Title :
A VCO-based current-to-digital converter for sensor applications
Author :
Prabha, Praveen ; Seong Joong Kim ; Reddy, Karthikeyan ; Sachin Rao ; Griesert, Nathanael ; Arun Rao ; Winter, Greg ; Hanumolu, Pavan Kumar
Author_Institution :
Oregon State Univ., Corvallis, OR, USA
Abstract :
A current sensing VCO based ADC architecture is realized using a passive integrator, VCO-based quantizer, and mostly digital circuits. A digital IIR filter is used instead of an analog loop filter to tackle VCO non-linearity in a power efficient and scaling friendly manner. The prototype circuit designed for an ambient light sensor application achieves 900pA accuracy over an input current range of 4μA, consumes a total of 77.8μA current, and occupies an active area of 0.36mm2 in 0.18μm CMOS process.
Keywords :
CMOS integrated circuits; IIR filters; analogue-digital conversion; electric current measurement; electric sensing devices; voltage-controlled oscillators; ADC architecture; CMOS process; VCO non-linearity; VCO-based quantizer; analog loop filter; current 4 muA; current 77.8 muA; current 900 pA; current sensing VCO; current-to-digital converter; digital IIR filter; digital circuits; light sensor; passive integrator; sensor applications; size 0.18 mum; size 0.36 mm; Clocks; Computer architecture; Current measurement; Microprocessors; Modulation; Prototypes; Voltage-controlled oscillators; Analog-digital conversion; Current measurement; Delta-sigma modulation; Optical sensors; Photodiodes; Sensor systems and applications; Voltage-controlled oscillators;
Conference_Titel :
Custom Integrated Circuits Conference (CICC), 2014 IEEE Proceedings of the
Conference_Location :
San Jose, CA
DOI :
10.1109/CICC.2014.6945990
