| 摘要 |
PURPOSE:To eliminate the fusion of a fuse link and to surely decide the using time of a stand-by memory cell by providing a stand-by memory cell using decision circuit consisting of at least one transistor and a gate control circuit with an RS flip-flop. CONSTITUTION:When the stand-by memory cell, is used the transistor invertedly acts with the output of the RS flip-flop in at least a second mode. When the stand-by memory cell is not used, a stand-by memory cell activation signal, the inverse of phiS remains high as it is in the normal mode, whereby the RS flip-flop 2 is not set. Then an output voltage VG remains low, and is held even in a stand by statge. The transistor Tr at that time remains to be turned off as it is. Even if the high voltage is impressed on an input terminal IN in such a state, an current is not conducted to the transistor Tr. By measuring the input current of the transistor Tr, whether the stand-by memory cell is used or not can be judge.
|
