Interface circuit of differential capacitance micro vibrating sensor

Abstract

The invention relates to an interface circuit of a differential capacitance micro vibrating sensor. The interface circuit is composed of a power supply voltage stabilizing circuit, a square wave exciting circuit, a C-V conversion circuit, an amplification filter circuit and a micro vibrating sensor sensing element. The interface circuit is in a single-supply power supply mode; and diodes D1 and D2 and capacitors C4 and C5 are employed inside the interface circuit to supply power for internal devices. A square wave excitation signal is generated by an RC crystal oscillator and passes through aresistor Rs1; and then the square wave excitation signal is divided into two paths of signals that respectively pass through a capacitor Cn1 and a capacitor Cn2; and charging and discharging are carried out on sensitive capacitors Cs1 and Cs2. The C-V conversion circuit linearly converts a differential capacitor delta C into a single-voltage signal Vsense; and then amplification and filtering arecarried out on the single-voltage signal Vsense and then the processed signal is output. According to the invention, the principle is simple and there is no large-scale integrated chip; and cost is low as well as miniaturization and low power consumption are easy to realize. The design is flexible; and temperature compensation, zero adjustment, and positive and negative sensitivity adjustment andthe like can be respectively carried out. And precision of detection on a weak signal generated by the differential capacitance micro vibrating sensor is high; a noise level is low; and stability is good.

Description

technical field

[0001] The invention relates to an interface circuit of a tolerance-type micro-vibration sensor, which belongs to the technical field of weak signal detection. Background technique

[0002] Vibration sensors have always played an important role in inertial navigation, earth observation, deep space exploration, and precise guidance of high-tech weapons. Sensors are in urgent need.

[0003] Capacitive vibration sensors have received special attention in recent years because of their characteristics in measurement accuracy, temperature characteristics, low power consumption, wide dynamic response range and simple structure, especially in the field of μg-level high-precision micro-vibration applications, and have been widely used. . The sensitive signal of the capacitive sensor is capacitance. The principle is generally that a parallel plate capacitor is formed between the sensitive mass and the substrate. When the measured substrate vibrates, the sensitive mas...

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