A generalized hardware architecture for real-time spiking neural networks

This article presents an area- and power-efficient hardware architecture for the brain-implantable spiking neural networks (SNNs). The proposed generalized hardware architecture is parameterizable and reconfigurable such that the maximum supported number of neurons, the interconnection structure among neurons, and the resolution of the time step can be readily adjusted for realizing various SNN topologies. The designed SNN hardware architecture is capable of emulating moderately-sized SNNs with tens of thousands of neurons in real-time with varying degrees of parallelism, while reducing the resource utilization by 34% for similarly sized SNNs implemented on a single field-programmable gate array (FPGA). We evaluate the model using the MNIST digit recognition benchmark and show that the network can accurately classify handwritten digits with 89.8% accuracy. Compared to the other recently implemented SNN emulators based on FPGAs, the designed and implemented single-FPGA system is able to emulate moderately-sized SNNs instead of using a cluster of FPGAs or CPUs. The application-specific integrated circuit (ASIC) implementation of a moderately-sized SNN is estimated to occupy 3.6 mm(2) of silicon area. Post-layout synthesis and simulation results show that the ASIC will dissipate 3.6 mW of power from a 1.16 V supply while operating at 34.7 MHz in a standard 32-nm CMOS process.