A current-mode CMOS fuzzy logic controller

Abstract

In this paper, design and simulation of a current-mode CMOS Fuzzy Logic Controller (FLC) is presented. The proposed controller is composed of Membership Function Circuit (MFC), fuzzy inference engine with min-product method and current-mode defuzzification circuit. MFC has a new architecture that generates basic four membership functions (trapezoidal, triangle, Z-shape and S-shape). These membership functions are simply tuneable by adjusted two voltages via setting some analogue switches in a shape/label select circuit block which is called programming unit. Also, a novelty designed current-mode defuzzification circuit is based on current-mode four-quadrant multipliers that have been constructed simple current squarer and substractor circuits. The proposed current-mode CMOS FLC has been simulated and verified for two inputs, one output and nine tuneable fuzzy rules by using PSPICE program with MIETEC 1.2 µm design parameters. The proposed architecture has an operation speed of 6.25 MFLIPS (6.25 × 106 Fuzzy Logic Inference per Second).