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. 24, 2012
Filed:
Apr. 07, 2009
Masaaki Yamada, Yokohama, JP;
Yusaku Katsube, Yokohama, JP;
Junichi Takahashi, Yokohama, JP;
Toshihito Habuka, Tamamura, JP;
Fumihito Yamaguchi, Maebashi, JP;
Masaaki Yamada, Yokohama, JP;
Yusaku Katsube, Yokohama, JP;
Junichi Takahashi, Yokohama, JP;
Toshihito Habuka, Tamamura, JP;
Fumihito Yamaguchi, Maebashi, JP;
Renesas Electronics Corporation, Kanagawa, JP;
Abstract
A filter circuit includes first capacitors, second capacitors capable of altering a cutoff frequency by being connected in parallel with the first capacitors, first switches for connecting the second capacitors in parallel with the first capacitors, and charging circuits for the second capacitors. The charging circuits include second switches, and resistances for attenuating the amplitudes of input voltages to be fed to the second capacitors, by being connected in series with the second capacitors. The second capacitors are charged through the resistances in a state where the first switches are turned OFF and where the second switches are turned ON. Thus, a DC offset which is ascribable to the cutoff frequency switching of a filter is reduced.