Abstract:
The self-repair method for a nonvolatile memory intervenes at the end of an operation of modification, selected between programming and erasing, in the event of detection of just one non-functioning cell, and carries out redundancy of the non-functioning cell. To this end, the memory array is divided into a basic portion, formed by a plurality of memory cells storing basic data, and into a in-the-field redundancy portion, said in-the-field redundancy portion being designed to store redundancy data including a correct content of the non-functioning cell, the address of the non-functioning cell, and an activated redundancy flag. The redundancy is activated only after applying a preset maximum number of modification pulses and uses a purposely designed redundancy replacement circuit and a purposely designed redundancy data verification circuit.
Abstract:
The method for using a nonvolatile memory having a plurality of cells, each of which stores a datum, is based upon the steps of performing an modification operation of erasing/programming the data of the memory; verifying the correctness of the data of the memory cells; and, if the step of verifying has revealed at least one incorrect datum, correcting on-the-field the incorrect datum, using an error correcting code. The verification of the correctness of the data is performed by determining the number of memory cells storing an incorrect datum; if the number of memory cells storing the incorrect datum is less than or equal to a threshold, the erroneous datum is corrected by the error correction code; otherwise, new erasing/programming pulses are supplied.