CN222215717U - Signal conditioning circuit of piezoelectric ceramic sensor - Google Patents

Abstract

The utility model relates to a signal conditioning circuit of a piezoelectric ceramic sensor, which comprises an input end, a filtering module, a field effect tube, a voltage reference chip and an output end, wherein the input end is provided with an input interface for receiving input signals, the filtering module is connected with the input interface, a grid electrode of the field effect tube is connected with the filtering module, a source electrode of the field effect tube is connected with a constant current source, a drain electrode of the field effect tube is grounded, a reference voltage port of the voltage reference chip is connected with the source electrode of the field effect tube, and the output end is provided with an I EPE interface for outputting signals. The utility model adopts fewer components with smaller packaging size, realizes the conversion from the piezoelectric ceramic output charge signal to the voltage signal and the conversion of the sensor circuit output by the standard I EPE interface, and is convenient for the sensor to be directly connected with a signal acquisition system for use.

Description

Signal conditioning circuit of piezoelectric ceramic sensor

Technical Field

The utility model relates to the technical field of signal processing of piezoelectric ceramic sensors, in particular to a signal conditioning circuit of a piezoelectric ceramic sensor.

Background

Currently, those piezoelectric ceramic sensors used to measure vibration, shock and acceleration generally need to be directly mounted to the object under test. However, some of the objects do not all weigh far more than the sensor. Therefore, when selecting the sensor, the sensor is required to be miniaturized as much as possible so as to minimize the influence of the sensor mounting on the characteristics of the object to be measured. Therefore, in designing the sensor, it is necessary to miniaturize and miniaturize the sensor as much as possible.

The sensor adopts piezoelectric ceramics as a measurement sensitive device, and when the sensor works, the piezoelectric ceramics can generate charge signals, and because the charge signals are weak, a signal conditioning circuit is required to process the charge signals generated by the piezoelectric ceramics. The signal conditioning circuit is used as a key part of the sensor, but the signal conditioning circuit in the prior art has the defects of more circuit components, complex circuit structure, larger packaging size and high cost, which severely limits the development of miniaturization and microminiaturization of the sensor, and the signals processed by the signal conditioning circuit in the prior art are not easy to be directly collected and used by a signal collecting system.

Therefore, there is an urgent need to propose an innovative signal conditioning circuit for a piezoceramic sensor to overcome the above technical drawbacks of the prior art.

Disclosure of utility model

Therefore, the technical problem to be solved by the utility model is to overcome the technical defects in the prior art, and provide the signal conditioning circuit of the piezoelectric ceramic sensor, which adopts fewer components with smaller packaging size, realizes the conversion from the piezoelectric ceramic output charge signal to the voltage signal and the conversion of the sensor circuit output by a standard I EPE interface, and is convenient for the sensor to be directly connected with a signal acquisition system for use.

In order to solve the technical problems, the utility model provides a signal conditioning circuit of a piezoelectric ceramic sensor, which comprises:

an input having an input interface for receiving an input signal;

a filtering module connected with the input interface;

The grid electrode of the field effect tube is connected with the filtering module, the source electrode of the field effect tube is connected with the constant current source, and the drain electrode of the field effect tube is grounded;

The reference voltage port of the voltage reference chip is connected with the source electrode of the field effect transistor;

An output having an iepe interface for outputting a signal.

In one embodiment of the present utility model, the first resistor is further included, and the first resistor is connected between the source of the field effect transistor and the constant current source.

In one embodiment of the utility model, the first capacitor is connected between the positive electrode and the negative electrode of the I EPE interface.

In one embodiment of the present utility model, the input interface includes a positive connection point and a negative connection point, the positive connection point being connected to the filter module, the negative connection point being grounded.

In one embodiment of the present utility model, the filtering module includes a second resistor, a third resistor, a second capacitor, and a third capacitor, where the third resistor, the second capacitor, and the third capacitor are all connected in parallel between the positive electrode connection point and the negative electrode connection point, and the second resistor is connected between the second capacitor and the positive electrode connection point.

In one embodiment of the present utility model, the device further includes a fourth resistor, and the fourth resistor is connected to the drain electrode of the field effect transistor.

In one embodiment of the present utility model, a power port of the voltage reference chip is connected to the constant current source, and a ground port of the voltage reference chip is grounded.

Compared with the prior art, the technical scheme of the utility model has the following advantages:

1. The signal conditioning circuit adopts fewer components with smaller packaging size, realizes the conversion from the piezoelectric ceramic output charge signal to the voltage signal and the conversion of the sensor circuit output by the standard I EPE interface, and is convenient for the sensor to be directly connected with a signal acquisition system for use;

2. The utility model provides a circuit scheme for realizing standardization of a signal conditioning interface of a piezoelectric ceramic sensor by using discrete devices, wherein a field effect transistor and a voltage reference chip are basic electronic components which are low in cost and easy to purchase, other circuit components only have resistance and capacitance, all electronic components have high replaceability, the circuit components are not limited to a certain model product of a certain manufacturer, but can be used only by corresponding parameter coincidence, and all electronic components in the design scheme have various different packaging sizes, so that the proper component packaging can be selected according to the design size of the sensor, and the mounting size requirement of piezoelectric sensors with different sizes on the signal conditioning circuit can be met.

Drawings

In order that the utility model may be more readily understood, a more particular description of the utility model will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings.

Fig. 1 is a schematic diagram of a signal conditioning circuit of a piezoelectric ceramic sensor according to an embodiment of the present utility model.

Detailed Description

The present utility model will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the utility model and practice it.

Referring to fig. 1, an embodiment of the utility model provides a signal conditioning circuit of a piezoelectric ceramic sensor, which comprises an input end, a filtering module, a field effect tube U2, a voltage reference chip U1 and an output end, wherein the input end is provided with an input interface for receiving input signals, the filtering module is connected with the input interface, a grid electrode of the field effect tube U2 is connected with the filtering module, a source electrode of the field effect tube U2 is connected with a constant current source, a drain electrode of the field effect tube U2 is grounded, a reference voltage port of the voltage reference chip U1 is connected with the source electrode of the field effect tube U2, and the output end is provided with an iepe interface for outputting signals.

The signal conditioning circuit provided by the utility model adopts fewer components with smaller packaging size, realizes conversion from a piezoelectric ceramic output charge signal to a voltage signal and conversion of a sensor circuit output by a standard I EPE interface, and is convenient for the sensor to be directly connected with a signal acquisition system for use.

The signal conditioning circuit of the piezoelectric ceramic sensor provided by the embodiment can conveniently condition and convert charge signals generated by piezoelectric ceramics of the piezoelectric sensor into voltage signals and output the voltage signals in a standard I EPE interface mode. As shown in fig. 1, an input interface of the signal conditioning circuit of the embodiment is connected with a piezoelectric ceramic output electrode of a sensor, and a charge signal is filtered through a filtering module after entering the circuit, and is subjected to signal conditioning amplification and conversion from the charge signal to a voltage signal through a field effect transistor U2 and a voltage reference chip U1 of the circuit, and then is output through an iepe interface.

The input interface comprises an anode connecting point T1 & lt+ & gt and a cathode connecting point T1 & lt- & gt, the anode connecting point T1 & lt+ & gt is connected with the filtering module, the cathode connecting point T1 & lt- & gt is grounded, the filtering module comprises a second resistor R2, a third resistor R3, a second capacitor C2 and a third capacitor C3, the third resistor R3, the second capacitor C2 and the third capacitor C3 are all connected between the anode connecting point T1 & lt+ & gt and the cathode connecting point T1 & lt- & gt in parallel, the second resistor R2 is connected between the second capacitor C2 and the anode connecting point T1 & lt+ & gt, a power port of the voltage reference chip U1 is connected with the constant current source, and a ground port of the voltage reference chip U1 is grounded. When the signal conditioning circuit specifically works, the positive electrode connecting point T1+ and the negative electrode connecting point T1-of the signal conditioning circuit are connected with the piezoelectric ceramic output electrode of the sensor, the charge signals are filtered through a filter module formed by components such as a resistor, a capacitor and the like of the circuit after entering the circuit, the signal conditioning amplification and the conversion from the charge signals to voltage signals are realized through the field effect transistor U2 and the voltage reference chip U1 of the circuit, and then the charge signals are connected and output through the I EPE interfaces of the H1 and the H2.

The signal conditioning circuit of the piezoelectric ceramic sensor provided by the embodiment further comprises a first resistor R1, a first capacitor C1 and a fourth resistor R4, wherein the first resistor R1 is connected between the source electrode and the constant current source of the field effect tube U2, the first capacitor C1 is connected between the positive pole I EPE+ and the negative pole I EPE-of the I EPE interface, and the fourth resistor R4 is connected with the drain electrode of the field effect tube U2. In this embodiment, the positive electrode connection point t1+ and the negative electrode connection point T1-are used for connecting the positive electrode and the negative electrode of the piezoelectric ceramic, H1 and H2 are output/input interfaces of the sensor iepe, H1 is connected to a constant current provided by the signal acquisition device, a constant current of 2-10mA is usually used (the constant current source is usually output at 24V/2-10mA and is usually output at 24V/4mA when the constant current source is not connected with a sensor load), the sensor output signal is loaded on the constant current source to be output in a voltage mode, a reference voltage is usually set after the constant current source enters the sensor, and is called as zero voltage in the sensor, in order to maximize the voltage amplitude range of the sensor output signal, the zero voltage of the sensor is usually set at about one half of the voltage amplitude of the constant current source provided by the acquisition device (for example, the constant current source is a 24V power source, the zero voltage of the sensor is generally set at about 12V, the zero voltage of the sensor is generally set between 8-15V in consideration of the fluctuation of the constant current source voltage of the acquisition device and the output amplitude range of the sensor, in the circuit of the embodiment, the first resistor R1 is used for setting the zero voltage of the sensor, the second resistor R2 is used for adjusting the flatness of the sensitivity curve of the sensor output high frequency band, the third resistor R3 is used for adjusting the flatness of the sensitivity curve of the sensor output low frequency band, the fourth resistor R4 is used for assisting in adjusting the sensitivity and the zero voltage of the sensor output, the first capacitor C1 is mainly used for power supply filtering on the iepe interface, if the installation space of the sensor signal conditioning circuit board is limited, the first capacitor C1 can be omitted, the second capacitor C2 and the third capacitor C3 are used for adjusting the sensitivity of the sensor output, in addition, the second resistor R2, the second capacitor C2 and the third capacitor C3 also have the function of low-pass filtering, and the low-pass filtering circuit can be used for compensating the rising of the high-frequency end of the amplitude-frequency response curve of the output signal caused by the resonance of the piezoelectric ceramic.

The utility model provides a circuit scheme for realizing standardization of a signal conditioning interface of a piezoelectric ceramic sensor by using discrete devices, wherein a field effect transistor U2 and a voltage reference chip U1 which are used are basic electronic components which are low in cost and easy to purchase, other circuit components only have resistors and capacitors, all electronic components have high replaceability and are not limited to a certain model product of a certain manufacturer, but can be used only by conforming to corresponding parameters, and all electronic components in the design scheme have various different packaging sizes, so that proper component packaging can be selected according to the design size of the sensor, and the mounting size requirement of piezoelectric sensors with different sizes on the signal conditioning circuit can be met.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present utility model will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present utility model.

Claims (7)

1. A piezoelectric ceramic sensor signal conditioning circuit, characterized in that it includes: An input terminal having an input interface for receiving an input signal; A filter module connected to the input interface; A field effect tube, a gate of which is connected to the filter module, a source of which is connected to a constant current source, and a drain of which is grounded; A voltage reference chip, whose reference voltage port is connected to the source of the field effect tube; An output end having an IEPE interface for outputting signals. 2. A piezoelectric ceramic sensor signal conditioning circuit according to claim 1, characterized in that it also includes a first resistor, wherein the first resistor is connected between the source of the field effect tube and the constant current source. 3. A piezoelectric ceramic sensor signal conditioning circuit according to claim 1 or 2, characterized in that it also includes a first capacitor, wherein the first capacitor is connected between the positive electrode and the negative electrode of the IEPE interface. 4. A piezoelectric ceramic sensor signal conditioning circuit according to claim 1 or 2, characterized in that: the input interface includes a positive connection point and a negative connection point, the positive connection point is connected to the filter module, and the negative connection point is grounded. 5. A piezoelectric ceramic sensor signal conditioning circuit according to claim 4, characterized in that: the filtering module includes a second resistor, a third resistor, a second capacitor and a third capacitor, the third resistor, the second capacitor and the third capacitor are all connected in parallel between the positive connection point and the negative connection point, and the second resistor is connected between the second capacitor and the positive connection point. 6 . The piezoelectric ceramic sensor signal conditioning circuit according to claim 4 , further comprising a fourth resistor, wherein the fourth resistor is connected to the drain of the field effect transistor. 7 . The piezoelectric ceramic sensor signal conditioning circuit according to claim 1 , wherein the power port of the voltage reference chip is connected to the constant current source, and the ground port of the voltage reference chip is grounded.