Sinceinmostapplicationsofthe decision treethefinal conclusionwill bethatthenetworkis fail2 reducing the computation time needed for generure free, weare interested mainly in decision trees containing. Sequential parallel fault simulator madhurima maddela abstract fault simulators are used to determine which faults are detected by a test sequence. Dynamic fault diagnosis of combinational and sequential. Fault tolerant design of combinational and sequential logic based on a parity check code sobeeh almukhaizim and yiorgos makris electrical engineering department yale university sobeeh. Abstractreversible circuits rely on an entirely different computing paradigm allowing to perform computations not only. Oscilloscope to test amplifier and many logic circuits, an oscilloscope is almost essential to view the. Fault detection and test minimization methods for combinational circuits a survey. Problems with fault model in general, ninput circuits require much less than 2n test inputs to cover all possible stuckatfaults in the. This method is an outgrowth of our previous work on delay fault diagnosis in combinational circuits, and is therefore based on a path tracing algorithm appropriate for sequential circuits. This invention relates to the architecture, fault detection and diagnostic capabilities of a sequential control circuit, or sequencer. In actual application of such a test to the hardware, the detection. Studies show the effectiveness of the region based model for single and multiple stuck faults and gate connection errors.
Functional fault equivalence and diagnostic test generation in combinational logic circuits using conventional atpg andreas veneris1. Diagnosis by uut reduction fault diagnosis for combinational circuits selfchecking design system level diagnosis. Consequently the output is solely a function of the current inputs. A fanoutfree combinational circuit with n primary t an input sequence. Fault tolerant design of combinational and sequential. Different types of sequential circuits basics and truth. In the next paragraph the application of the svm to analog fault diagnosis is presented. First, nominal and faulty response waveforms of a circuit are measured, respectively, and then are decomposed into intrinsic mode functions imfs with the eemd method. Diagnostic fault simulation of sequential circuits. In sequential fault diagnosis the process of fault location is carried out step by step, where each step depends on the result of the diagnostic experiment at the previous step. Easy to build using jk flipflops use the jk 11 to toggle. Pdf fault diagnosis and logic debugging using boolean.
Keywords genetic algorithm, sequential circuits, automatic test pattern generator, fault coverage, circuit under test, flipflop 1. Pdf a fault detection method for combinational circuits. The basic circuits from which all flipflops are constructed. Fault detection in logical circuits by samprakash majumdar, b. Data representation and number system, binary logic, basic gate, combined gates. Some attempts have been made, however, at diagnosis without fault simulation by deducing the location of a fault or faults from the. The method is based on automatically designing a circuit which. Hughes, virgil willis, fault diagnosis of sequential circuits 1969. Sections iii and iv give satbased formulations of modelfree logic diagnosis for combinational and sequential circuits, respectively.
Introduction digital systems produced today are extremely complex in nature. This paper presents a novel fault diagnosis method for analog circuits using ensemble empirical mode decomposition eemd, relative entropy, and extreme learning machine elm. On improving fault diagnosis for synchronous sequential. Home conferences dac proceedings eurodac 91 modelbased fault diagnosis of sequential circuits and its acceleration. Pdf fault detection and test minimization methods for. To ensure that only fault free systems are delivered. Diagnostic test pattern generation and fault simulation for stuckat. Pdf on redundancy and fault detection in sequential circuits. Unit v fault diagnosis in sequential circuits circuit test. Later, we will study circuits having a stored internal state, i. Finally, the output voltage vectors are used to form the observation sequences, which. Fault detection in linear sequential circuits by aleksa petrovic a thesis submitted in partial fulfillment of the requirements for the degree of master of science in electrical engineering thesis directors signature.
International journal of computer trends and technology volume2issue2 2011. Useful for storing binary information and for the design of asynchronous sequential circuits. Firstly, output voltage signals under faulty conditions are obtained with simulation. Pdf a dynamic diagnosis scheme for synchronous sequential circuits is proposed. On the other side, diagnosis of delay faults has received attention for the first category of circuits, but not for synchronous sequential circuits. Error diagnosis of sequential circuits using regionbased. But sequential circuit has memory so output can vary based on input. Fault diagnosis in digital circuits is normally based on prior computation of fault symptoms using explicit fault models and simulation followed by matching of the observed symptoms of a faulty circuit with one of the sets of precomputed symptoms. Us3812337a sequential control circuit having improved. Ripple counter increased delay as in ripplecarry adders delay proportional to the number of bits. We shall assume that the initial state of the faultfree cir. This paper is concerned with the diagnosis of faults in synchronous sequential machines. Conservative logic gates can be designed in any sequential circuits and can be tested using two test vectors. For combinational circuits, the limit of this research, the results in all cases were favorable to the test sequence.
A sequential circuit is a combination of combinational circuit and a storage element. Output is a function of both the present state and the input. International journal of computer trends and technology. This type of circuits uses previous input, output, clock and a memory element. A new method to fault diagnosis in combinational circuits is presented. Modelbased fault diagnosis of sequential circuits and its acceleration. Abadir3 sep seyedi1 abstract fault equivalence is an essential concept in digital design with signi. Sequential testing due to embedded state inside flipflops, it is difficult. This article describes an emulationbased method for locating stuckat faults in combinational and synchronous sequential circuits. Fault diagnosis occurs when a fabricated chip fails testing due to the presence of one or more defects 12. Design procedure for clocked sequential circuits duration. Testing of logic circuits fault models test generation and coverage fault detection design for test. Multiple stuckat fault diagnosis in logic circuits departement d. Sinclair electronics fault diagnosis fountain press argus books ltd.
The advance from one state to the next in the sequence is dependent on a combination of external signals from the. On improving fault diagnosis for synchronous sequential circuits irith pomeranz and sudhakar m. In circuits that process ac signals, such as audio amplifiers, it helps to. Subsequently, output voltages corresponding to the test frequencies are extracted from the response of analog circuits. Pdf diagnostic fault simulation of sequential circuits. Path sensitization method for fault diagnosis in combinational circuits duration. A mathematical framework for the testing and diagnosis of sequential machines is developed.
Fault detection methods in sequential systems sciencedirect. A thesis in electrical engineering submitted to the graduate faculty of texas tech university in partial fulfillment of the requirements for the degree of master of science in electrical engineering approved c accepted may, 1975. Faults are defined and classified, the problems of detection and diagnosis are discussed, and a previously presented algorithm for fault detection is outlined. Study on fault diagnosis in analog circuit scientific. A very general fault model is used in which a faulty machine is represented as a sequential machine, possibly with state and output sets different from those of the good machine. Physical defects are commonly modeled using fault models at the logic level. Designing fault simulators for sequential circuits is much more complicated than for. A model for sequential machine testing and diagnosis.
This table smith et al fault diagnosis and logic debugging using boolean satisfiability 1619 table v sequential modelbased fault diagnosis table vi sequential model free logic debugging table vii conflict clauses added during diagnosis shows the number of added clauses excluding those added in table viii. General terms sequential circuit, flip flop, algorithms et. Modelbased fault diagnosis of sequential circuits and its. This paper employs the survey on the fault diagnosis methods in binary digital circuits which can be further optimized for ternary digital circuits. A genetic algorithm based two phase fault simulator for. Yet, the svm algorithm 2629 is applied for soft and hard faults diagnosis in analog electronic circuits. While a combinational circuit is a function of present input only. Digital electronics part i combinational and sequential. On improving fault diagnosis for synchronous sequential circuits conference paper pdf available july 1994 with 25 reads how we measure reads. Avoid to use latches as possible in synchronous sequential circuits to avoid design problems 58 sr latch. The model takes locality aspect of errors and is based on a 3value, nonenumerative analysis technique.
Apr 15, 2020 basic concept of fault detection and location in sequential circuits notes edurev is made by best teachers of. Hidden markov model hmm for the diagnosis of incipient faults in analog circuits is presented. Binary counters simple design b bits can count from 0 to 2b. Issues controlling and observing internal states of a sequential circuit scan design solves this problem establishing a known initial state need for backtrace through multiple time. Gatelevel test generation for sequential circuits eecs at uc. Not practical for use in synchronous sequential circuits. A sequential circuit is a logical circuit, where the output depends on the present value of the input signal as well as the sequence of past inputs. Input data for diagnosis are 1 the gate level description of the circuit, 2 the set of test. The design of reversible sequential circuits using toffoli gate.
Fault diagnosis in sequential circuits 19 which distinguishes the most faults which. For fault detection, the test which detects the most faults which have not yet been detected, is the best choice. Block diagram flip flop flip flop is a sequential circuit which generally samples its inputs and changes its outputs only at. The sequential control circuit can be instructed to test any of a number of circuits by executing one of several fixed sequences. This document is highly rated by students and has been viewed 3462 times.
In this article, the time domain response for unit step excitation as well as soft and hard fault injection are considered. Given a faulty chip and a correct logic netlist, fault diagnosis is performed in order to identify locations in the. Pdf dynamic diagnosis of sequential circuits based on stuckat. Dynamic fault diagnosis of combinational and sequential circuits on reconfigurable hardware article in journal of electronic testing 235.
The significance of proposed work lies in the design of reversible sequential circuits and their equivalent circuits for maximum fault coverage. Fault diagnosis and logic debugging using boolean satisfiability. Algorithms to locate multiple design errors using regionbased model are studied for both combinational and sequential circuits. Delay fault diagnosis in sequential circuits request pdf. The method is based on automatically designing a circuit which implements a closestmatch fault location algorithm specialized for the circuit under diagnosis cud. To ensure that only fault free systems are delivered, before deploying any system in the field, it needs to be. Digital logic design textbook free download the trials of brother jero full text pdf, digital logic design by a.
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