Synthesis of delay-verifiable two-level circuits

We introduce a new type of delay test set, called a delay-verification test set, which detects the presence of any path delay fault(s) that can affect the timing of the circuit. Such test sets exist even for some circuits that are not completely delay testable. We provide necessary and sufficient conditions for delay-verifiable two-level circuits, which are less stringent than those for complete delay testability. We introduce a new type of test which is not a path delay fault test in the usual sense, but is necessary for verifying the temporal correctness of the circuit under test. A synthesis procedure for delay-verifiable two-level circuits is provided. Experimental data show that delay-verifiable implementations are generally more area-efficient than completely delay testable implementations