Low-cost thermal sigma-delta air flow sensor
Domínguez, M.; Masana, Fn; Jiménez, V.; Bermejo, S.; Amirola, J; Ballester, J.; Fueyo, N.; Castaner, Lm.
Ieee Sensors Journal. 2002
This paper describes the design and optimization of a hot-wire air flowmeter. A low-cost design of the packaging allows good thermal contact with the airflow, as well as good thermal isolation between the hot and cold points. It is a compact solution which allows easy PCB mounting and adaptation to standard-size small air pipes. The design has been optimized for low-cost applications. The sensor is read out by a thermal sigma-delta modulator. The dynamic range of this modulator has been extended by adding a constant power offset to its output. The fractal nature of the modulator response at low-clock frequencies is also experimentally shown.