Distributed Injection-Locking in Analog Ising Machines to Solve Combinatorial Optimizations

TL;DR

This paper introduces a distributed injection-locking technique for oscillator-based Ising machines, significantly accelerating phase-locking in solving combinatorial optimization problems with minimal power increase.

Contribution

It proposes and verifies a novel distributed injection-locking method that enhances the speed of oscillator-based Ising machines without substantial power or accuracy trade-offs.

Findings

Speed increased by 219.8% using the distributed technique.

Negligible increase in power dissipation.

Minimal phase-locking error maintained.

Abstract

The oscillator-based Ising machine (OIM) is a network of coupled CMOS oscillators that solves combinatorial optimization problems. In this paper, the distribution of the injection-locking oscillations throughout the circuit is proposed to accelerate the phase-locking of the OIM. The implications of the proposed technique theoretically investigated and verified by extensive simulations in EDA tools with a $130~nm$ PTM model. By distributing the injective signal of the super-harmonic oscillator, the speed is increased by $219.8\%$ with negligible increase in the power dissipation and phase-locking error of the device due to the distributed technique.