Semiconductor Memory Device Smart Refresh Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor memory devices integrate more densely, the reduced spacing between memory cells leads to increased interference between word lines, causing unintended charging or discharging of memory cells and resulting in data loss, and existing refresh operations consume unnecessary power by refreshing all cells at a high frequency.
Innovation Solution
A semiconductor memory device that controls refresh operations based on temperature information, using a control signal generator to determine when to perform smart refresh operations and normal refresh operations, optimizing the frequency of refreshes to prevent data loss while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refresh operations are performed at high frequency on all memory cells, then data loss is prevented, but power consumption increases unnecessarily
Solution Approach 1:
The patent applies local quality by differentiating refresh operations based on word line location. Memory cells adjacent to active word lines receive refresh operations while other cells do not, creating localized refresh zones rather than uniform global refresh. This resolves the contradiction by applying refresh only where data loss risk exists (high reliability need) rather than universally (low power consumption).
Solution Approach 2:
The patent implements partial action by performing refresh operations on only a subset of memory cells that are actually at risk due to interference from active word lines. Instead of refreshing all cells (excessive action), the system selectively refreshes only those in affected regions, reducing overall power consumption while maintaining data integrity where needed.
2Quantity of substance
If the spacing between memory cells is reduced to increase integration, then device density improves, but interference between word lines increases
Solution Approach 1:
The patent segments the memory bank into distinct regions based on proximity to active word lines. By dividing the memory space into affected and unaffected zones, the system can apply different operations to different segments, allowing high-density integration while managing interference through spatial segmentation rather than increasing spacing.
Solution Approach 2:
The patent converts the harmful interference effect into a useful indicator by using the presence of interference (voltage change in neighboring word lines) as the trigger condition for refresh operations. The interference that would normally cause data loss is instead used to identify which cells need refreshing, transforming a harmful phenomenon into a beneficial detection mechanism.
3Ease of operation
If active operations are performed on word lines to access memory cells, then data retrieval is enabled, but unintended charging or discharging of neighboring memory cells occurs
Solution Approach 1:
The patent applies preliminary action by performing refresh operations on memory cells adjacent to active word lines before the interference can cause data loss. The system detects the active word line operation and proactively refreshes affected cells in advance, preventing data integrity issues before they occur rather than reacting after damage happens.
Solution Approach 2:
The patent implements feedback by monitoring the state of neighboring word lines during active operations and using this information to control refresh operations. When voltage changes indicating interference are detected in neighboring word lines, the system responds by triggering refresh operations on adjacent memory cells, creating a closed-loop control system that maintains data integrity during memory access operations.
Data Source
AI summary
A semiconductor memory device includes a control signal generator suitable for generating a control signal corresponding to temperature information, a refresh controller suitable for enabling a refresh signal for a smart refresh operation at a predetermined moment in response to a refresh command signal and enabling the refresh signal for a normal refresh operation at a moment corresponding to the control signal in response to the refresh command signal, and a data storage suitable for storing a data and performing the smart refresh operation and the normal refresh operation in response to the refresh signal of the refresh controller.