Title
Resolution Enhancement of VCO-based ADCs by Passive Interpolation and Phase Injection
Abstract
This work describes a simple way to improve the resolution of low-pass voltage-controlled-oscillators based analog-to-digital converters (VCO-based ADCs) implemented with ring-oscillators. We propose to insert a passive resistive network into the differential delay cells of the oscillator to get additional interpolated phases. These interpolated phases are then injected to other similar oscillators. By increasing the number of phases coming from all the oscillators, the effective gain of the system is higher and enhances the resolution of the converter. To validate the idea, a prototype of an open-loop VCO-based ADC was built in VerilogA language with ring-oscillators designed with a 65-nm CMOS process. The results of transient simulations were compared to the results of a behavioral ideal model of the system built in MATLAB. As expected, the signal-to-noise ratio (SNR) was improved in concordance with the increase in the number of phases. Finally, it was checked that the proposed circuit used to extract and inject the interpolated phases did not penalize the total power consumption. The proposed circuit structure is particularly suitable for high-bandwidth applications, where the oversampling ratio (OSR) is strongly restricted and the gain is limited because of the oscillator non-linearity. Due to the highly digital nature of the VCO-based ADC structures, this solution may be of special interest to be implemented in new deep-submicron CMOS processes.
Year
DOI
Venue
2019
10.1109/DCIS201949030.2019.8959933
2019 XXXIV Conference on Design of Circuits and Integrated Systems (DCIS)
Keywords
Field
DocType
oversampling ratio,deep-submicron CMOS processes,open-loop VCO-based ADC,interpolated phases,differential delay cells,passive resistive network,analog-to-digital converters,low-pass voltage-controlled-oscillators,passive interpolation,resolution enhancement,VCO-based ADC structures,oscillator nonlinearity,ring-oscillators,size 65 nm
Flight dynamics (spacecraft),MATLAB,Oversampling,Resistive touchscreen,Computer science,Interpolation,Electronic engineering,Converters,Voltage-controlled oscillator,CMOS
Conference
ISSN
ISBN
Citations 
2471-6170
978-1-7281-5459-6
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Leidy Mabel Alvero-Gonzalez101.01
Luis Hernández200.34
Eric Gutierrez300.34