Design of an analog current mode CMOS based programmable interval Type-2 Fuzzy Inference System

This paper presents the design of a fully programmable Mamdani Interval Type-2 Fuzzy Inference System (IT2 FIS) which can be used in a general-purpose Interval Type-2 Fuzzy Logic Controller (IT2 FLC). In the proposed design Type-2 fuzzy membership functions are obtained by combining two Type-1 fuzzy membership functions and it is realized based on Type-1 membership function circuits (T1 MFC). The membership functions are made tunable by setting some reference signals on the IC pins. The circuit is designed to convert analog voltage mode input signals from the sensor system to current mode signal, so that the subsequent stages of FLC can operate in current mode. IT2 FIS architecture also employs Minimum (Min) circuits to join the antecedents of the rules and Maximum (Max) circuits to combine the consequent currents of the rules. It operates with a supply voltage of 1.5V. The MFC circuits are simulated using spice software.