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.

Date of Patent:
Oct. 19, 2004

Filed:

Dec. 23, 2002
Applicant:
Inventors:

Tsukasa Ooishi, Hyogo, JP;

Jun Ohtani, Hyogo, JP;

Hiroshi Kato, Hyogo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 1/600 ;
U.S. Cl.
CPC ...
G11C 1/600 ;
Abstract

A plurality of sense amplifiers are connected to a selected bit line. Each sense amplifier is supplied with a residual current corresponding to a current flowing in a memory cell and a reference current serving as a reference for a threshold voltage of the memory cell to sense the currents. Operations of the sense amplifiers are controlled such that different sense margins are provided to different sense amplifiers and a margin failure is detected according to coincidence/non-coincidence in logical level between output signals of the sense amplifiers. The address of a memory cell with the margin failure is registered. With such a construction, a threshold voltage defect of a non-volatile memory cell is compensated for to enable internal reading of memory cell data with correctness.


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