Smart Refresh Circuit Adjusts Frequency Based on Temperature
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Solution Overview
Problem
Memory devices face data retention issues due to charge leakage and the row hammering phenomenon, where data is lost or altered in memory cells connected to frequently activated word lines, and existing refresh operations do not effectively control the frequency based on temperature variations.
Innovation Solution
A memory device with a temperature sensor and smart refresh circuit that adjusts the frequency of normal and smart refresh operations based on temperature information, increasing the frequency at higher temperatures and decreasing it at lower temperatures to optimize data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refresh operations are performed more frequently to prevent data loss due to charge leakage, then data retention reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic refresh operation by adjusting the refresh period based on temperature conditions. At higher temperatures, the refresh period is shortened to maintain data retention reliability, while at lower temperatures, the refresh period is extended to reduce energy consumption. This dynamic adaptation resolves the contradiction between reliability and energy consumption.
Solution Approach 2:
The patent changes the refresh operation parameter (refresh period) according to temperature conditions. By monitoring temperature and adjusting the refresh period accordingly, the system optimizes the balance between data retention reliability and energy consumption, performing more frequent refreshes when needed and fewer refreshes when conditions permit.
2Reliability
If smart refresh operations are executed to address row hammering phenomenon, then data retention reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing smart refresh operations specifically for word lines that are frequently activated (such as WLK in the row hammering example), rather than uniformly refreshing all word lines. This targeted approach addresses the row hammering phenomenon at its source while avoiding unnecessary operations on less-active word lines, thereby managing complexity effectively.
Solution Approach 2:
The patent performs preliminary identification of frequently activated word lines and proactively applies smart refresh operations to them before data loss occurs. By detecting the pattern of word line activation and preparing refresh operations in advance for at-risk word lines, the system prevents data loss without requiring complex real-time intervention mechanisms.
Data Source
AI summary
A memory device may include a temperature sensor suitable for generating temperature information and a smart refresh circuit suitable for activating a smart refresh signal when an internal refresh signal is activated a set number of times, and controlling the set number based on the temperature information.