Invention Grant
US5867423A Memory circuit and method for multivalued logic storage by process
variations
失效
用于通过过程变化进行多值逻辑存储的存储器电路和方法
- Patent Title: Memory circuit and method for multivalued logic storage by process variations
- Patent Title (中): 用于通过过程变化进行多值逻辑存储的存储器电路和方法
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Application No.: US838799Application Date: 1997-04-10
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Publication No.: US5867423APublication Date: 1999-02-02
- Inventor: Ashok Kapoor , Alex Owens , Thomas R. Wik , Raymond T. Leung , V. Swamy Irrinki
- Applicant: Ashok Kapoor , Alex Owens , Thomas R. Wik , Raymond T. Leung , V. Swamy Irrinki
- Applicant Address: CA Milpitas
- Assignee: LSI Logic Corporation
- Current Assignee: LSI Logic Corporation
- Current Assignee Address: CA Milpitas
- Main IPC: G11C16/04
- IPC: G11C16/04 ; G11C11/56 ; G11C16/02 ; H01L21/8246 ; H01L27/112
Abstract:
A circuit and method which enables storage of more than two logic states in a memory cell by selectively setting threshold voltages of transistors in a memory array according to the present invention. In one embodiment, a memory circuit includes an array of storage transistors. Each storage transistor has a gate connected to an associated read line. When a read line is asserted, the current which flows through a selected storage transistor is indicative of the stored logic state. The current through each transistor is individually selected by setting the threshold voltage of each storage transistor during manufacture. Different transistors in the array are configured with differing threshold voltages to thereby represent different storage states. An analog-to-digital (A/D) converter is coupled to the selected storage transistor so as to sense the current and determine the state represented. Since each cell may represent one of more than two storage states, the memory circuit may advantageously allow an increased number of bits to be stored in each memory cell, thereby increasing the storage density and reducing the cost per bit.
Public/Granted literature
- US5275446A Twist coupling for vacuum pipes Public/Granted day:1994-01-04
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