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:
Apr. 11, 2006
Filed:
Jun. 15, 2005
Koji Inoue, Ikoma, JP;
Koji Inoue, Ikoma, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
In a semiconductor memory device having a crosspoint-type memory cell array, each reference level between two adjacent memory levels when memory levels of multi-level information stored in a memory cell are arranged in order of size of resistance values of a corresponding variable resistive element is defined by a reference current in a middle state between a first and a second current states. In the first current state, a readout current of high resistance selected cell in which the resistance is higher in the two adjacent memory levels becomes the largest state depending on a distribution pattern of a resistance state of the other unselected cell. In the second current state, a readout current of low resistance selected cell in which the resistance is lower in the two adjacent memory levels becomes a smallest state depending on a distribution pattern of a resistance state of the other unselected memory cell.