High speed and highly testable parallel two-rail code checker

In this article, we propose a high speed and highly testable parallel two-rail code checker, which features a compact structure and is totally-self-checking or strongly code-disjoint with respect to a wide set of realistic faults. The proposed checker is also particularly suitable to implement embedded two-rail code checkers, as it only requires two input codewords for fault detection. Our checker can be employed to check the correct operation of a connected functional block using the two-rail code, to implement the output two-rail code checker of "normal" checkers for unordered codes, or to join together the error messages produced by various checkers (possibly using different codes) present within the same self-checking system. The behavior of our checker has been verified by means of electrical level simulations (performed using HSPICE), considering both nominal values and statistical variations of electrical parameters.