Intel® Arria® 10 Core Fabric and General Purpose I/Os Handbook

ID 683461
Date 1/21/2022
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8.2.3. Triple-Module Redundancy

Use Triple-Module Redundancy (TMR) if your system cannot suffer downtime due to SEU. TMR is an established SEU mitigation technique for improving hardware fault tolerance. A TMR design has three identical instances of hardware with voting hardware at the output. If an SEU affects one of the hardware instances, the voting logic notes the majority output. This operation masks malfunctioning hardware.

With TMR, your design does not suffer downtime in the case of a single SEU; if the system detects a faulty module, the system can scrub the error by reprogramming the module. The error detection and correction time is many orders of magnitude less than the MTBF of SEU events. Therefore, the system can repair a soft interrupt before another SEU affects another instance in the TMR application.

The disadvantage of TMR is its hardware resource cost: it requires three times as much hardware in addition to voting logic. You can minimize this hardware cost by implementing TMR for only the most critical parts of your design.

There are several automated ways to generate TMR designs by automatically replicating designated functions and synthesizing the required voting logic. Synopsys offers automated TMR synthesis.