluorescent lamp power supply contained in the fixture and receiving power from AC mains. The LED lamp system includes an LED driver which comprises a power factor corrected driver circuit for achieving a power factor of at least about 0.8. The LED driver further comprises a current control circuit, responsive to the presence of a three-wire magnetic ballast in the fluorescent lamp power supply, for increasing the LED operating current above the nominal rated LED operating current and to a level sufficient to achieve power factor of the LED driver of at least about 0.8.