應用於電生理記錄之低功率可調增益CMOS放大器晶片設計

Abstract

神經科學家與臨床醫師對於觀察腦部數以千億計神經元的同步活動反應有非常重要的需求，多頻道神經元記錄電極是基礎神經科學研究對於獲取臨床和神經元應用的重要發展。近來由於微機電技術的快速進步，侵入式神經元記錄電極可觀察到更多的神經元同步的反應，因此對於低功率生醫放大器發展的需求大增。本論文設計一個低功率可調變增益電生理放大器，具有三種工作模式，可依實驗情況調整。本研究之低功率生醫放大器使用miller的概念來實現電生理頻寬的需求，可大量降低因為神經元訊號處於低頻造成被動元件過大而非常困難整合成積體電路的問題，並且可去除因為電極產生的極大DC offset (1-2V)。此晶片採用台積電（TSMC）0.35um 2p4m CMOS製程，可調式增益為59 dB ~ 88 dB，低頻3 dB頻率161 Hz，高頻3 dB頻率5.9 k Hz，供應電壓□1V，功率消耗54.5 uW，晶片面積1.58 mm □ 1.906 mm。

There is a great demand for technologies that enable neuroscientists and clinicians to observe the simultaneous activity of large numbers of neurons in the brain. Multi-electrode neural recordings are important development in basic neuroscience research and knowledge gained from these studies is beginning to enable clinical and neural prosthetic applications. Recent advances in MEMS (micro-electro-mechanical-system) technology enhancement, the advent of fully implantable multi-electrode arrays that can observe more the simultaneous activity of neurons has created the great need for fully integrated low power bio-amplifier. We design a low-power and programmable gain neural recording amplifier which has three kinds of work mode adjust the case of experiment. The low power bio-amplifier uses the concept of Miller effect to realize the bandwidth of neural recording and can greatly reduce the size of passive device which is too hard to be integrated on chip. Simultaneously it could reject very large DC offsets from electrode–electrolyte interface. The resulting amplifier built in a standard 0.35um 2p4m CMOS process、 programmable gain from 59 dB to 88 dB、 pass signal from 161 Hz to 5.9 k Hz、power supply □1v and a power dissipation of 54.5 uW while consuming 1.58 mm * 1.906 mm of chip area.