Paper Info
Title
A Highly Digital VCO-Based ADC Architecture for Current Sensing Applications
Abstract
This paper presents a voltage-controlled oscillator (VCO) based current to digital converter for sensor readout applications. Second order noise shaping of the quantization error is achieved by using implicit capacitance of the sensor to realize a passive integrator and a VCO-based quantizer. The non-linearity in voltage to frequency conversion of the VCO is tackled by placing the VCO in a loop consisting of a simple digital IIR filter and a passive integrator. The IIR filter provides large gain within the signal bandwidth and suppresses VCO input swing. As a result, non-linearity of the VCO is not exercised, thus greatly improving the proposed architecture's immunity to VCO nonlinearity. The use of a digital filter instead of an analog loop filter eases the design and makes it scaling friendly. Designed for an ambient light sensor application, the proposed circuit achieves 900 pA accuracy over an input current range of 4 A. Fabricated in a 0.18 m CMOS process, the readout circuit consumes a total of 77.8 A current, and occupies an active area of 0.36 mm .
Year
DOI
Venue
2015
10.1109/JSSC.2015.2414428
Journal of Solid-State Circuits
Keywords
Field
DocType
VCO based ADC, time based ADC, analog-to-digital conversion, current sensor, delta-sigma modulation, digital readout circuits, ambient light sensor, sensor applications
Digital filter,Control theory,Computer science,Integrator,Electronic engineering,Delta-sigma modulation,Voltage-controlled oscillator,Noise shaping,Bandwidth (signal processing),Current sensor,Quantization (signal processing),Electrical engineering
Journal
Volume
Issue
ISSN
PP
99
0018-9200
Citations 
PageRank 
References 
9
0.98
11
Authors
8
Name
Order
Citations
PageRank
Praveen Prabha190.98
Seong Joong Kim2478.95
Karthikeyan Reddy37410.57
Sachin Rao4847.85
Nathanael Griesert5213.20
Arun Rao6488.29
Greg Winter7202.11
Pavan Kumar Hanumolu855484.82