Search results for "Wheatstone bridge"

A novel current-based approach for very low variation detection of resistive sensors in wheatstone bridge configuration

2014

A tunnel magnetoresistive effect wattmeters-based wireless sensors network

2017

Abstract In the present work a wireless sensors network (WSN) for smart energy metering is presented using the ZigBee protocol as the communication link. Each network node process the electrical power by means of a Wheatstone bridge sensor based on the tunnel magnetoresistive (TMR) effect working as analogue multiplier. The electrical power is acquired and processed by a digital signal processor that extracts various parameters of interest like current and voltage load, active power and power factor by means of Fourier analysis. All the obtained electrical parameters at each node are served and shown in a web page that can be easily accessed by authorized users.

Design, fabrication, and analysis of a spin-valve based current sensor

2004

Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…

Measuring low H field and currents with AMR sensors

2017

The growing demand from the automotive industry for high accuracy magnetic sensors and the need to perform high resolution angular position measurements have been the drivers for the industrial research in magnetic sensing technologies. This paper describes the design and characterization of several experimental devices implementing simple magnetoresistive structures targeting contactless current measurement in the tens to hundreds of milliamps range with sub-mA resolution. The ultimate goal is to extend the application area of magnetoresistive sensors beyond their current niche in automotive into more general applications. The initial set of devices tested to-date has shown a sensitivity o…

A Non-Invasive Thermal Drift Compensation Technique Applied to a Spin-Valve Magnetoresistive Current Sensor

2011

A compensation method for the sensitivity drift of a magnetoresistive (MR) Wheatstone bridge current sensor is proposed. The technique was carried out by placing a ruthenium temperature sensor and the MR sensor to be compensated inside a generalized impedance converter circuit (GIC). No internal modification of the sensor bridge arms is required so that the circuit is capable of compensating practical industrial sensors. The method is based on the temperature modulation of the current supplied to the bridge, which improves previous solutions based on constant current compensation. Experimental results are shown using a microfabricated spin-valve MR current sensor. The temperature compensati…

Analytical compact modeling of GMR based current sensors: Application to power measurement at the IC level

2010

An analytical compact model for giant magnetoresistance (GMR) based current sensors has been developed. Different spin-valve based full Wheatstone bridge sensors, with the current straps integrated in the chip, have been considered. These devices have been experimentally characterized in order to extract the model parameters. In this respect, we have focused on the sensors linear operation regime. The model, which allows the individual description of the magnetoresistive elements, has been implemented in a circuit simulator by means of a behavioral description language: Verilog-A. We also propose the use of the devices in a direct power measurement application at the integrated circuit (IC)…

Active power analog front-end based on a Wheatstone-type magnetoresistive sensor

2011

Abstract In the proposed work a practical magnetoresistive wattmeter based on a commercial sensor is designed to measure active power at industrial frequencies. The electronic conditioning circuit uses differential blocks in order to preserve the sensor initial common mode rejection ratio. A 700 W power level has been reached with an uncertainty less than 1%. With few changes the proposed circuitry could be used in metering applications.

Modeling of Magnetoresistive-Based Electrical Current Sensors: A Technological Approach

2007

The utilization of modeling tools can, in many cases, help us in the design and final prototyping of any sort of sensors. In this paper, we describe a finite-element method (FEM) model applied to a hybrid technology involving a full Wheatstone bridge spin-valve-based electrical current sensor. After validating the model against experimental results, we focus our studies on geometrical aspects of the sensor configuration, in order to detect possible deviations that may have occurred during the fabrication process. In this regard, the characteristics of the behavior of the sensor depending on lateral displacements and inclination are included. Moreover, the frequency response of the sensor is…

Power monitoring in dielectric-loaded surface plasmon-polariton waveguides

2011

We report on propagating mode power monitoring in dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) by measuring the resistance of gold stripes supporting the DLSPPW mode propagation. Inevitable absorption of the DLSPPW mode in metal causes an increase in the stripe temperature and, thereby, in its resistance whose variations are monitored with an external Wheatstone bridge being accurately balanced in the absence of radiation in a waveguide. The investigated waveguide configuration consists of a 1-µm-thick and 10-µm-wide polymer ridges tapered laterally to a 1-µm-wide ridge placed on a 50-nm-thin and 4-µm-wide gold stripe, all supported by a magnesium fluoride substrate. Usi…

Quasi‐digital front‐ends for current measurement in integrated circuits with giant magnetoresistance technology

2014

In this study, the authors report on two different electronic interfaces for low-power integrated circuits electric current monitoring through current-to-frequency (I-f) conversion schemes. This proposal displays the intrinsic advantages of the quasi-digital systems regarding direct interfacing and self-calibrating capabilities. In addition, as current-sensing devices, they have made use of the giant magnetoresistance (GMR) technology because of its high sensitivity and compatibility with standard complementary metal oxide semiconductor processes. Single elements and Wheatstone bridges based on spin-valves and magnetic tunnel junctions have been considered. In this sense, schematic-level si…