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. 21, 2015
Filed:
Jul. 29, 2013
Panasonic Corporation, Osaka, JP;
Kazuhiro Kumada, Hyogo, JP;
Abstract
An LED lighting device includes a step-up chopper circuit for increasing an input voltage to a prescribed DC voltage, a voltage detection circuit for detecting the DC voltage, a step-down chopper circuit for decreasing the DC voltage to apply it across a light source, a step-down chopper controlling circuit for turning on and off a switching device of the step-down chopper circuit when the DC voltage is a threshold voltage or more, and an inrush current preventing circuit having a parallel circuit of a thyristor and a thermistor. When the DC voltage is less than the threshold voltage, only the induced voltage obtained from the step-up chopper circuit is employed as a drive power supply for the thyristor. When the DC voltage is the threshold voltage or more, only the induced voltage obtained from the step-down chopper circuit is employed as the drive power supply.