Patent ID: 6456532
Filing Date: 2002-09-24
Classification: G11C

Abstract:
A semiconductor memory device comprising: a memory cell in which analog and many-valued signals can be written and stored; a readout circuit having an output terminal which outputs the values stored in said memory cell to the outside as voltages; a comparator having an output terminal which outputs a write end signal when said output terminal voltage of said readout circuit equals to a predetermined voltage; a write voltage controlling circuit having an output terminal which outputs an output voltage corresponding to said analog and many-valued voltage values inputted to an input terminal as a writing voltage of said memory cell; and a write voltage switching circuit having a function which supplies said output voltage of said write voltage controlling circuit to said memory cell and stops to supply said output voltage of said write voltage controlling circuit to said memory cell when said write end signal is outputted to the output terminal of said comparator.