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:
Dec. 02, 2003
Filed:
Jun. 27, 2001
Satoshi Kominami, Katano, JP;
Kenichirou Takahashi, Katano, JP;
Masayoshi Gyoten, Otsu, JP;
Koji Miyazaki, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A ballast for a discharge lamp includes a fluorescent lamp, an AC/DC conversion portion, a dimming control portion, and a DC/AC conversion portion. The AC/DC conversion portion converts a phase-controlled input AC voltage to a DC voltage. The dimming control portion calculates a dimming control signal from the input AC voltage. The DC/AC conversion portion converts the DC voltage from the AC/DC conversion portion to a high frequency AC voltage to be applied to the fluorescent lamp and lights and dims the lamp in response to the dimming control signal. The DC/AC conversion portion has a first operation mode for maintaining the lighting of the fluorescent lamp and for lighting and dimming the same and a second operation mode for supplying the fluorescent lamp with a voltage lower than the starting voltage of the lamp in its non-operating state. The conducting period of the phase-controlled AC voltage can be detected even in the non-operating state of the fluorescent lamp so as to restart the lamp.