Phase change memory with flexible time-based cell decoding
US8830741B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Aug 27, 2013 |
| Grant date | Sep 9, 2014 |
| Priority date | — |
| Expiry date | Aug 27, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2013/0054
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and systems for time-based cell decoding for PCM memory. Generally, the higher the PCM element resistance, the longer it takes for a read output to change state. PCM memory output is determined using differentiated timings of read outputs changing state, rather than differentiated values of read outputs. In some single-bit single-ended sensing embodiments, a reference, with resistance between the resistances corresponding to a pair of adjacent logical states, is stored in multiple reference cells; a “vote” unit emits a clock signal when a majority of the reference cell read outputs transition at the vote unit. Timing units produce different binary outputs depending on whether a data read output or the clock signal changes state first at the timing unit. Time-based decoding provides advantages including improved temperature and drift resilience, improved state discrimination, improved reliability of multibit PCM, and fast and reliable sensing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.