Circuit Testing Using the Principles of Self–Nonself Discrimination

As complex very-large-scale integration circuit testing using external automatic test equipment is becoming increasingly expensive, built-in self-test (BIST) is an alternative technique that can significantly reduce the cost of testing. On the other hand, artificial immune systems have been considered as one of the most promising nature-inspired techniques used for novelty detection systems. One of the main features of such systems is self-nonself discrimination, which enables the body to distinguish any foreign cell from the body´s own cell. In this paper, based on the principles of self-nonself discrimination, an immune-based output response analyzer for BIST is presented. Using the proposed scheme, the evaluation of the circuit under test (CUT) is performed by a set of immune-based detectors that are capable of detecting faulty output responses. Since the number of detectors is proportional to the hardware overhead consumed by the scheme, it is also presented as an optimization algorithm to reduce the number of detectors. Using the reduced set of immune-based detectors, zero aliasing is achieved, and, in addition, the evaluation of the CUT is performed during the test. The experimental results show the effectiveness of the proposed scheme.