Memory Controller Write Modes for Power-Loss Data Retention
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Solution Overview
Problem
Existing memory systems face data loss due to unexpected power loss or voltage decrease, particularly when using NAND flash memory, as volatile data storage is not reliably protected.
Innovation Solution
A memory system with a power storage device that switches power supply from an external source to an internal storage during power loss, enabling continued operation and data transfer to non-volatile memory using a first or second write mode based on power storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power storage device is added to protect against power loss, then data integrity is improved, but device complexity increases
Solution Approach 1:
The power storage device acts as an intermediary component between the external power supply and the memory system, mediating power delivery to ensure continuous operation during power disruptions. This mediator approach allows the system to maintain data integrity without fundamentally redesigning the entire power architecture.
Solution Approach 2:
The power storage device is charged in advance during normal operation to store energy before power loss occurs. This preliminary charging action ensures that sufficient energy is available to complete data transfer from volatile to non-volatile memory when power is lost, preventing data loss without requiring complex real-time power management.
2Reliability
If the power storage capacity is increased to ensure complete data transfer, then data integrity is improved, but the size and cost of the power storage device increases
Solution Approach 1:
The system implements partial action by transferring only the critical data that requires protection during power loss, rather than attempting to transfer all data in the system. The power storage device is sized to provide just enough energy for this partial data transfer operation, avoiding the excessive capacity that would be needed to transfer entire memory contents.
Solution Approach 2:
The system dynamically adjusts operational parameters based on available power storage capacity. When capacity is limited, the system modifies data transfer priorities and selects critical data for protection. This parameter adjustment allows adequate data integrity protection with smaller power storage devices by changing what data is protected rather than increasing storage capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures data integrity by maintaining system functionality and transferring volatile data to non-volatile storage during power disruptions, minimizing data loss and ensuring reliable data retention.
Implementation Method 1
a power storage device 40 capable of storing electric energy and of supplying the electric energy to the memory device 20 and the memory controller 10 through the power supply circuit 30 in a case where power supply from the external power supply 3 is stopped
Data Source
AI summary
A memory system according to one embodiment includes a memory system includes a memory device, a memory controller, a power supply circuit, and a power storage device. The memory controller controls the memory device. The power supply circuit generates power for driving the memory device and the memory controller based on power supplied from an external power supply, and supplies the generated power to the memory device and the memory controller. The power storage device stores electric energy and to supply the electric energy to the memory device and the memory controller through the power supply circuit in a case where power supply from the external power supply is stopped. The memory controller applies one of first and second write modes having different power consumption to a write operation for the memory device according to a power storage capacity of the power storage device.