Current-mode A/D fuzzy converter

This paper presents a general architecture for an analog-to-digital (A/D) fuzzy converter which performs the A/D conversion and the fuzzification operation on the same functional block, through a programmable membership function. The solution uses as main blocks an A/D converter, a comparator, and some logic inverters and switches. It is characterized by good flexibility and programmability and, compared to conventional approaches, allows a significant amount of silicon area to be saved. The architecture proposed does not depend on the specific A/D converter adopted. However, low-voltage operation and reduced power dissipation as well as full compatibility with digital technologies can be achieved through the use of current-mode design techniques. A CMOS implementation is then proposed and nonidealities, limiting the resolution, are analytically evaluated in detail. Simulations based on a 0.35-mum standard technology, which are in excellent agreement with the theoretical results, are also given.