Reference cell array to generate the reference current for sense amplifier
US6226213A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 31, 2000 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Jan 31, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C7/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A novel reference cell array for normal cell reference is disclosed. The reference cell array comprises three word lines in the upper portion and three in the lower portion. Two portions are separated by a common source line. The common source line connects common sources of the middle two rows of cells to a ground potential. Each bit line has a bit line contact and an isolation region being respectively distributed at different portions and is like a black-white grid on a checkerboard to ensure the selected bit line connects only three cells. In addition, all floating gates are coupled to a potential reference to define their states and the middle four word lines are also coupled to a power source and left exterior two connected to a X_decoder to a select one. Since each reference bit line connects only 3 serial cells, a value of about 1/3 of normal cell current is naturally obtained. Because the reference cell is the same type as the normal cell it will easily trace the cell size variation and hence be easily handled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.