| 摘要 |
PURPOSE:To enable circuit design with a single power source without the necessity of impressing a high voltage by utilizing the latch-up phenomenon of a complementary field effect transistor. CONSTITUTION:In order to fuse a fuse 19, first when an address is selected by setting the output of a control circuit 13 at an ''H'' level, the output of an address decoder 12 turns at an ''L'' level. Therefore, a p-MOSFET 17 comes to an ON-state. Next, when a negative surge voltage is impressed on an input terminal 16, an n-p-n transistor 32 comes to an ON-state, and a current flows, in the direction from an output terminal 22 to the input terminal 16, through the base resistor 31 of a p-n-p transistor 30, thus leading the transistor 30 to an ON- state. Accordingly, the current flows from the output terminal 22 to a ground point 21 through the base resistor 34 of an n-p-n transistor 33, resulting in the ON-state of the n-p-n transistor 33; so-called a latch-up phenomenon occurs. Consequently, the fuse 19 fuses by the flow of this high current to said fuse, the output terminal 22 turns at the ''L'' level, and then becomes a mode whereby a redundant memory is driven. |
