On the Design of a Low Power Compact Spiking Neuron Cell Based on Charge-Coupled Synapses

A charge-coupled silicon synapse with a floating diffusion output is proposed as the basis for a new electronic, spiking neuron cell. The synapse is formed by a two-stage charge transfer device with the weight function stored in a floating gate over the first stage. The output of the synapses feeds into the multi-gate inputs of a MOSFET which themselves capacitively couple onto a common floating gate. This MOSFET provides a summing action and so acts as a point neuron. Thermal generation within the synaptic device, causes relaxation of the signals and this can be tailored to provide realistic postsynaptic potential (PSP) dependencies. Simulation results show that this architecture can generate a PSP that effectively mimics the spiking behaviour of real synapses. The cell is highly compact and intrinsically low power and so offers the potential for biologically plausible spiking neural networks (SNNs) in hardware.