Removal of redundancy in combinational circuits under classification of undetectable faults

This paper proposes a method for efficiently removing redundant elements using properties of undetectable faults obtained by test pattern generation. Lines of redundant elements have undetectable single stuck-at faults. We classify undetectable faults into three categories according to the test pattern generation process, and then assume that some redundant elements can be removed concurrently. Our method produces a nonredundant circuit efficiently by using these properties and generates test patterns with high fault coverage. Some experimental results for ISCAS '85 benchmark circuits are also shown.