Semiconductor memory device

摘要

The present invention is intended to provide a semiconductor memory circuit that can store analog and many-valued data at high speed and with a high degree of accuracy. The semiconductor memory circuit comprises 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 the memory cell to the outside as voltages, a comparator having an output terminal which outputs a write end signal when the output terminal voltage of the readout circuit equals to a predetermined voltage, a write voltage controlling circuit having an output terminal which outputs an output voltage corresponding to the analog and many-valued voltage values inputted to an input terminal as a writing voltage of the memory cell, and a write voltage switching circuit having a function which supplies the output voltage of the write voltage controlling circuit to the memory cell and stops to supply the output voltage of the write voltage controlling circuit to the memory cell when the write end signal is outputted to the output terminal of the comparator.