Self-checking, dual railed, leading edge synchronizer.

摘要

The present invention relates to a digital logic circuit and method for synchronizing the leading edges of a skewed true-complement signal pair. The circuit of the present invention is comprised of two similar, interconnected circuit halves, each of which includes three D flip-flop stages. The outputs from the second D flip-flop stages from the two circuit halves are applied to the two inputs of two identical logic gates, such that the signal pair is synchronously transmitted to a pair of output gates through a third D flip-flop stage in each circuit half. The second D flip-flop stages also prevent metastable states from reaching the synchronizer output. Metastable states may result if the input setup time is violated for the first D flip-flop stages. The third D flip-flop stage in each circuit half also eliminates any signal irregularities generated in the logic circuitry from appearing on the synchronizer output lines. The present invention is self-checking in that any single fault in the input signals or in the synchronizer circuit itself will result in the synchronizer output pair not having a true complement relationship.