A Low-Cost BIST Scheme for Test Vector Embedding in Accumulator-Generated Sequences

Abstract

Test set embedding built-in self test (BIST) schemes are a class of pseudorandom BIST techniques where the test set is embedded into the sequence generated by the BIST pattern generator, and they displace common pseudorandom schemes in cases where reverse-order simulation cannot be applied. Single-seed embedding schemes embed the test set into a single sequence and demand extremely small hardware overhead since no additional control or memory to reconfigure the test pattern generator is required. The challenge in this class of schemes is to choose the best pattern generator among various candidate configurations. This, in turn, calls for a need to evaluate the location of each test pattern in the sequence as fast as possible, in order to try as many candidate configurations as possible for the test pattern generator. This problem is known as the test vector-embedding problem. In this paper we present a novel solution to the test vector-embedding problem for sequences generated by accumulators. The time overhead of the solution is of the order O(1). The applicability of the presented method for embedding test sets for the testing of real-world circuits is investigated through experimental results in some well-known benchmarks; comparisons with previously proposed schemes indicate that comparable test lengths are achieved, while the time required for the calculations is accelerated by more than 30 times.