Abstract: An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared.

Abstract: An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive switches having complementary duty cycles, a control circuit for controlling the controllably conductive switches, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved power factor, THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive switch. In an especially preferred embodiment, the controllably conductive switch of the valley-fill circuit is also one of the switches of the inverter.

Abstract: An electronic ballast for a fluorescent lamp has a single-switch flyback inverter including a magnetizing inductance, a resonant circuit connected to the output of the inverter including a tank inductor, and a clamp circuit including a diode coupled to the primary winding of the flyback transformer for limiting the voltage across the magnetizing inductance when the switch is non-conductive. With the inverter switch conductive the resonant circuit has a first resonant frequency. With the inverter switch non-conductive, the resonant circuit, combined with the magnetizing inductance, has a second resonant frequency lower than the first. The magnetizing inductance is chosen such that the second resonant frequency is close to the first resonant frequency. The operating frequency of the inverter is controlled to be at or about the second resonant frequency, whereby zero current switching is achieved in the inverter switch.

Abstract: An electronic ballast for driving at least one gas discharge lamp from a source of AC power which has a substantially sinusoidal line voltage at a given line frequency includes a rectifying circuit; a valley fill circuit; and an inverter circuit connectable to the at least one gas discharge lamp; The inverter circuit has a single controllably conductive device and an inductor; the inductor connectable to the at least one gas discharge lamp; the inverter circuit being adapted to draw current from the source of AC power whereby the total current drawn from the source of AC power has a total harmonic distortion below about 33.3%; and whereby the lamp current crest factor below about 2.1.

Abstract: An electrical receptacle defines a receptacle formation of a mating formation pair to prevent a standard plug from establishing electrical connection while permitting an otherwise standard plug defining a corresponding plug formation to be sufficiently inserted to establish an electrical connection. The mating formation pair may include a projection on the receptacle adapted for receipt by a corresponding recess on a compatible plug. Alternatively, the mating formation pair is defined by an opening of the receptacle and a conductor of the plug, each having a cross-sectional height that is reduced from that of a standard receptacle and plug. The mating formation pair is particularly desirable for installation including a receptacle controlled by a dimmer to prevent electrical connection by a standard plug connected to a non-dimmable electrical load.

Abstract: An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive device having complementary duty cycles, a control circuit for controlling the controllably conductive device, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive device. In an especially preferred embodiment, the controllably conductive device of the valley-fill circuit is also one of the controllably conductive devices of the inverter.

Abstract: A method and apparatus are provided for detecting a short circuited semiconductor switch. The apparatus comprises a semiconductor switching device and a short circuited switch detection device. The semiconductor switching device comprises an input, an output, and a control input for switching the semiconductor switching device. The short circuited switch detection device comprises an input and an output. The input of the short circuited switch detection device is coupled to the semiconductor switching device, wherein the short circuited switch detection device detects a short circuit in the semiconductor switch switching device.

Abstract: A method and apparatus are provided for detecting a short circuited semiconductor switch. The apparatus comprises a semiconductor switching device and a short circuited switch detection device. The semiconductor switching device comprises an input, an output, and a control input for switching the semiconductor switching device. The short circuited switch detection device comprises an input and an output. The input of the short circuited switch detection device is coupled to the semiconductor switching device, wherein the short circuited switch detection device detects a short circuit in the semiconductor switch switching device.

Abstract: An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared.

Abstract: An electronic ballast for driving at least one gas discharge lamp from a source of AC power which has a substantially sinusoidal line voltage at a given line frequency.

Abstract: An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive switches having complementary duty cycles, a control circuit for controlling the controllably conductive switches, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved power factor, THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive switch. In an especially preferred embodiment, the controllably conductive switch of the valley-fill circuit is also one of the switches of the inverter.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive device having complementary duty cycles, a control circuit for controlling the controllably conductive device, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive device. In an especially preferred embodiment, the controllably conductive device of the valley-fill circuit is also one of the controllably conductive devices of the inverter.

Abstract: A phase controlled dimming system having an active filter for receiving the AC line voltage waveform, and for recovering the AC fundamental waveform therefrom is disclosed. The recovered AC fundamental waveform is supplied to a zero crossing detector that provides zero crossing indications of the AC fundamental waveform. The recovered AC fundamental is substantially free of noise or distortion, and of frequency components greater than at least second order harmonics, that may be present on the AC line voltage waveform, and that might otherwise result in faulty or incorrect zero crossing detection. An output of the zero crossing detector is supplied to a microprocessor that controls the gating of a controllably conductive device interposed between the controlled load and the AC source based on the zero crossing information. The filter may take an analog or digital (software) form.

Abstract: An elongated reelable shade, first and second spaced support brackets removably connected to first and second and opposite ends of said elongated reelable shade for supporting said reelable shade from a fixed support, an electrical drive motor having an output shaft for rotating said elongated reelable shade around its axis to selectively reel and unreel said shade, an electrical circuit for energizing and operating said motor, the electrical circuit including a controller coupled to and controlling the operation of said drive motor, and a coupler for removably coupling said output shaft of said motor to said first end of said elongated reelable shade, a single housing having said first bracket fixed thereto, said single housing containing and supporting said motor, said electrical circuit and said coupler, said coupler comprising an output driver which removably receives said first end of said shade with rotatable driving relationship.

Abstract: An elongated reelable shade, first and second spaced support brackets removably connected to first and second and opposite ends of said elongated reelable shade for supporting said reelable shade from a fixed support, an electrical drive motor having an output shaft for rotating said elongated reelable shade around its axis to selectively reel and unreel said shade, an electrical circuit for energizing and operating said motor, the electrical circuit including a controller coupled to and controlling the operation of said drive motor, and a coupler for removably coupling said output shaft of said motor to said first end of said elongated reelable shade, a single housing having said first bracket fixed thereto, said single housing containing and supporting said motor, said electrical circuit and said coupler, said coupler comprising an output driver which removably receives said first end of said shade with rotatable driving relationship.

Abstract: A phase controlled dimming system having an active filter for receiving the AC line voltage waveform, and for recovering the AC fundamental waveform therefrom is disclosed. The recovered AC fundamental waveform is supplied to a zero crossing detector that provides zero crossing indications of the AC fundamental waveform. The recovered AC fundamental is substantially free of noise or distortion, and of frequency components greater than at least second order harmonics, that may be present on the AC line voltage waveform, and that might otherwise result in faulty or incorrect zero crossing detection. An output of the zero crossing detector is supplied to a microprocessor that controls the gating of a controllably conductive device interposed between the controlled load and the AC source based on the zero crossing information. The filter may take an analog or digital (software) form.