350-fJ/spike, 30-Hz Bio-inspired Silicon Neuron Circuit in 0.2 V, 65 nm CMOS

Biologically inspired silicon neuron circuits must accurately mimic real neurons while being compact and low-power. Among all silicon neuron models, integrate-and-fire (I&F) models closely replicate the behaviour of real neurons while maintaining simplicity and computational efficiency. However, existing CMOS-based implementations of I&F neuron models lack optimal circuit performance and energy efficiency, primarily due to leakage and short-circuit currents associated with these designs. This paper presents an energy-efficient I&F silicon neuron (SiN) circuit that can produce biologically plausible neural dynamics by utilising the PMOS bulk cross-coupled inverter pair (PBXCIP) along with a low supply voltage to reduce leakage currents effectively. Moreover, it provides firing threshold tunability with improved control. The proposed SiN is implemented using 65 nm CMOS technology, operating at a supply voltage of 0.2 V, and consumes 350 fJ/spike at a spiking frequency of 30 Hz.