Journal of South China University of Technology (Natural Science Edition) ›› 2015, Vol. 43 ›› Issue (1): 15-20.doi: 10.3969/j.issn.1000-565X.2015.01.003

• Electronics, Communication & Automation Technology • Previous Articles     Next Articles

Implantable Analog Front-End with High PSRR and CMRR for Neural Signal Acquisition

Wu Zhao-hui Xie Yu-zhi Zhao Ming-jian Li Bin   

  1. School of Electronic and Information Engineering ， South China University of Technology ， Guangzhou 510640 ，Guangdong ， China
  • Received:2014-03-19 Revised:2014-10-16 Online:2015-01-25 Published:2014-12-01
  • Contact: 吴朝晖（1971-），男，博士，副教授，主要从事模数混合及模拟芯片设计研究 . E-mail:phzhwu@scut.edu.cn
  • About author:吴朝晖（1971-），男，博士，副教授，主要从事模数混合及模拟芯片设计研究 .
  • Supported by:
    Supported by the PhD Start-up Fund of Natural Science Foundation of Guangdong Province （ 2014A030310372 ）

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Abstract: As the in vivo electroneurographic signals are weak with high noise and strong environment interference ， an implantable low-noise analog front-end with high power supply rejection ratio （ PSRR ） and com-mon mode rejection ratio （ CMRR ） for neural signal acquisition is proposed. Fully differential structure is used to design the preamplifier ， switch capacitor filter and variable gain amplifier of the analog front-end. Chopper stabilization technology is used to reduce the low-frequency noise and a ripple reduction loop with current DAC is used to reduce the output ripple. In this way ， the proposed analog front-end can achieve high PSRR and CMRR without increasing the original low noise. Moreover ， a front-end chip is designed via 0.18μm CMOS technology and is used for simulation. The results of layout show that （ 1 ） input-referred noise of the analog front-end is 2.6μV at the interval of 0.1Hz~10kHz ；（ 2 ） the gain of the analog front-end can switch among 46.35 ， 52.18 ， 60.02 and 66.95dB ； and （ 3 ） the CMRR and PSRR of the analog front-end are respectively 146 and 108 dB. Thus ， it draws the conclusion that the proposed analog front-end is suitable for neural signal acquisition.

Key words: neural signal, analog circuit, analog front-end, implantable devices, high PSRR, high CMRR

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