Bi-Directional Gated Ring Oscillator Time Integrator

This paper presents the principle, design, and analysis of a bi-directional gated ring oscillator (BDGRO) time integrator for time-based signal processing. The time integrator features full compatibility with technology, rapid integration, low power consumption, a virtually unlimited dynamic range, built-in dynamic element matching, and self-digitization. A detailed analysis of the impact of the imperfections of the time integrator including nonlinearity, skew, supply voltage noise, device noise, and metastability-induced gating errors is provided, supported with simulation results. The time integrator is designed in a TSMC 130 nm 1.2 V CMOS technology and analyzed using Virtuoso/Spectre with BSIM3 device models. Time integration is confirmed using simulation results in both time and frequency domains. The time integrator exhibits a clean spectrum without noticeable harmonics and consumes 0.25 mW with a gain of 15.48 dB at 20 MS/s.