Estimation of memory cell read thresholds by sampling inside programming level distribution intervals
US8000135B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 2009 |
| Grant date | Aug 16, 2011 |
| Priority date | — |
| Expiry date | Jan 31, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5634
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for data storage includes storing data in a group of analog memory cells by writing into the memory cells in the group respective storage values, which program each of the analog memory cells to a respective programming state selected from a predefined set of programming states. The programming states include at least first and second programming states, which are applied respectively to first and second subsets of the memory cells, whereby the storage values held in the memory cells in the first and second subsets are distributed in accordance with respective first and second distributions. Respective first and second medians of the first and second distributions are estimated, and a read threshold is calculated based on the first and second medians. The data is retrieved from the analog memory cells in the group by reading the storage values using the calculated read threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.