Output measuring circuit and measuring method of capacitance differential pressure transducer

Abstract

The invention discloses an output measuring circuit of a capacitance-typed differential pressure sensor. The output measuring circuit comprises a switch unit and a sub capacitance measuring circuit, wherein, the sub capacitance measuring circuit comprises at least a digital capacitance converter that comprises a high-frequency signal output end and at least two signal input ends, one end of a capacitance C2 that is corresponding to negative cavity pressure of the sensor is serially connected with the switch unit and then connected with one of the signal input ends, one end of the other capacitance C1 that is corresponding to positive cavity pressure of the sensor is connected with the other signal input end, and the other ends of the capacitances C1 and C2 are mutually connected and then connected with the high-frequency signal output end. The digital capacitance converter is used for measuring the electric capacity difference Delta C between the measured capacitances C1 and C2 when the switch unit is on and measuring the electric capacity of the single capacitance C1 when the switch unit is off, the electric capacity value of C1 plus C2 is obtained by subtracting two times of the value of C1 with Delta C, and result of Delta C divided by the value of C1 plus C2 is calculated, thus obtaining the sensor output quantity that is proportional to the pressure difference. The invention further provides a corresponding measuring method.

Description

technical field [0001] The invention relates to a sensor signal processing method, in particular to an output measurement circuit in a capacitive differential pressure sensor and a corresponding implementation method. Background technique [0002] When measuring non-electrical quantities by electrical measurement, the measured non-electrical quantities must first be converted into electrical quantities and then input. Usually, the components that convert non-electrical quantities into electrical quantities are called converters; the related conversion devices designed according to the characteristics of different non-electrical quantities are called sensors, and the measured mechanical quantities (such as displacement, force, speed, etc.) are converted into A sensor that changes capacitance is called a capacitive sensor. Capacitive sensors are widely used in the testing of displacement, pressure, flow, liquid level, etc. Accuracy and stability of capacitive sensors are als...

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Problems solved by technology

[0013] An object of the present invention is to provide an output measurement circuit of a capacitive differential pressure sensor to solve the technical problem of low sensor output accuracy in the prior art

[0014] Another object of the present invention is to provide a method for measuring the output of a capacitive differential pressure sensor to solve the technical problem of low sensor output accuracy in the prior art

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