General Electric Company

Other

Federal Signal Corporation

Robertson Worldwide, Inc.

Joseph M Allison

John M Davenport

Richard L Hansler

Gary Robert Allen

Robert A Leskovec

Veijo Matias Tuoriniemi

William J Cassarly

Park French

Edward John Thomas

Kenneth S King

Raymond A Buchina

David J Moore

Tilton L Block

James D Mieskowski

Thomas R Stanton

Mark H Thomsen

A reliable strobe power supply is disclosed that provides requisite light energy for emergency uses without causing EMI problems. A two phase dual flyback power converter operating in transitional mode is disclosed containing a microcontroller that maintains a 180 degree displacement between the two phases by enabling a small, variable dead time between the cessation of stored energy in the flyback transformers and turn-on of the associated power switching transistor for one or the other phases. The power supply is capable of detecting a fault (neoning) and automatically correcting the condition by incrementing the flash capacitor charge off-time delay. The power supply is also capable of tolerating defective (persistently neoning) strobe tubes that cause an inordinate delay in capacitor charging by turning them off.

Flash strobe power supply system and method

A headset control system for operating a microcontroller based device includes a microphone, a first and a second speaker, and a user operated switch. The switch selectively disables said first speaker in a first state or said microphone in a second state. A momentary switch creates patterns of momentary switching from one of a first, a second and a third state to at least one other state and back. A switch detector comprises a plurality of comparators to implement threshold logic and produces a signal indicating the respective states of said user-operated switch and said momentary switching means. A microcontroller responsive to said switch detector includes a means to differentiate between different switching patterns of said momentary switching means and initiates respective function as a function of a pattern of momentary switching and state of said user-operated switch and current operational mode.

Headset control system for operating a microcontroller based device

A resonant fluorescent lamp ballast includes an IC driver for a half-bridge arrangement that supplies AC current to a lamp. The IC creates a frequency sweep from a pre-heat frequency, through a resonant frequency, to a still lower operating frequency. A pre-heat pin in the IC triggers a re-start or the frequency sweep when a first signal exceeds a first threshold level. A shut-down pin in the IC associated with an internal shut-down latch shuts down the driver when a second signal exceeds a second threshold level. Pre-heat trigger circuitry detects a current spike through half-bridge switches when the lamp has not yet started, supplying the pre-heat pin with a first signal exceeding the first threshold level. End-of-life circuitry provides to the shut-down pin a second signal exceeding the second threshold level if lamp current fails to reach a substantial portion of its normal level within a predetermined time. A DC current-supply path is provided from a DC current supply, through at least one filament of each lamp in the load circuit, to a power-supply pin for the IC. The end-of-life circuitry cooperates with the pre-heat trigger circuitry by limiting the number of the frequency sweeps to no more than occur during the predetermined time set by the end-of-life circuitry. The DC path cooperates with the end-of-life circuitry and the internal shut-down latch to reset the latch when the DC path is broken due to absence of the at least one filament in the path.

Fluorescent lamp ballast with integrated circuit

A constant wattage electronic ballast circuit for lamp comprises a circuit for producing a voltage feedback signal substantially proportional to voltage of the lamp. A diode function generator processes the voltage feedback signal so as to produce a processed signal which, within sequential bands of lamp voltage, varies less for a specified variation of lamp voltage in a higher voltage band than in a lower voltage band. A circuit produces a current feedback signal substantially proportional to current in the lamp. A circuit for controlling lamp current comprises a circuit for summing the processed signal with the current feedback signal to create a summed signal, and a circuit for adjusting lamp current in response to the difference between the summed signal and a reference signal.

Constant wattage electric ballast circuit for lamp

A portable communication and audio system includes a radio telephone for receiving a first audio signal and transmitting a corresponding first radio signal through a transmitter to another location, and for receiving a second radio signal through a receiver and converting it to a second audio signal. An audio device provides a third audio signal. A microphone receives the first audio signal. A headset with first and second speakers is provided for selectively listening to the second or the third audio signal. A user-operated switch selectively disables the first speaker in a first state or the microphone in a second state. A state-indicating apparatus produces a signal indicating the state of the user-operated switch. A control apparatus, responsive to the state-indicating apparatus, enables telephone usage by connecting the microphone to the transmitter and connecting the second speaker to the receiver when the user-operated switch is in the first state, and connects the first and second speakers to receive the third audio signal when the user-operated switch is in the second state. The system preferably includes a pivotable boom depending from the headset, with the microphone being located on the boom. The audio device can be separate from the radio telephone. The system preferably includes a momentary, user-controlled switch and control apparatus for implementing a control function for a selected one of the radio telephone and the audio device.

Personal portable communication and audio system

A universal electronic ballast self-accommodates to appropriately supply power to each one of a family of different fluorescent lamps, one at a time. The ballast comprises a circuit for supplying a.c. current to a lamp in such manner that current in the lamp varies as a function of an error voltage. A summing circuit is provided together with an error amplifier for amplifying the output of the summing circuit to produce the error voltage. A circuit produces a reference voltage that is supplied to the summing circuit. A current feedback circuit feeds back to the summing circuit a first signal that varies as a function of lamp current. A voltage feedback circuit feeds back to the summing circuit at least a second signal that varies as a function of lamp voltage in such manner as to realize a ballast current-voltage characteristic that intersects respective lamp current-voltage characteristics at desired operating power for each of the family of lamps.

Universal electronic ballast for a family of fluorescent lamps

A network of identical atmospheric hazard detectors communicates a locally sensed hazard condition directly to multiple neighboring detectors using RF command communication, without the use of wires and without a central control location. Each detector includes a sensor of an atmospheric hazard, a detection circuit for measuring the sensor output and creating a local hazard signal, an alarm indicator, an RF transmitter for sending a neighboring hazard signal to the network, and an RF receiver for receiving a neighboring hazard signal from the network. The local alarm and neighboring alarm control signals produce discernibly different alarm indications from the detector's alarm device, facilitating an attempt to locate the origin of a hazard. In the preferred embodiment, every detector functions as a receive/transmit relay station, enabling the network to be extended in spatial expanse without limit and without increasing the power output of the RF transmitter. Auxiliary devices are included, for example, a radio controlled light for emergency illumination.

Atmospheric hazard detector network

A high power factor electronic ballast for operating a high pressure gas discharge lamp comprises a boost converter function and a buck function. The boost converter function and the buck function have common components. The combination boost-buck converter reduces parts count, as compared to the parts count required for the separate boost and buck circuits of the prior art, by making some components of the single circuit act simultaneously in both the boost and buck functions. The rigid forcing of the ac input current waveform to follow the ac input voltage waveform is relaxed, to give performance priority to the buck function for the common components. Harmonics are allowed to enter the system in moderation in return for a less expensive and more reliable system that does not compromise lamp power control.

High power factor electronic ballast

An electrodeless neon discharge light source having a red color light output is provided for use in automotive applications. The light source has a lamp envelope containing a fill of neon gas which, when excited to a discharge state by introduction of an operating signal over a tuned circuit consisting of a resonant capacitor and a ferrite coil, produces a red color light output. A flash control input to a ballast circuit arrangement provides the ability to control the light output using bursts of high frequency sinusoidal energy. The use of the burst signal approach allows for providing varying levels of light intensity output thereby signifying the distinction between braking conditions and an on condition of the tail light. Furthermore, by controlling the rate of flashing of the light source, an indication of a hard braking or emergency condition, could be conveyed.

Electrodeless discharge lamp having a neon fill

Disclosed is an electronic ballast circuit for a high pressure gas discharge lamp with a reduced parts-count starting circuit. The circuit comprises an arrangement for supplying d.c. voltage from a d.c. source, and a main inductor for receiving energy from the d.c. source and supplying the energy to the lamp. The main inductor has a plurality of windings. A first winding of the inductor is coupled to receive energy from the d.c. source. Further included is a current-switching arrangement conductive during periodic first part cycles for transferring energy from the d.c. source to the main inductor, and non-conductive during periodic second part cycles. A first part cycle is followed by a second part cycle in successive periods of switching operation of the current-switching arrangement. The first winding of the main inductor has impressed across it substantially the d.c. source voltage during the first part cycles, and reflects substantially the lamp voltage during the second part cycles. The circuit further includes a starting circuit for providing a pulse in excess of 15,000 volts across the lamp to facilitate starting the lamp. The starting circuit comprises a spark gap device, a pulse transformer, and a voltage-generating circuit. The voltage-generating circuit comprises a starting capacitor for storing energy and impressing across a spark gap an increasing voltage, which reaches the breakdown voltage of the spark gap during a lamp start-up period, and also a circuit for charging the starting capacitor with energy from the main inductor during the second part cycles.

Gas discharge lamp ballast circuit with reduced parts-count starting

Disclosed is a ballast circuit for a high pressure gas discharge lamp, including a comparator circuit for producing a feedback error signal representing the difference between a feedback signal and a reference signal. The feedback signal is selectively one of a non-light feedback signal and a light feedback signal, as determined by a switching circuit. A power control circuit adjusts the level of power supplied to the lamp in response to the feedback error signal. A first, non-light feedback circuit supplies a non-light feedback signal to the comparator circuit, based on non-light information of the lamp that is fed back to the non-light feedback circuit. A light feedback circuit operative during a lamp warm-up period supplies a light feedback signal to the comparator circuit based on light intensity information that is fed back to the light feedback circuit. The light feedback circuit has an adjustable gain as determined by the difference between measured light intensity and magnitude of the light feedback signal produced. A calibration circuit, operative during steady state lamp operation when the comparator circuit is responsive to the non-light feedback signal, automatically adjusts the gain of the light feedback circuit until a state is reached in which switching to light feedback control would result in substantially no change in light intensity. The calibration circuit includes a calibration memory for storing the gain for use in a subsequent period of lamp warm-up.

Gas discharge lamp ballast circuit with automatically calibrated light

A low voltage DC input ballast circuit for a discharge lamp particularly suitable for a central lighting system includes an input filter stage which feeds into a first boost converter circuit controlled by way of a pulse width modulator device. The first boost converter provides warm-up and steady state run signals to the lamp in a voltage fed manner over a coupling circuit using components which are reduced in size relative to conventional discharge ballast circuits. Control circuitry provides various monitoring functions, an example of which is that, in the event of a low input voltage, the lamp will operate in a dimmed or faded manner rather than maintain lumen output by drawing additional current. A second boost converter circuit is associated with a starter circuit arrangement and operates such that starting pulses can be generated and repeated if necessary in a very rapid manner.

Low voltage ballast circuit for a high brightness discharge light source

Miniature high pressure arc lamps containing a substantial pressure of xenon, in addition to metal halide and mercury, can provide instant light at turn-on and are suitable for automotive headlamps. The xenon aggravates convection which causes arc-bowing and overheating of the envelope above the arc. By operating the lamps on unidirectional current upon which a frequency-modulated high frequency ripple has been imposed, acoustic resonance is used to straighten out the arc. The use of unidirectional current permits a reduction in cost and size of the ballast control circuits operated from auto storage battery. Frequency modulation of the ripple broadens the band allowing acoustic straightening of the arc. Additional control of the arc plus reduction of cataphoresis may be achieved through a horizontal magnetic field at the arc, transverse to current flow.

Acoustic resonance operation of xenon-metal halide lamps on

Miniature high pressure arc lamps containing a substantial pressure of xenon, in addition to metal halide and mercury, can provide instant light at turn-on and are suitable for automotive headlamps. The high pressure of xenon aggravates convection which causes arc bowing and overheating of the envelope above the arc. By operating the lamp at high frequency within selected bands, acoustic modes are excited in the fill which straighten the arc and make the envelope more isothermal. Frequency modulation of the input can be used to broaden the band selected for acoustic operation and relax the tolerance on arc tube and circuit parameters needed for a match. Acoustic operation may also be used to effect physical displacement of the arc for beam switching.

Acoustic resonance operation of xenon-metal halide lamps

A method and a ballast circuit are disclosed for operating a xenon-metal halide lamp particularly suited for automotive applications with a direct curernt (DC) levels having selectable amount of ripple imposed thereon. The ripple provides for acoustically straightening the arc between the electrodes of the xenon-metal halide lamp. The DC acoustic operation has the capability of utilizing cataphoresis effect so as to provide a less distracting forward beam illumination for a vehicle.

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Euclid, OH, United States of America

Joseph M Allison