Ultraviolet erasable nonvolatile memory with current mirror circuit type sense amplifier
US5198997A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 8, 1992 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Jan 8, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/18
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An ultraviolet erasable nonvolatile memory device comprising a plurality of memory cells which are erasable by ultraviolet rays employs a sense amplifier consisting a current mirror circuit. The current mirror circuit is connected to the memory cells and a reference cell respectively for readout. In one example, an effective control gate voltage of the reference cell is set to a lower value than that of the memory cells. The current drivability of the reference cell exhibits an intermediate value between that of erased memory cell and that of programmed memory cell. In another example, a constant current source is provided at a node between the memory cells and the current mirror circuit, so that a current on the reference cell side is subtracted by the constant current source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.