Dimming Circuit For Fluorescent Lamps Patents (Class 315/DIG4)
  • Patent number: 6153984
    Abstract: The invention provides a system for lighting a plurality of compact fluorescent lamps (CFL), each connectable in parallel to a power supply line via an adaptor, the system comprising a central dimming device connectable to receive power from mains and having outlet terminals for supplying predetermined, selectable power to the power supply line to which the plurality of CFL are connectable.
    Type: Grant
    Filed: November 16, 1998
    Date of Patent: November 28, 2000
    Assignee: Ein Hashofet Electrical Accesseries
    Inventors: Omri Fishbein, Ya'Akov Shofar
  • Patent number: 6150775
    Abstract: A lamp device includes an oscillating circuit and a brightness control circuit coupled to the lamp member. The brightness control circuit has two or more capacitors of different capacitances for energizing the lamp device to different brightnesses. A contacting control circuit is coupled to the brightness control circuit via an integrated circuit for actuating the lamp device via the integrated circuit by contacting a terminal of the contacting control circuit. A switching circuit is coupled to the brightness control circuit for selectively actuating the capacitors.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: November 21, 2000
    Inventor: Steven Kau
  • Patent number: 6147463
    Abstract: Control device (3) for the operation of a load, in particular at least one gas discharge lamp (10, 15). The control device (3) is divided into a first purely software controlled control unit (3a) a second control unit (3b) realized purely in hardware. The two control units (3a, 3b) are connected with one another via a bidirectional connection line, the second control unit receiving exclusively internal operating state information (I.sub.intern) and the first control unit (3a) receiving external control information (I.sub.extern) By means of the division of the control device into a purely software controlled control unit (3a) and a control unit constructed purely of hardware (3b) the control device (3) in accordance with the invention has both a speed sufficient for rapid control procedures and also a sufficient flexibility with regard to alterations. Advantageously, the control device (3) in accordance with the invention is employed in an electronic ballast for the operation of gas discharge lamps (10, 15).
    Type: Grant
    Filed: September 1, 1999
    Date of Patent: November 14, 2000
    Assignee: Tridonic Bauelemente GmbH
    Inventors: Siegfried Luger, Alfred Trostl
  • Patent number: 6144169
    Abstract: A triac dimmable electronic ballast having a single stage feedback power factor inverter is configured to isolate the resonant circuit current from a DC bias, or a DC transient caused by activations of the triac. The resonant circuit is driven by a high frequency inverter, and contains a feedback path to a DC storage element. Two DC blocking devices are provided, one between the resonant circuit and the inverter, and one between the resonant circuit and the DC storage element.
    Type: Grant
    Filed: December 29, 1998
    Date of Patent: November 7, 2000
    Assignee: Philips Electronics North America Corporation
    Inventor: Jerzy Janczak
  • Patent number: 6137240
    Abstract: A universal ballast control circuit allows a universal ballast to accommodate a gas discharge lamp within a relatively wide wattage range using a low-speed microcontroller. The control circuit drives the ballast to start, run and dim a particular lamp type by providing a control voltage signal to a conventional inverter MOSFET driver to effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. In one aspect of the invention, the control circuit comprises a generator for generating a periodic analog voltage signal, a source for producing a DC voltage signal, a controller which includes a low-speed microcontroller for varying the frequency of the periodic analog voltage signal and the magnitude of the DC voltage signal, and a comparator for comparing the periodic analog voltage signal and the DC voltage signal to produce a control voltage signal.
    Type: Grant
    Filed: December 31, 1998
    Date of Patent: October 24, 2000
    Assignee: Lumion Corporation
    Inventor: Alexei Bogdan
  • Patent number: 6138241
    Abstract: An apparatus for and method of inhibiting and overriding the normal operating mode of one or more input devices connected to a communications network. The present invention functions within an electrical network made up of a plurality of input devices wherein a group of input devices is capable of commanding an electrical control device to apply and remove electrical power from an electrical load connected thereto. The input devices or nodes communicate with the electrical control device over a communications network. When one of the input devices is turned off, the normal operating mode of all the other input sensors is inhibited. The electrical control device remains inhibited until all the input devices are no longer in the off position. Thus, electrical power to the load controlled by the electrical control device remains disconnected until all input devices are in the on position. Local and remote signaling, control and indication diagnostic and monitoring functions are also provided.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: October 24, 2000
    Assignee: Leviton Manufacturing Co., Inc.
    Inventors: David P. Eckel, Gaetano Bonasia
  • Patent number: 6133697
    Abstract: The present invention is to provide a fluorescent lamp dimming apparatus capable of continuously dimming the fluorescent lamp, and capable of eliminating a fluctuation of light outputs, and in particular, capable of turning ON the fluorescent lamp in a low temperature.
    Type: Grant
    Filed: September 23, 1999
    Date of Patent: October 17, 2000
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Mitsubishi Lighting Fixture Co., Ltd.
    Inventors: Satoshi Nagai, Kenichiro Nishi, Takahisa Hamaguchi, Kentaro Eguchi, Jun Bunya, Osamu Ishikawa
  • Patent number: 6133696
    Abstract: A dimmer applies a phase-controlled AC voltage to a lighting assembly which includes a fluorescent lamp operated with a magnetic ballast. A microprocessor performs a calibration routine in which the phase angle used in phase control is increment from 0 toward 180 degrees. The microprocessor monitors current conducted by the lighting assembly in response to each incrementing, effectively determining an operative range of phase angles free of flickering or drop-out. During steady-state operation, the microprocessor converts nominal power settings into corresponding phase angle settings within the operative range, preventing operation in undesirable states.
    Type: Grant
    Filed: October 1, 1997
    Date of Patent: October 17, 2000
    Assignee: Joao F. Tavares
    Inventors: Joao F. Tavares, Barna Szabados, Youssef H. Dableh
  • Patent number: 6124684
    Abstract: A power saving dimming apparatus for gas discharge lamps activates a system of gas discharge lamps through a phototransistor network sensitive to the infrared spectrum rather than the normal visible spectrum. The phototransistor network allows power to be supplied to the apparatus, resulting in the turning on of the lamps whenever daylight conditions exist which are insufficient to produce infrared light. When power is applied to the apparatus, either at initial turn on or after a momentary interruption, the apparatus applies full power to the primaries of the lamp ballasts for a preselected time period, thus ensuring all the lamps in the system light. After the preselected time period has passed, the apparatus automatically dims the lamps and maintains them in the dimmed state.
    Type: Grant
    Filed: March 21, 1994
    Date of Patent: September 26, 2000
    Inventor: Richard L. Sievers
  • Patent number: 6121734
    Abstract: A current controlled dimmer for controlling the output intensity of a fluorescent lamp with a magnetic ballast. The current controlled dimmer generates an AC current which follows the shape of the AC line voltage for the fluorescent lamp. The light intensity output of the fluorescent lamp is controlled by varying the amplitude of the AC current. The AC current is generated using a pulse width modulator (PWM) to modulate the AC line voltage. The current controlled dimmer 10 utilizes a feedback control loop which applies proportional and integral (PI) control to the PWM modulation. In another embodiment of the current controlled dimmer, the AC current is generated by rectifying the AC line voltage and modulating the rectified voltage by a pulse width modulator (PWM) into positive and negative cycles to generate a 60 Hz AC current signal.
    Type: Grant
    Filed: October 16, 1998
    Date of Patent: September 19, 2000
    Inventor: Barna Szabados
  • Patent number: 6118228
    Abstract: A high-frequency filtered dimmable electronic ballast circuit for powering low-pressure fluorescent lamps includes an input protection device; a radio-frequency filter connected to an output of the input protection device; a rectifier connected to an output of the radio-frequency filter; a power factor correcting switching power supply device connected to an output of the rectifier; a current controlled push-pull converter connected to an output of the switching power supply device; a series-parallel resonant filter composed of a capacitor in series with two inductors having a common connection in parallel with an additional capacitor connected to an output of the push-pull converter to maintain voltage wave forms essentially sinusoidal and of constant amplitude regardless of loading; a fluorescent lamp connected to an output of the resonant filter; and an external on/off switching circuit connected directly or by an optical or magnetic insulation device to an input of the push-pull converter for renotely tur
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: September 12, 2000
    Inventor: Sandor Pal
  • Patent number: 6114813
    Abstract: A light sensitive dimmer switch circuit for controlling the illumination level of a light as a function of the ambient illumination level surrounding the dimmer switch circuit by selectively controlling an AC power signal provided to the light includes a photocell and a phase control circuit. The photocell is responsive to the ambient illumination level and has a conduction state associated therewith. The conduction state changes, in response to the ambient illumination level, such that the photocell effectively exhibits either a substantially open circuit or a substantially short circuit. The phase control circuit selectively varies a conduction phase angle associated with the AC power signal which correspondingly causes a variation in the illumination level of the light.
    Type: Grant
    Filed: July 30, 1998
    Date of Patent: September 5, 2000
    Assignee: Holmes Products Corp.
    Inventors: David Lo, Tan Yuen Hung
  • Patent number: 6111363
    Abstract: A ballast circuit 10 for a gas discharge lamp 14, incorporates a shutdown circuit 12 for limiting voltage output of a d.c.-to-a.c. converter 21. The shutdown circuit includes a pair of terminals 66 and 68 connecting across an inductor 48 in order to sense the inductive voltage of the d.c.-to-a.c. converter 21. A rectifier network 70-76 receives the inductor voltage and generates a full-wave rectified voltage. A latch 84 is arranged to receive the rectified voltage and to enter an active state when the rectified voltage is above a pre-determined value. A time delay circuit 118 located between the rectifier network 70-76 and the latch 84 provides an adjustable delay time prior to activation of the latch network. Upon activation of the latch, the inductor voltage is decreased and the ballast circuit 10 is taken out of resonance thereby lowering the voltage and current applied to the resonant circuit 28.
    Type: Grant
    Filed: July 21, 1999
    Date of Patent: August 29, 2000
    Assignee: General Electric Company
    Inventor: Louis R. Nerone
  • Patent number: 6107751
    Abstract: A circuit for supplying AC voltage and current to a gaseous discharge lamp upon the application of DC voltage and current, the circuit comprising: a transformer including a first and a second primary windings; a first capacitance means, coupled across the primary windings to define a resonant circuit; a start-up current source coupled to a drive terminal; first and second transistors coupled to the drive terminal; at least one drive winding coupled on one end to the drive terminal and coupled on the other end to the base of one of the transistors; and first and second current-blocking devices, in one embodiment a diode and in another embodiment a transistor, each current-blocking device configured so as to block a current from flowing into the emitter element of one of the transistors.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: August 22, 2000
    Inventor: Keith Billings
  • Patent number: 6107749
    Abstract: In a power-line-operated high-frequency electronic ballast, a half-bridge inverter is powered from a DC supply voltage and a fluorescent lamp is connected with the inverter's more-or-less asymmetrical squarewave output voltage by way of a of a series-resonant L-C circuit. The amount of power supplied by the inverter to the series-resonant L-C circuit and/or to the fluorescent lamp at any given moment depends on four significant factors: (i) the instantaneous magnitude of the DC supply voltage, (ii) the instantaneous frequency of the inverter's squarewave output voltage, (iii) the symmetry of the inverter's squarewave output voltage (which determines the effective magnitude of of its fundamental frequency voltage component), and (iv) the instantaneous operational characteristics of the fluorescent lamp.
    Type: Grant
    Filed: July 11, 1994
    Date of Patent: August 22, 2000
    Inventor: Ole K. Nilssen
  • Patent number: 6100643
    Abstract: A fluorescent lighting system has: (A) a central power supply connected with regular power line voltage and including a number of power supply modules (e.g., eight), each such module having: (i) a parallel-resonant self-oscillating bridge inverter operative to provide a 35 kHz sinusoidal output voltage at a pair of primary output terminals; (ii) a tank-inductor and a tank-capacitor parallel-connected across the primary output terminals; and (iii) several (e.g., four) pairs of secondary output terminals, each connected with the primary output terminals via its own dedicated current-limiting sub- circuit; thereby to prevent a load connected with a pair of secondary output terminals from drawing more than a certain amount of power; thereby, in turn, to render each pair of secondary output terminals fire-hazard-safe; (B) a plurality of lighting fixtures (e.g.
    Type: Grant
    Filed: January 8, 1997
    Date of Patent: August 8, 2000
    Inventor: Ole K. Nilssen
  • Patent number: 6100647
    Abstract: An electronic ballast for an electron discharge lamp includes a resonant inverter driven by a high frequency switching signal supplied by a drive circuit which is substantially comprised in an integrated circuit, the lamp being connected in an output circuit of the inverter and powered thereby. The lamp intensity is controlled by changing the switching signal frequency, thereby changing the power supplied to the lamp. In order to prevent parasitic capacitance of remote wiring between the ballast and the lamp from causing inaccuracies in determination of the power being supplied to the lamp, the ballast takes into account the phase difference between lamp current and voltage in making such determination. For example, by deriving the product of rectified lamp voltage and rectified lamp current, and using the arithmetic summation of such products during each operating cycle as a measure of lamp power.
    Type: Grant
    Filed: December 28, 1998
    Date of Patent: August 8, 2000
    Assignee: Philips Electronics North America Corp.
    Inventors: Demetri J. Giannopoulos, Ihor T. Wacyk, Sreeraman Venkitasubrahmanian
  • Patent number: 6097162
    Abstract: A broad range of brightness in a fluorescent lamp may be achieved by applying low-frequency, pulse-width modulated voltage or current to the lamp for a low level of brightness, or high-frequency voltage or current for a high level of brightness. Switching is provided to select between the two signals.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: August 1, 2000
    Assignee: AlliedSignal Inc.
    Inventors: Ronald F. Welch, Jr., William R. Tombs, Muthu Murugan, Robert Saccomanno
  • Patent number: 6091205
    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.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: July 18, 2000
    Assignee: Lutron Electronics Co., Inc.
    Inventors: Robert C. Newman, Jr., Donald F. Hausman, Robin C. Moseley
  • Patent number: 6087786
    Abstract: Methods of controlling the brightness of a glow discharge which switches from a low brightness state to a high brightness state a given time after the start of an excitation pulse are described. In the first method, conventional pulse duration modulation produces a dimming ratio much greater than the ratio of duty factor variation. In the second method, a plurality of sets of pulses having different fixed durations but variable repetition rates are employed. In the third method, a plurality of sets of pulses having different relative durations have their pulse durations modulated in synchrony.
    Type: Grant
    Filed: December 24, 1998
    Date of Patent: July 11, 2000
    Assignee: Central Research Laboratories Limited
    Inventors: Philip Charles Allen, Andrew David Barnes, Ian Gordon Gibb, Alan Cooper Sharp, Steven Edward Coe, Gregory Colin Truman
  • Patent number: 6072284
    Abstract: A compact fluorescent lamp and an electronic ballast therefor are mounted on a three-terminal base which can be fitted into a three-way-switched standard AC lamp socket, so as to be responsive to the three powered switch positions of the socket for generating three light output levels. The ballast includes an AC-to-DC conversion circuit which supplies a lamp driver including a DC-to-AC conversion circuit, an oscillatory circuit and a resonant circuit. In one embodiment the AC-to-DC conversion circuit includes a full bridge rectifier and a voltage doubler producing two operating voltage levels for the lamp driver and two frequency control voltage levels for the oscillator, the ballast generating three light output levels by using two operating voltages and two operating frequencies.
    Type: Grant
    Filed: July 20, 1998
    Date of Patent: June 6, 2000
    Assignee: Duro-Test Corporation
    Inventor: Lin Lin
  • Patent number: 6069457
    Abstract: A dimmer for dimming gas discharge and incandescent lamps can be installed in place of a standard wall-mounted light switch and connected to existing wiring. The dimmer has a switch coupling one or more full wave bridge rectifiers to a main AC source and to existing power wires running through the wall to the fixture. The bridge rectifiers are controlled by the dimming switch such that either the normal AC source waveform is transmitted over the power wires, or a full wave positively or negatively rectified AC waveform is transmitted, or else no voltage is transmitted. At the fixture, the transmitted power waveform is applied to the lamp power terminal of the lamp or ballast as well as to a decoder. A dimming interface receives the decoder output and appropriately adjusts lamp brightness by changing the operating conditions of the lamp in accordance with this output. The dimmer may also be used to control general household devices containing a front-end full wave bridge rectifier.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: May 30, 2000
    Assignee: Lumion University
    Inventor: Alexei Bogdan
  • Patent number: 6064160
    Abstract: A light modulation circuit is provided which includes: a cold cathode tube; an inverter for turning the cold cathode tube on and off; and an adjustor for adjusting a current flowed through the cold cathode tube.
    Type: Grant
    Filed: April 1, 1998
    Date of Patent: May 16, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Kyotaro Nakamura
  • Patent number: 6057652
    Abstract: High voltage stress on the semiconductor devices at light load conditions, high total harmonic distortion (THD) of the line current, and poor crest factor (CF) of lamp current of "charge pump" electronic ballast circuits make them difficult to manufacture cost-effectively. To overcome these deficiencies, the DC bus voltage is reduced at light loads by providing a second resonance. One technique, high-frequency second-stage resonance, provides sufficient preheating at low V.sub.dc. Combined with the instant startup and the proper restart scheme, this technique can greatly reduce the maximum V.sub.dc at ignition. Another technique, low-frequency second-stage resonance, can reduce the steady state V.sub.dc at light loads, including during start-up. Consequently, high ignition voltage can be continuously impressed on the lamp without increasing V.sub.dc. Further, a diode clamping technique smooths the envelope of V.sub.a, thereby achieving near unity power factor, low THD and low CF without close-loop control.
    Type: Grant
    Filed: February 9, 1996
    Date of Patent: May 2, 2000
    Assignees: Matsushita Electric Works, Ltd., Virginia Tech Intellectual Properties, Inc.
    Inventors: Wei Chen, Fred C. Lee, Koji Nishiura, Tokushi Yamauchi, Yoshinobu Murakami, Minoru Maehara
  • Patent number: 6051940
    Abstract: A series resonant ballast safety control circuit for controlling the operation of a ballast when a lamp is removed from a lamp fixture. The safety control circuit senses a diode clamp current and activates a transistor to ground one of the terminals of a dimming control circuit. The dimming control circuit reduces the duty cycle of one of the inverter transistors to decrease the available output voltage and reduce the through-lamp leakage current to safe levels. Once the lamp is replaced in the lamp fixture, the safety control circuit no longer controls the dimming control circuit and the ballast returns to normal operation. In another embodiment, the safety control circuit is used with a boost power factor correction circuit in a non-dimming ballast system to reduce the current provided to the lamp load.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: April 18, 2000
    Assignee: MagneTek, Inc.
    Inventor: Ganesh Arun
  • Patent number: 6046550
    Abstract: A diagnostic apparatus for use in a light dimming circuit of the tape which selectively controls the current flow through a lighting load to adjust its luminous output. The dimming circuit has a controllably conductive device, such as a triac, connectable in series between an A.C. power source and a lighting load, and a control circuit which responds to a dimming level control signal to selectively apply a selected portion of an A.C. voltage waveform produced by the A.C. power source to the lighting load to adjust the RMS voltage across the load. The selected portion is determined by a firing angle at which the control circuit causes the controllably conductive device to conduct power during each half cycle of the A.C. waveform. The diagnostic appararus has a senior to sense the operating status of a component of the dimming circuit and/or the presence of the dimming level control signal.
    Type: Grant
    Filed: June 16, 1999
    Date of Patent: April 4, 2000
    Assignee: Lutron Electronics Co., Inc.
    Inventors: Jonathan H. Ference, Donald F. Hausman, John F. Loar, Robert S. Spehalski, Walter S. Zaharchuk
  • Patent number: 6043615
    Abstract: A method and apparatus for signaling promotional operation of a gaming device using existing fluorescent illumination lamps. An illumination lamp on a gaming device is operated continuously during normal operation, then flashed to signal promotional operation. Alternatively, an illumination lamp can be dimmed during normal operation, then operated at full brightness during promotional operation. To achieve flashing and dimming operation, a conventional starter is removed from a socket in a fluorescent lamp fixture and replaced with a controllable starter that fits into the same socket. The starter has a pair of wire leads for receiving a control signal for flashing or dimming the lamp. The controllable starter includes a starter circuit having a switch connected between two power terminals of the starter. When the switch closes responsive to the control signal, it shorts circuits the lamp, thereby extinguishing the arc and allowing preheat current to flow in the heating filaments of the lamp.
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: March 28, 2000
    Assignee: Acres Gaming Incorporated
    Inventor: Mark G. Forbes
  • Patent number: 6043611
    Abstract: A compact flourescent lamp in which the level of illumination is controlled by a triac dimmer. Premature turn off of the triac dimmer is avoided through the serial combination of at least one resistor and at least one capacitor forming a snubber placed across the output of the electromagnetic interference filter of the compact flourescent lamp ballast. The snubber dampens oscillations generated within the compact flourescent lamp whereby sufficient power is drawn by the compact flourescent lamp to sustain conduction of the triac dimmer throughout the dimming range of the latter.
    Type: Grant
    Filed: April 10, 1997
    Date of Patent: March 28, 2000
    Assignee: Philips Electronics North America Corporation
    Inventors: Pawel M. Gradzki, Jerzy Janczak
  • Patent number: 6040660
    Abstract: A device for controlling the intensity of the light emitted by a lighting element of a lighting apparatus, in particular a flashlight, is embodied as a module which can be arranged in series with the lighting element for the supply of the latter with current. A circuit device for controlling the light-intensity of the lighting element, and a central control device for detecting a detection signal of the detection device as well as for triggering the circuit device are provided. It is made possible with the present invention to dim the intensity of the light emitted by it by variation, in particular in several stages.
    Type: Grant
    Filed: June 13, 1997
    Date of Patent: March 21, 2000
    Inventors: Rudolf Schmidt, Augustin Thalhofer
  • Patent number: 6040661
    Abstract: A programmable universal ballast can be programmed to accommodate a gas discharge lamp within a relatively wide wattage range. The ballast uses a microprocessor to store and execute various routines to start, run and dim a particular lamp type. A host computer produces customized routines which are downloaded into a microprocessor located within the ballast. These routines output signals to the MOSFET transistors of the inverter which effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. By selectively changing simultaneously both the frequency and duty cycle of the inverter signal, the energy spectrum of the resonance network is altered and circuit voltages and currents can be controlled to accurately match required lamp characteristics and operational requirements. The ballast may include an inductive element in parallel with the lamp allowing dimming to 1% of full light output.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: March 21, 2000
    Assignee: Lumion Corporation
    Inventor: Alexei Bogdan
  • Patent number: 6037722
    Abstract: A dimmable electronic ballast for a gas discharge lamp utilizing a modified self-resonant split inductor configuration. The voltage supplied to the lamp load is controlled by varying the duty cycle of the output stage which, in turn, feeds back a driving signal to the boost converter to synchronize the DC voltage with the needs of the load. The circuit also performs power factor and THD control. The ballast circuit controls the start-up of the lamp by proving a warming current to the filaments and then boosts the voltage to strike the lamps. If the lamps are at end-of-life wherein the filaments are intact but vapor and coatings are diminished, the ballast will apply bursts of higher voltage until the lamp strikes. Additionally, if the filaments are open, the circuit stops operation.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: March 14, 2000
    Assignee: Pacific Scientific
    Inventor: Mihail S. Moisin
  • Patent number: 6031340
    Abstract: A zero current crossing capacitive switching scheme for controlling the switching of a capacitor into and out of an HID lead ballast circuit at a time when a current through the capacitor is at or near zero. The capacitor switching enabling bi-level operation of an HID lamp such that the HID lamp operates at full power mode or in a reduced power mode. The zero current crossing is achieved by delaying the capacitor switching, a duration equal to about 5.degree. to 10.degree. lag from the zero volt crossing. The device can be used in a method of controlling a plurality of HID lamps using an isolated class 2 wiring scheme. Potential damage to the HID lamp caused by aborted lamp ignitions is also disclosed. The method includes suppressing off input signals during the warm up period.
    Type: Grant
    Filed: July 31, 1998
    Date of Patent: February 29, 2000
    Assignee: MagneTek, Inc.
    Inventor: William L. Brosius
  • Patent number: 6023132
    Abstract: An ballast includes a variable frequency boost circuit and a driven half-bridge inverter having a series resonant, direct coupled, parallel output. A control circuit includes a variable frequency driver section, a multivibrator section, and a sensing section. The variable frequency driver changes frequency smoothly, i.e. without discontinuities. The multivibrator section acts as a switch that is enabled or disabled by the sensing section for controlling the frequency of the inverter. Lamp current is required for continued operation of the control circuit. The multivibrator section controls starting by causing the inverter to produce an output signal having a trapezoidal envelope. In the event of an arc, the control circuit quenches the arc and the multivibrator periodically pulses the lamp to attempt to re-start the lamp.
    Type: Grant
    Filed: October 12, 1998
    Date of Patent: February 8, 2000
    Assignee: Energy Savings, Inc.
    Inventors: Kent E. Crouse, Peter W. Shackle, Patrick J. Keegan, Ronald J. Bezdon
  • Patent number: 6020659
    Abstract: The present invention relates to an electronic switch system for controlling AC power to a load. The switch has ON, OFF and RAMP down modes that can be selected by means of momentary touch switches. When put into the RAMP down mode, the power to the load decreases slowly at a gradual continuous uninterrupted predetermined rate. This switch system has particular utility in brightness control of lamps. It has been found that the use of a lamp controlled by an electronic switch of the present invention often will induce sleep for people that have difficulty going to sleep, particularly young children and older persons. Thus the electronic switch system and devices embodying this system are particularly useful in a method to induce sleep.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: February 1, 2000
    Assignee: Primed Products Inc.
    Inventors: Jonathan Crowther, Earl T. Jackson
  • Patent number: 6011357
    Abstract: A triac dimmable compact fluorescent lamp having a low power factor. A power feedback circuit coupled between the input and output stages of the lamp ballast creates sufficient current demand to sustain triac conduction at low dim levels. The power fed back from the output stage to the input stage, which includes a voltage doubler, reflects the voltage across the lamp.
    Type: Grant
    Filed: April 10, 1997
    Date of Patent: January 4, 2000
    Assignee: Philips Electronics North America Corporation
    Inventors: Pawel M. Gradzki, Jerzy Janczak
  • Patent number: 6008593
    Abstract: A novel monolithic electronic ballast controller IC for driving two MOS gated power semiconductors, such as power MOSFETs or IGBTs, connected in a totem pole or half-bridge arrangement. Advantageously, the present invention provides programmable preheat time and current, programmable end-of-life protection, lamp fault protection, over-temperature protection. The first embodiment of the invention is a closed-loop ballast controller IC intended for multiple lamp configurations, with three current-sensing inputs and programmable lamp power. Closed-loop control is accomplished through phase control, or, more specifically, a phase-locked loop (PLL) around a resonant type output stage driving a fluorescent lamp. The second embodiment of the present invention has a similar architecture to that of the first embodiment, with some modifications which allow dimming down to low light levels.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: December 28, 1999
    Assignee: International Rectifier Corporation
    Inventor: Thomas J. Ribarich
  • Patent number: 6002210
    Abstract: In an electronic ballast, a half-bridge inverter is powered from a DC voltage and provides an AC output voltage having a waveform with trapezoidally shaped half-cycles. The DC voltage is obtained by way of a pre-converter with a control input operative to permit control of the magnitude of the DC voltage. The AC voltage is applied across the primary winding of a leakage transformer, whose loosely coupled secondary winding is connected across a gas discharge lamp. The internal inductive reactance of the secondary winding constitutes a lamp ballasting means by way of limiting the magnitude of the resulting lamp current to a desired level. Prior to the flow of lamp current, the magnitude of the DC voltage is controlled by negative feedback to the control input so as to remain at a maximum level. After lamp current has started to flow, by negative feedback derived from the lamp current itself, the magnitude of the DC voltage is reduced so as to bring the magnitude of the lamp current down to the desired level.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: December 14, 1999
    Inventor: Ole K. Nilssen
  • Patent number: 6002213
    Abstract: A MOS gate drive (MGD) integrated circuit drives a pair of MOS gated power semiconductor devices such as are used in a half bridge circuit to drive a load in a resonant power supply circuit or to drive a gas discharge lamp in a ballast circuit. The gate drive circuit includes dead time circuitry which prevents simultaneous conduction in both MOS gated devices. The duration of the dead time is controlled in response to a feedback signal that is sensed from the output supplied to the load or the lamp. A dimming function is attained by controlling the voltage of the feedback signal.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: December 14, 1999
    Assignee: International Rectifier Corporation
    Inventor: Peter N. Wood
  • Patent number: 6002214
    Abstract: A circuit for controlling the operating power of a fluorescent lamp by detecting the phase of the lamp resonant circuit current and regulating the phase of the current, thereby regulating the lamp power. In the preferred embodiment of the circuit, the phase of the resonant circuit current is detected using a sense resistor disposed between the low side power transistor of a half-bridge driver and ground, or between the lower voltage lamp filament and ground. The zero-crossings of the resonant circuit current is detected by comparing the voltage across the sense resistor to zero voltage. Using these zero crossings, a phase pulse is generated representing the lamp resonant circuit current as a function of time. This phase pulse is compared to a reference pulse to generate an error signal indicative of the phase difference between the phase pulse and the reference pulse.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: December 14, 1999
    Assignee: International Rectifier Corporation
    Inventor: Thomas J. Ribarich
  • Patent number: 5994848
    Abstract: A triac dimmable compact fluorescent lamp including a power feedback circuit. The power feedback circuit helps to maintain the level of current drawn from the triac to at least the level of the triac holding current especially during low dim levels. In one preferred embodiment, the feedback circuit is fed into a junction joining together a pair of fast recovery diodes for converting the high frequency square wave signal into a unidirectional signal supplied to an inverter. Overboost voltages across a buffer capacitor are minimized during low dim levels.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: November 30, 1999
    Assignee: Philips Electronics North America Corporation
    Inventor: Jerzy Janczak
  • Patent number: 5990634
    Abstract: An improved dynamic range dimmer for gas discharge lamps is provided in which the frequency is shifted during the startup of the lamp, and the frequency is shifted and the duty cycle is varied to dim the light emitted by the lamp. When dimming is desired the frequency is shifted to increase the voltage available to the lamp, which then has its power reduced by controlling its duty cycle. Such an arrangement provides a greater range of light intensity variation. If the lamp is turned off while set to a dimmed level, then the frequency is automatically restored to the resonant value used when starting the lamp, to assure breakdown of the plasma in the lamp for proper ignition.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: November 23, 1999
    Assignee: Logic Laboratories, Inc.
    Inventor: Craig Brown
  • Patent number: 5990635
    Abstract: A lighting dimmer for controlling the current through a lighting load includes circuitry for applying a predetermined dimming level control signal to a control circuit in response to the absence of a dimming level control signal and the cycling OFF and ON of a circuit breaker. The dimmer further includes voltage compensation circuitry for maintaining a constant lighting load current notwithstanding short-lived changes in nominal line voltage.
    Type: Grant
    Filed: June 22, 1998
    Date of Patent: November 23, 1999
    Assignee: Lutron Electronics Co., Inc.
    Inventors: Jonathan H. Ference, Donald F. Hausman, John F. Loar, Robert S. Spehalski, Walter S. Zaharchuk
  • Patent number: 5982112
    Abstract: Disclosed is a low pressure xenon lamp (12) and the driver circuitry therefor for producing relatively short bursts of intense light from the lamp (12). The lamp (12), including its associated driver circuitry (50) can be used in theatrical, stage, movie and/or video production to simulate, among other things, bursts of lighting. The lamp (12) is installed in a fixture together with a power supply (20) and a control system (50) is provided for controlling when the lamp (12) is turned on and off. Preferably, the control system (50) includes manually operated switches (53, 57, 54) and preferably one or more controllers (50) can be coupled together in a series fashion, should it be desired to control the lamp (12) for a greater number of time cycles then permitted by a single controller (50). Alternative power supplies (20) are disclosed. One power supply (20) permits the intensity of the flashes of light (12) to be controlled.
    Type: Grant
    Filed: March 22, 1994
    Date of Patent: November 9, 1999
    Assignee: David A. Pringle
    Inventors: David A. Pringle, David McDonald, Zhong Fang Yan, George Johnson
  • Patent number: 5982111
    Abstract: An improved ballast circuit for use with a compact fluorescent lamp includes an EMI filter, a rectifier and a voltage amplification stage, an active resonant circuit, a dimming circuit, and a power factor correction stage which is connected in parallel to a lamp load. In one embodiment, the ballast circuit operates in cooperation with a three way switch to adjust the light output of the lamp to three discrete levels corresponding to each setting of the three way switch. In another embodiment the ballast circuit includes a feedback capacitor which provides a feedback path for a portion of the high frequency current to the rectifier and voltage amplification stage. In still another embodiment, the ballast circuit is configured to accept input from a triac or a SCR device. In all of the embodiments, the dimming circuit works with the active resonant circuit to vary the amount of power that is supplied to the lamp load.
    Type: Grant
    Filed: June 11, 1997
    Date of Patent: November 9, 1999
    Assignee: Pacific Scientific Company
    Inventor: Mihail S. Moisin
  • Patent number: 5973455
    Abstract: An electronic ballast for a gas discharge lamp includes an AC to DC converter for changing alternating current at power line voltage to direct current and an inverter powered by the converter and having a series resonant, direct coupled output coupled to the lamp. The inverter includes an AC switch having a diode bridge defining an AC diagonal and a DC diagonal and a transistor connected across the DC diagonal. The primary winding of a filament transformer is connected across the AC diagonal of the bridge and the transistor is coupled to the microprocessor for controlling current through the primary winding. The microprocessor is programmed to close the AC switch while the lamp is starting and to open the switch after the lamp is started, thereby cutting off the filaments from a source of power and reducing the power consumed by the ballast during normal operation. A resistor in series with the transistor is used to detect filament resistance and provide an indication of lamp type.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: October 26, 1999
    Assignee: Energy Savings, Inc.
    Inventors: Grigoriy Mirskiy, William L. Keith, Kent E. Crouse, Peter W. Shackle, Patrick J. Keegan, Ronald J. Bezdon
  • Patent number: 5973458
    Abstract: A sequential feedback control system for an electronic ballast provides feedback control during soft start and dimming operations. The system includes a feedback control portion that generates a feedback signal responsive to the power consumption of the ballast and receives a control signal for controlling the power consumption of the ballast. A dimming controller generates a dimming signal responsive to a time signal, and a soft start controller generates a soft start signal responsive to the time signal. An adder generates the control signal by adding the feedback signal and the dimming signal. The dimming controller includes a first resistor for setting the steady state power level during dimming operations and a second resistor for setting the rate of change of the power level.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: October 26, 1999
    Assignee: Samsung Electronics, Co., Ltd.
    Inventors: Maeng-Ho Seo, Nak-Choon Choi
  • Patent number: 5965985
    Abstract: A dimmable ballast circuit for a gas discharge lamp comprises a resonant load circuit with a resonant inductance, a resonant capacitance and circuitry for connecting to a gas discharge lamp. A d.c.-to-a.c. converter circuit is coupled to the resonant load circuit for inducing a.c. current therein, and comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor. The voltage between a reference node and a control node of each switch determines the conduction state of the associated switch. The respective reference nodes of the switches are interconnected at a common node through which the a.c. current flows, and the respective control nodes of the switches are substantially directly interconnected. A gate drive arrangement for regeneratively controlling the switches comprises a driving inductor connected between the common node and the control nodes and mutually coupled to the resonant inductor for sensing current therein.
    Type: Grant
    Filed: March 31, 1998
    Date of Patent: October 12, 1999
    Assignee: General Electric Company
    Inventor: Louis R. Nerone
  • Patent number: 5965989
    Abstract: A circuit that senses a current signal in a secondary winding of a transformer by monitoring a current signal in a primary winding of the transformer. The monitored current signal contains an effective current component and a magnetization current component. The magnitude of the effective current signal is related to the magnitude of the current signal in the secondary winding by the turns ratio of the transformer. The magnetization current signal produces flux in the transformer core and does not contribute to producing current in the secondary winding of the transformer. In addition, the magnetization current is 90 degrees out of phase with the effective current signal in the primary winding. The effective current signal in the primary winding is in phase with the voltage signal applied to the primary winding. The invention integrates the monitored current signal over 0 degrees to 180 degrees of the effective current signal waveform.
    Type: Grant
    Filed: July 30, 1996
    Date of Patent: October 12, 1999
    Assignee: Micro Linear Corporation
    Inventor: Urs H. Mader
  • Patent number: 5962988
    Abstract: A discharge lamp operating circuit is connected to a source of alternating current (AC) voltage, and has a discharge lamp and a semi-resonant circuit connected to the source of alternating current voltage and in series with the lamp. A starting circuit for initiating operation of said discharge lamp is also connected in the circuit. The lamp switching maintains the series semi-resonant circuit in oscillation and the series semi-resonant circuit maintains the lamp in operation after operation has been initiated by the starting circuit. Highly efficient energy transfer between inductive and capacitive components of the system result in low loss and high power factor. A variable capacitance circuit is provided to allow use of the discharge lamp operating circuit with different line voltages, and to allow dimming.
    Type: Grant
    Filed: November 12, 1997
    Date of Patent: October 5, 1999
    Assignee: Hubbell Incorporated
    Inventors: Joe Allen Nuckolls, Lily Li Lin
  • Patent number: 5962992
    Abstract: A lighting control system (LCS) (50) is provided to remotely and centrally control the operation of lamps and other electrical appliances. The LCS (50) includes a master controller (100), zone controllers (110), slave units (120), an IR controller (160). The master controller (100), zone controllers (110), and slave units (120) are electrically linked together over a common powerline through a process of installation. A process of verification is provided to confirm that the master controller (100), zone controllers (110), and slave units (120) are installed properly. The slave units (120) are further linked with a corresponding electrical appliance. Appropriate commands applied by a user of the LCS (50) to the master controller (100), the zone controllers (110), the slave units (120), and the IR controller (160) control the operation of electrical appliances individually or collectively. The LCS (50) allows the program and recall of configurations of operating levels of the electrical appliances.
    Type: Grant
    Filed: October 14, 1997
    Date of Patent: October 5, 1999
    Assignee: Chaw Khong Co., Ltd.
    Inventors: Shih-Wei Huang, Irene H. Lin