摘要 |
One or more groups of charge-storing memory cells are selected from a plurality of regular charge-storing memory cells of a storage device. The selected memory cells are initialized with initial binary data, by charging them with corresponding amounts of electric charge, or the selected memory cells are simply used as is containing user data. Then, while the selected memory cells undergo a self discharge process, collective changes in the binary states of the selected memory cells are used to estimate discharge-determining conditions such as elapsed time, wear rate or wear level of the memory cells. The adverse effects of the erratic behavior of individual charge-storing memory cells on such estimations is mitigated by using a large group of charge-storing memory cells, and the effect of temperature on the aforesaid estimations is reduced by using two or more large groups of charge-storing memory cells.
|