Exploring a new method for improving dynamic range of instrumentation amplifier for processing low voltage signals

This paper presents a new approach based on the use of a Current Steering (CS) technique for the design of fully integrated Gm–C Low Pass Filters (LPF) with sub-Hz to kHz tunable cut-off frequencies and an enhanced power-area-dynamic range trade-off. The proposed approach has been experimentally validated by two different first-order single-ended LPFs designed in a 0.18 µm CMOS technology powered by a 1.0 V single supply: a folded-OTA based LPF and a mirrored-OTA based LPF. The first one exhibits a constant power consumption of 180 nW at 100 nA bias current with an active area of 0.00135 mm2 and a tunable cutoff frequency that spans over 4 orders of magnitude (~100 mHz–152 Hz @ CL = 50 pF) preserving dynamic figures greater than 78 dB. The second one exhibits a power consumption of 1.75 µW at 500 nA with an active area of 0.0137 mm2 and a tunable cutoff frequency that spans over 5 orders of magnitude (~80 mHz–~1.2 kHz @ CL = 50 pF) preserving a dynamic range greater than 73 dB. Compared with previously reported filters, this proposal is a competitive solution while satisfying the low-voltage low-power on-chip constraints, becoming a preferable choice for general-purpose reconfigurable front-end sensor interfaces.

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An improved AC-amplifier for electrophysiology

Journal of Automatic Control ◽

10.2298/jac0901007j ◽

2009 ◽

Vol 19 (1) ◽

pp. 7-12

Author(s):

Nikola Jorgovanovic ◽

Dubravka Bojanic ◽

Vojin Ilic ◽

Darko Stanisic

Keyword(s):

Dynamic Range ◽

Cutoff Frequency ◽

Instrumentation Amplifier ◽

Single Chip ◽

Common Mode ◽

Differential Signal ◽

Op Amp ◽

Chip Technology ◽

The Common ◽

Dc Component

We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA). The design target was to increase the common mode rejection ratio (CMRR), thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

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Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters

Electronics ◽

10.3390/electronics10232931 ◽

2021 ◽

Vol 10 (23) ◽

pp. 2931

Author(s):

Waldemar Jendernalik ◽

Jacek Jakusz ◽

Grzegorz Blakiewicz

Keyword(s):

Dynamic Range ◽

Low Voltage ◽

Supply Voltage ◽

Low Frequency ◽

Cmos Technology ◽

Pass Filter ◽

Low Pass Filter ◽

Biomedical Sensors ◽

Filter Synthesis ◽

Cascade Method

Buffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more general method for buffer-based filter synthesis is developed and presented. The method uses RLC ladder prototypes to obtain filters of arbitrary orders. In addition, a set of novel circuit solutions with ultra-low voltage and power are proposed. The introduced circuits were synthesized and simulated using 180-nm CMOS technology of X-FAB. One of the designed circuits is a fourth-order, low-pass filter that features: 100-Hz passband, 0.4-V supply voltage, power consumption of less than 5 nW, and dynamic range above 60 dB. Moreover, the total capacitance of the proposed filter (31 pF) is 25% lower compared to the structure synthesized using a conventional cascade method (40 pF).

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Dynamic range limitations in linear OTA-based low-voltage continuous-time filters

Proceedings of 1994 37th Midwest Symposium on Circuits and Systems ◽

10.1109/mwscas.1994.519197 ◽

2002 ◽

Cited By ~ 2

Author(s):

J. Silva-Martinez ◽

G. Espinosa

Keyword(s):

Continuous Time ◽

Dynamic Range ◽

Low Voltage ◽

Continuous Time Filters

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Development of a shutterless continuous rotation method using an X-ray CMOS detector for protein crystallography

Journal of Applied Crystallography ◽

10.1107/s0021889809042277 ◽

2009 ◽

Vol 42 (6) ◽

pp. 1165-1175 ◽

Cited By ~ 16

Author(s):

Kazuya Hasegawa ◽

Kunio Hirata ◽

Tetsuya Shimizu ◽

Nobutaka Shimizu ◽

Takaaki Hikima ◽

...

Keyword(s):

Data Collection ◽

Dynamic Range ◽

Protein Structures ◽

Protein Crystallography ◽

New Method ◽

Oxide Semiconductor ◽

X Ray ◽

Rotation Method ◽

Continuous Rotation ◽

Wide Range

A new shutterless continuous rotation method using an X-ray complementary metal-oxide semiconductor (CMOS) detector has been developed for high-speed, precise data collection in protein crystallography. The principle of operation and the basic performance of the X-ray CMOS detector (Hamamatsu Photonics KK C10158DK) have been shown to be appropriate to the shutterless continuous rotation method. The data quality of the continuous rotation method is comparable to that of the conventional oscillation method using a CCD detector and, furthermore, the combination with fine φ slicing improves the data accuracy without increasing the data-collection time. The new method is more sensitive to diffraction intensity because of the narrow dynamic range of the CMOS detector. However, the strong diffraction spots were found to be precisely measured by recording them on successive multiple images by selecting an adequate rotation step. The new method has been used to successfully determine three protein structures by multi- and single-wavelength anomalous diffraction phasing and has thereby been proved applicable in protein crystallography. The apparatus and method may become a powerful tool at synchrotron protein crystallography beamlines with important potential across a wide range of X-ray wavelengths.

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