A synthesis of fuzzy control surfaces in CMOS technology

A new design of a monolithic CMOS analog function synthesizer based on current-mode techniques is presented together with its application to fuzzy logic controllers. The system fuzzy control strategy has previously been simulated, thus obtaining the control surface which is then approximated by planes. The integrated circuit realizes the implicit equation of each plane whose coefficients are previously introduced in a static RAM memory. The approximated control surface allows us to obtain the control action directly. This controller is specially adequate to control systems where the fast response in control loop is necessary. The simulation shows that the maximum propagation delay (from a step change in the inputs) is 200 nsec. To illustrate the use of this circuit this controller is applied to control a DC-DC switching regulator