Memory Device Power Noise Reduction in Refresh Operations
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Solution Overview
Problem
High integration density in memory devices leads to increased power noise during refresh operations due to simultaneous refreshing of numerous word lines, degrading data retention characteristics and reliability.
Innovation Solution
Implementing a method where normal and target refresh operations are optimally scheduled across multiple refresh timings, with a greater number of word lines refreshed simultaneously during normal refresh operations and fewer during target refresh operations, reducing power noise by spreading out refresh cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the integration density of the memory device is increased, then the capacity and speed are improved, but the power noise increases during refresh operations
Solution Approach 1:
The refresh operations are segmented into two distinct types: normal refresh operations that refresh a larger number of word lines simultaneously, and target refresh operations that refresh fewer word lines (specifically victim word lines adjacent to frequently activated word lines) separately. This segmentation allows the memory device to handle the increased integration density by distributing refresh tasks across different time points, thereby reducing power noise while maintaining the required refresh coverage for high-capacity memory arrays.
2Reliability
If multiple word lines are refreshed simultaneously to maintain data reliability, then data retention characteristics are improved, but power noise increases
Solution Approach 1:
Different refresh strategies are applied to different word lines based on their specific needs. Victim word lines (those adjacent to frequently activated word lines and thus more prone to data retention issues) receive targeted refresh operations, while other word lines receive normal refresh operations. This local differentiation ensures that data reliability is maintained for vulnerable word lines without unnecessarily refreshing all word lines simultaneously, thereby reducing overall power noise.
3Reliability
If the number of refresh operations is increased within a refresh cycle, then data reliability is improved, but the time available for each operation is reduced
Solution Approach 1:
The refresh operations are organized into periodic cycles with distinct phases. Within each refresh cycle, normal refresh operations and target refresh operations are performed at different time points rather than simultaneously. This periodic structuring allows sufficient time for each refresh operation to complete while ensuring that both normal and target refresh tasks are accomplished within the overall refresh cycle, maintaining data reliability without excessive time loss.
Data Source
AI summary
The present disclosure provides methods, apparatuses, and systems having reduced power noise in a refresh operation. In some embodiments, an operating method includes: performing, in response to receiving a first refresh command, a first normal refresh, at a first refresh timing, in which first N word lines of a plurality of word lines are simultaneously refreshed, and a first target refresh, at a second refresh timing, on at least one first victim word line that is adjacent to a maximum activated word line that is most frequently activated from among the plurality of word lines; and performing, in response to receiving a second refresh command, a second normal refresh, at a third refresh timing, in which second N word lines are simultaneously refreshed, and a second target refresh, at a fourth refresh timing, on at least one second victim word line that is adjacent to the maximum activated word line.