Distributed Refresh Control for Dynamic Memory Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
System-on-chip (SOC) devices face reduced processing speed and increased power consumption due to the need for periodic memory refreshing, which requires bringing the entire memory array out of a low power state, affecting performance and power management.
Innovation Solution
Implementing a distributed refresh control method where local refresh controllers manage individual memories, receiving refresh opportunity commands from a master refresh controller, and refreshing only when necessary, thereby minimizing the number of clock cycles and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire memory array is brought out of low power state for periodic refreshing using a global refresh controller, then all memories are refreshed reliably, but power consumption increases and processing speed decreases
Solution Approach 1:
The memory array is segmented into multiple independent memory banks, each with its own local refresh controller. This allows selective refreshing of individual banks rather than the entire array, enabling banks that are not currently accessed to be refreshed while others remain in low power state, thus reducing overall power consumption while maintaining refresh reliability for each bank
Solution Approach 2:
The refresh control system dynamically determines which memory banks need refreshing based on access patterns. The local refresh controllers receive refresh opportunity commands and autonomously manage refresh operations for their respective banks, adapting refresh activity to actual memory usage rather than using fixed periodic global refreshes
2Reliability
If the entire memory array is brought out of low power state for periodic refreshing, then all memories are refreshed, but processing speed is reduced
Solution Approach 1:
By dividing the memory array into independent banks with separate refresh controllers, the system can perform refresh operations on individual banks without affecting other banks. This segmentation allows processing to continue on non-refreshed banks, eliminating the need to halt entire array operations and thus maintaining processing speed while ensuring refresh completeness
Solution Approach 2:
The system proactively identifies refresh opportunities by monitoring memory access patterns and determines which banks need refreshing before processing demands arise. This preliminary identification allows refresh operations to be scheduled during idle periods or when banks are naturally inaccessible, ensuring refresh completeness without impacting processing speed
3Device complexity
If global refresh controller manages entire memory array, then refresh coordination is simplified, but power consumption and processing speed are adversely affected
Solution Approach 1:
The refresh control function is segmented between a master refresh controller that coordinates overall refresh opportunities and multiple local refresh controllers that execute refresh operations for individual banks. This segmentation distributes control responsibilities, allowing the system to maintain coordination simplicity while reducing power consumption through selective bank refreshing
Solution Approach 2:
The master refresh controller acts as an intermediary that sends refresh opportunity commands to local refresh controllers based on overall memory array status. This intermediary role allows centralized coordination logic to remain simple while delegating autonomous refresh decisions to local controllers, reducing power consumption without significantly increasing overall system complexity
Data Source
AI summary
A method for refreshing memory is provided. The method comprises determining when a first memory of a plurality of memories is not being accessed and sending a refresh opportunity command from a master refresh controller to one of a plurality of local refresh controllers when the first memory is not being accessed, wherein the one of a plurality of local refresh controllers controls only the first memory. The method further comprises determining when the first memory needs refreshing and refreshing the first memory.