Memory Component Refresh via Write Count Threshold
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Solution Overview
Problem
Conventional memory sub-systems face performance degradation due to write disturb, which causes errors in adjacent memory cells, leading to increased error correction operations and resource consumption, especially in cross-point array memory where small managing units result in high write counts and significant metadata overhead.
Innovation Solution
Refreshing data stored in memory components based on a single write count threshold for the entire memory component, rather than each managing unit, mitigates write disturb effects by identifying and refreshing proximate memory cells when the write operation count exceeds a threshold value determined by probability, temperature, drift time, and die-to-die variance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If write count tracking is performed for each managing unit in cross-point array memory, then write disturb effects can be mitigated, but metadata overhead and device complexity increase significantly
Solution Approach 1:
The patent merges the write count tracking from individual managing units to a component-level approach. Instead of maintaining separate write counts for each small managing unit in the cross-point array, the system uses a single write count for the entire memory component, significantly reducing metadata overhead while still enabling effective refresh operations to mitigate write disturb effects.
Solution Approach 2:
The patent implements a universal refresh mechanism that applies to the entire memory component rather than individual managing units. This universal approach uses temperature sensors and drift time calculations to determine refresh needs across all memory cells, reducing the complexity of tracking write counts for each small managing unit while maintaining reliability.
2Reliability
If frequent refresh operations are performed on proximate memory cells, then error rates from write disturb are reduced, but resource consumption increases
Solution Approach 1:
The patent implements dynamic refresh operations based on temperature and drift time characteristics. Instead of performing fixed frequent refreshes, the system adjusts refresh timing and frequency based on real-time temperature sensor readings and calculated drift times, optimizing the balance between error mitigation and resource consumption.
Solution Approach 2:
The patent uses temperature sensors and drift time calculations as feedback mechanisms to determine when refresh operations are needed. The system continuously monitors temperature and calculates drift times to dynamically adjust refresh timing, ensuring errors are mitigated while avoiding unnecessary refresh operations that would waste resources.
3Quantity of substance
If component-level write count threshold is used instead of managing unit level, then metadata storage is minimized, but precision in tracking write operations is reduced
Solution Approach 1:
The patent introduces temperature sensors and drift time calculations as intermediary mechanisms to compensate for the reduced precision of component-level write count tracking. These intermediaries provide additional information about memory cell stress and degradation, enabling the system to make informed refresh decisions without requiring precise per-managing-unit write count tracking.
Data Source
AI summary
One or more write operations are performed on a memory component. First data stored at the memory component is read. A determination is made as to whether an error rate associated with the first data stored at the memory component exceeds an error rate threshold. If the error rate exceeds the error rate threshold, a threshold value is adjusted. A determination is made as to whether a number of the plurality of write operations performed on the memory component since performance of a refresh operation on the memory component exceeds the threshold value. In response to determining that the number of write operations performed on the memory component exceeds the threshold value, a memory cell of the memory component is identified based on the plurality of write operations. Second data stored at memory cells of the memory component that are proximate to the identified memory cell is refreshed.