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:
Sep. 03, 2013
Filed:
Jul. 11, 2011
Yusaku Katsube, Yokohama, JP;
Yutaka Igarashi, Yokohama, JP;
Akio Yamamoto, Hiratsuka, JP;
Renesas Electronics Corporation, Kawasaki-shi, JP;
Abstract
The disclosed invention enables the cutoff frequency of a filter to be automatically adjusted to an arbitrary setting value within the adjustment range. An automatic cutoff frequency adjusting circuit includes a voltage/current converter circuit, a charge circuit, a discharge circuit, a digital capacitance having a plurality of electrostatic capacitances, a comparator for comparing a voltage inputted to the digital capacitance with a reference voltage, and a capacitance control circuit for controlling the digital capacitance. The time until the comparator detects that the voltage inputted to the digital capacitance is higher than the reference voltage after a reset signal has become a predetermined logic level is measured, and the digital capacitance is controlled by repeating, under a predetermined condition, processing for obtaining a next setting value of the digital capacitance, based on a measurement result, a target value of the digital capacitance, and the current value of the digital capacitance.