Vehicle Trip Data Retention During Voltage Drops
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Solution Overview
Problem
Trip data in vehicle clusters is lost or reset unexpectedly due to instantaneous low voltage states during vehicle start-up or large electric loads, without additional voltage stabilizers or EEPROMs, leading to user confusion and increased manufacturing costs.
Innovation Solution
Partitioning the RAM into a clear volatile region and a nonvolatile region, where trip data is stored in the clear region and backed up to the nonvolatile region upon new data generation, and rewritten back to the clear region after a voltage drop, with checksum verification to ensure data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trip data is stored only in volatile RAM, then the system operates with simple hardware and low cost, but the data is lost during instantaneous low voltage states
Solution Approach 1:
The RAM is segmented into a clear volatile region for active trip data storage and a nonvolatile region for backup data storage. This segmentation allows the system to maintain simplicity while protecting against data loss by dividing the memory function into two distinct areas with different volatility characteristics.
Solution Approach 2:
The system performs preliminary backup of trip data from the clear volatile region to the nonvolatile region before voltage drops occur. This advance action ensures that data is preserved in a safe location before the harmful voltage drop event can cause data loss.
2Reliability
If additional voltage stabilizer or EEPROM is added, then data loss during voltage drops is prevented, but manufacturing cost increases
Solution Approach 1:
The patent merges the volatile RAM and nonvolatile EEPROM functionalities into a single integrated memory device. This combination eliminates the need for separate voltage stabilizer circuits and multiple discrete memory components, reducing manufacturing complexity and cost while maintaining data retention reliability.
Solution Approach 2:
The integrated memory device performs multiple functions: it provides volatile storage for active data, nonvolatile backup storage for data protection, and automatic data migration between regions. This multi-functionality replaces what would traditionally require separate voltage stabilization circuits and multiple memory devices.
3Reliability
If trip data is backed up to nonvolatile region, then data integrity is maintained during voltage drops, but data management complexity increases
Solution Approach 1:
The memory system automatically performs backup and restoration operations without requiring external control logic or complex management systems. The memory device itself services the data protection function through automatic detection of voltage drops and self-initiated data migration between volatile and nonvolatile regions.
Solution Approach 2:
The system uses checksum verification as a feedback mechanism to ensure data integrity during backup and restoration operations. The checksum calculation and comparison provide automatic verification that data has been correctly transferred and stored, maintaining reliability without complex management overhead.
4Manufacturing precision
If checksum verification is implemented, then data integrity during restore is ensured, but processing time increases
Solution Approach 1:
The checksum verification performs partial validation by checking only critical data integrity markers rather than verifying every byte of restored data. This selective verification approach ensures data integrity for the most important aspects while minimizing the time penalty compared to complete data verification.
Data Source
AI summary
Disclosed herein is a method for preventing a loss of trip data of a vehicle during a substantial instantaneous voltage drop in a vehicle cluster. In the method, the trip data calculated by a processor of a trip computer are stored in a clear region of a memory and the trip data stored in the clear region are backed up in a nonvolatile region of the memory when new trip data is generated. The processor collects the trip data backed up in the nonvolatile region to rewrite the trip data in the clear region after a substantially instantaneous voltage drop occurs.