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:
Nov. 06, 2012
Filed:
Jul. 21, 2010
Fumio Horiuchi, Ashikaga, JP;
Toru Imaizumi, Ota, JP;
Takaya Kusabe, Ota, JP;
Semiconductor Components Industries, LLC, Phoenix, AZ (US);
Sanyo Semiconductor Co., Ltd., Gunma, JP;
Abstract
A light-emitting diode driver circuit includes: a first-rectifier circuit to output a first-rectified voltage; a transformer including primary and secondary coils and an auxiliary coil inductively coupled to the primary or secondary coils, the primary coil being applied with the first-rectified voltage; a transistor connected in series to the primary coil; a second-rectifier circuit to output a second-rectified voltage obtained by rectifying a voltage generated in the auxiliary coil; a capacitor to be charged with the second-rectified voltage; and a control circuit to control on and off of the transistor based on a charging voltage of the capacitor so that the charging voltage becomes equal to a predetermined voltage, the secondary coil outputting a voltage that varies with a frequency corresponding to a frequency of the first-rectified voltage and that corresponds to a turns ratio between the primary and secondary coils, as a voltage for driving a light-emitting diode.