Cmos Mixed Signal Design of Fuzzy Logic Based Systems

Abstract

Limits to precision impose limits to the complexity of analog circuits, hence fuzzy analog controllers are usually oriented to fast low-power systems with low medium complexity. This paper presents a strategy to preserve most of the advantages of an analog implementation, while allowing a marked increment in system complexity. A digitally-programmable analogue fuzzy logic controller (FLC) is presented. Input and output signals are processed in the analog domain whereas the parameters of the controller are stored in a built-in digital memory. Design emphasis has been placed on consequents and defuzzifiers. The singleton or zero-order Sugenopsilas method is chosen since it offers a good trade off between simplicity and accuracy. The circuits have been simulated using Tanner tools.