Patent Document ID: 5570456
Application ID: 08214431
Patent Flag: 1

Claim One:
1. A fuzzy logic controller for implementation in an analog circuit and which permits the implementation of at least one rule defining the causal relationship between input variables (X;Iin) and output variables (Y), each rule having at least one condition having a degree of truth, and being expressed by a relational operator between said input variables (X; Iin) and a reference value (A; IA), said controller functioning to supply from a set of said output variables (Y) magnitudes (Vout) which are determined on the basis of predetermined values (VA) by weighing each of them by an overall degree of truth of the rules, said overall degree of truth being determined by combining the degrees of truth of the different conditions of said rule, said degree of truth of a condition being equal to 1 when said condition is strictly verified and being equal to 0 when the condition is considered non-verified, said controller having at least one determination circuit of the overall degree of truth of the different conditions of each of said rules, and further having a circuit for determining said magnitudes (Vout) of said output variables (Y) by weighting said overall degree of truth of said rule, said determination circuit of the overall degree of truth comprising a plurality of Euclidian distance determination circuits which each provide at its output, an output current the intensity of which is 0 when said condition between said input variable (X; Iin) and said reference value (A; IA) is verified, and which is an increasing function of the Euclidian difference between each component of said input variable (X;Iin) and of said reference value (A;IA) when said condition is non-verified; and wherein said outputs of said distance determination circuits are each connected to a common node so as to obtain at said common node a summation signal which is equal to the sum (Iout) of the amplitudes of said output currents; and at least one transformation circuit for receiving said summation signal and for delivering a signal (Iweight) which equals 0 when said sum is greater than a given threshold value, which equals 1 when said sum is at a minimum value, and which assumes continuously increasing values between 0 and 1 when said sum varies between, respectively, said given threshold value and said minimum value.