Paired least recently used block replacement system
Address mapping for memory
Block associative memory
Simplified cache with automatic update
Quasi content addressable memory Patent #: 4758982
ApplicationNo. 377181 filed on 07/10/1989
US Classes:365/200, Bad bit365/49, ASSOCIATIVE MEMORIES365/168, Ternary365/185.2, Reference signal (e.g., dummy cell)365/207Differential sensing
ExaminersPrimary: Fears, Terrell W.
Attorney, Agent or Firm
International ClassG11C 013/00
Foreign Application Priority Data1986-04-23 JP
AbstractIn a defect relieving technology which replaces defective memory cells of a semiconductor memory device by spare memory cells, use is made of an associative memory. Address information of a defective memory cell is stored as a reference data of the associative memory, and new address information of a spare memory cell is written down as output data of the associative memory. A variety of improvements are made to the associative memory. For instance, a plurality of coincidence detection signal lines of the associative memory are divided into at least two groups, and one group among them is selected by switching means. Reference data of the associative memory comprises three values consisting of binary information of "0" and "1", and don't care value "X". The associative memory further includes a plurality of electrically programable non-volatile semiconductor memory elements.