Peripheral Control Path Redundancy Using Timeout Value Comparison
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computing hardware in safety-critical applications faces challenges in maintaining functional safety due to single event upsets, which can cause data corruption and errors, especially in control paths where redundancy is costly and less frequently updated, leading to potential incorrect operations.
Innovation Solution
A circuit and method utilizing a functional safety controller with a timeout counter and comparator to verify consistency between primary and secondary control values in a peripheral's control path, ensuring that only matching values are loaded into control registers, thereby providing redundancy without complete duplication of hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete hardware duplication is used to provide fault tolerance, then system reliability is improved, but cost increases
Solution Approach 1:
The control path is segmented into two separate paths (first control path and second control path) that can be independently evaluated. Each path has its own registers and control logic, allowing parallel operation and comparison without requiring complete hardware duplication. This segmentation enables fault detection while reducing overall system complexity and cost.
Solution Approach 2:
Instead of duplicating entire hardware systems, the patent creates a simplified copy of the control path logic. The second control path mirrors the essential control functions of the first path, allowing comparison of control values without requiring full hardware redundancy. This selective copying maintains reliability while reducing device complexity.
2Difficulty of detecting and measuring
If complete hardware duplication is used to detect errors, then fault detection capability is improved, but cost increases
Solution Approach 1:
The patent implements a feedback mechanism where control values from both paths are continuously compared. The functional safety controller monitors the comparison results and can trigger safety responses when discrepancies are detected. This feedback loop provides robust fault detection without requiring complete hardware duplication, as the comparison logic identifies errors efficiently.
Solution Approach 2:
The patent replaces physical hardware duplication with a logical comparison mechanism. Instead of using separate physical systems to detect errors, the invention uses a functional safety controller that compares control values from duplicated logic paths. This substitution reduces device complexity while maintaining fault detection capability.
3Reliability
If redundant control paths are implemented, then functional safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple control paths into a unified comparison mechanism. The functional safety controller combines the control values from both paths and determines whether they match, then loads the appropriate value into the control register. This merging approach improves functional safety while managing device complexity through integrated control logic.
Solution Approach 2:
The functional safety controller performs multiple functions: it monitors both control paths, compares their outputs, determines safety status, and loads control values into registers. This multi-functional component provides comprehensive safety assurance without requiring separate dedicated hardware for each function, thereby improving functional safety while controlling device complexity.
Data Source
AI summary
Techniques including receiving a first control value, starting a timeout counter based on receiving the first control value, receiving a second control value, determining whether the second control value is received before the timeout counter expires, and based on the determination that the second control value is received before the timeout counter expires: determining whether the first control value is the same as the second control value, and loading the first control value into a set of control registers based on the determination that the first control value is the same as the second control value.