Semiconductor device, system, and method of controlling accessing to memory
AssigneeNEC Corporation
InventorShinichi Shionoya
Life of this patent
Estimating the term…
Abstract
Test circuits, which determine whether memory blocks including at least one redundant block are defective, are included in the memory blocks, respectively. A decoding rule generating circuit so generates a decoding rule that a defective block can not be accessed, and outputs the generated decoding rule as a decoding-rule signal RUL. Under the decoding rule, the redundant address decoder decodes the address signal ADDR, to permit access to the memory blocks except the defective block(s).
Claims7
A semiconductor device comprising:
- a memory circuit including a plurality of memory blocks and at least one redundant memory block;
- a test circuit which performs functional testing of said memory circuit in unit of blocks;
- a selecting-rule generating circuit which generates a selecting rule for selecting accessible memory blocks, so that the one or more memory block(s) among the plurality of the memory blocks which is(are) determined as defective by said test circuit will be avoided, while the at least one redundant memory block of the same number of the one or more memory block(s) determined as defective will be accessible;
- a block selecting circuit which selects the accessible memory blocks, based on the selecting rule generated by said selecting-rule generating circuit;
- and
- a logical circuit which accesses the accessible memory blocks to read/write data therefrom/thereto.
A method of controlling accessing to a memory circuit comprising a plurality of memory blocks and at least one redundant memory block, said method comprising:
- performing functional testing of said memory circuit in unit of the memory blocks, and determining whether each of the plurality of memory blocks is defective;
- generating a selecting rule for selecting accessible memory blocks, so that the one or more memory block(s) among the plurality of the memory blocks which is(are) determined as defective by said testing will be avoided, while the at least one redundant memory block of the same number of the one or more memory block(s) determined as defective will be accessible;
- selecting the accessible memory blocks, based on the selecting rule generated;
- and
- accessing the accessible memory blocks to read/write data therefrom/thereto.
Dependencies are inferred from the claim text.