Test Pattern Generation Hardware Motivated by Psudo-Exhaustive Test Techniques

The efficiency of pseudo-exhaustive test generation is strictly limited by the maximal number of inputs to be enumerated, since n inputs require a test length of 2n . In contrast to other approaches, the proposed self-test method also takes the fault model into account. In addition to the conventionally used structural circuit information, so-called "functional independencies" can be computed. While preserving the original fault coverage, functional independencies allow the corresponding input pairs to be stimulated with the same value that directly reduces the number of inputs to be enumerated. The given experimental results emphasize the efficiency of this innovative approach: with only three exceptions, all 32 analyzed sequential and combinational ISCAS benchmark circuits can be pseudo-exhaustively tested with less than 221 test patterns within a single test session. It should be noted that the proposed self-test method is very similar to, but by construction not a pseudoexhaustive approach.