For storing more first files during initialization during initialization, capable of non-volatile more first memory arrangement with a memory cell

摘要

PROBLEM TO BE SOLVED: To shorten the time required for writing without dead writing period and to simplify the constitution of the writing circuit. ;SOLUTION: Input digital data is held in a data register 20, and converted into a multi-valued analog amount by a resistor-divider 21 and a decoder 22. The analog amount read from a nod-volatile memory cell 60 is compared with the converted analog amount by a comparator 23, and a write voltage is supplied to the cell 60 in response to the comparison result. Simultaneously, a first bias generator 500 for generating two types of different bias voltages VBLH and VBLL as the write voltage is provided. MOS transistors 27, 28 are inserted as switches to the supply line of the bias voltages, either the transistor 27 or 28 is selectively controlled to be turned ON, OFF in response to the upper order bit D1 of the input digital data, and the writing voltage is switched.;COPYRIGHT: (C)1997,JPO