Methods and apparatuses for refreshing non-volatile memory
US7535787B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Jun 6, 2007 |
| Grant date | May 19, 2009 |
| Priority date | — |
| Expiry date | Jun 6, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/4062
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatuses for refreshing non-volatile memories due to changes in memory cell charges, such as charge loss, are disclosed. Embodiments generally comprise a voltage generator to create a sub-threshold voltage for a memory state of memory cells in a block. Once the sub-threshold voltage is applied to a word line a state reader determines states of memory cells coupled to the word line. If the state reader determines that one or more of the memory cells coupled to the word line is in the memory state, despite the sub-threshold voltage, a memory refresher may program a number of memory cells in the block. Method embodiments generally comprise applying a sub-threshold voltage to a word line for a plurality of memory cells, detecting at least one memory cell of the plurality violates a state parameter, and refreshing a block of memory cells associated with the plurality of cells.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.