A CMOS Analog Current-Mode Direct and Complementary Membership Function Circuit for Fuzzy Logic Controller Applications

This paper presents a novel programmable direct membership function circuit (DMFC) and complementary membership function circuit (CMFC) that can be used in adaptive fuzzy logic controllers (FLC). The memberships are tunable by varying some voltages on the IC pins. The circuit has a very simple structure and utilizes very less number of transistors. The proposed work presents a three Gaussian membership function DMFC and CMFC that can extend to obtain any number of membership functions as per the requirements. The simulation results are given using SPICE simulator software. The highly accurate and easily tunable characteristics of the proposed membership function circuit make it suitable for embedded system and industrial control applications.