| 摘要 |
PURPOSE: A circuit for establishing a threshold voltage of a reference memory cell is provided to adjust the threshold voltage of the reference memory cell accurately without requiring time. CONSTITUTION: To establish a threshold voltage of a reference memory cell(31), a circuit comprises: the reference memory cell comprising a source, a drain, a control gate and a floating gate; the first power source(32) supplying a voltage to the drain of the reference memory cell by the control of a current detection part(35) when programming the reference memory cell; the second power source(33) supplying a voltage to the control gate when programming or reading the reference memory cell; the third power source(34) connected to the source of the reference memory cell; a switch(37) which controls a path to measure a current from the external flowing to the reference memory cell according to a measuring signal, being connected to the drain of the reference memory cell; and the current detection part which monitors the current flowing to the reference memory cell when programming the reference memory cell by receiving a program signal by being connected between the first power source and the drain of the reference memory cell, and when the monitored current is equal to a reference stop current, forces the program operation of the reference memory cell to end by outputting a stop signal to the first and the second power source.
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