Shared Sense Amplifier Switching for Disturbance-Resistant Memory
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Solution Overview
Problem
The increasing electromagnetic coupling between memory cells due to higher chip densities leads to usage-based disturbances, causing incorrect state determinations by sense amplifiers, which results in memory errors and data loss, especially in volatile memory devices like DRAM.
Innovation Solution
A sense amplifier is shared between two or more memory cells using switching devices to connect and disconnect bitlines, optimizing space utilization and reducing area consumption, while implementing usage-based-disturbance mitigation operations to combat interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If higher chip densities are used to increase bit density, then storage capacity is improved, but electromagnetic coupling between memory cells increases causing usage-based disturbances and memory errors
Solution Approach 1:
The memory array is divided into multiple sub-arrays, with each sub-array having its own dedicated sense amplifier. This segmentation isolates the electromagnetic interference within each sub-array, preventing usage-based disturbances from propagating across the entire memory array, thereby maintaining reliability while supporting high bit density
Solution Approach 2:
Bitline switches are introduced as intermediary components between memory cells and sense amplifiers. These switches enable selective connection and disconnection of bitlines, allowing the sense amplifier to be shared between multiple memory cells in different sub-arrays while controlling electromagnetic coupling and preventing interference
2Measurement precision
If more sense amplifiers are allocated to each memory cell to improve reliability, then measurement precision is improved, but device complexity and area consumption increase
Solution Approach 1:
Each sense amplifier is designed to serve multiple memory cells across different sub-arrays through time-division and switching control. The sense amplifier performs the same measurement function for multiple cells sequentially, eliminating the need for dedicated amplifiers for each cell while maintaining measurement precision
Solution Approach 2:
Multiple sense amplifier functions are merged into a single shared sense amplifier unit. By combining the functions of multiple dedicated amplifiers into one shared resource that serves multiple sub-arrays through switching control, the overall device complexity and area consumption are significantly reduced
3Device complexity
If bitline switches are added to enable sense amplifier sharing, then device complexity increases, but space utilization is optimized and area consumption is reduced
Solution Approach 1:
The bitline switches are integrated directly into the existing bitline structure, merging the switching function with the signal transmission path. This integration minimizes additional area consumption while enabling sense amplifier sharing between multiple memory cells in different sub-arrays
Data Source
AI summary
Apparatuses and techniques for sharing a sense amplifier between memory cells of a memory device are described. To enable sharing of a sense amplifier between two memory cells, a memory device includes switching devices that selectively couple bitlines of two memory cells to a single sense amplifier. During a first time period, for a differential sense amplifier, the switching devices are controlled to connect terminals of the sense amplifier to bitlines of a first memory cell and to disconnect bitlines of a second memory cell from the terminals of the sense amplifier. During a second time period, the switching devices are controlled to connect terminals of the sense amplifier to the bitlines of the second memory cell and disconnect the bitlines of the first memory cell from the terminals of the sense amplifier. Accordingly, a single sense amplifier may be utilized to read the stored values from different memory cells.