NOVRAM cell using two differential decouplable nonvolatile memory elements
US4980859A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1989 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | Apr 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C14/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A nonvolatile, semiconductor randon access memory cell comprising a static RAM element and a nonvolatile memory element having differential charge storage capabilities is presented. The static RAM and nonvolatile memory elements are interconnected to allow information to be exchanged between two elements, thus allowing the faster static RAM element to serve as the primary memory to the system and allowing the nonvolatile memory element to serve as permanent storage during power-down conditions. In one embodiment, the nonvolatile memory element comprises two electrically erasable PROM devices (EEPROMs). The two EEPROM devices store differential charges corresponding to the complementary outputs of the static RAM element. The nature of the differential charge storage allows lower programming voltages to be used on the EEPROM devices, resulting in increased storage intergrity and increased endurance of the EEPROM devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.