Low-drift flow sensor with zero-offset thermopile-based power feedback
| Autor: | Dijkstra, M., Lammerink, T.S.J., de Boer, M.J., Berenschot, J.W., Wiegerink, R.J., Elwenspoek, M., Bright, Victor M. |
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| Rok vydání: | 2008 |
| Předmět: |
Temperature control
Materials science Physics::Instrumentation and Detectors business.industry Water flow Acoustics Thermal resistance Electrical engineering Feedback loop Thermopile Temperature measurement Computer Science::Other law.invention Volumetric flow rate Physics::Fluid Dynamics law TST-SENSORS Resistor business |
| Zdroj: | Collection of papers presented at the DTIP of MEMS & MOEMS: Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS: 9-11 April 2008, Nice, France Collection of papers presented at the DTIP of MEMS & MOEMS |
| Popis: | A thermal flow sensor has been realised consisting of freely-suspended silicon-rich silicon-nitride microchannels with an integrated Al/poly-Si++ thermopile in combination with up- and downstream Al heater resistors. The inherently zero offset of the thermopile is exploited in a feedback loop controlling the dissipated power in the heater resistors, eliminating inevitable influences of resistance drift and mismatch of the thin-film metal resistors. The control system cancels the flow-induced temperature difference across the thermopile by controlling a power difference between both heater resistors, thereby giving a measure for the flow rate. The flow sensor was characterised for power difference versus water flow rates up to 1.5 mul-min-1, being in good agreement with a thermal model of the sensor, and the correct low-drift operation of the temperature-balancing control system has been verified. |
| Databáze: | OpenAIRE |
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