Configuration of fuzzy membership function circuits using current mode
Yuji Shirai, Fumio B. Ueno, Takahiro Inoue · Electronics and Communications in Japan (Part II Electronics) · 1987
Abstract This paper presents a realization of the membership functions (S, Z, ir and U functions) which serve as the input units of the fuzzy logical system, using the bounded difference of the fuzzy logic. The bounded‐difference circuit is constructed by the current mode using the current mirror based on the bipolar transistor array. The circuit for each membership function is realized and the modification of the circuit to other functions is discussed. The multifunction membership function (called N function) is proposed anew, which can realize the four forementioned membership functions flexibly by adjusting the parameters. The circuit for N function is constructed in the same way as the four preceding functions. The optimum circuit construction is presented based on theory and experiment. It is also shown that the membership circuit can be simplified using Nand P‐channel FET arrays. An FET circuit is presented which can eliminate the essential error in the current mirror composed of bipolar transistors.