Analysis of Multiple Faults in Synchronous Sequential Circuits by Boolean Difference Techniques

摘要

The Boolean difference is a mathematical concept which has found significant application in the study of single and multiple ''stuck at'' faults in combinational logic circuits. The concept of vector Boolean difference is extended to the analysis of multiple stuck-at faults in synchronous sequential circuits. A vector Boolean difference technique is utilized to determine the set of input/state pairs that will produce a difference in either output or next-state between the fault-free and faulty circuits. Assuming that the fault-free and faulty circuits start in the same initial state, they must be driven by applying a sequence of input vectors to a state in which either a difference in output or next-state is evidenced. If a difference in output cannot be achieved immediately, a second sequence of input vectors must be applied in order to propagate the state difference to the output. Methods for combining the Boolean difference analysis with techniques for deriving the required input vector sequence are discussed. (ERA citation 03:048566)