High-Level Time-Accurate Model for the Design of Self-Timed Ring Oscillators

Self-timed rings are now considered as a promising solution for generating high-resolution timing signals. One of the main constraints for designing oscillators based on self-timed rings is to avoid burst oscillating modes and to produce uniformly spaced events in order to act as a periodic timebase. This paper presents a time-accurate model for self-timed rings based on a high-level behavioural model enriched by stage timing information. This provides a framework to understand and analyse the temporal behaviour and the performances of oscillating asynchronous rings, especially the robustness to process variability. Moreover, it offers designers the ability to easily prevent burst oscillating modes by applying simple ring sizing rules. Electrical simulations demonstrate the correctness and efficiency of the approach.