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. 02, 2010
Filed:
Jun. 26, 2008
Fumiyuki Osanai, Tokyo, JP;
Hiroki Fujisawa, Tokyo, JP;
Fumiyuki Osanai, Tokyo, JP;
Hiroki Fujisawa, Tokyo, JP;
Elpida Memory, Inc., Tokyo, JP;
Abstract
A calibration circuit includes: replica buffers; an up-down counter that changes impedance codes of the replica buffers; latch circuits each holding the impedance codes; an end-determining circuit that activates the latch circuits in response to a completion of impedance adjustments of the replica buffers; and a 32 tCK cycle counter that forcibly activates the latch circuits in response to a lapse of a predetermined period since issuance of the calibration command. Thereby, even when the adjustment is not completed during one calibration period, a subsequent calibration operation can be executed from a previous point.