Nonvolatile static random access memory cell
US4460978A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1981 |
| Grant date | Jul 17, 1984 |
| Priority date | — |
| Expiry date | Nov 19, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C14/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A nonvolatile static random access memory cell (10) includes a pair of cross-coupled transistors (12, 14) which function as a bistable circuit to store data states. Variable threshold transistors (36, 41) are respectively connected in series between the driver transistors (12, 14) and load devices (48, 50). A control node (40) is driven to a high voltage state to cause one of the variable threshold transistors (36, 41) to be driven to have a higher threshold voltage and thereby store the data state held in the cross-coupled transistors (12, 14). The data state is thus stored in nonvolatile form. Upon recall the memory cell (10) is reactivated and the threshold differential between the variable threshold transistors (36, 41) causes the driver transistors (12, 14) to be set at the stored data state. The data recalled by the memory cell (10) is in true rather than in complementary form. The variable threshold transistors (36, 41) are reset by driving the power terminal V.sub.cc to a high voltage state to reestablish common threshold voltages for the variable threshold voltage transistors (36, 41).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.