scholarly journals An ultra-low noise capacitance to voltage converter for sensor applications in 0.35  µm CMOS

2017 ◽  
Vol 6 (2) ◽  
pp. 285-301 ◽  
Author(s):  
Alexander Utz ◽  
Christian Walk ◽  
Norbert Haas ◽  
Tatjana Fedtschenko ◽  
Alexander Stanitzki ◽  
...  

Abstract. In this paper we present a readout circuit for capacitive micro-electro-mechanical system (MEMS) sensors such as accelerometers, gyroscopes or pressure sensors. A flexible interface allows connection of a wide range of types of sensing elements. The ASIC (application-specific integrated circuit) was designed with a focus on ultra-low noise operation and high analog measurement performance. Theoretical considerations on system noise are presented which lead to design requirements affecting the reachable overall measurement performance. Special emphasis is put on the design of the fully differential operational amplifiers, as these have the dominant influence on the achievable overall performance. The measured input referred noise is below 50 zF/Hz within a bandwidth of 10 Hz to 10 kHz. Four adjustable gain settings allow the adaption to measurement ranges from ±750 fF to ±3 pF. This ensures compatibility with a wide range of sensor applications. The full input signal bandwidth ranges from 0 Hz to more than 50 kHz. A high-precision accelerometer system was built from the described ASIC and a high-sensitivity, low-noise sensor MEMS. The design of the MEMS is outlined and the overall system performance, which yields a combined noise floor of 200 ng/Hz, is demonstrated. Finally, we show an application using the ASIC together with a CMOS integrated capacitive pressure sensor, which yields a measurement signal-to-noise ratio (SNR) of more than 100 dB.

2013 ◽  
Vol 313-314 ◽  
pp. 666-670 ◽  
Author(s):  
K.J. Suja ◽  
Bhanu Pratap Chaudhary ◽  
Rama Komaragiri

MEMS (Micro Electro Mechanical System) are usually defined as highly miniaturized devices combining both electrical and mechanical components that are fabricated using integrated circuit batch processing techniques. Pressure sensors are usually manufactured using square or circular diaphragms of constant thickness in the order of few microns. In this work, a comparison between circular diaphragm and square diaphragm indicates that square diaphragm has better perspectives. A new method for designing diaphragm of the Piezoresistive pressure sensor for linearity over a wide pressure range (approximately double) is designed, simulated and compared with existing single diaphragm design with respect to diaphragm deflection and sensor output voltage.


2019 ◽  
Vol 11 (12) ◽  
pp. 11928-11935 ◽  
Author(s):  
Jian Wang ◽  
Ryuki Suzuki ◽  
Marine Shao ◽  
Frédéric Gillot ◽  
Seimei Shiratori

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6588
Author(s):  
Jun Ho Lee ◽  
Jae Sang Heo ◽  
Keon Woo Lee ◽  
Jae Cheol Shin ◽  
Jeong-Wan Jo ◽  
...  

For wearable health monitoring systems and soft robotics, stretchable/flexible pressure sensors have continuously drawn attention owing to a wide range of potential applications such as the detection of human physiological and activity signals, and electronic skin (e-skin). Here, we demonstrated a highly stretchable pressure sensor using silver nanowires (AgNWs) and photo-patternable polyurethane acrylate (PUA). In particular, the characteristics of the pressure sensors could be moderately controlled through a micro-patterned hole structure in the PUA spacer and size-designs of the patterned hole area. With the structural-tuning strategies, adequate control of the site-specific sensitivity in the range of 47~83 kPa−1 and in the sensing range from 0.1 to 20 kPa was achieved. Moreover, stacked AgNW/PUA/AgNW (APA) structural designed pressure sensors with mixed hole sizes of 10/200 µm and spacer thickness of 800 µm exhibited high sensitivity (~171.5 kPa−1) in the pressure sensing range of 0~20 kPa, fast response (100~110 ms), and high stretchability (40%). From the results, we envision that the effective structural-tuning strategy capable of controlling the sensing properties of the APA pressure sensor would be employed in a large-area stretchable pressure sensor system, which needs site-specific sensing properties, providing monolithic implementation by simply arranging appropriate micro-patterned hole architectures.


Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3673
Author(s):  
Christopher Rogi ◽  
Cesare Buffa ◽  
Niccolo De Milleri ◽  
Richard Gaggl ◽  
Enrique Prefasi

This article focuses on a proposed Switched-Capacitor Dual-Slope based CDC. Special attention is paid to the measurement setup using a real pressure sensor. Performance scaling potential as well as dead zones are pointed out and discussed. In depth knowledge of the physical sensor behavior is key to design an optimal readout circuit. While this is true for high-end applications, low-performance IoT (Internet of Things) sensors aim at moderate resolution with very low power consumption. This article also provides insights into basic MEMS (Micro-Electro-Mechanical-System) physics. Based on that, an ambient air pressure sensor model for SPICE (Simulation-Program-with-Integrated-Circuit-Emphasis) circuit simulators is presented. The converter concept was proven on silicon in a 0.13 μ m process using both a real pressure sensor and an on-chip dummy MEMS bridge. A 3.2-ms measurement results in 13-bit resolution while consuming 35 μ A from a 1.5-V supply occupying 0.148 mm2. A state-of-the-art comparison identifies potential room for improvements towards hybrid solutions, which is proposed in subsequent publications already.


Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3379 ◽  
Author(s):  
Caterina Travan ◽  
Alexander Bergmann

Graphene is a good candidate for filling the market requirements for cheap, high sensitivity, robust towards contamination, low noise, and low power consumption gas sensors, thanks to its unique properties, i.e., large surface, high mobility, and long-term stability. Inkjet printing is a cheap additive manufacturing method allowing fast, relatively precise and contactless deposition of a wide range of materials; it can be considered therefore the ideal technique for fast deposition of graphene films on thin substrates. In this paper, the sensitivity of graphene-based chemiresistor gas sensors, fabricated through inkjet printing, is investigated using different concentrations of graphene in the inks. Samples have been produced and characterized in terms of response towards humidity, nitrogen dioxide, and ammonia. The presented results highlight the importance of tuning the layer thickness and achieving good film homogeneity in order to maximize the sensitivity of the sensor.


2014 ◽  
Vol 174 ◽  
pp. 357-367 ◽  
Author(s):  
Lynn Dennany ◽  
Zahera Mohsan ◽  
Alexander L. Kanibolotsky ◽  
Peter J. Skabara

Electrochemiluminescence (ECL) uses redox reactions to generate light at an electrode surface, and is gaining increasing attention for biosensor development due to its high sensitivity and excellent signal-to-noise ratio. ECL studies of monodisperse oligofluorene–truxenes (T4 series) have been reported previously, showing the production of stable radical cations and radical anions, generating blue ECL. The compound in this study differs from the original structures, in that there are 2,1,3-benzothiadazole (BT) units inserted between the first and second fluorene units of the quarterfluorenyl arms. It was therefore anticipated that the incorporation of these highly luminescent and ECL-active compounds into sensor development would lead to significant decreases in detection limits. In this contribution, we report on the impact of incorporating these novel complexes into sensor devices on the ECL efficiency, as well as the ability of these to improve the detection sensitivity and decrease the limit of detection using the reagent-free detection of model analytes. The real world impact of these compounds is elucidated through the comparison with more standard ECL materials such as ruthenium-based compounds. The potential for multiple applications is to be examined within this contribution.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4,000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated.


2015 ◽  
Vol 28 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Milos Frantlovic ◽  
Ivana Jokic ◽  
Zarko Lazic ◽  
Branko Vukelic ◽  
Marko Obradov ◽  
...  

Temperature and pressure are the most common parameters to be measured and monitored not only in industrial processes but in many other fields from vehicles and healthcare to household appliances. Silicon microelectromechanical (MEMS) piezoresistive pressure sensors are the first and the most successful MEMS sensors, offering high sensitivity, solid-state reliability and small dimensions at a low cost achieved by mass production. The inherent temperature dependence of the output signal of such sensors adversely affects their pressure measurement performance, necessitating the use of correction methods in a majority of cases. However, the same effect can be utilized for temperature measurement, thus enabling new sensor applications. In this paper we perform characterization of MEMS piezoresistive pressure sensors for temperature measurement, propose a sensor correction method, and demonstrate that the measurement error as low as ? 0.3?C can be achieved.


2021 ◽  
Author(s):  
Ankur Gupta

Swiftly emerging research prospects in the Micro-Electro-Mechanical System (MEMS) enable to build of complex and sophisticated microstructures on a substrate containing moving masses, cantilevers, flexures, levers, linkages, dampers, gears, detectors, actuators, and many more on a single chip. One of the MEMS initial products that emerged into the micro-system technology is the MEMS pressure sensor. Because of their high performance, low cost, and compact size, these sensors are extensively being adopted in numerous applications viz., aerospace, automobile, and bio-medical domain, etc. These application requirements drive and impose tremendous conditions on sensor design to overcome the tedious design and fabrication procedure before its reality. MEMS-based pressure sensors enable a wide range of pressure measurements as per the application requirements. Considering its vast utility in industries, this paper presents a detailed review of MEMS-based pressure sensors and their wide area of applications, their design aspects, and challenges, to provide state of an art gist to the researchers of a similar domain in one place.


Sign in / Sign up

Export Citation Format

Share Document