Electric lamp and discharge devices: systems – Plural series connected load devices – Christmas lights
Reexamination Certificate
1995-11-03
2001-03-06
Shingleton, Michael B. (Department: 2817)
Electric lamp and discharge devices: systems
Plural series connected load devices
Christmas lights
C315S324000, C315S224000, C362S133000, C362S225000
Reexamination Certificate
active
06198228
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to gas discharge lighting means, particularly of a type wherein one or more instant-start fluorescent lamps may be disconnectably series-connected and powered from a single plug-in frequency-converting power supply.
DESCRIPTION OF PRIOR ART
For a description of pertinent prior art, reference is made to U.S. Pat. No. 4,677,345 to Nilssen; which patent issued from a Division of application Ser. No. 06/178,107 filed Aug. 14, 1980; which application is the original progenitor of instant application.
Otherwise, reference is made to the following U.S. Patents: U.S. Pat. Nos. 3,263,122 to Genuit; 3,320,510 to Locklair; 3,996,493 to Davenport et el.; 4,100,476 to Ghiringhelli; 4,262,327 to Kovacik et al.; 4,370,600 to Zansky; 4,634,932 to Nilssen; and 4,857,806 to Nilssen.
SUMMARY OF THE INVENTION
Objects of the Invention
An object of the present invention is that of providing for a cost-effective gas discharge lighting system.
This as well as other objects, features and advantages of the present invention will become apparent from the following description and claims.
Brief Description
The present invention is directed to providing improved inverter circuits for powering and controlling gas discharge lamps. The inverter circuits according to the present invention are highly efficient, can be compactly constructed and are ideally suited for energizing gas discharge lamps, particularly “instant-start” and “self-ballasted” fluorescent lamps.
According to one form of the present invention, a series-connected combination of an inductor and a capacitor is provided in circuit with the inverter transistors to be energized upon periodic transistor conduction. Transistor drive current is preferably provided through the use of at least one saturable inductor to control the transistor inversion frequency to be equal to or greater than the nature resonant frequency of the inductor and capacitor combination. The high voltages efficiently developed by loading the inverter with the inductor and capacitor are ideally suited for energizing external loads such as gas discharge lamps. In such an application, the use of an adjustable inductor permits control of the inverter output as a means of adjusting the level of lamp illumination.
According to another important form of the present invention, reliable and highly efficient half-bridge inverters include a saturable inductor in a current feedback circuit to drive the transistors for alternate conduction. The inverters also include a load having an inductance sufficient to effect periodic energy storage for self-sustained transistor inversion. Importantly, improved reliability is achieved because of the relatively low and transient-free voltages across the transistors in these half-bridge inverters.
Further, according to another feature of the present invention, novel and economical power supplies particularly useful with the disclosed inverter circuits convert conventional AC input voltages to DC for supplying to the inverters.
In a still different form, the present invention features a frequency-converting power supply mounted on a power plug operable to be plugged into and held by an ordinary household electric power receptacle. Through an inductive internal impedance, this power supply provides a 20-40 kHz output voltage to a pair of output terminals that connect, by way of a female plug at the end of a light-weight power cord, with the input terminals of a fluorescent lamp assembly; across which input terminals is connected a capacitor of such capacitance value as to resonate with the power supply's inductive internal impedance, thereby providing the required lamp starting voltage and operating current. Also across the input terminals is connected a series-combination of a first instant-start fluorescent lamp and a special (self-shorting) female receptacle means adapted to receive and disconnectably hold a special male plug; which, in turn, is connected with the terminals of a second instant-start fluorescent lamp. Thus, by way of disconnectable plug-receptacle means, one, two or more instant-start fluorescent lamps may be series-connected and properly started and operated from the frequency-converting plug-in power supply.
REFERENCES:
patent: 2965804 (1960-12-01), Roesel, Jr. et al.
patent: 4001571 (1977-01-01), Martin
patent: 4005335 (1977-01-01), Perper
patent: 4053813 (1977-10-01), Kornrumpf et al.
patent: 4060752 (1977-11-01), Walker
patent: 4127795 (1978-11-01), Knoll
patent: 4134045 (1979-01-01), Quin
patent: 4257088 (1981-03-01), Nilssen
patent: 4262327 (1981-04-01), Kovscik et al.
patent: 4300073 (1981-11-01), Skwirut et al.
patent: 4441055 (1984-04-01), Balchjunas et al.
patent: 4677345 (1987-06-01), Nilssen
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