SEMICONDUCTOR MEMORY DEVICE

PURPOSE:To obtain the semiconductor memory device of large capacity to be completely operated at a low cost by storing the presence and absence of a defective memory cell for each block in the memory cell of each memory element and switching a bus line so as to select the other memory element when t...

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Bibliographic Details
Main Author BABA FUMIO
Format Patent
LanguageEnglish
Published 30.01.1991
Subjects
BASIC ELECTRIC ELEMENTS
ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
INFORMATION STORAGE
PHYSICS
SEMICONDUCTOR DEVICES
STATIC STORES
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Summary:PURPOSE:To obtain the semiconductor memory device of large capacity to be completely operated at a low cost by storing the presence and absence of a defective memory cell for each block in the memory cell of each memory element and switching a bus line so as to select the other memory element when the block equipped with the defective memory cell is designated. CONSTITUTION:A control means 6 stores the presence and absence of the defective cell in the form of a map for each block in each memory element 1 to a ROM, etc. When an address signal ADD designate one row, which is composed of M-pieces of the elements 1 more than a unit bit number N of data, through a designating means 3, the means 6 refers the contents of the ROM. In the case of a block X equipped with the defective bit, a bus switching means 5 is controlled and a bus 2 is switched. Then, out of external buses 4, one corresponding bus is connected. Thus, the data of the N bits can be read from the element 1 and the device of the large capacity to be stably operated can be obtained at a low cost.
Bibliography:Application Number: JP19900068676