Non-volatile Hierarchical Temporal Memory: Hardware for Spatial Pooling

Abstract: Hierarchical Temporal Memory (HTM) is a biomimetic machine learning algorithm imbibing the structural and algorithmic properties of the neocortex. Two main functional components of HTM that enable spatio-temporal processing are the spatial pooler and temporal memory. In this research, we explore a scalable hardware realization of the spatial pooler closely coupled with the mathematical formulation of spatial pooler. This class of neuromorphic algorithms are advantageous in solving a subset of the future engineering problems by extracting nonintuitive patterns in complex data. The proposed architecture, Non-volatile HTM (NVHTM), leverages large-scale solid state flash memory to realize a optimal memory organization, area and power envelope. A behavioral model of NVHTM is evaluated against the MNIST dataset, yielding 91.98% classification accuracy. A full custom layout is developed to validate the design in a TSMC 180nm process. The area and power profile of the spatial pooler are 30.538mm2 and 64.394mW, respectively. This design is a proof-of-concept that storage processing is a viable platform for large scale HTM network models.