A Survey on Emerging Technologies and Architectures of Low Power Preamplifiers for Biomedical Applications
Abstract
Unlike other commercial devices, developing implantable microsystems for biomedical
applications requires critical analyses in terms of specifications, technologies, and design
techniques because of the devices’ safety and efficacy. As the industry of medical
implantable devices develops, lowering the power consumption as much as possible is
essential in improving the service time of the battery, which cannot be replaced frequently.
Hence, low power design has become the main concern for battery‐powered implants.
Biosignals such as EEG and ECG are weak signals, typically ranging from 0.5μV to 5mV
with high source impedance and superimposed high level interference and noise. Hence,
there is a need of a pre‐amplification stage in the analog front end of a biomedical
acquisition system so that these biosignals can be amplified for measurement and testing
purposes, without degrading the signal‐to‐noise ratio. The purpose is to provide
amplification that is selective to physiological signal, reject noise, and other sources of
interference. In this paper, an in‐depth study of various low power pre‐amplifiers proposed
for different biomedical applications were made, along with performance comparison in
terms of various amplification‐related specifications such as gain, bandwidth, signal‐tonoise
ratio, CMRR, and slew rate among other specifications.