Memory Controller Refresh Method Selection for DRAM Efficiency
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Solution Overview
Problem
The inefficiency in memory use due to the need for regular timing adjustments and calibrations between signals in dynamic random access memory (DRAM), which disrupts memory access and reduces efficiency, especially with the introduction of per-bank refresh methods that complicate these adjustments.
Innovation Solution
A memory controller that selects an appropriate refresh method between all-bank and per-bank refresh based on whether a specific event, such as timing adjustments or calibrations, occurs during the refresh execution period, thereby optimizing memory access and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If timing adjustment and calibration are executed during refresh execution period, then memory use efficiency is improved, but timing adjustment precision deteriorates due to per-bank refresh overlapping with specific events
Solution Approach 1:
The patent dynamically switches between all-bank refresh and per-bank refresh methods based on whether a specific event (timing adjustment or calibration) is occurring. When a specific event is detected, the system transitions to all-bank refresh to ensure complete disablement of memory access, providing a stable environment for timing-critical operations. This dynamic adaptation resolves the contradiction by adjusting the refresh strategy in real-time according to system state.
Solution Approach 2:
The patent changes the refresh execution parameter (from per-bank to all-bank) based on the timing of specific events. By detecting whether a specific event coincides with the refresh execution period, the system modifies the refresh mode to maintain both memory efficiency and timing precision. This parameter change allows the system to optimize for precision when needed while maintaining efficiency during normal operation.
2Measurement precision
If all-bank refresh is used to perform timing adjustment and calibration, then timing adjustment precision is improved, but memory use efficiency deteriorates due to complete memory access disablement
Solution Approach 1:
The system dynamically selects between all-bank refresh and per-bank refresh based on operational context. All-bank refresh is activated only when timing adjustment or calibration events are detected, providing precise timing control when necessary. During normal operation, per-bank refresh maintains higher memory efficiency. This dynamic selection resolves the contradiction by applying the more efficient method whenever possible and reserving the more precise method for critical timing operations.
Solution Approach 2:
The refresh mode parameter is changed based on system state detection. When specific events requiring precise timing are identified, the system switches to all-bank refresh mode. Otherwise, it operates in per-bank refresh mode. This conditional parameter change allows the system to optimize for the appropriate metric (precision or efficiency) based on current operational requirements.
3Productivity
If per-bank refresh is used to improve memory use efficiency, then memory use efficiency is improved, but timing adjustment reliability deteriorates due to incomplete memory access disablement
Solution Approach 1:
The patent implements dynamic refresh method selection that responds to system events. When a specific event requiring reliable timing adjustment occurs, the system transitions from per-bank refresh to all-bank refresh, ensuring complete memory access disablement and reliable timing synchronization. This dynamic response maintains both efficiency and reliability by adapting to operational context.
Solution Approach 2:
The system proactively switches to all-bank refresh mode when detecting that a specific event (timing adjustment or calibration) is about to occur or is occurring. This preliminary action prevents the reliability issue before it arises by ensuring complete memory access disablement during critical timing operations, rather than attempting to correct timing issues after per-bank refresh has already caused problems.
Data Source
AI summary
In a memory controller, at least one of a plurality of refresh methods varying in refresh target area of a dynamic random access memory (DRAM) is a refresh method of refreshing an entire area of the DRAM, and a specific event that disables access to the entire area of the DRAM occurs in a cycle longer than a refresh execution cycle using the refresh method of refreshing the entire area of the DRAM. The memory controller includes a selection unit configured to select one refresh method from among the plurality of refresh methods, depending on whether the specific event that disables the access to the entire area of the DRAM is to occur in a refresh execution period.