| 摘要 |
<p>PURPOSE:To cut a fuse which controls the use or non-use of a redundant circuit with the proper voltage by impressing the 2nd power supply a voltage higher than the 1st power supply voltage to the fuse for cutting said fuse. CONSTITUTION:Control signal generating circuits 61-69 produce control signals BR1...BR9 respectively in accordance with the make and break of a fuse containing a polysilicon layer, etc. The signals BR1...BR9 are set at ''L'' levels when the fuse is not cut off. Then the outputs of memory cell blocks 21...28 are connected as they are to output buffers 41...48 respectively. The signal NEW is set at an ''H'' level and at the same time the output Q1 is forcibly set at an ''L'' level from outside when a specific memory cell block, e.g., 21 is replaced with a redundant memory cell block 29. Thus fuse cutting signals FC1 and FC9 are set at ''H'' levels, and therefore the fuses in the circuits 61 and 69 are cut off.</p> |
