Temperature-Adaptive Memory Refresh Circuit for Lower Current Waste
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Solution Overview
Problem
Conventional refresh circuits in volatile memory waste current due to unnecessary refresh operations at varying temperatures, as they maintain a fixed number of rows refreshed per command, leading to inefficiency in data hold times.
Innovation Solution
A refresh circuit that adjusts the number of rows refreshed based on temperature signals, increasing the number at higher temperatures and decreasing it at lower temperatures, ensuring all rows are refreshed within the data hold time while minimizing current waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed number of rows are refreshed per refresh command, then the refresh operation is simple to implement, but current is wasted at low temperatures where data hold time is longer
Solution Approach 1:
The patent applies dynamics by making the number of rows refreshed per command dynamic rather than fixed. The refresh control module adjusts the preset value (number of rows to refresh) based on temperature signals. At high temperatures where data hold time is short, more rows are refreshed per command; at low temperatures where data hold time is long, fewer rows are refreshed per command. This dynamic adjustment optimizes current consumption while adapting to temperature variations.
Solution Approach 2:
The patent changes the parameter of the number of rows refreshed per command based on temperature. The refresh control module receives temperature signals and adjusts the preset value accordingly. This parameter change allows the system to match the refresh operation to the actual data hold time requirements at different temperatures, reducing unnecessary current consumption at low temperatures while ensuring adequate refresh at high temperatures.
2Reliability
If more rows are refreshed per command, then refresh completion is ensured at high temperatures, but current waste increases at low temperatures
Solution Approach 1:
The system dynamically adjusts the number of rows refreshed per command based on temperature conditions. At high temperatures, the preset value is increased to ensure all rows are refreshed within the shorter data hold time, maintaining reliability. At low temperatures, the preset value is decreased to avoid refreshing rows unnecessarily, thus reducing current waste while still ensuring refresh completion within the longer data hold time.
Solution Approach 2:
The patent changes the refresh parameter (number of rows per command) according to temperature. The refresh control module receives temperature signals and adjusts the preset value to optimize the balance between refresh reliability and current consumption. This ensures that at high temperatures, enough rows are refreshed to meet the shorter data hold time requirement, while at low temperatures, fewer rows are refreshed to avoid current waste.
3Loss of energy
If the preset value is adjusted based on temperature, then current efficiency is improved, but the control mechanism becomes more complex
Solution Approach 1:
The patent introduces a temperature signal as an intermediary between the physical condition (temperature) and the refresh control. The refresh control module receives temperature signals and uses them to adjust the preset value. This intermediary approach allows the system to respond to temperature changes without requiring complex direct temperature sensing and decision-making logic, simplifying the overall control mechanism while still achieving current efficiency.
4Speed
If a larger preset value is used, then all rows are refreshed within shorter data hold time at high temperatures, but repeated refresh occurs at low temperatures
Solution Approach 1:
The patent applies dynamics by adjusting the preset value according to temperature. At high temperatures where data hold time is short, a larger preset value is used to refresh more rows per command, ensuring all rows are refreshed within the shorter time window. At low temperatures where data hold time is long, a smaller preset value is used to avoid refreshing rows multiple times, thus preventing current waste from repeated refresh operations.
Solution Approach 2:
The patent changes the preset value parameter based on temperature conditions. At high temperatures, the preset value is increased to match the faster refresh rate needed for shorter data hold time. At low temperatures, the preset value is decreased to prevent over-refreshing. This parameter change optimizes both refresh speed and current efficiency across different temperature conditions.
Data Source
AI summary
A refresh circuit includes: a refresh control module configured to receive a refresh command to output a row address refresh signal, the row address refresh signal being outputted a number of times of a preset value each time the refresh command is received; and further configured to receive a temperature signal to adjust the preset value, the higher a temperature represented by the temperature signal, the greater the adjusted preset value; a row addresser configured to receive the row address refresh signal and output a to-be-refreshed single-row address; and an array refresh device configured to perform a single-row refresh operation according to the single-row address and output a single-row refresh end signal after the end of single-row refresh.