Fault Diagnosis on Multiple Fault Models by Using Pass/Fail Information.
ABSTRACT In general, we do not know which fault model can explain the cause of the faulty values at the primary outputs in a circuit under test before starting diagnosis. Moreover, under Built-In Self Test (BIST) environment, it is difficult to know which primary output has a faulty value on the application of a failing test pattern. In this paper, we propose an effective diagnosis method on multiple fault models, based on only pass/fail information on the applied test patterns. The proposed method deduces both the fault model and the fault location based on the number of detections for the single stuck-at fault at each line, by performing single stuck-at fault simulation with both passing and failing test patterns. To improve the ability of fault diagnosis, our method uses the logic values of lines and the condition whether the stuck-at faults at the lines are detected or not by passing and failing test patterns. Experimental results show that our method can accurately identify the fault models (stuck-at fault model, AND/OR bridging fault model, dominance bridging fault model, or open fault model) for 90% faulty circuits and that the faulty sites are located within two candidate faults.
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Conference Paper: A diagnostic test generation system and a coverage metric.[Show abstract] [Hide abstract]
ABSTRACT: A diagnostic automatic test pattern generation (DATPG) system is constructed by adding new algorithmic capabilities to conventional ATPG and fault simulation programs. The system generates tests to distinguish between fault pairs through different output responses. Given a fault pair, by modifying circuit netlist a new single fault is modeled and targeted for detection by a conventional ATPG. The test distinguishes the given fault pair. In the fault simulator faults are partitioned into different groups according to their output responses. Thus, fault pairs that a simulated vector can distinguish between are split among separate groups. Faults that form single-fault groups are dropped from further simulation. Using a proposed diagnostic coverage (DC) metric, we observe improved DC in most benchmark circuits. Cases of low DC have helped identify new open problems.15th European Test Symposium (ETS 2010), May 24-28, 2010, Prague, Czech Republic; 01/2010
Conference Paper: A diagnostic test generation system.[Show abstract] [Hide abstract]
ABSTRACT: A diagnostic automatic test pattern generation (DATPG) system is constructed by adding new algorithmic capabilities to conventional ATPG and fault simulation programs. The DATPG aim to generate tests to distinguish fault pairs, i.e., two faults must have different output responses. Given a fault pair, by modifying circuit netlist a new single fault is modeled. Then we use a conventional ATPG to target that fault. If a test is generated it distinguishes the given fault pair. A fast diagnostic fault simulation algorithm is implemented to find undistinguished fault pairs from a fault list for a given test vector set. We use a proposed diagnostic coverage (DC) metric, defined as the ratio of the number of fault groups to the number of total faults. The diagnostic ATPG system starts by first generating conventional fault coverage vectors. Those vectors are then simulated to determine the DC, followed by repeated applications of diagnostic test generation and simulation. We observe improved DC in all benchmark circuits.2011 IEEE International Test Conference, ITC 2010, Austin, TX, USA, November 2-4, 2010; 01/2010