Journal of the Institute of Electronics and Information Engineers (전자공학회논문지)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지
DOI QR코드

DOI QR Code

On-chip Magnetic Sensor with Embedded High Inductance Coil for Bio-magnetic Signal Measurement

생체자기 신호측정을 위한 고인덕턴스 코일 내장형 온칩 자기센서

  • Lyu, HyunJune (Department of Electronics Engineering, Graduate School, Kyungpook National University) ;
  • Choi, Jun Rim (Department of Electronics Engineering, Graduate School, Kyungpook National University)
  • 류현준 (경북대학교 전자공학부) ;
  • 최준림 (경북대학교 전자공학부)
  • Received : 2013.02.26
  • Published : 2013.06.25
Download PDF
⟨ Previous Next ⟩

Abstract

Magnetic sensor chip for measuring bio-magnetism is implemented in $0.18{\mu}m$ CMOS technology. The magnetic sensor chip consists of a small-sized high inductance coil sensor and an instrumentation amplifier (IA). High inductance coil sensor with suitable sensitivity and bandwidth for measurement of bio-magnetic signal is designed using electromagnetic field simulation. Low gm operational transconductance amplifier (OTA) using transconductance reduction techniques is designed for on-chip solution. Output signal sensitivity of magnetic sensor chip is $3.25fT/{\mu}V$ and reference noise of 21.1fT/${\surd}$Hz. Proposed IA is designed along with band pass filters(BPF) to reduce magnetic signal noise by using current feedback techniques. Proposed IA achieves a common mode rejection ratio of 117.5dB while the input noise referred is kept below $0.87{\mu}V$.

생체자기신호 측정을 위해 고인덕턴스 코일과 계측 증폭기를 내장한 자기센서칩을 $0.18{\mu}m$ CMOS공정으로 제작하였다. 생체자기신호를 측정하기 적합한 감도와 대역폭을 가지는 고인덕턴스 코일센서를 전자기장 시뮬레이션 프로그램으로 설계하였으며, 온칩에 구현하기 위해 트렌스컨덕턴스 감쇄방법 적용한 low gm OTA를 구현하였다. 자기센서칩의 출력신호 감도는 $3.25fT/{\mu}V$이며, output reference noise는 21.1fT/${\surd}$Hz이다. 계측 증폭기부분은 current feedback 기반으로 설계되었으며, 자기 신호 잡음을 줄이기 위해서 0.5~5kHz의 대역의 BPF를 설계하였다. MPW칩 테스트에서 common mode rejection ratio(CMRR)는 117.5dB로 측정하였으며, input reference noise가 $0.87{\mu}V$ 이하로 유지되도록 설계하였다.

Keywords

References

  1. G. M, Baule, and R. McFee, Am. Heart. J. 55, 95 (1963).
  2. D. Cohen, E. A. Edelsack, J. E. Zimmerman, Appl. Phys. Lett.16, 278 (1970). https://doi.org/10.1063/1.1653195
  3. J. Malmivuo and R. Plonsey, Bioelectromagnetism -Principles and Applications of Bioelectric and Biomagnetic Fields (Oxford University Press, 1995).
  4. H. Nyquist, Phys. Rev. 32, 110 (1928). https://doi.org/10.1103/PhysRev.32.110
  5. F. Reif, Fundamentals of Statistical and Thermal Physics (McGraw-Hill, New York, 1965), pp. 567-600.
  6. H.-C. Chow and J.-Y. Wang, "High CMRR instrumentation amplifier for biomedical applications," 9th Int. Symp. on Signal Processing and Its Applications, pp. 1-4, Feb. 2007.
  7. R. Martins, S. Selberherr and F. Vaz, "A CMOS IC for Portable EEG Acquisition systems", IEEE Transactions on Instrumentation and Measurement, vol. 47, no. 5, Oct. 1998.
  8. C. Nanda, J. Mukhopadhyay, D. Mandal and S. Chakrabarti, "1 V CMOS instrumentation amplifier with high DC electrode offset cancellation for ECG acquisition systems," IEEE, Students' Technology Symposium (TechSym), kharagpur, pp. 21-25, April 2010.
  9. Honglei Wu and Yong-Ping Xu, "A Low-Voltage Low-Noise CMOS Instrumentation Amplifier for Portable Medical Monitoring Systems", IEEE-NEWCAS Conference, pp. 295-298, Jun. 2005.
  10. Chia-Hao Hsu, Chi-Chun Huang, kian Siong, Wei-Chih Hsiao, Chua-Chin Wang, "A high performance current-balancing instrumentation amplifier for ECG monitoring systems", SoC Design Conference (ISOCC), pp. 83-86, 22-24 Nov. 2009.
  11. 임신일, 바이오 메디칼용 칩 회로 설계 기술, 전자공학회지, 제37권 제10호, 48-62쪽, 2010년 10월
  12. Alain Courteville, Tijani Gharbi, Jean-Yves Cornu, "MMG Measurement: A High-Sensitivity Microphone-Based Sensor for Clinical Use", IEEE Transactions on Biobedical Enginnering, vol.45, no. 2, feb. 1998