Volatile-to-Nonvolatile Memory Backup for Standby Power Reduction
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Solution Overview
Problem
Volatile memory devices, such as DRAM, consume power during standby mode due to continuous self-refresh operations when the host device is turned off, leading to unnecessary power consumption.
Innovation Solution
A memory system that includes a volatile memory device and a non-volatile memory device, with a processor controlling data transfer between them, where data is backed up from the volatile memory to the non-volatile memory after a specified time period, and self-refresh is stopped, reducing power consumption during standby.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volatile memory device continuously performs self-refresh to preserve data when the host device is turned off, then data preservation is ensured, but power consumption increases unnecessarily
Solution Approach 1:
The system performs preliminary data backup from volatile memory to non-volatile memory before the host device is fully turned off. This preliminary action ensures data preservation without requiring continuous self-refresh operations, thereby eliminating unnecessary power consumption while maintaining data reliability.
2Use of energy by moving object
If the volatile memory device stops self-refresh to reduce power consumption, then power consumption decreases, but data may be lost
Solution Approach 1:
The non-volatile memory device serves as an intermediary storage medium. Data is first transferred from volatile memory to this intermediary non-volatile memory before the host device shuts down. This intermediary storage ensures data preservation even after volatile memory stops self-refresh, allowing power consumption to be reduced without sacrificing data reliability.
3Use of energy by moving object
If data is immediately backed up to non-volatile memory when the host device turns off, then power consumption is reduced, but there is a time delay in preserving data
Solution Approach 1:
The system implements periodic self-refresh operations at reduced frequency after the initial data backup is completed. This periodic action maintains data integrity during the transition period while consuming minimal power, bridging the time gap between host device shutdown and complete data backup without requiring continuous high-power self-refresh.
Data Source
AI summary
A memory system is included in a host device. The memory system incudes: a volatile memory device that performs self-refresh until the host device turns on duty when detecting that the host device is off duty; a non-volatile memory device; and a processor that controls a read operation or a write operation of the volatile memory device and the nonvolatile memory device. The processor backs up data stored in the volatile memory device to the non-volatile memory device after a first time period elapses from when the host device is off duty. The volatile memory device stops the self-refresh after a second time period elapses from a time point when the data stored in the volatile memory device is backed up to the nonvolatile memory device.