An Offset Compensation Method With Low Residual Drift for Integrated Thermal Flow Sensors

Bruschi, P.; Dei, Michele; Piotto, M.

doi:10.1109/jsen.2010.2083651

Cited by 27 publications

(22 citation statements)

References 22 publications

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“…The main advantage of the model is the separation of the transduction process into distinct phases, which can be independently analyzed in order to find concise expressions to be used for global optimization of the device. A linearity hypothesis, based on reasonable approximations and supported by experimental results, is used to analyze multi-heater sensors, which have been recently proposed as an effective method to cancel the sensor offset [23] and extend the operating range [17,24]. The expressions derived from the proposed schematization include several sensor specifications and may constitute a framework for organizing new data obtained with further experimental investigations or fluid-dynamic simulations.…”

Section: Discussionmentioning

confidence: 99%

“…The basic operating principle of the sensor is simple: as the flow progressively increases, heat transfer in the downwind direction increases as well, producing a temperature difference that is sensed by the thermopiles. The typical configuration includes a single heater whereas multi-heater structures can be used to perform particular functions [17,[22][23][24] or simply extend the effective heater area with no adverse consequences on the etching time required to release the suspending membranes. Possible alternatives to the structure shown in Figure 1(a) are often used.…”

Section: Description Of the Sensor Structure And Main Performance Parmentioning

confidence: 99%

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Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

Bruschi

Piotto

2012

Micromachines

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Flow sensors are the key elements in most systems for monitoring and controlling fluid flows. With the introduction of MEMS thermal flow sensors, unprecedented performances, such as ultra wide measurement ranges, low power consumptions and extreme miniaturization, have been achieved, although several critical issues have still to be solved. In this work, a systematic approach to the design of integrated thermal flow sensors, with specification of resolution, dynamic range, power consumption and pressure insertion loss is proposed. All the critical components of the sensors, namely thermal microstructure, package and read-out interface are examined, showing their impact on the sensor performance and indicating effective optimization strategies. The proposed design procedures are supported by experiments performed using a recently developed test chip, including several different sensing structures and a flexible electronic interface.

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Section: Discussionmentioning

confidence: 99%

Section: Description Of the Sensor Structure And Main Performance Parmentioning

confidence: 99%

Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

Bruschi

Piotto

2012

Micromachines

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“…9.2 ). The sensing structures used in this work are made up of (1) a heater, split into two identical sections in order to perform offset compensation varying the power fed to the two resistors [ 7 ], and (2) two temperature probes placed upstream and downstream of the heater, respectively. Each heater is a 2 kΩ polysilicon resistor placed over a suspended silicon dioxide poly thermocouples with the hot contacts at the tip of a cantilever beam and the cold contacts on the silicon substrate.…”

Section: Device Description and Fabricationmentioning

confidence: 99%

“…In order to solve the problem, a solution without epoxy resin was proposed ( Fig. 9.3b ) [ 7 ]. A holder, connected to the guide with screws, keeps the conveyor pressed to the chip.…”

Section: Device Description and Fabricationmentioning

confidence: 99%

Smart Flow Sensors Based on Advanced Packaging Techniques Applied to Single Chip Sensing Devices

Piotto

Butti

Pennelli

et al. 2013

Lecture Notes in Electrical Engineering

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A smart flow sensor capable of measuring two distinct gas flows with two different linearity ranges is proposed. The device is based on a chip, designed with a commercial CMOS process, which includes different sensing structures and a read-out interface. The chip is fabricated applying a post-processing technique based on a silicon anisotropic etching in a TMAH solution. A simple and low cost packaging technique is used to convey two distinct gas flows to two selected sensing structures by means of channels of different cross sections. Three methods for sealing the interface between the chip and the gas conveyor are proposed and discussed

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“…Still, the method enabled rapid initialization of the sensor with a precision of about 1% of the resistance at zero flow, which probably could be improved further by employing computer control with feedback. 21 Defining the sensor output as the difference between the upstream and downstream resistors, the transfer curve of the sensor was more or less linear, Figure 3.…”

mentioning

confidence: 99%

A high-temperature calorimetric flow sensor employing ion conduction in zirconia

Persson

Lekholm

Thornell

et al. 2015

Applied Physics Letters

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This paper presents the use of the temperature-dependent ion conductivity of 8 mol % yttria-stabilized zirconia (YSZ8) in a miniature high-temperature calorimetric flow sensor. The sensor consists of 4 layers of high-temperature co-fired ceramic (HTCC) YSZ8 tape with a 400 μm wide, 100 μm deep, and 12 500 μm long internal flow channel. Across the center of the channel, four platinum conductors, each 80 μm wide with a spacing of 160 μm, were printed. The two center conductors were used as heaters, and the outer, up- and downstream conductors were used to probe the resistance through the zirconia substrate around the heaters. The thermal profile surrounding the two heaters could be made symmetrical by powering them independently, and hence, the temperature sensing elements could be balanced at zero flow. With nitrogen flowing through the channel, forced convection shifted the thermal profile downstream, and the resistance of the temperature sensing elements diverged. The sensor was characterized at nitrogen flows from 0 to 40 sccm, and resistances at zero-flow from 10 to 50 MΩ. A peak sensitivity of 3.1 MΩ/sccm was obtained. Moreover, the sensor response was found to be linear over the whole flow range, with R2 of around 0.999, and easy to tune with the individual temperature control of the heaters. The ability of the sensor to operate in high temperatures makes it promising for use in different harsh environments, e.g., for close integration with microthrusters.

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An Offset Compensation Method With Low Residual Drift for Integrated Thermal Flow Sensors

Cited by 27 publications

References 22 publications

Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

Smart Flow Sensors Based on Advanced Packaging Techniques Applied to Single Chip Sensing Devices

A high-temperature calorimetric flow sensor employing ion conduction in zirconia

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