Programmable Refractory Period Implementations in a Mixed-Signal Integrate-And-Fire Neuron

In this paper, in an effort to emulate the properties of a biological neuron in silicon, we design a mixed-signal Integrate-And-Fire (IAF) neuron with two different approaches for the refractory period mechanism. The two approaches, one digital and one analog, have been designed to behave equivalently, except for the use of external programming signals. Neurons using both refractory blocks have been simulated using a 65nm CMOS process and their performances have been quantified in terms of area and power consumption. We find that although the analog refractory block can be made smaller than the digital counterpart by using a smaller capacitor, the area-power trade-off resulting from the use of a high programming current overshadows this advantage. The digital block is also found to perform better in terms of power consumption and programming precision.