AC-Driven Temperature-Balance Flow Sensor

Lammerink, Theodorus S.J.; Tas, Niels Roelof; Honschoten, J.W. van; Krijnen, Gijs; Baar, J.J. van; Elwenspoek, M.

doi:10.1007/978-3-642-59497-7_335

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…The sensitivity curves as a function of the convection coefficient were calculated for the three hot resistors and for both the operating conditions [8,9,10] which are at constant electrical dissipated power and at constant temperature difference between the two resistors. The obtained plots are shown in Fig 3a and Fig.…”

Section: Thermal Simulationsmentioning

confidence: 99%

Study of water speed sensitivity in a multifunctional thick-film sensor by analytical thermal simulations and experiments

Stefani

Bagnoli

Luschi

2007

2007 13th International Workshop on Thermal Investigation of ICs and Systems (THERMINIC)

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A multifunctional (temperature, liquid flow, pressure and electrical conductivity) thick film sensor for monitoring water pipelines is here presented. This work is mainly focused on the theoretical and experimental characterization of the water flow sensitivity based on a planar version of the well-known hot-wire anemometer. The simulations of the temperature displacement on the sensor surface under several electrical biases and heat convection conditions were performed by means of the fast analytical thermal simulator DJOSER, thus providing an example of the capability and the utility of this simulation program. The calculated sensitivity curves to the heat convection coefficient and/or to the water speed were found to be in agreement with the experimental data measured on the sensor mounted within a closed pipeline which allows changing the water speed until 1000 liters/hour. I.

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Section: Thermal Simulationsmentioning

confidence: 99%

Study of water speed sensitivity in a multifunctional thick-film sensor by analytical thermal simulations and experiments

Stefani

Bagnoli

Luschi

2007

2007 13th International Workshop on Thermal Investigation of ICs and Systems (THERMINIC)

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“…A different low-drift approach is described in this paper, only requiring thin-film resistors. The presented thermal-wave balancing flow sensor applies sinusoidal currents on two heater resistors [12,13], where a lock-in amplifier measures the resulting thermal waves on a single sensing resistor. The thermal-wave balancing measurement method and use of a lock-in amplifier rejects nearly all low frequency drift of the sensor, thus providing a flow sensor nearly independent of resistance drift and thermal gradient across the chip.…”

Section: Introductionmentioning

confidence: 99%

Thermal-wave balancing flow sensor with low-drift power feedback

Dijkstra

Lammerink²,

Pjetri³

et al. 2014

J. Micromech. Microeng.

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A control system using a low-drift power-feedback signal was implemented applying thermal waves, giving a sensor output independent of resistance drift and thermo-electric offset voltages on interface wires. Kelvin-contact sensing and power control is used on heater resistors, thereby inhibiting the influence of heater resistance drift. The thermal waves are detected with a sensing resistor using a lock-in amplifier and are mutually cancelled by a thermal-wave balancing controller. Offset due to thermal gradient across the chip and resistor drift are eliminated by the lock-in amplifier and power controller, and therefore do not influence the sensor output signal. A microchannel thermal-wave balancing flow sensor with integrated Al resistors has successfully been fabricated. The thermal flow sensor is capable of measuring water flow rates with nl · min −1 precision, up to about 500 nl · min −1 full scale. Measurement results are in good agreement with a dynamic model of the flow sensor. Drift measurements show the sensor output signal to be compensated for resistance drift and thermal gradient across the chip.

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