Analysis and Design of Oscillator Coupling for Solving Combinatorial Optimization Problems
Markus Graber, Klaus Hofmann · 2022 29th IEEE International Conference on Electronics, Circuits and Systems (ICECS) · 2022
The demand for high-efficiency computing power is steadily increasing. Despite improvements in classical topologies, non-conventional hardware approaches are of growing interest. Oscillator-based Ising Machines (OIMs) implemented on integrated CMOS circuits are a promising emerging technology. OIMs can solve combinatorial optimization problems in a fraction of time while having an energy consumption several orders of magnitude lower than conventional computing architectures. Their operating principle is based on the individually configurable coupling of a multitude of oscillators. Designing such oscillator-based computers poses unique challenges. While the behavior of oscillators including injection locking is well understood, the interaction inside the OIMs for computation purposes has not been investigated extensively. Hence, this paper discusses the coupling of oscillators and draws attention to important design trade-offs. The OIM system is briefly described and the general coupling mechanics are demonstrated using ideal resistors as coupling elements. The unique challenges of transistor-based couplers are extensively discussed and a coupler circuit that balances design trade-offs is proposed.