Register File Scan Chain Error Correction Feedback Loop

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Solution Overview

Problem

Existing register files in electronic devices face challenges in maintaining the integrity of stored parameters, particularly in detecting and correcting unintended changes such as Single Event Upsets (SEUs) that can occur due to cosmic rays, which are critical for safety-critical applications like automotive systems where high diagnostic coverage is required.

Innovation Solution

A register file apparatus with a scan chain arrangement and error correction element that serially shifts parameters for output, detects errors using predetermined error correcting code data, and feeds corrected parameters back to restore the original state, incorporating a feedback arrangement and error correcting code data determination element to ensure parameter integrity across different operational modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If error correction code data determination element and error correction element are added to detect and correct errors in register files, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveparameter integrityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the error correction element receives parameters from the scan chain arrangement, corrects errors using predetermined error correcting code data, and feeds the corrected parameters back through the feedback arrangement to restore the original state in the register file. This feedback loop ensures continuous monitoring and correction of errors, thereby improving reliability while managing complexity through systematic error handling.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent calculates and stores predetermined error correcting code data in advance for each possible parameter state in the register file. This preliminary action allows the error correction element to quickly identify and correct errors without complex real-time calculations, reducing the operational complexity while maintaining high reliability through pre-computed correction strategies.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If scan chain arrangement is used to sequentially output parameters for error detection, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improveerror detection accuracyVSAvoidcorrection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent maintains continuous operation by implementing overlapping scan chains that can be activated in different modes (application mode and correction mode). While one chain is being corrected, another can be preparing or operating, ensuring that the system continues to function with minimal interruption. This continuity reduces the effective time loss while maintaining precise error detection through systematic scanning of all parameter chains.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3364301B1Apparatus and associated method
Publication Date: 2020.04.01 NXP BV
  • EP3364301B1 patent drawingFigure 1
  • EP3364301B1 patent drawingFigure 2~3

AI summary

An apparatus comprising: a register file comprising a plurality of registers serially connected in a chain, each register configured to store a parameter in use, the chain having an input node at a first end and an output node at an opposed end, the register file including a scan chain arrangement configured to provide for sequential output, at the output node, of the parameters stored in the chain by way of sequentially shifting the parameters stored in each register of the chain to an adjacent register in the chain toward the output node; an error correction element configured to correct one or more errors in the parameters provided at the output node by the scan chain arrangement and provide the parameters to a feedback arrangement configured to feed back to the input node thereby providing for restoration of the parameters stored in the chain of registers.