Fast internal reference cell trimming for flash EEPROM memory
US5608679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1996 |
| Grant date | Mar 4, 1997 |
| Priority date | — |
| Expiry date | Jan 31, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5634
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for storing a charge on memory devices which includes the steps of providing a first charging pulse to a memory device to charge the device to a first level less than a final level; testing the value of the charge to determine whether the charge is greater than the first level; if the value of the charge is less than the first level, providing a second set of charging pulses to the memory device, each of the pulses of the second set of pulses having a duration which is a fraction of the duration of the first pulse and a value sufficient to charge the device to the first level; testing the value of the charge to determine whether the charge is greater than the first level after each pulse of the second set of pulses; and once the charge has tested greater than the first level, providing a third set of charging pulses to terminals of the memory device, each of the pulses of the third set of pulses having a duration which is a fraction of the duration of the pulses of the second set of pulses and a value such that the charge furnished by each pulse is approximately equal to an allowable variation of the charge from the final value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.