A CMOS chaotic Boltzmann machine circuit and three-neuron network operation

This paper proposes CMOS VLSI implementation of a chaotic Boltzmann machine (CBM) model, which uses analog nonlinear dynamics instead of stochastic operation as in the original Boltzmann machine model. The CBM model is suitable for efficient VLSI implementation of Boltzmann machines because it requires no random number generator circuits, which consume a considerable footprint on a VLSI chip as well as considerable power. We describe the design results of CMOS circuits of neuron and synapse units. The neuron circuit uses subthreshold operation of MOSFETs to realize the exponential function used in the CBM model. We also provide measurement results of a fabricated CMOS chip for single-neuron unit circuit operation and demonstrate chaotic behavior in a three-neuron network.