A Capacitive Sensor Interface Circuit Based on Phase Differential Method
A new interface circuit for capacitive sensor is
presented. This paper presents the design and simulation of soil
moisture capacitive sensor interface circuit based on phase
differential technique. The circuit has been designed and fabricated
using MIMOS- 0.35"m CMOS technology. Simulation and test
results show linear characteristic from 36 – 52 degree phase
difference, representing 0 – 100% in soil moisture level. Test result
shows the circuit has sensitivity of 0.79mV/0.10 phase difference,
translating into resolution of 10% soil moisture level.
[1] T. C. Lu, Y. J. Huang and H. P. Chou, "A Novel Interface Circuit for
Capacitive Sensors Using Correlated Double Sampling Demodulation
Technique", in Proc. 2008 Second International Conference on Sensor
Technologies and Applications, pp. 396-400.
[2] A. Heidary and G. C. M. Meijer, "A Low-Noise Switched-Capacitor
Front End for Capacitive Sensor", IEEE SENSORS, 2007, pp. 40-43.
[3] R.B. McIntosh and M. E. Casada, "Fringing Field Capacitance Sensor
for Measuring the Moisture Content of Agricultural Commodities,"
IEEE Sensors Journal, Volume 8, No. 3, 2008, pp:240-247.
[4] A. Srivastava, M. R. Gumma, J. Cherukuri, "Readout interface circuits
for MOS C-V sensors, " Proc. of 37th Midwest Symposium on Circuit
and Systems, 1994, pp:187-190.
[5] J. Das, S. Dey, S. M. Hossain, Z. M. C. Rittersma and H. Saha, "A
Hygrometer Comprising a Porous Silicon Humidity Sensor with Phase-
Detection Electronics," IEEE Sensors Journal, Volume 3, Issue 4, 2003,
pp. 414-420.
[6] P. D. Dimitropoulos et al, "A Low-Power/Low-Noise Readout Circuit
for Integrated Capacitive Sensors," IEEE Sensors Journal, Volume 6,
No. 3, 2006, pp. 755-769.
[7] G. de Rosny et al. "Numerical Modeling of a Capacitance Probe
Response," Soil Science Society of America Journal, vol. 65, 2001, pp.
13-18.
[8] J.F. Posada, J. J. Liou and R.N. Miller, "An Automated Data
Acquisition System for Modeling the Characteristics of a Soil Moisture
Sensor," IEEE Transaction on Instrumentation and Measurement,
1991, Volume 40, No. 5, pp. 836-841.
[9] Behzad Razavi, "Design of analog CMOS integrated circuits,"
McGraw-Hill, 2001.
[10] MIMOS Invention.
[1] T. C. Lu, Y. J. Huang and H. P. Chou, "A Novel Interface Circuit for
Capacitive Sensors Using Correlated Double Sampling Demodulation
Technique", in Proc. 2008 Second International Conference on Sensor
Technologies and Applications, pp. 396-400.
[2] A. Heidary and G. C. M. Meijer, "A Low-Noise Switched-Capacitor
Front End for Capacitive Sensor", IEEE SENSORS, 2007, pp. 40-43.
[3] R.B. McIntosh and M. E. Casada, "Fringing Field Capacitance Sensor
for Measuring the Moisture Content of Agricultural Commodities,"
IEEE Sensors Journal, Volume 8, No. 3, 2008, pp:240-247.
[4] A. Srivastava, M. R. Gumma, J. Cherukuri, "Readout interface circuits
for MOS C-V sensors, " Proc. of 37th Midwest Symposium on Circuit
and Systems, 1994, pp:187-190.
[5] J. Das, S. Dey, S. M. Hossain, Z. M. C. Rittersma and H. Saha, "A
Hygrometer Comprising a Porous Silicon Humidity Sensor with Phase-
Detection Electronics," IEEE Sensors Journal, Volume 3, Issue 4, 2003,
pp. 414-420.
[6] P. D. Dimitropoulos et al, "A Low-Power/Low-Noise Readout Circuit
for Integrated Capacitive Sensors," IEEE Sensors Journal, Volume 6,
No. 3, 2006, pp. 755-769.
[7] G. de Rosny et al. "Numerical Modeling of a Capacitance Probe
Response," Soil Science Society of America Journal, vol. 65, 2001, pp.
13-18.
[8] J.F. Posada, J. J. Liou and R.N. Miller, "An Automated Data
Acquisition System for Modeling the Characteristics of a Soil Moisture
Sensor," IEEE Transaction on Instrumentation and Measurement,
1991, Volume 40, No. 5, pp. 836-841.
[9] Behzad Razavi, "Design of analog CMOS integrated circuits,"
McGraw-Hill, 2001.
[10] MIMOS Invention.
@article{"International Journal of Electrical, Electronic and Communication Sciences:59505", author = "H. A. Majid and N. Razali and M. S. Sulaiman and A. K. A'ain", title = "A Capacitive Sensor Interface Circuit Based on Phase Differential Method", abstract = "A new interface circuit for capacitive sensor is
presented. This paper presents the design and simulation of soil
moisture capacitive sensor interface circuit based on phase
differential technique. The circuit has been designed and fabricated
using MIMOS- 0.35"m CMOS technology. Simulation and test
results show linear characteristic from 36 – 52 degree phase
difference, representing 0 – 100% in soil moisture level. Test result
shows the circuit has sensitivity of 0.79mV/0.10 phase difference,
translating into resolution of 10% soil moisture level.", keywords = "Capacitive sensor, interface, phase differential.", volume = "3", number = "7", pages = "1464-4", }