Balasubramanian P
School of Computer Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798 Singapore.
Springerplus. 2016 May 16;5:628. doi: 10.1186/s40064-016-2249-7. eCollection 2016.
N-modular redundancy (NMR) is a generic fault tolerance scheme that is widely used in safety-critical circuit/system designs to guarantee the correct operation with enhanced reliability. In passive NMR, at least a majority (N + 1)/2 out of N function modules is expected to operate correctly at any time, where N is odd. Apart from a conventional realization of the NMR system, it would be useful to provide a concurrent indication of the system's health so that an appropriate remedial action may be initiated depending upon an application's safety criticality. In this context, this article presents the novel design of a generic NMR system health monitor which features: (i) early fault warning logic, that is activated upon the production of a conflicting result by even one output of any arbitrary function module, and (ii) error signalling logic, which signals an error when the number of faulty function modules unfortunately attains a majority and the system outputs may no more be reliable. Two sample implementations of NMR systems viz. triple modular redundancy and quintuple modular redundancy with the proposed system health monitoring are presented in this work, with a 4-bit ALU used for the function modules. The simulations are performed using a 32/28 nm CMOS process technology.
N 模冗余（NMR）是一种通用的容错方案，广泛应用于对安全至关重要的电路/系统设计中，以确保在提高可靠性的情况下正确运行。在无源 NMR 中，N 个功能模块中至少有多数（N + 1）/2 在任何时候都应正确运行，其中 N 为奇数。除了 NMR 系统的传统实现方式外，提供系统健康状况的并发指示将很有用，以便根据应用的安全关键程度启动适当的补救措施。在这种背景下，本文介绍了一种通用 NMR 系统健康监测器的新颖设计，其特点包括：（i）早期故障预警逻辑，在任何任意功能模块的哪怕一个输出产生冲突结果时激活；（ii）错误信号逻辑，当故障功能模块的数量不幸达到多数且系统输出可能不再可靠时发出错误信号。本文给出了 NMR 系统的两个示例实现，即采用所提出的系统健康监测的三重模冗余和五重模冗余，功能模块使用 4 位算术逻辑单元（ALU）。使用 32/28 nm 互补金属氧化物半导体（CMOS）工艺技术进行了仿真。
