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. 19, 2012
Filed:
Jun. 25, 2009
Masafumi Yamamoto, Osaka, JP;
Tetsuya Hamana, Nara, JP;
Hiroyuki Asano, Nara, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An electronic ballast A includes an inverter circuit for converting a DC voltage into a high-frequency voltage, a resonant circuit which is connected between outputs of the inverter circuit and lights a discharge lamp at a high frequency by a resonant action, a dimming circuit for changing an output voltage to the discharge lamp by changing an operating frequency of the inverter circuit, a DC component detecting circuit for detecting a DC voltage component of the discharge lamp and a control operating circuit which detects an output signal of the DC component detecting circuit for every predetermined period to reduce or stop an output to the discharge lamp in the case where the output signal exceeds a predetermined reference value and to prohibit the protection operation when periodic change amount in the output signal reaches a predetermined value or higher.