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We present a circuit for strain and vibration sensing from piezoelectric film elements (PVDF). The target application is the monitoring of low-frequency vibration in a biomedical wearable device. Since standard PVDF sensors produce an open-circuit voltage that is too large for direct amplification on an integrated circuit, the circuit performs input signal folding as well as output voltage attenuation...
We present a second generation current conveyor (CCII) based electronic interface for differential capacitive sensors. The sensor interface performs a capacitance-to-voltage conversion and has been designed in a discrete board as well as in an integrated version showing a linear input/output characteristic. Simulated and experimental results conducted on the discrete element board employing the low...
This paper presents a symmetrical hybrid nine-level inverter with reduced voltage sensors. A capacitor voltage estimation method is proposed based on phase-shifted PWM by only measuring the total DC-link voltage and the multilevel phase voltage. Under certain conditions, a modified algorithm to further reduce the number of voltage sensors is given. Simulation results are presented to demonstrate these...
In this work, we present two analog current-mode interfaces performing differential sensor capacitance measurements through a voltage reading. The AC peak-to-peak output voltage is proportional to the measurand x that is directly related to the differential capacitance variation. The first interface is able to read the sensor change through a current-to-voltage conversion, while the second one employs...
Modular multilevel converter (MMC) is an attractive choice for transformer-less and filter-less high power conversion system due to its ability to upscale to high voltage levels by the use of semiconductors. The capacitor voltages on each converter cell are important variables to be monitored not only for the proper control of MMC but also for the fault detection and protection. At the same time,...
This paper describes a simple approach to perform differential capacitance measurements by the design and characterization of a dedicated electronic circuit. Capacitance transducers provide information about changes in capacitance in response to a physical variation. They are used in many types of applications such as linear displacement sensors, pressure transducers and accelerometers. The operating...
This paper presents an online paper thickness detection method based on capacitive sensor. The detector uses CAV424 as capacitance measuring device and system on chip MSP430F149 as the control core. Fault conditions can be controlled in real time by comparing the real-time voltage signal. C language is used to build interactive interface. Fault conditions and paper thickness can be displayed on the...
In this paper, a liquid level transmitter using cylindrical capacitive sensor and an improved linearized network for capacitance measurement has been proposed to measure the liquid level and to convert level changes into an electrical current which can be transmitted to a remote indicator. The change in capacitance of cylindrical capacitive sensor due to change in liquid level is measured by an improved...
We report the noise analysis of a capacitor to voltage converter (CVC) with a zoom-in concept, used as a first stage in capacitive sensor interfaces for measuring very small capacitance variations. We will show that the zoom-in concept introduced in the first stage can not only relax the resolution requirement of the following stages, i.e. an analog-to-digital converter (ADC), but it can also increase...
This paper presents a novel circuit topology to be used with a differential capacitive microsensor. Adopting sampling switches and utilizing modified digital blocks has resulted in a remarkably compact and low-power design. The high linearity in conversion of charge to voltage and the wide range applicability of proposed topology satisfies the design criteria for many applications. The proposed topology...
A low-power CMOS capacitance-to-digital converter for capacitive sensors array is presented. It consists of a 16-channel MUX, a front-end with wide dynamic range for capacitance-voltage conversion and a novel voltage-pulses convertor. This novel circuit charges the measured capacitor indirectly and converts it into a proportional voltage, and then produces a 16-bits pulses-formed single-line output...
Muslims have genuine concerns regarding origin of the meat at the market. On the other hand, several Muslim countries import meat whose origin is doubtful and bearing an unverifiable HALAL-label. This is because there is no intelligence device available to check either meat is slaughtered or not? Therefore, the purpose of this study is to determine the values of the dielectric constant of chicken...
Long term stability of a DC voltage standard based on a MEMS plate capacitor was investigated. Square wave voltage excitation was used to cancel the effect of slow charging appearing in the dielectric layers and capacitor plate surfaces of the MEMS capacitor. The key properties of a MEMS capacitor and the operational principle of the apparatus that implements the voltage standard are explained.
We present a capacitive measurement technique used to measure small displacement in industrial environments without electrical contact with the target. The range of the measured capacitance is up to 10 pF in less than 100 μs. This type of technique also enables remote sensing of small displacement since the feedforward active shielding technique is used to obtain a tolerance of up to 10 meters cables...
This paper reviews the need for feedback to damp the resonance of a low-noise capacitive microphone, evaluates alternative feedback structures with different measurement mechanisms for their control effectiveness, and finally investigates the feasibility of a low-cost mechanism that uses the voltage across the capacitive sensor as the feedback variable. This capacitive sensing mechanism leads to a...
A capacitive sensor has been developed for the measurements of very fast transient over-voltages (VFTO) in GIS. Step response measurement was performed on the sensor. It is shown from the test that the settling time is less than 20 ns and the response time is less than 2 ns, suitable to the IEC1321-1. The sensor has been calibrated by power frequency voltage, impulse voltage, the division ratio of...
We designed a fast capacitive high voltage probe for a Marx generator. Since the capacitive probe works on differential mode, we designed also a fast passive integrator to integrate the signals. We tested the probe's performance by using a simple pulse generator to simulate the Marx generator signals. We calibrated the probe using a calibrated water load which act as a resistive voltage divider. We...
The Reconfigurable Smart Sensory Chip (RSSC) is a powerful tool for fast prototyping sensory microsystems. Innovative design ideas can be quickly realized and tested in hardware without doing time-consuming and expensive silicon fabrication. The RSSC is a large-scale floating-gate based IC containing 8 universal sensor interface blocks, each of which can be configured for voltage sensing, capacitive...
In this paper, a micropower low-dropout regulator (LDO) for a low-power capacitive sensor interface fabricated in a 0.25 mum BiCMOS process is presented. The LDO with on-chip voltage and current references, and an on-chip programmable load capacitor, occupies an active silicon area of 0.18 mm2. It is stable with zero load current over the load capacitance range from 0 to 1 nF. The input voltage range...
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