Energy-Efficient Ising Machines Using Capacitance-Coupled Latches for MaxCut Solving

Latch-based Ising machines (LIMs) have aroused research interest due to their speed and area efficiency for solving combinatorial optimization problems (COPs). However, existing LIMs based on resistive coupling are sensitive to many design parameters and suffer from solution quality degradation. This paper explores a capacitive-coupling approach that improves the robustness of the LIM to variations in the system design parameters. Evaluation results show that the LIMs using capacitive coupling can solve the MaxCut problem with high solution quality in a ∼1000× wider range of coupling strength compared to the resistive coupling approach. It also achieves an energy-time product of 313.5 nJ•s, with an 84.3% and 86.4% reduction compared to the state-of-the-art resistance-coupled and capacitance-coupled counterparts respectively.