Invention Grant
- Patent Title: Redundancy circuit and semiconductor memory device
- Patent Title (中): 冗余电路和半导体存储器件
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Application No.: US12000373Application Date: 2007-12-12
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Publication No.: US08015457B2Publication Date: 2011-09-06
- Inventor: Yasuji Koshikawa , Yousuke Kawamata
- Applicant: Yasuji Koshikawa , Yousuke Kawamata
- Applicant Address: JP Tokyo
- Assignee: Elpida Memory, Inc.
- Current Assignee: Elpida Memory, Inc.
- Current Assignee Address: JP Tokyo
- Agency: Foley & Lardner LLP
- Priority: JP2006-335802 20061213
- Main IPC: G11C29/44
- IPC: G11C29/44 ; G11C29/50

Abstract:
Disclosed is a circuit for deciding whether or not a plural number of redundancy ROM circuits have been programmed in a preset order, with regards to addresses. In at least one of first to n-th redundancy memory circuits, an address to be substituted by a redundant address is recorded and a redundancy selection signal is output when an access address is coincident with the programmed address. It is presupposed that repair addresses are programmed from the first to the n-th redundancy ROM circuits in an ascending order with regards to address. If it is detected under this condition that a redundancy selection signal has been output from the i+1'st redundancy memory circuit while no redundancy selection signal is being output from the i-th redundancy memory circuit, an SR flip-flop is set and the sequence of the substitution decision outputs is decided to be a reversed sequence.
Public/Granted literature
- US20080144410A1 Redundancy circuit and semiconductor memory device Public/Granted day:2008-06-19
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