NAND Flash Data Refresh for Onboard Vehicle Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
NAND-type flash memory in onboard storage devices experiences increased error rates due to temperature fluctuations and the soldering process, leading to shorter data retention times and prolonged manufacturing processes when traditional refresh controls are applied.
Innovation Solution
A data-refresh apparatus with a first refresh portion that performs refresh control at predetermined intervals and a second refresh portion that operates when the vehicle is in service, allowing for error detection and correction without extending the manufacturing process, utilizing a CPU and ECC function to manage error correction across all data stored in the NAND-type flash memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refresh control is performed after the soldering process to correct errors, then data integrity is improved, but the manufacturing process time is prolonged
Solution Approach 1:
The patent applies preliminary action by performing refresh control before the soldering process. The controller executes error detection and correction on all data stored in the flash memory prior to soldering, ensuring data integrity is maintained through the high-temperature soldering process without requiring post-soldering refresh operations that would extend manufacturing time.
Solution Approach 2:
The patent applies preliminary anti-action by preemptively counteracting the harmful effects of the soldering process. By performing refresh control before soldering, the system prevents error accumulation during the high-temperature exposure, effectively countering the adverse impact of soldering on data retention without adding time to the manufacturing process.
2Reliability
If refresh control is performed to correct errors caused by temperature increase, then data retention is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by incorporating refresh control into the pre-soldering sequence. The controller automatically executes error detection and correction before the soldering process, ensuring data retention is maintained throughout the manufacturing process without requiring additional complex post-soldering operations or special handling procedures.
Data Source
AI summary
A data-refresh apparatus performs a refresh control on a storage device being included in an onboard apparatus and including a NAND-type flash memory. The refresh control detects an error of all data and corrects a detected error. The data-refresh apparatus comprises a first refresh portion; and a second refresh portion that performs the refresh control when the onboard apparatus is installed to a vehicle and the vehicle subsequently becomes a predetermined service state. The storage device is written with data and subsequently soldered to a circuit board in manufacturing of the onboard apparatus. The second refresh portion includes a travel determination portion that determines whether the vehicle remains a travel state. The second refresh portion performs the refresh control while assuming that the vehicle becomes the predetermined service state, when the travel determination portion determines that the vehicle remains the travel state.