Circuits and Methods for Asynchronous Adiabatic Quantum Flux Parametron System Design

Increasing computing demand from high-performance computing, artificial intelligence, scientific computing, and other data-intensive applications has placed growing pressure on the energy efficiency of conventional semiconductor processors. CMOS systems consume substantial energy both during computation and through static and dynamic power losses, creating significant power and cooling challenges at large scale. Superconducting electronics offer an alternative computing platform capable of extremely low-energy switching, with adiabatic quantum-flux-parametron (AQFP) technology providing particularly low energy dissipation by operating Josephson-junction circuits adiabatically. Traditional AQFP logic, however, is generally synchronous and relies on multiphase activation signals that determine when data moves between successive logic stages. This dependence on carefully coordinated activation phases can introduce clock-skew, timing, routing, and design challenges as superconducting circuits become larger and more complex. Conventional asynchronous logic techniques are not directly transferable to AQFP circuits because AQFP devices have distinctive activation and data-propagation behavior. The disclosed technology addresses these limitations with phase-synchronization and asynchronous circuit techniques specifically designed for AQFP systems.

Technology Description

This technology provides circuits and design methods for implementing asynchronous digital logic by using AQFP devices. AQFP circuits encode and process binary information by using superconducting loops and Josephson junctions driven by multiphase activation signals. The architecture introduces phase-synchronizer circuits that allow data to propagate between circuit elements without requiring a conventional global clock or precise knowledge of when input data will arrive. Individual AQFP stages can hold, fire, and block data according to the relationship between their activation phases, enabling asynchronous pipelines, logic gates, buffers, token-passing circuits, and more complex computational structures. The approach combines the exceptionally low switching energy of superconducting AQFP logic with asynchronous operation, addressing synchronization and timing constraints that can complicate large-scale AQFP systems. The disclosed circuits can accept data arriving during any portion of an activation cycle, synchronize them with subsequent processing stages, and propagate valid data through a computational pipeline. Simulations and fabricated test circuits demonstrate asynchronous AQFP logic operation, while the architecture supports standard logical functions and larger circuit building blocks. This approach provides a pathway toward scalable, ultra-low-power superconducting processors without requiring the rigid global timing structures associated with conventional synchronous designs.