The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 29, 1999
Filed:
Jul. 21, 1997
Louis R Nerone, Brecksville, OH (US);
David J Kachmarik, Strongsville, OH (US);
Michael M Secen, Mentor, OH (US);
General Electric Company, Schenectady, NY (US);
Abstract
A ballast circuit for a gas discharge lamp comprises a resonant load circuit including the lamp. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and being connected together at a common node through which the a.c. load current flows. The first and second switches each comprise a reference node and a control node, the voltage between such nodes determining the conduction state of the associated switch. The respective reference nodes of the first and second switches are interconnected at the common node. The respective control nodes of the first and second switches are interconnected. An inductance is connected between the control nodes and the common node. A starting pulse-supplying capacitance is connected in series with the inductance, between the control nodes and the common node. A network is connected to the control nodes for supplying the starting pulse-supplying capacitance with charge so as to create a starting pulse during lamp starting, and for setting the voltage of the control nodes sufficiently close to that of the common node during steady state lamp operation so as to prevent the capacitance from supplying a starting pulse during the steady state lamp operation. A polarity-determining impedance is connected between the common node and one of the bus conductor and the reference conductor, to set the initial polarity of pulse to be generated by the starting pulse-supplying capacitor.