(searched for: doi:10.4236/ojab.2013.24014)
Electronics, Volume 11; https://doi.org/10.3390/electronics11152402
The past century has seen the ongoing development of amplifiers for different electrophysiological signals to study the work of the heart. Since the vacuum tube era, engineers and designers of bioamplifiers for recording electrophysiological signals have been trying to achieve similar objectives: increasing the input impedance and common-mode rejection ratio, as well as reducing power consumption and the size of the bioamplifier. This review traces the evolution of bioamplifiers, starting from circuits on vacuum tubes and discrete transistors through circuits on operational and instrumental amplifiers, and to combined analog-digital solutions on analog front-end integrated circuits. Examples of circuits and their technical features are provided for each stage of the bioamplifier development. Special emphasis is placed on the review of modern analog front-end solutions for biopotential registration, including their generalized structural diagram and table of comparative characteristics. A detailed review of analog front-end circuit integration in various practical applications is provided, with examples of the latest achievements in the field of electrocardiogram, electroencephalogram, and electromyogram registration. The review concludes with key points and insights for the future development of the analog front-end concept applied to bioelectric signal registration.
Published: 1 December 2017
Conference: 2017 29th International Conference on Microelectronics (ICM), 2017-12-10 - 2017-12-13, Beirut, Lebanon
A CMOS G m -C Notch filter for powerline interference rejection in EEG systems is described. The pass-band covers all the four bands of brain wave and, with a bandwidth of 2.17 kHz, enables a deep study of the frequencies of less interest. Besides that, a capacitor programmable circuit makes the filter possible to reject with more than 90 dB the powerline interference for 50 Hz or 60 Hz. The notch filter employs operational transconductance amplifiers working in the weak region, with transconductance of 1.259 nA/V, enabling the use of small capacitors for on-chip integration. In this project, we designed a circuit in 0.13 μm CMOS technology, for a 1.0 V power supply and 10 nA bias current. Simulations conducted on CADENCE (Virtuoso Analog Design Environment) show good performance of the filter for filtering the noise in acquired EEG signals.
Microelectronics Journal, Volume 64, pp 86-91; https://doi.org/10.1016/j.mejo.2017.04.012
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Published: 1 December 2016
Conference: 2016 IEEE International Symposium on Nanoelectronic and Information Systems (iNIS), 2016-12-19 - 2016-12-21, Gwalior, India
A realization of on-chip large resistance using aswitched-capacitor series to parallel topology is presented in thispaper. Using this scheme, a band-pass filter for various biomedicalapplications such as EEG, ECG, EOG at a very low cornerfrequency upto 0.01 Hz in 180 nm CMOS, N-well technology with1.8 V supply voltage and was simulated using Cadence Spectresimulator. Simulation results show that the band pass filter wasdesigned with different bandwidth ranges for various biomedicaldevice application.
Chemical Reviews, Volume 115, pp 5116-5158; https://doi.org/10.1021/cr500554n
Published: 1 August 2014
Conference: 2014 IEEE 57th International Midwest Symposium on Circuits and Systems (MWSCAS), 2014-8-3 - 2014-8-6
This paper presents the design of a monolithic low power CMOS low-noise instrumentation amplifier (INA) for low-power biosensor applications. To achieve high-fidelity cardiac signal acquisition, the INA circuit and system design requirements are discussed. Design strategies for mitigating the in-band flicker noise and thermal noise using chopper-stabilization and current scaling techniques are investigated. Sub-threshold operation is also utilized to reduce power. The INA achieves a simulated noise spectral density of 39.9 nV/√Hz from dc to 300Hz in 4.6μW, with an outstanding noise efficiency factor (NEF) of 2.47.