eFuse Integrity Checks for ASIL D Safety-Critical ICs
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Solution Overview
Problem
Existing eFuse implementations in safety critical integrated circuits face challenges in achieving high ASIL (Automotive Safety Integrity Level) ratings, particularly ASIL D, while minimizing duplication and cost, especially when the number of fuses grows significant.
Innovation Solution
Implementing precomputed CRC checksums for eFuses, combined with hardware integrity checks like TMR, MBIST, and software BIST, to ensure fault detection and integrity, thereby reducing the number of physical eFuses required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple physical eFuses are duplicated to ensure ASIL D safety integrity, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
Instead of duplicating physical eFuse components, the patent creates virtual copies through software-based fuse management. Multiple virtual eFuses are implemented within a single physical eFuse using software state management, allowing ASIL D safety integrity without physical duplication. This reduces device complexity while maintaining reliability through software-controlled redundancy.
Solution Approach 2:
The patent replaces the mechanical/physical duplication of eFuse components with a software-based system. Rather than having multiple physical fuse elements, the invention uses software state machines and virtual fuse representations to achieve safety integrity, substituting physical redundancy with software-based fault tolerance mechanisms.
2Reliability
If multiple physical eFuses are duplicated to ensure ASIL D safety integrity, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent implements multiple virtual eFuses within a single physical eFuse using software state management. This eliminates the need to manufacture and assemble multiple physical fuse components, significantly reducing manufacturing cost while maintaining ASIL D safety integrity through software-controlled redundancy.
Solution Approach 2:
The patent merges multiple virtual eFuse representations into a single physical eFuse component. Instead of manufacturing separate physical fuses for each safety function, the system combines multiple safety-critical fuse functions into one physical element managed by software, reducing component count and manufacturing complexity.
3Reliability
If CRC checksums and integrity checks are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service integrity checking where the system automatically verifies eFuse state consistency through CRC checksums and state machine validation without external intervention. The integrity checks are performed autonomously during normal operation, reducing the need for additional complex monitoring systems while maintaining reliability.
Solution Approach 2:
The patent uses feedback mechanisms where CRC checksums and state machine validations continuously monitor eFuse integrity and provide feedback for corrective actions. This feedback loop enables automatic detection and response to faults, improving reliability through systematic monitoring without requiring overly complex additional hardware.
Data Source
AI summary
Aspects of the disclosure relate to an integrated circuit that operates an approach for functionally safe processing using hardware integrity checks of one or more electronic components. An apparatus may use CRC checksum computation on eFuses. In addition, safety mechanisms, such as triple modular redundancy, hardware logic, memory built-in-self-test, or software built-in-self-test may be used in conjunction to ensure integrity of the eFuses.