Metaplasticity in Multistate Memristor Synaptic Networks

Recent studies have shown that metaplastic synapses can retain information longer than simple binary synapses and are beneficial for continual learning. In this paper, we explore the multistate metaplastic synapse characteristics in the context of high retention and reception of information. Inherent behavior of a memristor emulating the multistate synapse is employed to capture the metaplastic behavior. An integrated neural network study for learning and memory retention is performed by integrating the synapse in a 5×3 crossbar at the circuit level and 128×128 network at the architectural level. An on-device training circuitry ensures the dynamic learning in the network. In the 128×128 network, it is observed that the number of input patterns the multistate synapse can classify is simeq 2.1x that of a simple binary synapse model, at a mean accuracy of ≥ 75% .