Nonvolatile Memory Warming Command for Temperature Cross Errors
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Solution Overview
Problem
Nonvolatile memory systems, such as NAND type flash memory, face reliability issues due to temperature variations between writing and reading operations, leading to data unreadability caused by temperature cross, which affects read accuracy.
Innovation Solution
A memory system with a memory controller that issues a warming command to increase the temperature of the nonvolatile memory when it falls below a certain threshold, ensuring that operations are performed at a consistent temperature by causing current to flow through bit lines, thereby preventing temperature cross-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the nonvolatile memory is operated at low temperature to reduce thermal stress, then the device longevity is improved, but the threshold voltage distribution shifts causing temperature cross and data unreadability
Solution Approach 1:
The memory controller performs a warming operation before read operations when the memory temperature is below a predetermined threshold. This preliminary heating action adjusts the threshold voltage distribution to match the read voltage characteristics, preventing temperature cross and ensuring reliable data reading while allowing the memory to operate at lower temperatures for extended periods
2Measurement precision
If the memory temperature is increased to maintain consistent threshold voltage distribution, then read accuracy is improved, but energy consumption increases due to additional warming operations
Solution Approach 1:
The memory controller monitors the memory temperature and dynamically adjusts the warming operation based on the detected temperature. When the temperature is below the predetermined value, the controller issues a warming command; when the temperature is sufficient, no warming is performed. This feedback mechanism ensures read accuracy is maintained only when necessary, minimizing unnecessary energy consumption
3Reliability
If warming operation is performed frequently to maintain optimal temperature, then data integrity is preserved, but the operational time for actual data operations is reduced
Solution Approach 1:
The system changes the temperature parameter dynamically based on operational requirements. By setting a predetermined temperature threshold and only performing warming operations when the temperature falls below this threshold, the system maintains data integrity while minimizing the frequency and duration of warming operations, thereby preserving more operational time for actual data operations
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
The warming operation maintains consistent temperature conditions, enhancing read accuracy and preventing deterioration of data integrity by minimizing the impact of temperature variations on memory cell threshold voltage distributions.
Implementation Method 1
causing current to flow through bit lines, thereby preventing temperature cross-related errors
Data Source
AI summary
A memory system includes a nonvolatile memory including a plurality of blocks, in each of which a plurality of memory cells is arranged between bit lines and a source line, and a memory controller configured to control an operation of the nonvolatile memory. The memory controller is configured to issue a warming command to the nonvolatile memory when a temperature of the nonvolatile memory is lower than a first temperature, and the nonvolatile memory, in response to the warming command, causes current to flow through at least one bit line connected to memory cells of a first block.