Non-Volatile Memory Refresh During Automotive Power-Down
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-volatile memory devices programmed at extreme temperatures experience unreliable data storage and retention due to varying operating characteristics, particularly affecting multi-level cell devices, leading to read failures and data loss when the system cools down.
Innovation Solution
A host system controller monitors environmental inputs to trigger a refresh operation on non-volatile memory after the automotive system powers down, ensuring memory cells programmed at extreme temperatures are refreshed as the system temperature normalizes, using a refresh command to maintain data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If non-volatile memory blocks are programmed at extreme temperatures, then the memory device can store data during automotive operation, but data retention and read reliability deteriorate when the system cools down
Solution Approach 1:
The patent applies preliminary action by performing a refresh operation on non-volatile memory blocks before the system fully powers down. The host system controller detects that the automotive system is powering down and initiates a refresh command to the memory system while it is still in a power-off state, ensuring that data programmed at extreme temperatures is refreshed while the system temperature is still elevated, thereby maintaining read reliability after cooling down
Solution Approach 2:
The patent implements feedback by having the host system controller monitor the power state of the automotive system and detect when it is powering down. This feedback mechanism triggers the refresh operation at the appropriate time, creating a closed-loop control system that adapts to the thermal and power conditions of the automotive environment
2Use of energy by moving object
If the host system enters power-off state immediately upon automotive power down, then power consumption is reduced, but refresh operations cannot be performed on non-volatile memory
Solution Approach 1:
The patent applies dynamics by creating a transitional power state between full operation and complete power-off. The host system controller enters a partial power-off state that consumes reduced power but maintains enough functionality to issue refresh commands to the memory system. This dynamic power management allows the system to balance energy savings with the need to perform refresh operations on non-volatile memory
Solution Approach 2:
The patent uses an intermediary approach by maintaining a minimal operational mode of the host system controller during the power-off state. This intermediary state allows the controller to communicate with the memory system and trigger refresh operations without requiring full system power, serving as a bridge between complete operation and total shutdown
3Quantity of substance
If multi-level cell memory devices are used to increase storage capacity, then memory density is improved, but reliability at extreme temperatures deteriorates due to smaller voltage threshold differences
Solution Approach 1:
The patent applies preliminary action by refreshing multi-level cell memory blocks before the system cools down, when the voltage thresholds are still well-defined from the elevated temperature programming process. This refresh operation reinforces the stored data states while the thermal conditions favor stable voltage thresholds, compensating for the inherently smaller threshold differences in MLC devices
Data Source
AI summary
Methods, systems, and devices for triggering a refresh for non-volatile memory are described. A host system may communicate with a memory system, where the host system and memory system may be included within a vehicle (e.g., an automotive system). The host system may receive an indication that the vehicle is powering down and may enter a power off state in response to the indication. The host system may detect a trigger (e.g., using a time or temperature input) to switch back to a power on state while the vehicle is powered down, the trigger associated with performing a refresh operation at the memory system. The host system may enter the power on state and may transmit a power on command to the memory system. The memory system may perform the refresh operation on one or more memory cells while the vehicle remains in the powered down state.