Multi-input variable-threshold circuits for multi-valued logic functions

In this paper, two-types of Multi-Input Variable-Threshold (M-I V-T) circuits and their applications to Multi-Valued Logic (MVL) are proposed. M-I V-T circuits are extensions of binary CMOS NAND and NOR gates to multi-valued logic. First, definitions of M-I V-T functions realized with M-I V-T circuits are presented, they are implemented using neuron-MOS transistors. The neuron-MOS transistor is a novel device with multi-input gates and can be fabricated by the standard CMOS process with a double-poly layer. Therefore, the proposed circuits can be easily fabricated by the standard CMOS process instead of using the multi-level ion implantation process. Second, the characteristics of the proposed circuits are evaluated using HSPICE simulations. Third, realization of a product term using M-I V-T circuits is presented. The circuit implementation of the product term is extended naturally from the literal circuit and is more powerful than the literal circuit. Finally, the synthesis of a MVL function with M-I V-T circuits is discussed.