Synthesis of operational transconductance amplifier-based analog fuzzy functional blocks and its application

A synthesis of analog fuzzy functional blocks (a complementary membership function circuit, a maximum circuit, a complementary maximum circuit, and a defuzzifier circuit) based on operational transconductance amplifiers (OTA´s) is presented. The complementary membership function circuit and the maximum circuit are synthesized from the formulations using bounded-difference operations. The defuzzifier circuit is synthesized as the follower-aggregation circuit composed of multiplier-type OTA´s, SPICE simulations showed that the proposed fuzzy functional blocks feature high-speed operations and low power consumption. The complementary membership function circuit, the maximum circuit, and the complementary maximum circuit were built with discrete components and commercially available OTA´s, and the performances of these circuits were confirmed by experiments. As an application, a singleton fuzzy controller with 3×3 rules is synthesized using the proposed circuits. The simulation of this controller showed that the inference speed of the order of 15 MRPS (rules per second) is easily realizable