We present a fast, dynamic fault coverage estimation technique for sequential circuits that achieves high degrees of accuracy by signi cantly reducing the number of injected faults and faulty-eventevaluations. Speci cally, we dynamically reduce injection of two types of faults: 1 hyperactive faults that never get detected, and 2 faults whose effects never propagate to a ip- op or primary output. The cost of fault simulation is greatly reduced as injection of most of these two types of faults is prevented. Experiments show that our technique gives very accurate estimates with frequently greater speedups than the sampling techniques for most circuits. Most signi cantly, the proposed technique can be combined with the sampling approach to obtain speedups equivalent of small sample sizes and retain estimation accuracy of large fault samples.
Michael S. Hsiao