Due to the shrinking of feature size, reduction in supply voltage and technology scaling, the sensitivity to radiation induced transient faults of digital systems has dramatically increased. Soft error causes transient distortion in circuit operation and is expected to More
Due to the shrinking of feature size, reduction in supply voltage and technology scaling, the sensitivity to radiation induced transient faults of digital systems has dramatically increased. Soft error causes transient distortion in circuit operation and is expected to become very important in combinational logic with increment of the circuit frequency. In this paper, we introduce an optimized method for hardening of combinational logic circuits against soft errors. In this method, first we have found the most sensitive nodes of the circuit by observability computations. Next for optimizing power-delay product and area, the reliability of the circuit has been computed and the number of the necessary nodes for hardening will be identified. In the next step, three different hardening methods including time redundancy, Schmitt trigger and transistor feedback have been carried out on standard test circuits as our vehicles. The comparison of three method results show that the hardened circuits with Schmitt trigger have the most cumulative critical charge and the least power-delay product and lead to an optimum hardening. Moreover, the simulation results approve the optimized hardening is obtained from suitable selecting the number of required nodes considering observability concepts and reliability computations together with the best node hardening method. Monte-Carlo simulations also approve the performance of the proposed method against process variations.
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One of the popular methods in design for testability (DFT) is scan design which leads on increase observability and controllability in circuit nodes. In this paper, we present a scan cell design which decreases the number of transistors, improves PDP and decreases energ More
One of the popular methods in design for testability (DFT) is scan design which leads on increase observability and controllability in circuit nodes. In this paper, we present a scan cell design which decreases the number of transistors, improves PDP and decreases energy usage. The first proposed design is an optimized version of integrated low power gating scan cell, and the main idea of this design is reducing leakage current in the part of the circuit which is not used. Also, this design has the ability of reducing the propagation delay due to decreasing output parasitic capacitance. In the second proposed design, the scan cell is designed for controlling in pull down part of the inverter at slave latch so that static power consumption is diminished when current path is cut in unnecessary position. Simulations are carried out in 22 nm PTM technology CMOS by Hspice software. The results show that the proposed designs are superior to the previous designs considering propagation delay which is decreased, and enhanced static power consumption.
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