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:
Feb. 26, 2008
Filed:
Apr. 06, 2006
Koji Takekawa, Kasugai, JP;
Takahiro Watai, Kasugai, JP;
Masaya Mizutani, Kasugai, JP;
Takuya Okajima, Kasugia, JP;
Koji Takekawa, Kasugai, JP;
Takahiro Watai, Kasugai, JP;
Masaya Mizutani, Kasugai, JP;
Takuya Okajima, Kasugia, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
This invention provides a comparator circuit which outputs a stable waveform without oscillation even if a gradient of a change of a comparison input signal is small and determines a magnitude of the comparison input signal within a predetermined threshold value regardless of the increase/decrease direction of the comparison input signal. A comparator circuitcomprises a capacitative elementwhich is charged or discharged corresponding to a difference of potential between a comparison input signal IN and a reference input signal REF, an analog buffer portionwhich outputs high level if the voltage is above a threshold voltage Vth and low level if it is less than the threshold voltage Vth, an edge detecting portionwhich detects leading and trailing edges of the analog buffer portionso as to output an up signal UP and a down signal DOWN and a charge pump portionwhich charges a capacitative portion corresponding to the up signal UP and discharges the capacitative portion corresponding to the down signal DOWN.