Design of a High-Precision Time-Domain Comparator

Abstract

This paper presents a high-speed and high-precision time-domain comparator integrated circuit. The proposed comparator adopts a voltage-controlled oscillator circuit and a time amplifier, to convert the analog input voltage to a phase difference in time domain with high precision. By introducing a feedback for VCO and using the phase detector in the following stage to judge the phase differences between two signals directly, the input signals can be compared in a high speed. The comparator is designed in SMIC $\mathbf{0.18\ \mu m}$ CMOS process technology. The simulation results show that under 1 V power supply, this comparator achieves $\mathbf{0.1\ \mu V}$ accuracy, 181 MHz maximum response speed, and $\mathbf{86\ \mu W}$ power consumption.