Multi-phase ring-coupled oscillator for TDC using a differential inverter with an oscillation frequency booster circuit

Abstract

A multi-phase ring coupled oscillator is a time measuring component of a time-to-digital converter (TDC). The proposed multi-phase ring coupled oscillator consists of a differential inverter ring oscillator. For improving the time resolution, an enhanced sub-oscillator is added to boost the oscillation frequency. Oscillation mode analysis and the start-up technique discussed are for the multi-phase ring coupled oscillator to oscillate in a specified mode. The proposed circuit performance simulates by CADENCE hspiceD. The simulation model used is a 0.18um 1-poly 5-metal CMOS transistor model.