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:
Jan. 29, 2013
Filed:
Sep. 26, 2008
Haruo Nagase, Kitakatsuragi, JP;
Haruo Nagase, Kitakatsuragi, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A light emitting diode drive device includes a drive circuit section that applies a direct-current voltage to a light source including a plurality of light emitting diodes connected in series to allow the light source to light up, a voltage detection circuit section that detects a voltage across the light source, and a malfunction determination circuit section that determines that the light emitting diode is short-circuited when the voltage detection circuit section detects a voltage drop and a potential between the voltage before being dropped and the voltage after being dropped is equal to or more than a predetermined threshold value. Thus, it is possible to detect a fact that a light emitting diode, which lights up, is short-circuited or is not short-circuited, with a simple circuit configuration.