DRAM Bank Sub-bank Row Hammer Region Sharing
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Solution Overview
Problem
The row hammer effect in DRAM memory devices causes data loss in adjacent memory cells when a specific wordline is aggressively accessed, impacting data integrity.
Innovation Solution
A memory device is designed with at least one bank comprising a first sub-bank and a second sub-bank, where the first sub-bank has normal data regions and the second sub-bank has metadata regions, both sets of wordlines forming pairs to share a row hammer region for storing access times, thereby preventing data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate row hammer regions are provided for each sub-bank to prevent row hammer effect, then data integrity is improved, but device area increases
Solution Approach 1:
The patent merges the row hammer regions of multiple sub-banks into a single shared region. Instead of providing separate row hammer regions for each sub-bank, the invention creates one common row hammer region that serves all sub-banks, thereby reducing the total area required while maintaining the ability to prevent row hammer effects across all sub-banks.
Solution Approach 2:
The shared row hammer region is designed to serve multiple sub-banks simultaneously, making it a universal structure. The row hammer region can store and manage access count information for wordlines from different sub-banks, allowing a single structure to perform the protective function for multiple sub-banks without requiring separate dedicated regions for each.
2Measurement precision
If access count information is stored separately for each sub-bank, then row hammer prevention accuracy is improved, but storage space increases
Solution Approach 1:
The patent combines the storage of access count information from multiple sub-banks into a single shared row hammer region. By merging the storage resources, the total quantity of storage space required is reduced while the system maintains the ability to accurately track and prevent row hammer effects through centralized management of access counts.
Solution Approach 2:
The invention changes the organizational parameter of access count storage from distributed (separate per sub-bank) to centralized (shared across sub-banks). This parameter change allows the system to use less total storage space while maintaining prevention accuracy through unified management of access information across all sub-banks.
Data Source
AI summary
A memory device includes at least one bank including at least a first sub-bank and a second sub-bank disposed in a wordline direction. The first sub-bank may include a normal data region connected to a plurality of first wordlines and storing normal data, the second sub-bank may include a metadata region connected to a plurality of second wordlines and storing metadata corresponding to the normal data, the plurality of first wordlines may match the plurality of second wordlines to form a plurality of wordline pairs, and the first sub-bank and the second sub-bank may share a row hammer region storing a number of access times to the plurality of wordline pairs.