| With the development of the information,the extraction of weak neural signals plays an important role in the analysis,treatment and monitoring of diseases.In this paper,based on the wearable medical monitoring system,a 28 nm CMOS integrated process is used to design a low-power low-noise analog front-end that can be used for brain neural signal monitoring chips.After simulation,it can effectively detect and amplify weak neural signal.The article first introduces the background knowledge of the analog front-end,including development overview,bioelectrical signal characteristics,system architecture,and definition of related performance specification.And then,the modules of the analog front-end are introduced in detail,including chopper amplifiers,variable gain amplifier,high-Q switched capacitor band-pass filter and MUX data selection circuit.finally,the UMC 28 nm CMOS process is used to complete the front-end layout and overall simulation verification.The analog front-end has a power supply voltage of 1V,and a channel sampling frequency of 6.4MHz.The simulation results show that the equivalent input noise of the analog front-end is 0.324?Vrms(10Hz?40Hz),and the power consumption is 0.4m W/channel.It can collect data on eight channels at the same time,which completes the detection and amplification of weak signals.Features,The analog front-end also realizes gain and bandwidth adjustable functions.The gains are 62 d B,56 d B,50 d B,and 44 d B.The bandwidth depends on the switching frequency fsc.The gain and switching frequency can be flexibly selected according to the strength and frequency of the neural signal.In this paper,the industry's most advanced 28 nm planar integration process is used to realize the design and layout of the 8-channel low-power and low-noise analog front-end with low voltage characteristics of the device.It provides a practical reference for the integration of the brain neural signal monitoring chip in engineering. |
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