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. 13, 2012
Filed:
Nov. 10, 2010
Jun Yabuzaki, Matsumoto, JP;
Jian Chen, Matsumoto, JP;
Jun Yabuzaki, Matsumoto, JP;
Jian Chen, Matsumoto, JP;
Fuji Electric Co., Ltd., , JP;
Abstract
A power factor correction type switching power supply unit can change reference values of an overcurrent limit at an optimum timing at a time of an overcurrent protection of a step-up type converter, so that no sudden change occurs in an inductor current. A detection level selection circuit selects one of first and second threshold values with a selection signal, and outputs it as an overcurrent detection level to an overcurrent detection circuit. An input voltage monitoring circuit determines the selection signal in such a way that the larger of two threshold values is selected when an alternating current input voltage exceeds a first reference voltage, and the smaller threshold value is selected when the alternating current input voltage does not exceed a second reference voltage, and outputs the selection signal to the detection level selection circuit at a timing at which the alternating current input voltage approaches a zero.