| 摘要 |
PURPOSE:To enlarge redundancy and to increase yield by providing an address converting change-over circuit to generate an address input and a chip selecting input which are converted to the second memory when the address signal is coincident with a defective address. CONSTITUTION:An address converting change-over circuit 170, when the defect is included at memory elements 110-1-110-8 in the first memory 110, accumulates the address information which goes to be a defect. For example, when address signals A0 -An are supplied, an address is coincident to the accumulated address information, then, a chip selecting CS1 of the memory 110 is turned off, a chip selecting CS2 of the second memory 120 is turned on, the data input output is changed over from the memory 110 to the memory 120, and when the address is dissident to the accumulated address information, the chip selecting CS1 is turned on, the CS2 is turned off and the memory 110 are controlled so that the memory can be used as the ordinary memory.
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