Asynchronous quasi delay insensitive majority voters corresponding to quintuple modular redundancy for mission/safety-critical applications

Electronic circuits and systems employed in mission- and safety-critical applications such as space, aerospace, nuclear plants etc. tend to suffer from multiple faults due to radiation and other harsh external phenomena. To overcome single or multiple faults from affecting electronic circuits and systems, progressive module redundancy (PMR) has been suggested as a potential solution that recommends the use of different levels of redundancy for the vulnerable portions of a circuit or system depending upon their criticality. According to PMR, triple modular redundancy (TMR) can be used where a single fault is likely to occur and should be masked, and quintuple modular redundancy (QMR) can be used where double faults are likely to occur and should be masked. In this article, we present asynchronous QDI majority voter designs for QMR and state which are preferable from cycle time (i.e., speed), area, power, and energy perspectives. Towards this, we implemented example QMR circuits in a robust QDI asynchronous design style by employing a delay insensitive dual rail code for data encoding and adopting four-phase handshake protocols for data communication. Based on physical implementations using a 32/28nm CMOS process, we find that our proposed QMR majority voter achieves improved optimization in speed and energy.