REFERENCE FOR DECIDING ONE STATE IN PLURAL POSSIBLE STATES STORED BY MEMORY CELL IN MEMORY ARRAY, MEMORY DEVICE FOR PROGRAMMING PLURAL REFERENCE CELLS USED FOR READING THRESHOLD VOLTAGE OF ARRAY CELL, METHOD FOR PROGRAMMING N-PIECES OF REFERENCE CELLS, AND METHOD FOR READING ARRAY CELL

摘要

PURPOSE: To provide a programmable reference used for recognizing the state of an EEPROM cell by comparing output which is read by giving a word address and selection voltage to an array cell with the output of the EEPROM cell and outputting them. ;CONSTITUTION: The array cell 400 is read by giving the word address decoded by a word selection circuit 404 and applying selection voltage VSEL to the gate of the array cell 400. Selection voltage is similarly given to the gates of program possible reference cells 402-1 to 402-(n-1). A comparison circuit 406 compares the thresholds by comparing the output of the cell 400 with the outputs of the cells 402-1 to 402-(n-1) so as to output a comparison result.;COPYRIGHT: (C)1995,JPO