US5294868A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual lamp electronic ballast with independent control means
Assignee: Robertshaw Controls Co
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Filing: 1992-09-08
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Granted: 1994-03-15
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Expires: 2012-09-08
Abstract
Abstract An electronic ballast circuit for two fluorescent lamps connected in parallel. A single switching inverter connected through a common coupling circuit provides high frequency alternating current for operation of both lamps independently of each other insuring operation of one lamp should the other cease operation. A dual toroidal transformer in the inverter insures both lamps receive current of the same frequency.
Inventors
- 👤 William H. Jones
- 👤 John R. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:26
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/282; H05B41/2825; Y; Y10; Y10S; Y10S315/00; Y10S315/07
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
170 words
An electronic ballast for first and second fluorescent lamps, said ballast comprising: a rectifier circuit connected to a source of alternating current, operated to produce direct current; a switching type inverter circuit connected to said rectifier circuit, operated to generate a high frequency alternating current; first and second parallel connected resonant circuits each connected to said inverter circuit by means of a common coupling means; said first resonant circuit operated to conduct said high frequency alternating current to said first fluorescent lamp whereby said lamp is operated; said second resonant circuit operated to conduct said high frequency alternating current to said second fluorescent lamp whereby said lamp is operated; said first and second resonant circuits each including an LC circuit comprising an inductor in series with a capacitance, said capacitance connected in parallel with an associated one of said fluorescent lamps; and said capacitance comprising first and second capacitors in series including a center tap between said capacitors connected to said rectifier circuit by means of first and second diodes.
Claim 2
Dependent Claim
170 words
An electronic ballast for first and second fluorescent lamps, said ballast comprising: a rectifier circuit connected to a source of alternating current, operated to produce direct current; a switching type inverter circuit connected to said rectifier circuit, operated to generate a high frequency alternating current; first and second parallel connected resonant circuits each connected to said inverter circuit by means of a common coupling means; said first resonant circuit operated to conduct said high frequency alternating current to said first fluorescent lamp whereby said lamp is operated; said second resonant circuit operated to conduct said high frequency alternating current to said second fluorescent lamp whereby said lamp is operated; said first and second resonant circuits each including an LC circuit comprising an inductor in series with a capacitance, said capacitance connected in parallel with an associated one of said fluorescent lamps; and said capacitance comprising first and second capacitors in series including a center tap between said capacitors connected to said rectifier circuit by means of first and second diodes.
Claim 3
Dependent Claim
17 words
An electronic ballast as claimed in claim 1 wherein: said rectifier circuit is a voltage doubler circuit.
Claim 4
Dependent Claim
16 words
An electronic ballast as claimed in claim 2 wherein: said rectifier circuit further includes filter means.
Claim 5
Dependent Claim
16 words
An electronic ballast as claimed in claim 2 wherein: said rectifier circuit further includes fusing means.
Claim 6
Dependent Claim
28 words
An electronic ballast as claimed in claim 1 wherein: said switching type inverter circuit includes first and second transistors each including circuit connections to said common coupling means.
Claim 7
Dependent Claim
54 words
An electronic ballast as claimed in claim 5 wherein: said switching type inverter circuit in combination with said common coupling means operates as an oscillator to generate a high frequency alternating current providing operating current of said high frequency to both said first and second lamps, through said first and second resonant circuits, respectively.
Claim 8
Dependent Claim
46 words
An electronic ballast as claimed in claim 1 wherein: there is further included a third capacitor connected in series between said inductor and said first and second capacitors in said first and second resonant circuits; said third capacitor assisting in the starting of said associated lamp.
Claim 9
Dependent Claim
38 words
An electronic ballast as claimed in claim 1 wherein: said common coupling means comprise a dual toroidal transformer including circuit connections to said first and second transistors to said first resonant circuit and to said second resonant circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-14 | 1997-09-13 | 1998-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-14 | 2001-09-13 | 2002-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-14 | 2005-09-13 | 2006-03-15 | $7700.00 | Window Closed / Lapsed |