Memory Rank Self-Refresh Mode Switching
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Solution Overview
Problem
Current memory refresh management methods fail to conserve power effectively as they require all memory ranks to be in an idle state for self-refresh mode, leading to prolonged wait times for instant access requests when only one rank is active.
Innovation Solution
Each memory rank is individually switched between auto-refresh and self-refresh modes based on its idle time, using counters to determine when to switch to self-refresh mode after a predetermined idle period, allowing non-idle ranks to remain in auto-refresh mode for immediate access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If all memory ranks must be in idle state to enter self-refresh mode, then power consumption is reduced, but access request response time increases
Solution Approach 1:
The patent divides the memory system into individual memory ranks, allowing each rank to independently determine its refresh mode. Instead of requiring all ranks to be idle for system-wide self-refresh, each rank can independently switch to self-refresh mode when its local idle counter reaches the threshold, thereby reducing power consumption without blocking access requests to active ranks.
Solution Approach 2:
The patent introduces dynamic idle counters for each memory rank that track the number of idle auto-refresh cycles. This dynamic tracking mechanism allows the system to adaptively determine when each rank should switch to self-refresh mode based on its actual usage pattern, rather than using a static system-wide idle state requirement, thus optimizing both power saving and access responsiveness.
2Use of energy by moving object
If memory ranks switch to self-refresh mode when idle, then power consumption decreases, but system complexity increases
Solution Approach 1:
Each memory rank maintains its own idle counter that automatically increments during idle auto-refresh cycles and resets when access requests occur. This self-service mechanism allows each rank to independently track its idle state and trigger self-refresh mode without requiring complex external control logic, thereby reducing overall system complexity while achieving power savings.
Data Source
AI summary
A memory refresh method applicable in a system memory is disclosed. The memory system comprises a plurality of memory ranks. It is to determine whether an access request corresponds to the memory rank, and an idle auto-refresh number of the memory rank is calculated if there is no access request corresponds to the memory rank. The memory rank is switched from an auto-refresh mode to a self-refresh mode when the idle auto-refresh number of the memory rank reaches a predetermined value.