Bridge-output-to-frequency converter for smart thermal air-flow sensors

Author

Van Dijk, Gert J A ; Huijsing, Johan H.

Author_Institution

Delft Univ. of Technol., Netherlands

Volume

44

Issue

4

fYear

1995

fDate

8/1/1995 12:00:00 AM

Firstpage

881

Lastpage

886

Abstract

A fully integrated bridge-output-to-frequency converter has been realized as signal-conditioning circuitry for a one-chip smart thermal mass-flow sensor. The frequency converter reads out four separate resistor bridges of the air-flow sensor in order to realize high sensitivity and directional flow measurement over the full angle range of 360°. The converter selects the sensor bridges individually by means of a microprocessor-controlled analog multiplexer. The flow velocity and direction are also calculated by the microprocessor. The relative measurement cancels all first-order errors. The center frequency is 10 kHz and the sensitivity 1 Hz/(μV/V). A bridge-offset of 10 mV/V is allowed, and the linearity error is 0.1%

Keywords

bridge circuits; computerised instrumentation; flow measurement; flowmeters; intelligent sensors; signal processing equipment; voltage-frequency convertors; 10 kHz; air-flow sensor; bridge-offset; bridge-output-to-frequency converter; center frequency; directional flow measurement; flow direction; flow velocity; integrated bridge-output-to-frequency converter; microprocessor-controlled analog multiplexer; one-chip smart thermal mass-flow sensor; resistor bridges; sensitivity; signal-conditioning circuitry; smart thermal air-flow sensors; Bridge circuits; Fluid flow measurement; Frequency conversion; Frequency measurement; Integrated circuit measurements; Intelligent sensors; Microprocessors; Multiplexing; Resistors; Thermal sensors;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.392875

Filename

392875