ScTMR: A scan chain-based error recovery technique for TMR systems in safety-critical applications

We propose a roll-forward error recovery technique based on multiple scan chains for TMR systems, called Scan chained TMR (ScTMR). ScTMR reuses the scan chain flip-flops employed for testability purposes to restore the correct state of a TMR system in the presence of transient or permanent errors. In the proposed ScTMR technique, we present a voter circuitry to locate the faulty module and a controller circuitry to restore the system to the fault-free state. As a case study, we have implemented the proposed ScTMR technique on an embedded processor, suited for safety-critical applications. Exhaustive fault injection experiments reveal that the proposed architecture has the error detection and recovery coverage of 100% with respect to Single Event Upset (SEU) while imposing a negligible area and performance overhead as compared to traditional TMR-based techniques.