A current-mode CMOS/memristor hybrid implementation of an extreme learning machine

Abstract

In this work, we propose a current-mode CMOS/memristor hybrid implementation of an extreme learning machine (ELM) architecture. We present novel circuit designs for linear, sigmoid,and threshold neuronal activation functions, as well as memristor-based bipolar synaptic weighting. In addition, this work proposes a stochastic version of the least-mean-squares (LMS) training algorithm for adapting the weights between the ELM's hidden and output layers. We simulated our top-level ELM architecture using Cadence AMS Designer with 45 nm CMOS models and an empirical piecewise linear memristor model based on experimental data from an HfOx device. With 10 hidden node neurons, the ELM was able to learn a 2-input XOR function after 150 training epochs.