A floating-gate programmable array of silicon neurons for central pattern generating networks

A new central pattern generator chip with 24 silicon neurons and reprogrammable connectivity is presented. The 3mm x 3mm chip fabricated in a 3M2P 0.5 mu m process contains 1032 synapses, each with multiple floating gates for storing parameters governing synaptic strength and polarity. Every neuron includes a dendritic compartment with 12 externally-addressable synaptic inputs and 24 recurrent synaptic inputs, enabling construction of a fully-interconnected network with sensory feedback from off-chip elements. In addition to describing the chip architecture and neuron circuits, preliminary results from single oscillating neurons and pairs of phase-locked neurons are shown. This work represents the realization of a design presented at ISCAS'05, and an improvement over our 2nd generation CPG chip presented at ISCAS'04.