System and method for charge restoration in a non-volatile memory device

Abstract

A non-volatile memory device comprising logic for charge restoration. The restore logic controls a read circuit for determining a value associated with the threshold voltage of a memory cell selected from a memory cell array, and compares the value to one or more boundary values to determine whether or not the memory cell value is out of bounds. In the event that the memory cell value is out of bounds, a target value for the memory cell is established. The restore logic controls a write circuit that applies a write pulse to the memory cell. The read and write process is repeated as necessary until the target value for the memory cell is achieved. The restore logic may include a processor for performing a statistical analysis on the memory cell array in order to determine target restoration values. Memory cells within the array may be reserved for use by the restore logic.