A COORDINATED CIRCUIT PARTITIONING AND TEST-GENERATION METHOD FOR PSEUDO-EXHAUSTIVE TESTING OF VLSI CIRCUITS

In this paper, we present a circuit partitioning and test pattern generation technique for pseudo-exhaustive built-in self-testing of VLSI circuits. The circuit partitioning process divides a given circuit into a set of subcircuits which can be exhaustively tested, while the test pattern generation process generates reduced exhaustive test patterns for each subcircuit using a linear feedback shift register (LFSR). In conventional approaches, these two problems are considered separately. However, in this paper, both problems are considered and solved in the same phase. A graph theoretic model of VLSI circuits is proposed. Based on this model, a circuit partitioning algorithm using the concept of minimum vertex cut is devised to partition the circuit into a set of exhaustively testable subcircuits with restricted hardware overhead. Each time a subcircuit is generated by the partitioning algorithm, the test pattern generation problem is considered. A new algorithm, based on the subcircuit modification technique, is proposed with the objective of generating reduced exhaustive test patterns of limited length (e.g., less than or equal to 2(20)) using LFSR's, for each of the subcircuits. This task is embedded in the circuit partitioning process itself, leading to an efficient and well-coordinated solution. Experiments using ISCAS benchmark circuit simulation have been conducted. The results demonstrate that the proposed method is very good.