Mixed structural-functional path delay test generation and compaction

This work considers the use of a mixed structural-functional approach to path delay fault test generation and compaction. K Longest Paths per Gate (KLPG) are generated using structural information and filtered using direct implications and heuristics. These paths are then justified using Boolean satisfiability (SAT) algorithms. The paths are dynamically compacted into test patterns, using structural information to identify most conflicts, before final checking with SAT. Advanced SAT algorithms based on structural information of the circuit are investigated to improve SAT performance. Compared to structural-only approaches, the combined structural-functional approach achieves a better test compaction ratio in less CPU time on benchmark circuits. The improvement is more apparent when generating pseudo functional KLPG tests.