Reading memory cells using multiple thresholds
US8145984B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2011 |
| Grant date | Mar 27, 2012 |
| Priority date | — |
| Expiry date | May 24, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C27/005
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for operating a memory (28) includes storing data, which is encoded with an Error Correction Code (ECC), in analog memory cells (32) of the memory by writing respective analog input values selected from a set of nominal values to the analog memory cells. The stored data is read by performing multiple read operations that compare analog output values of the analog memory cells to different, respective read thresholds so as to produce multiple comparison results for each of the analog memory cells. At least two of the read thresholds are positioned between a pair of the nominal values that are adjacent to one another in the set of the nominal values. Soft metrics are computed responsively to the multiple comparison results. The ECC is decoded using the soft metrics, so as to extract the data stored in the analog memory cells.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.