Ternary Circuits for Null Convention Logic

Null Convention Logic (NCL) adds a control value (NULL i.e., DATA not valid) to its Boolean set to create a symbolically complete logic system that is inherently self determined, locally autonomous, self synchronizing and delay insensitive. NCL circuits typically employ a dual-rail binary scheme to represent these three levels. In this paper, we propose using an offset ternary logic system where the logic set {t, N, O} maps to voltage levels {+V DO' V 00/2, OV}. Low-power circuits for basic components such as DATAINULL Detector circuit and a Ternary Register are described based on the characteristics of a commercial silicon-on-sapphire MOS process that offers multiple simultaneous transistor thresholds.