Samiei Aria, Hashemi Hossein
Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089 USA.
IEEE Solid State Circuits Lett. 2019 Mar;2(3):17-20. doi: 10.1109/lssc.2019.2916754. Epub 2019 May 14.
Advanced neural prosthetics requires high density neural recording and stimulation electrodes interfacing with the tissue. For an implantable device, area, power consumption, and noise performance are the key design metrics. Due to the low-frequency nature of the recorded signals, chopping technique is inevitable to satisfy the noise requirement while maintaining a small area and low power consumption. However, chopping leads to a significant drop in input impedance, which leads to potential attenuation of neural signals recorded from high impedance miniature electrodes, and an unacceptable large input current drawn from the tissue. This work presents a chopper stabilized, current feedback amplifier (CFA) with input impedance boosted to 3.0 GΩ. The amplifier has an adjustable voltage gain of 40-60 dB, and an adjustable high-pass cut-off frequency of 0.5 - 5 Hz, with a power consumption of 2.6 W and noise efficiency factor (NEF) of 3.2.
先进的神经假体需要与组织接口的高密度神经记录和刺激电极。对于可植入设备，面积、功耗和噪声性能是关键的设计指标。由于记录信号的低频特性，斩波技术对于在保持小面积和低功耗的同时满足噪声要求是不可避免的。然而，斩波会导致输入阻抗显著下降，这会导致从高阻抗微型电极记录的神经信号出现潜在衰减，以及从组织汲取不可接受的大输入电流。本文提出了一种斩波稳定的电流反馈放大器（CFA），其输入阻抗提高到了3.0 GΩ。该放大器具有40 - 60 dB的可调电压增益和0.5 - 5 Hz的可调高通截止频率，功耗为2.6 W，噪声效率因子（NEF）为3.2。
