Method for performing analog over-program and under-program detection for a multistate memory cell
US5764568A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1996 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Oct 24, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5644
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for detecting an under-programming or over-programming condition in a multistate memory cell. The method uses three sense amplifiers, each with an associated reference cell which produces a reference voltage for input to each of the sense amplifiers. Control circuitry is used which allows the reference cell currents to be varied to produce the reference voltages or pairs of reference voltages needed to accurately determine the threshold voltage and hence state of a programmed or erased memory cell. This information is used by a controller to determine if a memory cell has been over-programmed, under-programmed, or properly programmed. If the cell has not been properly programmed, then additional programming pulses are applied (in the case of under-programming) or an error flag is set and the programming algorithm is terminated (in the case of an over-programmed cell).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.