Efficient Design of Spiking Neural Network with STDP Learning Based on Fast CORDIC

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First Author:Jiajun Wu

Correspondence Author:C. Wang

Co-author:Y. Zhan,Z. Peng,X. Ji,G. Yu,R. Zhao

Journal:IEEE Trans. on Circuits and Systems-I Regular Papers (TCAS-I) 2021

Included Journals:SCI

Document Type:J

DOI number:10.1109/TCSI.2021.3061766.

Date of Publication:2021-03-02

Impact Factor:4.14

Abstract:In emerging Spiking Neural Network (SNN) based neuromorphic hardware design, energy efficiency and on-line learning are attractive advantages mainly contributed by bio-inspired local learning with nonlinear dynamics and at the cost of associated hardware complexity. This paper presents a novel SNN design employing fast COordinate Rotation DIgital Computer (CORDIC) algorithm to achieve fast spike timing–dependent plasticity (STDP) learning with high hardware efficiency. In this study, a system design and evaluation method of CORDIC-based SNN is proposed for finding optimal CORDIC type and precision, from theoretical CORDIC-level error to application-level learning performance. From the proposed design and evaluation method, a reconfigurable SNN design based on fast-convergence CORDIC is designed to achieve high classification accuracy on MNIST, fast on-line learning and good energy efficiency. By utilizing SNN’s fault tolerance and time-division-multiplexing (TDM) strategy, the reconfigurable SNN design employs 8-bit fast-convergence CORDIC and TDM-based hardware accelerator for high efficiency. FPGA implementation results confirm that the proposed fast-convergence CORDIC SNN design outperforms the state-of-the-art CORDIC method by 38.5%−45.3% in terms of learning speed and energy efficiency, with the STDP learning of 30.2 ns/SOP, energy efficiency of 176.6 pJ/SOP, processing speed of 6.1 ms/image, and on-line learning convergence of 21.4 s (time to reach the final accuracy, on average), on MNIST benchmark.

Links to published journals:https://ieeexplore.ieee.org/document/9366935