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US 5,294,868 AGranted
Dual lamp electronic ballast with independent control means
AssigneeAppliance Control Technology, Inc.
InventorsWilliam H. Jones, John R. Nelson
Life of this patent
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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.
Claims8
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.
5 more elements
Dependencies are inferred from the claim text.