An Analog Self-Organizing Neural Network Chip

This paper describes an analog version of a self-organizing feature map circuit. The design implements Kohonen's self-organizing feature map algorithm [Kohonen, 1988] with some modifications imposed by practical circuit limitations. The feature map algorithm automatically adapts connection weights to nodes in the network such that each node comes to represent a distinct class of features in the input space. The system also self-organizes such that neighboring nodes become responsive to similar input classes. The prototype circuit was fabricated in two parts (for testability); a 4 node, 4 input synaptic array, and a weight adaptation and refresh circuit.