Dynamic Memory Refresh Rate Control for Power Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High density memory architectures are susceptible to state changes due to external power fluctuations, leading to instability and potential data loss if memory cells are not timely refreshed, especially during transitions from externally controlled to self-refresh modes.
Innovation Solution
A self-refresh mode controller that adjusts refresh rates, initially operating at a higher frequency to ensure complete refresh cycles and then switching to a lower frequency once confirmed, using a counter or timer to manage the transition and maintain data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory refresh rate is increased during transition periods, then memory reliability is improved, but power consumption increases
Solution Approach 1:
The refresh rate is made dynamic rather than static. The system automatically adjusts the refresh rate based on the operational phase: using a first (higher) refresh rate during transition periods when reliability is critical, and switching to a second (lower) refresh rate during stable periods to conserve power. This dynamic adaptation resolves the contradiction by optimizing both reliability and power consumption at different times.
Solution Approach 2:
The system implements periodic refresh cycles with varying rates. During transition from external to self-refresh control (or vice versa), the system applies a higher refresh rate periodically to ensure stability. Once the transition is complete and stability is achieved, the system switches to a lower periodic refresh rate, thus maintaining reliability during critical periods while reducing power consumption during stable operation.
2Use of energy by moving object
If memory refresh rate is decreased to conserve power, then power consumption is reduced, but memory stability deteriorates during transition periods
Solution Approach 1:
The system performs preliminary high-rate refreshing during transition periods before settling into a lower power mode. By proactively maintaining higher refresh rates during the vulnerable transition phase from external to self-refresh control, the system ensures memory stability is established before reducing the refresh rate to conserve power. This preliminary action prevents instability that would occur if low-rate refreshing were applied too early.
Solution Approach 2:
The refresh rate is dynamically adjusted based on system state. Rather than using a fixed low refresh rate that would compromise stability, the system transitions from a higher refresh rate during unstable transition periods to a lower refresh rate during stable periods. This dynamic control ensures stability is maintained when needed while allowing power savings when the system is stable.
3Use of energy by moving object
If external control is switched to self-refresh control, then power consumption is reduced, but a period of instability occurs during transition
Solution Approach 1:
Before fully transitioning to self-refresh control, the system performs preliminary high-rate refresh operations to ensure memory stability is established. This preliminary action during the transition phase prevents data loss and maintains reliability while the control mechanism shifts from external to internal, allowing the system to safely enter the lower-power self-refresh mode afterward.
Solution Approach 2:
During the transition from external to self-refresh control, the system implements periodic high-rate refresh cycles to maintain stability. These periodic actions ensure that memory cells are refreshed at appropriate intervals during the vulnerable transition period, preventing instability while the system establishes self-refresh operation, after which the periodic rate can be reduced for power savings.
Data Source
AI summary
Apparatuses and methods for memory refreshing memory cells is described. An example method includes receiving a self refresh command at a memory. The method further includes refreshing the memory at a first refresh rate after receiving the self refresh command. The method further includes refreshing the memory at a second refresh rate in response to a determination that each memory cell of the memory has been refreshed at the first refresh rate. The first refresh rate is greater than a second refresh rate.