Fault testing and diagnosis in combinational digital circuits. Concurrent fault detection in random combinational logic. Methods of fault detection in this chapter most of the major techniques of fault detection are described. A fault detection technique is proposed which can detect logical faults in combinational circuits by measuring the supply current instead of the output logic, and the effectiveness is evaluated by experiments of the circuits made of ttl transistorstransistor logic ics. Fault detection and test minimization methods for combinational circuits a survey. Concurrent error detection for combinational and sequential. Difference between combinational and sequential circuits table. Since electronic circuits are employed in a wide range of applications, concurrent test methods of various cost and ef. An algorithm for generating test sets to detect all the multiple stuckatfaults in combinational logic circuits is presented. A set of operations is defined through which the minimal test set for detecting stuckat faults is obtained from the compressed fault table. It addresses all aspects of combinational logic and provides a detailed understanding of logic gates that are the basic components in the implementation of circuits used to perform functions and operations of boolean algebra.
Testing paritybased error detection and correction circuits. Path sensitization for combinational logic circuits one powerful approach to test generation relies on path sensitizing, the applica tion of input such that the output depends directly on the condition of the lead being tested. This thesis is concerned with the detection of non transient faults in linear sequential circuits lsc over gf2 8. Compaction of passfailbased diagnostic test vectors for combinational and sequential circuits. Fault detection of combinational circuits based on supply. Easy to build using jk flipflops use the jk 11 to toggle. Two algorithms, the complete cutting algorithm and the gate blocking algorithm, are presented that always produce true lower bounds on the detection probability of a fault.
Defects may also arise during assembling and manufacturing. Fault detection and isolation techniques for quasi delay. Abstract this paper presents a novel circuit fault detection and isolation technique for quasi delayinsensitive asynchronous circuits. Single stuckat model is the most common model for fault detection. While hardware overhead is very low, the method relies on an ordered appearance of. International journal of computer trends and technology volume2issue2 2011. Jul 19, 2015 apr 15, 2020 basic concept of fault detection and location in sequential circuits notes edurev is made by best teachers of. Initialization fault fault prevents initialization of the faulty circuit. Basic concept of fault detection and location in sequential. Department of computer engineering and information technology amirkabir university. Consequently the output is solely a function of the current inputs.
Hyperactive fault fault induces much internal signal activity without reaching po. Efficient test compaction for combinational circuits based on. Suggestions for designing networks to yield a minimum number of tests in the multiple fault detection test set are included. The concept of augmented boolean matrices is introduced and the same is used to derive an algorithm to find the boolean differences, and hence fault detection tests for combinational circuits.
In this paper, we present agfc, an approximate global fault collapsing tool for combinational circuits. Later, we will study circuits having a stored internal state, i. This article describes an emulationbased method for locating stuckat faults in combinational and synchronous sequential circuits. A method is developed for obtaining a highly compressed fault table for twolevel combinational circuits. Soft error, transient fault, faulttolerance, combinational circuits, full adder. Testing of logic circuits fault models test generation and coverage fault detection design for test cs 150 fall 2005 lec. Some of the characteristics of combinational circuits are following. Fault detection in tfcmosdfcmos combinational gates.
Pdf multiple fault detection in combinational networks. For such circuits with many input and output terminals, the suggested algorithm simultaneously gives the boolean differences with respect to all the variables. This paper proposes and evaluates a logic level faulttolerant method based on parity for designing combinational circuits. Binary counters simple design b bits can count from 0 to 2b. It is assumed that all testing must be performed on the external terminals of the circuits. Fault detection and isolation techniques for quasi delayinsensitive circuits christopher lafrieda and rajit manohar computer systems laboratory cornell university ithaca ny 14853, u. This algorithm generates a test set using a set of functions, called representative functions, which consists of much fewer functions than all possible multiple stuckat fault functions, but is sufficient for test generation. Parity circuits basic operation and design testing parity trees 9ctestable for known connections 9pseudoexhaustive test set for unknown connections. Combinational logic circuits are characterized by outputs that depend only on the actual input values. Towards this end, we devise a concurrent fault detection method for random combinational logic that reduces hardware overhead at the cost of introducing fault detection latency. Keywords combinational circuits, fault detection, genetic.
Bounding fault detection probabilities in combinational circuits. Multiple transient faults in combinational and sequential. The output of combinational circuit at any instant of time, depends only on the levels present at input terminals. Multiple fault detection in fanoutfree combinational networks. Reddy department of electrical and computer engineering university of iowa, iowa city, iowa 52242.
For a gate level fault model of stuckopen faults in cmos circuits, srslowrise and sfslowfall gate transition faults we develop a neural network representation. A combinational circuit consists of input variables n, logic gates, and output variables m. Fault detection in combinational circuits using boolean matrices. A very big number of fault detection models already have been projected in digital logic circuits 10, 11.
The method is based on automatically designing a circuit which. A new set of formulas was obtained to calculate the boolean derivative. Fault detection in combinational circuits using boolean. Soft error, transient fault, faulttolerance, combinational circuits. International journal of computer trends and technology volume2issue2 2011 fault detection and test minimization methods for combinational circuits a. In this article, an automatic test pattern generation technique using neural network models for stuckopen faults in cmos combinational circuits is presented. Fault detection and test minimization methods for combinational. Cbist 3 employs input monitoring to perform concurrent selftest. Department of electrical and computer engineering, university of wisconsinmadison. The faultdetection test set for a combinational circuit using the pathsensitizing method is very attractive from the point of two basic approaches. Pdf fault detection and test minimization methods for.
Several lowcost, nonintrusive, concurrent fault detection cfd methods have been proposed for stuckat faults in combinational circuits. Abstractthe problem of designing test schedules for the. Integration, the vlsi journal 15 1993 201227 201 elsevier fault detection in tfcmosdfcmos combinational gates giacomo buonanno a, fabrizio lombardi b, donatella sciuto a and y. Pdf a gate level model for cmos combinational logic. Combinational circuit is a circuit in which we combine the different gates in the circuit, for example encoder, decoder, multiplexer and demultiplexer. That is, a detection test in this case must consist of applying certain signals at the circuits external input terminals and ob. Pdf a fault detection method for combinational circuits. B multiple stuckat fault for example, the figure 1a shows the single stuckatfault in a logical circuit.
For n input variables there are 2n possible combinations of binary input values. Mar 11, 2018 difference between combinational and sequential circuits in combinational circuits, the outputs are at any instant determined only by the present combination of inputs but in sequential circuits, outputs depend on the present input and also on the states of the memory location and elements. Boolean derivative calculation with application to fault. Testing of logic circuits university of california, berkeley. This paper focuses on the problem of bounding fault detection probabilities in combinational circuits. Exact global fault collapsing can be easily applied locally at the logic gates, however, it is often ignored for large circuits due to its high demand of execution time andor memory. For such circuits with many input and output terminals, the suggested algorithm simultaneously gives. For certain circuits, including all twolevel singleoutput circuits, it is shown that the detection of all single faults implies the detection of all multiple faults. Fault detection in combinational circuits using a compressed fault table. Dudam2 amit kumar sinha3 1,2,3department of vlsi design 1,3vel tech university, chennai, india 2pune institute of computer technology, pune abstractin any circuit that comprises the logic gates. Compaction of passfailbased diagnostic test vectors for.
This document is highly rated by students and has been viewed 3462 times. Both algorithms can be used to identify difficulttotest faults and to quickly construct test sets for specific faults. First approach is to examine each view of not requiring the construction of the fault table and is individual fault. In this letter we show that an algorithm developed by berger and kohavi for generating minimal length fault detection test sets for single permanent faults in fanoutfree combinational logic networks also detects all possible multiple faults in the network. A fault detection method for combinational circuits. Testing 2 fault model stuckat model assume selected wires gate input or output are stuck at logic value 0 or 1 models curtain kinds of fabrication flaws that short circuit. International journal of computer trends and technology. A set of operations is defined through which the minimal. For each possible input combination there is one and only one possible output combination, a combinational circuit can be. Fault detection in combinational circuits using a compressed. In this paper, we have investigated the boolean derivative calculation with application to fault detection of combinational circuits, and presented some new results by using the semitensor product method. Fault detection of combinational circuits based on supply current abstract. Introduction as the transistor dimensions have shrunk and the largescale integration in electronic switches has increased, chip fabricators can insert more than one billion transistors in a single chip.
Experimental results show th at i agfc reduces the num. Digital electronics part i combinational and sequential logic. A fault detection method for combinational circuits aliabbasszoraghchian1, moslem didehban2, mohammadreza mehrabian3 1. The framework described here models all important factors involved in transient fault propagation in logic circuits in a unified manner and allows for comprehensive probabilistic analysis of circuit reliability. Apr 15, 2020 basic concept of fault detection and location in sequential circuits notes edurev is made by best teachers of. A gate level model for cmos combinational logic circuits with application to fault detection sudhakar m.
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