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.

Date of Patent:
Aug. 11, 2015

Filed:

Oct. 24, 2012
Applicant:

Richtek Technology Corp., Chupei, Hsinchu, TW;

Inventors:

Roland Van Roy, Eindhoven, NL;

Leng-Nien Hsiu, Zhubei, TW;

Pei-Yuan Chen, Longtan Township, Taoyuan County, TW;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G05F 5/00 (2006.01); H02M 1/42 (2007.01); H02M 1/00 (2007.01);
U.S. Cl.
CPC ...
H02M 1/4258 (2013.01); H02M 2001/0025 (2013.01); Y02B 70/126 (2013.01);
Abstract

A power-factor-improving circuit and method for an offline converter block the DC component and obtain the AC component of an input voltage of the offline converter. The AC component is superpositioned onto a DC bias signal to generate a dimming signal for the offline converter to adjust an output current of the offline converter. The offline converter has a high power factor due to the dimming signal with the AC component of the input voltage. In addition, the average of the dimming signal is determined by the DC bias signal, hence the output current can be precisely controlled according to the DC bias signal.


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