Capacitance testing circuit and capacitance-type sensor interface circuit chip thereof

Abstract

The invention discloses a capacitance testing circuit and capacitance-type sensor interface circuit chip thereof, which relates to the sensor device field and resolves problems that the capacitance testing circuit has complicated structure and the capacitance-type sensor interface circuit chip has large volume and is inefficient. The capacitance testing circuit includes a capacitance readout front end circuit, a demodulation amplifying circuit whose input end is connected to the capacitance readout front end circuit, and a buffering amplifying circuit whose input end is connected to the demodulation amplifying circuit. The capacitance-type sensor interface circuit chip includes a self measuring circuit, a bias current producing circuit, a sensor zero bias compensating circuit, a reference voltage generation circuit, a clock generation circuit, and a capacitance testing circuit respectively connected to the circuits; the self measuring circuit and the sensor zero bias compensating circuit are respectively connected to a outer capacity sensor; the capacitance-type sensor interface circuit chip is prepared by using an integrate circuit technique. The invention is suitable for open-loop or equilibrium closed-loop accelerameter and vibratory rate gyroscope.

Description

technical field [0001] The invention relates to the field of sensor devices, in particular to a capacitive detection circuit capable of simplifying structure and better suppressing low-frequency noise and a capacitive sensor interface circuit thereof. Background technique [0002] Capacitive microsensors are generally small in size, simple in structure, and have the advantages of low power consumption, high sensitivity, and low temperature sensitivity, and are widely used in civilian industrial control and military fields. In the design of the capacitive microsensor system, the interface circuit of the capacitive microsensor determines the resolution of the microsensor system to the detection quantity to a certain extent. The existing capacitive readout circuit structure that is easy to integrate and widely used is mainly based on the continuous-time voltage detection technology of modulation and demodulation. The structure is relatively complicated, and it is not easy to be...

AI Technical Summary

Problems solved by technology

The existing easy-to-integrate and widely used capacitive readout circuit structure is mainly based on the continuous-time voltage detection technology of modulation and demodulation, the structure is relatively complex, and it is not easy to be compatible with the traditional CMOS process

Moreover, the existing capacitive microsensor interface circuit is made of discrete components, which not only has a large volume and low resolution, but also has high repeatability, low reliability, and high cost, which greatly reduces the advantages of microsensors.

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