CN114189221A - Constant current source power supply charge amplification system - Google Patents

Constant current source power supply charge amplification system Download PDF

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Publication number
CN114189221A
CN114189221A CN202111513397.0A CN202111513397A CN114189221A CN 114189221 A CN114189221 A CN 114189221A CN 202111513397 A CN202111513397 A CN 202111513397A CN 114189221 A CN114189221 A CN 114189221A
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module
resistor
operational amplifier
reference voltage
charge
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Inventor
陈俊峰
彭大松
戴志华
王晓东
杜晓强
谭子岳
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Quanzhou Yunjian Measurement And Control And Perception Technology Innovation Research Institute
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Quanzhou Yunjian Measurement And Control And Perception Technology Innovation Research Institute
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/70—Charge amplifiers
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Nonlinear Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Amplifiers (AREA)

Abstract

The invention discloses a constant current source power supply charge amplification system, and relates to the field of sensor signal processing. The constant current source is adopted for power supply and voltage signal output, so that the input and the output can be shared to one signal line, and a two-wire system working mode is realized by using a common ground wire. The system specifically comprises: the device comprises a shell, a charge-voltage conversion module, a blocking module, an amplification module, an emitter following module and a reference voltage source module. The specific principle of the system is as follows: the charge-voltage conversion module can convert a charge signal output by the piezoelectric crystal into a voltage signal, the voltage signal is filtered by the blocking module to remove a direct current signal, amplified by the amplification module and finally output by the emitter following module. The constant current source generates reference voltage through the reference voltage source module, provides level reference for the sensor signal and supplies power for the whole system.

Description

Constant current source power supply charge amplification system
Technical Field
The invention relates to the technical field of sensor signal processing, in particular to a constant current source power supply charge amplification system for piezoelectric sensor charge signal processing.
Background
When the piezoelectric crystal is deformed under the action of external force, the polarization phenomenon can be generated in the piezoelectric crystal, charges with opposite positive and negative polarities appear on two opposite surfaces of the piezoelectric crystal, and the crystal is restored to an uncharged state after the external force is removed; when the direction of the external force action is changed, the polarity of the charges is changed; the charge quantity generated by the crystal under the action of force is in direct proportion to the magnitude of the external force. By utilizing this phenomenon, piezoelectric crystals can be used to manufacture sensors for detecting physical quantities such as force, displacement, acceleration, and the like, such as piezoelectric acceleration sensors in general.
The piezoelectric sensor takes the piezoelectric crystal as a sensitive element, and has the advantages of small volume, light weight, wide frequency band, simple structure, reliable work and the like. The method is widely applied to the fields of vibration testing, signal analysis, vibration calibration, mechanical dynamic experiments and the like of aviation, ships, bridges and buildings. However, the piezoelectric element generates a small amount of electric charge after being stressed, the signal is extremely weak, and the piezoelectric element can be equivalent to a high-output impedance charge source, which brings certain difficulty to a subsequent measuring circuit. The charge amplification system has the characteristics of high input impedance and low output impedance, can perform impedance conversion on charge signals, converts the charge signals into voltage signals which are easy to collect, and has the functions of amplification gain, filtering and the like.
In a traditional charge amplification system, a circuit structure needs to supply power to a single end or double ends of a power supply, a power supply line, a signal line and a ground wire need to be wired independently, and the requirements on the number, the wiring and the cost of the signal lines are high. And the charge amplification system adopting the constant current source for power supply can reduce the signal line of the sensor to a two-wire system, simplify the circuit structure and increase the reliability. The two-wire system charge amplification system is characterized in that constant current is converted into voltage inside the system to supply power for each module of the system. The current-to-voltage module in the conventional two-wire system charge amplification system needs more components, has a more complex structure and has higher requirements on cost and reliability. Therefore, it is necessary to provide a solution to the above problems.
Disclosure of Invention
The invention solves the technical problem of providing a piezoelectric sensor charge amplification system which has high input impedance, low output impedance and strong anti-interference capability and adopts a constant current source for power supply.
In order to solve the technical problems, the technical scheme of the invention is as follows: a constant current source power supply charge amplification system specifically comprises: the device comprises a shell, a charge-voltage conversion module, a blocking module, an amplification module, an emitter following module and a reference voltage source module. The specific principle of the system is as follows: the charge-voltage conversion module can convert a charge signal output by the piezoelectric crystal into a voltage signal, the voltage signal is filtered by the blocking module to remove a direct current signal, amplified by the amplification module and finally output by the emitter following module. The constant current source generates reference voltage through the reference voltage source module, provides level reference for the sensor signal and supplies power for the whole system.
As a preferred technical solution, the housing includes a housing, a BNC head 1, and a BNC head 2, where the BNC head 1 is the input end of the charge amplification system, and the BNC head 2 is the output end of the charge amplification system.
Preferably, the charge-voltage conversion module includes an operational amplifier U1A, a feedback capacitor C1, and an input resistor R1. After the feedback capacitor C1 is connected with the input resistor R1 in parallel, one end of the feedback capacitor C1 is connected with the inverting input end of the operational amplifier U1A, and the other end of the feedback capacitor C1 is connected with the output end of the operational amplifier U1A to form a feedback circuit; the inverting input end of the operational amplifier U1A is connected with the BNC head 1; the operational amplifier U1A ground is connected to common ground, which is further connected to BNC header 1 of claim 3.
Preferably, the blocking module includes a blocking capacitor C3.
Preferably, the amplifying module comprises an operational amplifier U1B, a resistor R5, a resistor R2, and a capacitor C2. One end of the resistor R5 is connected with the blocking capacitor C3, and the other end of the resistor R5 is connected with the inverting input end of the operational amplifier U1B; the capacitor C2 is connected in parallel with the resistor R2, one end of the capacitor C2 is connected with the inverting input end of the operational amplifier U1B, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1B to form an amplifying circuit. The magnification a is equal to:
Figure 402852DEST_PATH_IMAGE001
。
preferably, the emitter follower module includes a resistor R6, a transistor Q1, and a resistor R3. One end of the resistor R6 is connected with the output end of the operational amplifier U1B, and the other end of the resistor R6 is connected with the base electrode of the triode Q1; one end of the resistor R3 is connected with the emitting electrode of the triode Q1, and the other end is connected with the BNC head 2.
Preferably, the reference voltage source module includes a resistor R4, a precision reference zener diode D3, a precision reference zener diode D2, and a TVS tube D1. One end of the resistor R4 is connected with the cathode of the precision reference voltage-stabilizing diode D3, and the other end of the resistor R4 is connected with the BNC head 2; the anode of the precision reference voltage-stabilizing diode D3 is connected with the cathode of the precision reference voltage-stabilizing diode D2; the cathode of the precision reference voltage-stabilizing diode D2 is also connected with the non-inverting input end of the operational amplifier U1A and is connected with the non-inverting input end of the operational amplifier U1B; the anode of the precision reference zener diode D2 is connected to the common ground and to the BNC header 2.
Due to the adoption of the technical scheme, the constant current source is adopted for supplying power, the voltage signal is output, the input and the output can be shared to one signal line, and the two-wire system working mode is realized by using the common ground wire. The system specifically comprises: the device comprises a shell, a charge-voltage conversion module, a blocking module, an amplification module, an emitter following module and a reference voltage source module. The specific principle of the system is as follows: the charge-voltage conversion module can convert a charge signal output by the piezoelectric crystal into a voltage signal, the voltage signal is filtered by the blocking module to remove a direct current signal, amplified by the amplification module and finally output by the emitter following module. The constant current source generates reference voltage through the reference voltage source module, provides level reference for the sensor signal and supplies power for the whole system. Through the processing of the charge amplification system, the high internal resistance charge signal of the piezoelectric sensor can be converted into a voltage signal with strong load capacity, the signal noise is effectively reduced, and the anti-interference capacity of the sensor is improved.
Drawings
The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:
FIG. 1 is a functional block diagram of an embodiment of the present invention;
FIG. 2 is a block diagram of an outer shell of the embodiment of the present invention;
fig. 3 is a circuit schematic of an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the specific examples and the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1, the piezoelectric sensor 1 is connected to the charge conversion module 2, the blocking module 3 is connected to the charge conversion module 2, the amplifying module 4 is connected to the blocking module 3, the emitter follower module 5 is connected to the amplifying module 4, and the precision reference voltage source module 6 is connected to the charge conversion module 2, the amplifying module 4, and the emitter follower module 5.
As shown in fig. 2, the BNC head 1 is connected to the input end of the charge amplification system, the BNC head 2 is connected to the output end of the charge amplification system, and the housing plays a role in protecting and shielding the external interference.
As shown in fig. 3, the charge-voltage conversion module can convert the charge signal output by the piezoelectric crystal into a voltage signal, and the voltage signal is filtered by the blocking module to remove the dc signal, amplified by the amplification module, and finally output by the emitter follower module. The constant current source generates reference voltage through the precision reference voltage source, provides level reference for the sensor signal and supplies power for the whole system.
As shown in fig. 3, the charge-voltage conversion module includes an operational amplifier U1A, a feedback capacitor C1, and an input resistor R1. After the feedback capacitor C1 is connected in parallel with the resistor R1, one end of the feedback capacitor C1 is connected with the inverting input end of the operational amplifier U1A, and the other end of the feedback capacitor C1 is connected with the output end of the operational amplifier U1A. The inverting input terminal of the operational amplifier U1A is further connected to the BNC header 1. The grounding end of the operational amplifier U1A is connected with the common ground and then connected with the BNC head 1. The resistor R1 is used as an input resistor of the whole system circuit, and is required to have a high resistance value.
As shown in fig. 3, the feedback capacitor C1 and the resistor R1 cooperate with the operational amplifier U1A to realize impedance transformation. The resistor R1 adopts a low-temperature drift resistor of 2G omega, the operational amplifier U1A adopts AD8642 manufactured by ADI company, and the feedback capacitor C1 adopts a multilayer ceramic capacitor of 680 pf. The charge-voltage conversion circuit of the connection mode realizes the conversion from the charge signal of the high output resistance to the voltage signal of the low output resistance.
As shown in fig. 3, the dc blocking capacitor C3 functions to block ac and dc. Direct current interference in a preceding stage signal can be filtered, and in order to ensure that a low-frequency alternating current signal can not be distorted, the direct current blocking capacitor C3 adopts a multilayer ceramic capacitor of 100 uF.
As shown in fig. 3, the amplifying module includes an operational amplifier U1B, a resistor R5, a resistor R2, and a capacitor C2. One end of the resistor R5 is connected with the blocking capacitor C3, and the other end is connected with the inverting input end of the operational amplifier U1B. The capacitor C2 is connected in parallel with the resistor R2, one end of the capacitor C2 is connected with the inverting input end of the operational amplifier U1B, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1B to form an amplifying circuit. The capacitor C2 can play a certain role in filtering high-frequency noise, and the amplification factor A is equal to:
Figure 697567DEST_PATH_IMAGE001
。
the resistor R5 adopts a low-temperature drift resistor with the precision of 10K omega and 1%, the resistor R2 adopts a low-temperature drift resistor with the precision of 100K omega and 1%, and the obtained amplification factor A is 10; the capacitor C3 adopts a 22pf multilayer ceramic capacitor.
As shown in fig. 3, the emitter follower module includes a resistor R6, a transistor Q1, and a resistor R3. One end of the resistor R6 is connected with the output end of the operational amplifier U1B, and the other end of the resistor R6 is connected with the base electrode of the triode Q1; one end of the resistor R3 is connected with the emitter of the triode Q1, the other end of the resistor R3 is connected with the BNC head 2, and direct-current bias voltage can be generated; the resistor R6 is a low-temperature drift resistor with the precision of 1% and the resistor R3 is a low-temperature drift resistor with the precision of 1% and 3.3K omega, and the triode Q1 is MMBT3906 produced by Infineon company. The emitter follower module is characterized by high input impedance and low output impedance, so that the current required from a signal source is small, the load capacity is high, and the signal output capacity of the piezoelectric sensor can be improved.
As shown in fig. 3, the reference voltage source module includes a resistor R4, a precision reference zener diode D3, a precision reference zener diode D2, and a TVS transistor D1. One end of the resistor R4 is connected with the cathode of the precision reference voltage-stabilizing diode D3, and the other end of the resistor R4 is connected with the BNC head 2; the anode of the precision reference voltage-stabilizing diode D3 is connected with the cathode of the precision reference voltage-stabilizing diode D2; the cathode of the precision reference voltage-stabilizing diode D2 is connected with the non-inverting input end of the operational amplifier U1A and is connected with the non-inverting input end of the operational amplifier U1B. The anode of the precision reference zener diode D2 is connected to the common ground and to the BNC header 2. The resistor R4 adopts a low-temperature drift resistor with the precision of 51K omega and 1 percent, the precision reference voltage stabilizing diode D2 adopts LM4040C25 manufactured by TI company, and the reference voltage source module can generate stable voltage of 2.5V and provide differential reference level for the operational amplifier U1A and the operational amplifier U1B; the precision reference voltage-stabilizing diode D3 adopts LM4040DIM3-10.0 manufactured by TI company, the reference voltage source module can generate stable voltage of 10V, and the stable voltage is superposed with the voltage of the precision reference voltage-stabilizing diode D2 to supply power for the whole system; the TVS tube D1 adopts V30MLA0603N manufactured by Littelfuse company, and can absorb surge voltage for protecting the whole circuit.
The invention discloses a constant current source power supply charge amplification system, and relates to the field of sensor signal processing. The constant current source is adopted for power supply and voltage signal output, so that the input and the output can be shared to one signal line, and a two-wire system working mode is realized by using a common ground wire. The system specifically comprises: the device comprises a shell, a charge-voltage conversion module, a blocking module, an amplification module, an emitter following module and a reference voltage source module. The specific principle of the system is as follows: the charge-voltage conversion module can convert a charge signal output by the piezoelectric crystal into a voltage signal, the voltage signal is filtered by the blocking module to remove a direct current signal, amplified by the amplification module and finally output by the emitter following module. The constant current source generates reference voltage through the reference voltage source module, provides level reference for the sensor signal and supplies power for the whole system.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (8)

1. A constant current source powered charge amplification system, characterized by: the system component specifically comprises a shell, a charge-voltage conversion module, a blocking module, an amplification module, an emitter following module and a reference voltage source module.
2. A constant current source powered charge amplification system, characterized by: the system specifically works in the way that a charge-voltage conversion module converts charge signals output by a piezoelectric crystal into voltage signals, the voltage signals are filtered by a blocking module to remove direct-current signals, amplified by an amplification module and finally output by an emitter following module; the constant current source generates reference voltage through the precision reference voltage source, provides level reference for the sensor signal and supplies power for the whole system.
3. The constant current source powered charge amplification system of claim 1, wherein: the shell comprises a shell body, a BNC head 1 and a BNC head 2, wherein the BNC head 1 is the input end of the charge amplification system, and the BNC head 2 is the output end of the charge amplification system.
4. The constant current source powered charge amplification system of claim 1, wherein: the charge-voltage conversion module comprises an operational amplifier U1A, a feedback capacitor C1 and an input resistor R1; the feedback circuit is formed by connecting the feedback capacitor C1 and the input resistor R1 in parallel, connecting one end of the feedback capacitor C1 with the inverting input end of the operational amplifier U1A, and connecting the other end of the feedback capacitor C1 with the output end of the operational amplifier U1A; the inverting input terminal of the operational amplifier U1A is further connected to the BNC header 1 of claim 3; the operational amplifier U1A ground is connected to common ground, which is further connected to BNC header 1 of claim 3.
5. The constant current source powered charge amplification system of claim 1, wherein: the blocking module comprises a blocking capacitor C3.
6. The constant current source powered charge amplification system of claim 1, wherein: the amplifying module comprises an operational amplifier U1B, a resistor R5, a resistor R2 and a capacitor C2; the specific structure is that one end of the resistor R5 is connected with the DC blocking capacitor C3 of claim 5, and the other end is connected with the inverting input end of the operational amplifier U1B; the capacitor C2 is connected with the resistor R2 in parallel, one end of the capacitor C2 is connected with the inverting input end of the operational amplifier U1B, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1B to form an amplifying circuit;
the magnification a is equal to:
Figure DEST_PATH_IMAGE001
。
7. the constant current source powered charge amplification system of claim 1, wherein: the emitter following module comprises a resistor R6, a triode Q1 and a resistor R3; the specific structure is that one end of the resistor R6 is connected with the output end of the operational amplifier U1B of claim 6, and the other end is connected with the base electrode of the triode Q1; the resistor R3 is connected to the emitter of the transistor Q1 at one end and to the BNC header 2 of claim 3 at the other end.
8. The constant current source powered charge amplification system of claim 1, wherein: the reference voltage source module comprises a resistor R4, a precision reference voltage stabilizing diode D3, a precision reference voltage stabilizing diode D2 and a TVS tube D1; the specific structure is that one end of the resistor R4 is connected with the cathode of the precision reference voltage-stabilizing diode D3, and the other end is connected with the BNC head 2 of claim 3; the anode of the precision reference voltage-stabilizing diode D3 is connected with the cathode of the precision reference voltage-stabilizing diode D2; the cathode of the precision reference voltage-stabilizing diode D2 is further connected to the non-inverting input terminal of the operational amplifier U1A in claim 4, to the non-inverting input terminal of the operational amplifier U1B in claim 6, and the anode of the precision reference voltage-stabilizing diode D2 is connected to the common ground and to the BNC header 2 in claim 3.
CN202111513397.0A 2021-12-13 2021-12-13 Constant current source power supply charge amplification system Pending CN114189221A (en)

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CN202111513397.0A CN114189221A (en) 2021-12-13 2021-12-13 Constant current source power supply charge amplification system

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