Automating the Design of Asynchronous Logic Control for AMS Electronics

Analog and mixed signal (AMS) electronics becomes increasingly complex and needs to be digitally enhanced by its own control circuitry. The RTL synthesis flow routinely used for digital logic is, however, optimized for synchronous data processing and produces inefficient control for AMS. In this paper, we demonstrate the evident benefits of asynchronous circuits in the context of AMS systems, and propose an asynchronous design for analog electronics (A4A) flow for their specification, synthesis, and formal verification. A library of specialized analog-to-asynchronous (A2A) components is developed for interfacing analog and asynchronous worlds. A4A flow is automated in the Workcraft framework and evaluated using a multiphase buck converter case study, where A2A components are employed to sanitize analog sensor readings. Timing analysis of asynchronous buck control shows improved response time: 4× reaction to high-load and 7× to under-voltage condition, compared with a 333 MHz clocked controller (to achieve a similar response time, a clocked controller would require ~3 GHz frequency). The simulation results of a 4-phase asynchronous buck demonstrate improved voltage ripple and peak current -16% and 12% reduction, respectively. These benefits lead to the higher efficiency of power conversion, and can be traded off for the cost of analog components, e.g., coils. Moreover, the use of the proposed design flow and tools helps to improve design productivity and overall robustness of AMS circuits.