A multi-modal and tunable Radial-Basis-Funtion circuit with supply and temperature compensation

Abstract

We propose an analog Radial-Basis-Function (RBF) circuit that generates 4 different types of RBFs, which are spline, Gaussian, multi-quadratic, and log-like spline curves. Moreover, the proposed RBF circuit is designed to have high tunability on centers, heights, and widths. The proposed RBF circuit is also robust to both temperature variation (-37~87□C) and supply voltage variation (1~2V). The sum of area and power consumption of each RBF from 3 different previous works is 13, 622μm 2 and 121μW, respectively. On the other hand, the proposed circuit occupies only 1,050μm 2 and consumes 10.5μW which are only 13% and 11.5%, respectively. For its verification, an analog/digital mixed-mode RBF Neural Network (RBFNN) classifier is designed which adopted the proposed RBF circuit.