Increasing Self-Timed Circuit Soft Error Tolerance

Abstract

Indication subcircuit is an essential part of the self-timed circuits. It provides acknowledgment of the self-timed circuit switching completion and ensures correct handshake interaction between functional blocks. Besides, indication subcircuit complexity is comparable with the indicated self-timed circuit's complexity. So short-term soft errors, induced by the external and internal causes in both the indication subcircuit and the indicated self-timed circuit, are equally dangerous. Indication subcircuit soft error tolerance depends, the first, on its immunity to soft errors in the indicated self-timed circuit and, the second, on its failure protection. The first aspect becomes lower critical due to the XOR cell on the first stage of the indication subcircuit. An appropriate circuitry basis decreases indication subcircuit sensitivity to the possible soft errors induced in it. Static and semi-static Muller's C-element is a traditional base component used for indication purposes. Its dual interlocked implementation improves the indication subcircuit failure protection against soft errors in its internal nodes, but not sufficiently. The article proposes a new C-element's schematic that fully tolerates it against the soft errors in all internal nodes. Besides, using C-elements with in-phase inputs and output in an indication pyramid ensures indication subcircuit protection against soft errors induced at the output of the C-elements. The proposed approach makes an indication subcircuit fully protected against all soft errors induced in it.