Sequential circuits with combinational test generation complexity under single-fault assumption

We show that the test generation problem for all single stuck-at faults in sequential circuits with internally balanced structures can be reduced into the test generation problem for single stuck-at faults in combinational circuits. In our previous work, we introduced internally balanced structures as a class of sequential circuits with the combinational test generation complexity. However, single stuck-at faults on some primary inputs, called separable primary inputs, corresponded to multiple stuck-at faults in a transformed combinational circuit. In this paper, we resolve this problem. We show how to generate a test sequence and identify undetectability for single stuck-at faults on separable primary inputs.