Abstract: Provided is a step up/down converter, in which the inductor current can be easily detected by a simple configuration in any connecting mode of the switches.

Abstract: Apparatus and associated methods reduce harmonic distortion of a excitation current by diverting the excitation current substantially away from a number of LEDs arranged in a series circuit until the current or its associated periodic excitation voltage reaches a predetermined threshold level, and ceasing the current diversion while the excitation current or voltage is substantially above the predetermined threshold level. In an illustrative embodiment, a rectifier may receive an AC (e.g., sinusoidal) voltage and deliver unidirectional current to a string of series-connected LEDs. An effective turn-on threshold voltage of the diode string may be reduced by diverting current around at least one of the diodes in the string while the AC voltage is below a predetermined level. In various examples, selective current diversion within the LED string may extend the input current conduction angle and thereby substantially reduce harmonic distortion for AC LED lighting systems.

Abstract: A flange, which forms a portion of a vacuum container, has a rectangular opening surrounded by an insulating frame. A plate-shaped radio-frequency antenna conductor 13 is provided so as to cover the opening, with the insulating frame clamped thereby. In this structure, a radio-frequency power source is connected via a matching box to one end along the length of the radio-frequency antenna conductor, the other end is connected to ground, and electric power is supplied so that a radio-frequency current flows from one end of the radio-frequency antenna conductor to the other. By this method, the impedance of the radio-frequency antenna conductor can be lowered, and high-density plasma with a low electron temperature can be efficiently generated.

Abstract: An illumination system detects a peak value of a voltage of a transformer supplying an LED module by analyzing the current value of the voltage and an on-time of the voltage. Based on the detected peak value, a property of the illumination system is adjusted.

Abstract: A power supply apparatus for applying a method of supplying a loading with an electric power within a predetermined range of a default power, which includes a driving unit, a voltage sensing unit, and a feedback control unit. The driving unit receives power from a power source, and supplies the loading with a working voltage and a working current; the voltage sensing unit detects the working voltage; the feedback control unit keeps a plurality of reference voltages, wherein each two neighboring reference voltages are defined to have a voltage section therebetween. The feedback control unit sends a current signal to the driving unit according to the working voltage and a slope parameter of the voltage section which the working voltage falls in, and the driving unit supplies the working current according to the current signal to maintain the electric power in the predetermined range of the default power.

Abstract: A power supply apparatus and a display apparatus including the same are provided. The power supply apparatus according to an exemplary embodiment includes a power factor correction circuit unit which corrects a power factor of input power and outputs the corrected power factor and a controller which controls whether to operate the power factor correction circuit unit according to an input status of a first signal indicating a status of power supplied to the display apparatus and an input status of a second signal indicating an operation status of a display unit included in the display apparatus.

Abstract: The present invention provides an LED backlight drive circuit, which includes a first power supply module, an electrical inductor, a rectifier diode, a MOS transistor, an electrolytic capacitor, an LED light string, a voltage division module, a voltage comparator, a second power supply module, and an LED constant-current drive chip. The LED backlight drive circuit is arranged to include a voltage comparator in an external circuit of the LED constant-current drive chip to detect output voltage of the drive circuit so that high voltage, the voltage comparator is caused to supply a low voltage level to forcibly pull down a PWM dimming signal or an ENA enabling signal of the LED constant-current drive chip to achieve an over-voltage protection function and also enable removal of over-voltage protection module from a conventional LED constant-current drive chip.

Abstract: A color temperature adjustable LED lamp is disclosed, which includes a 3-way lamp socket and a 3-way lamp head. The 3-way lamp socket has a 3-way switch. The 3-way lamp head is connected to the 3-way lamp socket and has a first LED array and a second LED array. The color temperature of the first LED array is different from the color temperature of the second LED array. The color temperature adjustable LED lamp includes a mains detecting circuit for detecting a conducting state of a first live wire and a second live wire in the 3-way switch to selectively operate the first LED array, the second LED array or alternatively operates the first and second LED array.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: A protection circuit of a DC-DC converter is disclosed. An input terminal of the DC-DC converter receives an input voltage and an output terminal of the DC-DC converter provides an output voltage. The DC-DC converter includes an output stage between the input terminal and the output terminal. The protection circuit includes a current sensor, a comparator, a determining circuit, and a protection control circuit. The current sensor provides a sensing signal. The comparator compares a default over-voltage with the sensing signal to provide an over-current control signal. The determining circuit provides a determining control signal. The protection control circuit determines whether to enable a short protection according to the over-current control signal and the determining control signal.

Abstract: A modular lighting system for lighting a work area is disclosed. The system includes a power supply with power outlets for powering LED fixtures. The power supply preferably operates at or below a fixed power output level, such as to illuminate the work area using less than 0.2 Watts per square foot of energy. The lighting system also includes an occupancy sensor and/or a light level sensor for controlling lighting levels in the work area in response to detection of a person, ambient light levels and/or a combination thereof. The lighting system can also include computer unit with a micro-processor and a memory unit for running software or firmware the executes lighting programs, stores light usage histories and/or provides system reports to a remote computer by a wireless means and/or over a computer network.

Abstract: The present invention relates to a high efficiency LED driver and driving method thereof. In one embodiment, a high efficiency LED driving method configured for a LED device can include: (i) receiving a DC bus voltage and generating a driving voltage for the LED device through a power switch; (ii) comparing the DC bus voltage against a sum of the driving voltage and a first reference voltage; (iii) where when the DC bus voltage is greater than the sum of the driving voltage and the first reference voltage, generating a first output current; (iv) where when the DC bus voltage is greater than the driving voltage and less than the sum of the driving voltage and the first reference voltage, generating a second output current; and (v) matching an average current of the first output current and the second output current with a corresponding driving current.

Abstract: In accordance with certain embodiments, an illumination system comprising a plurality of power strings features elements facilitating compensation for failure of one or more light-emitting elements connected along each power string.

Abstract: A method and apparatus for controlling a light string is provided. A controller is coupled to the light string and is used to bias one or more of the multicolor LEDs within each bulb on the light string. Using a prearranged determination of 1) the multicolor LEDs within each bulb, 2) the placement of the bulbs within the light string, and 3) the proper biasing of the plurality of leads within the light string, the controller can be used to change the entire light string from one complex holiday color scheme to another using a simple switching mechanism to select from one a of a plurality of desired color schemes.

Abstract: A lighting system adapted for being retrofit into a conventional lighting fixture, or adapted to replace the conventional fixture. The lighting system includes a lighting device having a substrate and a plurality of light-emitting elements disposed on the substrate. The lighting system further includes a power supply for delivering D/C current to the lighting device. The lighting device may be installed into a conventional lighting socket in the conventional lighting fixture or mounted independently utilizing some parts of the conventional fixture. The power supply is installed into the conventional lighting fixture or other suitable fixture external to the lighting device. In exemplary embodiments, the lighting system includes a plurality of lighting devices rotatably mounted in the conventional lighting fixture. Each lighting device is powered by an independent power supply and may be independently rotated and powered to customize light coverage.

Abstract: A system including a first transistor, a second transistor, and a comparator. The first transistor is configured to supply a first current to a first load connected to a first terminal of the first transistor. The second transistor is configured to supply a second current to a second load connected to a first terminal of the second transistor, wherein the first current and the second current have a predetermined ratio. The comparator is configured to compare a voltage at the first terminal of the first transistor or a voltage at the first terminal of the second transistor to a reference voltage, and to adjust, based on the comparison, biasing of the first transistor and the second transistor to maintain the predetermined ratio between the first current and the second current.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: A driving circuit includes a plurality of light-emitting units, a plurality of switches, and a bias current module, wherein the light-emitting units are coupled with each other in series and are driven with an input voltage varying according to a frequency. Each switch has a reference voltage and a critical activation voltage and includes a light-emitting end and a bias end opposite to the light-emitting end, wherein the light-emitting end is coupled with the light-emitting units, and the bias ends of the switches are coupled with each other. The bias current module is coupled with the bias ends of the switches and has an operating bias voltage varying according to the frequency, wherein each switch is driven to be activated or to be deactivated according to a relation of the critical activation voltage and a difference between the reference voltage and the operating bias voltage.

Abstract: A vehicle lamp include san LED package as a light source. The LED package includes a first series element section having a plurality of LED elements connected in series with each other, a second series element section having at least one LED element, the number of which is smaller than the number of LED elements of the firs series element section, a first anode electrode provided on an anode side of the first series element section, a first cathode electrode provided on a cathode side of the first series element section, a second anode electrode provided on an anode side of the second series element section, and a second cathode electrode provided on a cathode side of the second series element section.

Abstract: A lighting apparatus includes a string of Light Emitting Diode (LED) sets coupled in series, each set including at least one LED, a light spreading circuit configured to incrementally turn on respective ones of the LED sets responsive to a power signal, and an energy storage module that is configured to store energy during a first interval of a period of the power signal and to apply the stored energy to the string during a second interval of the period of the power signal.