SEU-Hardened Flip-Flop Using Muller Element and Bus Keeper
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Solution Overview
Problem
Existing flip-flops are prone to single event upsets (SEUs) which cause soft errors leading to potential system malfunctions and safety issues, and existing solutions like triple voting flops and lockstep cores require significant additional circuitry.
Innovation Solution
A flip-flop design incorporating a master latch coupled with replicated slave latches, a Muller element, and a bus keeper to maintain logic levels during SEUs, using minimal additional hardware to self-correct and output an error signal for safe-stating the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If triple voting flops (TVF) are used to reduce SEU failure rate, then reliability is improved, but device complexity increases significantly
Solution Approach 1:
The flip-flop is segmented into a master latch and multiple slave latches (first and second slave latches). Each latch processes the signal independently, and their outputs are compared to detect SEU events. This segmentation allows error detection without requiring full triple voting redundancy, reducing complexity while maintaining reliability.
Solution Approach 2:
A Muller element is introduced as an intermediary component between the slave latches and the output. The Muller element receives inputs from multiple slave latches and produces a self-correcting output that inherently rejects SEU-induced errors. This intermediary structure provides SEU hardening without the need for complex voting logic or additional redundant flops.
2Reliability
If shadow registers or lockstep cores are implemented to minimize SEU errors, then reliability is improved, but device complexity and resource usage increase
Solution Approach 1:
The error detection and correction functions are merged into the core flip-flop structure itself. The master latch and slave latches work together in a unified circuit where the Muller element simultaneously performs signal transmission and SEU error detection/correction. This integration eliminates the need for separate shadow registers or lockstep core implementations.
Solution Approach 2:
The flip-flop circuit is designed to self-correct SEU errors through its inherent structure. The Muller element's self-correcting property automatically detects and corrects errors without requiring external intervention, shadow registers, or additional correction logic. The circuit serves its own error correction needs, reducing overall system complexity.
Data Source
AI summary
A single event upset (SEU) hardened flip-flop comprises a master latch and a plurality of slave latches, where an output of the master latch is coupled to a respective input of the slave latches. A Muller element which has an input which is coupled to a respective output of the slave latches and an output which is coupled to a bus keeper. The bus keeper maintains a logic level output in presence of the SEU.