Invention Grant
US5808932A Memory system which enables storage and retrieval of more than two
states in a memory cell
失效
能够在存储单元中存储和检索两个以上状态的存储器系统
- Patent Title: Memory system which enables storage and retrieval of more than two states in a memory cell
- Patent Title (中): 能够在存储单元中存储和检索两个以上状态的存储器系统
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Application No.: US779991Application Date: 1996-12-23
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Publication No.: US5808932APublication Date: 1998-09-15
- Inventor: V. Swamy Irrinki , Ashok Kapoor , Raymond T. Leung , Alex Owens , Thomas R. Wik
- Applicant: V. Swamy Irrinki , Ashok Kapoor , Raymond T. Leung , Alex Owens , Thomas R. Wik
- Applicant Address: CA Milpitas
- Assignee: LSI Logic Corporation
- Current Assignee: LSI Logic Corporation
- Current Assignee Address: CA Milpitas
- Main IPC: G11C11/41
- IPC: G11C11/41 ; G11C11/56 ; G11C11/24
Abstract:
A memory circuit which enables storage of more than two logic states in a memory cell. Since the additional logic states may be used to represent additional information bits, this memory circuit increases the number of bits that may be stored per memory cell, thereby increasing the storage density and reducing the cost per bit. The disclosed memory circuit comprises an analog-to-digital converter coupled to detect a current through a transistor in a memory cell. The current is determined by a charge stored on the transistor's gate. By enabling the current to be detected in discrete increments, it becomes possible to represent more than one bit of information with the charge stored in the memory cell. Usage of additional increments necessitates more precise storage and detection circuitry. In one embodiment, the storage circuitry uses feedback to obtain a greater logic state retrieval accuracy.
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