Memory system
US6064591A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 9, 1998 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Oct 9, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5644
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A memory system according to the present invention includes a memory portion including a memory cell for storing n-level data (n is an integer equal to or larger than 3, for example, 4) data, wherein the memory cell is operated as an n-level data storing memory cell when the number of times of write-erase sequence is smaller than a predetermined number of times, and the memory cell is operated as an m-level (m is an integer smaller than n, for example, 3) data storing memory cell when the number of times of write-erase sequence has exceeded the predetermined number of times. The number of information items (values) which can be stored in one memory cell is decreased with respect to a predetermined number of times of write-erase sequence. Thus, a memory system including a multi-level data storing memory cell and exhibiting improved durability against write-erase sequence operations is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.