| 摘要 |
<p>PURPOSE:To make a nonvolatile memory writable or erasable even when the characteristics of the memory cell of the memory changes by sampling the characteristics of the memory cell and setting a writing or erasing time in accordance with the characteristics of the memory cell. CONSTITUTION:When a write request 10 or erase request 11 is outputted at the time of write or erase request, a write and erase control circuit 2 applies a write or erase voltage generated by a write and erase voltage generating circuit 3 across a memory cell against the address indicated by a column and row decoders 15 and 16. The write and erase voltage generating circuit 3 supplies the write or erase voltage to the write and erase control circuit synchronously to the write or erase time set by a write and erase time control circuit 4. The write and erase time control circuit 4 sets a write or erase time in accordance with the data of a comparator circuit 5. Therefore, write or erase can be performed stably even when the characteristics of the memory cell change and, as a result, the service life of the memory cell can be extended.</p> |
