Achieving Wave Pipelining in Spin Wave Technology

TL;DR

This paper explores pulse operation in spin wave technology to reduce energy consumption and enable wave pipelining, demonstrating significant energy savings and increased throughput through micromagnetic simulations.

Contribution

It introduces pulse mode operation for spin wave majority gates and validates wave pipelining, showing substantial energy reduction and throughput enhancement.

Findings

Pulse mode reduces energy consumption by a factor of 18.

Wave pipelining increases throughput by 3.6 times in cascaded gates.

Micromagnetic simulations confirm the feasibility of pulse operation and wave pipelining.

Abstract

By their very nature, voltage/current excited Spin Waves (SWs) propagate through waveguides without consuming noticeable power. If SW excitation is performed by the continuous application of voltages/currents to the input, which is usually the case, the overall energy consumption is determined by the transducer power and the circuit critical path delay, which leads to high energy consumption because of SWs slowness. However, if transducers are operated in pulses the energy becomes circuit delay independent and it is mainly determined by the transducer power and delay, thus pulse operation should be targeted. In this paper, we utilize a 3-input Majority gate (MAJ) to investigate the Continuous Mode Operation (CMO), and Pulse Mode Operation (PMO). Moreover, we validate CMO and PMO 3-input Majority gate by means of micromagnetic simulations. Furthermore, we evaluate and compare the CMO and PMO Majority gate implementations in term of energy. The results indicate that PMO diminishes MAJ gate energy consumption by a factor of 18. In addition, we describe how PMO can open the road towards the utilization of the Wave Pipelining (WP) concept in SW circuits. We validate the WP concept by means of micromagnetic simulations and we evaluate its implications in term of throughput. Our evaluation indicates that for a circuit formed by four cascaded MAJ gates WP increases the throughput by 3.6x.