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:
Aug. 10, 2010
Filed:
Sep. 15, 2006
Nobuyuki Yamada, Kyoto, JP;
Yoshihiro Ikefuji, Kyoto, JP;
Nobuyuki Yamada, Kyoto, JP;
Yoshihiro Ikefuji, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A filter circuit has: a first and a second current mirror circuit that are each built with a plurality of transistors and that respectively pass a first and a second mirror current according to a constant current; an input terminal via which an input pulse signal is fed in; a first transistor that, in response to the signal fed in via the input terminal and by using a supply voltage, makes the first current mirror circuit operate; a second transistor that, operating in inverted synchronism with the first transistor, in response to the signal fed in via the input terminal and by using a ground voltage, makes the second current mirror circuit operate; a capacitor that is charged by the first mirror current and that is discharged by the second mirror current; and an output terminal via which a voltage at one end of the capacitor is fed out. Thus, the filter circuit permits its filter constant to be set accurately in a wide range without relying on the driving capacity of the input signal, and can be integrated without an undue increase in device scale.