Sensing circuit for on-line detection of delay faults

A sensing circuit for on-line testing of delay faults is presented. It can be used to monitor the outputs of circuits that are either general, or designed to be self-checking with respect to steady-state errors. Detailed analyses of the proposed circuit have shown that it is preferable to alternate solutions from the point of view of both the accuracy and the self-testing capability that make it suitable for self-checking applications. Checking architectures for delay faults, making use of the proposed sensing circuit and of standard checkers, are presented.