Memory Cell Degradation Measurement Using ECC Readback
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Solution Overview
Problem
Existing storage devices lack the capability to accurately determine the degree of degradation of memory cells, which can lead to potential failures that may result in critical accidents, especially in automotive systems.
Innovation Solution
A storage device equipped with a cell degradation measurement circuit that writes data to a memory cell, reads it after a predetermined time, and generates cell degradation information based on error detection operations, allowing for accurate assessment of memory cell degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a storage device performs error detection operations to determine memory cell degradation, then measurement precision is improved, but device complexity increases due to the need for additional measurement circuits and operations
Solution Approach 1:
The cell degradation measurement circuit is integrated into the existing storage device controller, allowing the same hardware to perform both normal storage operations and degradation measurement operations. The circuit uses existing memory cells and control logic to execute write operations, wait for predetermined time periods, read data back, and perform error detection, thereby achieving degradation measurement without adding separate dedicated measurement hardware.
Solution Approach 2:
The storage device performs self-diagnosis by using its own internal resources (memory cells, write/read circuits, error detection logic) to measure its own degradation. The device writes test data to memory cells, waits for degradation to occur over time, reads the data back, and detects errors using its existing error correction code (ECC) logic, eliminating the need for external measurement equipment.
2Measurement precision
If the storage device waits for a predetermined time before reading data, then measurement precision is improved by allowing degradation to manifest, but loss of time increases due to the waiting period
Solution Approach 1:
The degradation measurement is performed periodically by waiting for predetermined time intervals between write and read operations. This allows the system to capture degradation effects that manifest over time while maintaining a structured, repeatable measurement process. The predetermined time period can be optimized to balance between detecting early degradation signs and minimizing measurement time.
Solution Approach 2:
The system performs preliminary write operations to memory cells before the degradation measurement period begins. By pre-positioning test data in the memory cells, the system ensures that when the predetermined time elapses and the read operation occurs, any degradation can be immediately detected without additional preparation time, thus optimizing the overall measurement timeline.
Data Source
AI summary
A storage device includes a cell degradation measurement circuit configured to receive a cell degradation information request command that requests cell degradation information from a host, and provide first cell degradation information to the host in response to the cell degradation information request command, and a non-volatile memory including a plurality of memory cells. The cell degradation measurement circuit writes data to any one of the plurality of memory cells in response to the cell degradation information request command. The cell degradation measurement circuit reads the written data after a predetermined time has elapsed. The first cell degradation information is generated based on an error detection operation performed on the read data.