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:
Jul. 06, 1999
Filed:
Oct. 27, 1997
Takashi Kanda, Kadoma, JP;
Kazuo Yoshida, Kadoma, JP;
Masahiro Naruo, Kadoma, JP;
Kazuhiro Hori, Kadoma, JP;
Masahito Ohnishi, Kadoma, JP;
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
An electronic ballast for discharge lamps comprises a main resonance circuit for applying a voltage necessary for operating of a discharge lamp having filaments to both ends of the discharge lamp and a filament resonance circuit for supplying a filament current to the filaments, wherein the main resonance circuit and filament resonance circuit have resonance circuits having different resonance characteristics in an output path leading to the discharge lamp and also change their outputs depending on an operating frequency of switching elements. Thereby a filament current and a voltage across the discharge lamp can be set at suitable one of respective operational modes of the discharge lamp according to an operational state of the discharge lamp.