Miniaturized thermal flow sensors based on thin film technology and Si-micromachining offer air-flow sensitivities in the cm/s range and respond within milliseconds. The descending slope of the sensor characteristic gives sufficient dynamic compression to extend the flow measurement range over five orders of magnitude. With a novel design approach advanced transduction principles become feasible, which enable added system functionality like autonomous self-check, adaptive sensitivity and transduction fault analysis. Closed loop transduction and the redundancy of all key elements of the sensor are generic foundations of the approach. All temperature sensors and the thermal actuators are designed for pulsed-mode operation and match directly with the i/o characteristics of highly integrated microelectronic circuitry.
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