title: A CMOS power-efficient low-noise current-mode front-end amplifier for neural signal recording.
abstract: In this paper, a new current-mode front-end amplifier (CMFEA) for neural signal recording systems is proposed. In the proposed CMFEA, a current-mode preamplifier with an active feedback loop operated at very low frequency is designed as the first gain stage to bypass any dc offset current generated by the electrode-tissue interface and to achieve a low high-pass cutoff frequency below 0.5 Hz. No reset signal or ultra-large pseudo resistor is required. The current-mode preamplifier has low dc operation current to enhance low-noise performance and decrease power consumption. A programmable current gain stage is adopted to provide adjustable gain for adaptive signal scaling. A following current-mode filter is designed to adjust the low-pass cutoff frequency for different neural signals. The proposed CMFEA is designed and fabricated in 0.18-μm CMOS technology and the area of the core circuit is 0.076 mm(2). The measured high-pass cutoff frequency is as low as 0.3 Hz and the low-pass cutoff frequency is adjustable from 1 kHz to 10 kHz. The measured maximum current gain is 55.9 dB. The measured input-referred current noise density is 153 fA /√Hz , and the power consumption is 13 μW at 1-V power supply. The fabricated CMFEA has been successfully applied to the animal test for recording the seizure ECoG of Long-Evan rats.
authors.affiliation: Department of Electronics Engineering, Institute of Electronics, National Chiao Tung University, Hsinchu 300, Taiwan. peterwu@mail.nctu.edu.tw
authors.forename: Chung-Yu
authors.initials: CY
authors.lastname: Wu
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Chen
authors.forename: Liang-Ting
authors.initials: LT
authors.lastname: Kuo
mesh_terms: D000669:Amplifiers, Electronic; D000818:Animals; D001698:Biomedical Engineering; D004195:Disease Models, Animal; D011211:Electric Power Supplies; D004582:Electronics, Medical / Q000295:instrumentation; D004827:Epilepsy / Q000503:physiopathology*; D004867:Equipment Design; D005246:Feedback; D008959:Models, Neurological; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D012815:Signal Processing, Computer-Assisted