阅读说明：本技术 一种飞安级直流微电流信号测量系统 (Fly-ampere-level direct-current micro-current signal measuring system ) 是由 贾云涛 张力丹 彭婧宇 胡耀元 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种飞安级直流微电流信号测量系统,属于电流信号测试领域,该系统包括：输入接口单元、电流-电压转换单元、输出接口单元和屏蔽盒单元；输入接口单元、电流-电压转换单元和输出接口单元依次连接；电流-电压转换单元位于屏蔽盒单元内,输入接口单元和输出接口单元分别与屏蔽盒单元连接；利用电流-电压转换单元的精密运算放大器结合高精密反馈电阻及反馈电容,使转换电路的输入阻抗很大,将飞安级直流微电流信号转换为方便测量的微弱的直流电压信号,满足飞安级直流微电流的信号调理,实现对飞安级直流微电流的准确测量。(The invention discloses a system for measuring a microampere-level direct-current micro-current signal, which belongs to the field of current signal testing and comprises: the device comprises an input interface unit, a current-voltage conversion unit, an output interface unit and a shielding box unit; the input interface unit, the current-voltage conversion unit and the output interface unit are connected in sequence; the current-voltage conversion unit is positioned in the shielding box unit, and the input interface unit and the output interface unit are respectively connected with the shielding box unit; the precise operational amplifier of the current-voltage conversion unit is combined with the high-precision feedback resistor and the feedback capacitor, so that the input impedance of the conversion circuit is very large, the flying-safety-level direct-current micro-current signal is converted into a weak direct-current voltage signal which is convenient to measure, the signal conditioning of the flying-safety-level direct-current micro-current is met, and the accurate measurement of the flying-safety-level direct-current micro-current is realized.)

1. A system for measuring a fly-by-wire DC micro-current signal, the system comprising:

the input interface unit is used for receiving a to-be-detected flying safety level direct current micro-current signal;

the current-voltage conversion unit is connected with the input interface unit and is used for converting the to-be-detected flying safety level direct-current micro-current signal into a weak voltage signal;

the output interface unit is connected with the current-voltage conversion unit and used for outputting the weak voltage signal;

a shield case unit; the current-voltage conversion unit is located inside the shielding box unit, and the input interface unit and the output interface unit are respectively connected with the shielding box unit.

2. The flying amp-level direct current micro-current signal measurement system of claim 1, wherein the current-voltage conversion unit comprises: the circuit comprises an operational amplifier, a first capacitor and a resistor;

the inverting input end of the operational amplifier is connected with the to-be-detected flying safety level direct current micro-current signal, and the non-inverting input end of the operational amplifier is grounded;

the output end of the operational amplifier is connected with the inverting input end of the operational amplifier through the first capacitor and the resistor; the first capacitor is connected with the resistor in parallel;

and the output end of the operational amplifier is connected with the output interface unit.

3. The flying amp-level dc micro-current signal measurement system of claim 2, wherein the operational amplifier comprises: a positive power supply circuit and a negative power supply circuit;

the positive power supply circuit includes: a first inductor, a second capacitor and a third capacitor; one end of the first inductor is connected with the positive electrode of a power supply, and the other end of the first inductor is connected with the positive power supply of the operational amplifier; the other end of the first inductor is also connected with the second capacitor and the third capacitor respectively, and the second capacitor and the third capacitor are grounded in parallel;

the negative power supply circuit includes: a second inductor, a fifth capacitor and a sixth capacitor; one end of the second inductor is connected with the negative electrode of the power supply, and the other end of the second inductor is connected with the negative power supply of the operational amplifier; the other end of the second inductor is further connected with the fifth capacitor and the sixth capacitor respectively, and the fifth capacitor and the sixth capacitor are grounded in parallel.

4. The system according to claim 2 or 3, wherein the operational amplifier is of the type ADA 4530-1.

5. The flying amp-level dc micro-current signal measuring system of claim 2, wherein the resistance is a 100G high value resistance.

6. The flying amp-level dc micro-current signal measuring system of claim 2, wherein the first capacitor has a capacitance of 5 pF.

7. The system according to claim 1, wherein the input interface unit is a triaxial input connector and the output interface unit is a triaxial output connector.

8. The flying amp-level dc micro-current signal measurement system of claim 1, further comprising: a power supply unit;

the power supply unit is connected with the current-voltage conversion unit and used for supplying power to the current-voltage conversion unit.

9. The system according to claim 8, wherein the power supply unit provides the following voltages: 18650 lithium batteries with rated output of 3.3V are subjected to voltage boosting conversion by a power chip ADP5070 and then are converted into high-precision +/-5V voltage by power chips ADP7118 and ADP7182 respectively.

10. The system according to claim 1, wherein the shielding box unit is an all-aluminum closed structure.

Technical Field

The invention relates to the technical field of current signal testing, in particular to a system for measuring a fly-safe level direct current micro-current signal.

Background

The precision measurement is the basis of modern information technology, and with the progress of science and technology, the precision measurement of weak current signals is widely required, for example, in the fields of aerospace measurement and control, semiconductor integrated circuit test, novel material research, analysis test required by life science development, light and space ion beam measurement and the like.

In the prior art, a method for obtaining a micro current signal mostly converts the current signal into a voltage signal through a conversion circuit for processing, realizes the separation of error dark current and signal current through a differential amplification circuit, and utilizes differential characteristics to solve the difference and offset the error.

Disclosure of Invention

The invention aims to provide a system for measuring a fly-safe level direct current micro-current signal, which is more convenient and accurate in measurement.

In order to achieve the purpose, the invention provides the following scheme:

a flying-ampere-grade direct-current micro-current signal measurement system, the measurement system comprising:

the input interface unit is used for receiving a to-be-detected flying safety level direct current micro-current signal;

the current-voltage conversion unit is connected with the input interface unit and is used for converting the to-be-detected flying safety level direct-current micro-current signal into a weak voltage signal;

the output interface unit is connected with the current-voltage conversion unit and used for outputting the weak voltage signal;

a shield case unit; the current-voltage conversion unit is located inside the shielding box unit, and the input interface unit and the output interface unit are respectively connected with the shielding box unit.

Optionally, the current-voltage conversion unit includes: the circuit comprises an operational amplifier, a first capacitor and a resistor;

the inverting input end of the operational amplifier is connected with the to-be-detected flying safety level direct current micro-current signal, and the non-inverting input end of the operational amplifier is grounded;

the output end of the operational amplifier is connected with the inverting input end of the operational amplifier through the first capacitor and the resistor; the first capacitor is connected with the resistor in parallel;

and the output end of the operational amplifier is connected with the output interface unit.

Optionally, the operational amplifier includes: a positive power supply circuit and a negative power supply circuit;

the positive power supply circuit includes: a first inductor, a second capacitor and a third capacitor; one end of the first inductor is connected with the positive electrode of a power supply, and the other end of the first inductor is connected with the positive power supply of the operational amplifier; the other end of the first inductor is also connected with the second capacitor and the third capacitor respectively, and the second capacitor and the third capacitor are grounded in parallel;

the negative power supply circuit includes: a second inductor, a fifth capacitor and a sixth capacitor; one end of the second inductor is connected with the negative electrode of the power supply, and the other end of the second inductor is connected with the negative power supply of the operational amplifier; the other end of the second inductor is further connected with the fifth capacitor and the sixth capacitor respectively, and the fifth capacitor and the sixth capacitor are grounded in parallel.

Optionally, the model of the operational amplifier is ADA 4530-1.

Optionally, the resistor is a 100G high value resistor.

Optionally, the capacitance of the first capacitor is 5 pF.

Optionally, the input interface unit is a triaxial input connector, and the output interface unit is a triaxial output connector.

Optionally, the measurement system further includes: a power supply unit;

the power supply unit is connected with the current-voltage conversion unit and used for supplying power to the current-voltage conversion unit.

Optionally, the voltage provided by the power supply unit is: 18650 lithium batteries with rated output of 3.3V are subjected to voltage boosting conversion by a power chip ADP5070 and then are converted into high-precision +/-5V voltage by power chips ADP7118 and ADP7182 respectively.

Optionally, the shielding box unit adopts an all-aluminum closed structure.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the system for measuring the flying-safety-level direct-current micro-current signal comprises a current-voltage conversion unit, a precision operational amplifier, a high-precision feedback resistor and a feedback capacitor, so that the input impedance of a conversion circuit is very large, the flying-safety-level direct-current micro-current signal is converted into a weak direct-current voltage signal which is convenient to measure, the signal conditioning of the flying-safety-level direct-current micro-current is met, and the accurate measurement of the flying-safety-level direct-current micro-current is realized.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the accompanying drawings and not in limitation thereof, in which elements having the same reference numeral designations are shown as like elements and not in limitation thereof, and wherein:

FIG. 1 is a schematic diagram of a flying-ampere-level DC micro-current signal measurement system;

FIG. 2 is a schematic diagram of a current-voltage conversion unit;

FIG. 3 is a schematic view of a triple coaxial connector;

FIG. 4 is a side view of a shield can unit construction;

FIG. 5 is a schematic diagram of a power supply unit;

reference numerals:

1-an input interface unit, 2-a current-voltage conversion unit, 3-a power supply unit, 4-an output interface unit and 5-a shielding box unit;

101-core wire, 102-inner shield, 103-outer shield.

Detailed Description

So that the manner in which the features and elements of the disclosed embodiments can be understood in detail, a more particular description of the disclosed embodiments, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. However, one or more embodiments may be practiced without these details. In other instances, well-known structures and devices may be shown in simplified form in order to simplify the drawing.

The invention aims to provide a measuring system for a fly-by-wire level direct current micro-current signal, which is convenient to measure and accurate in measurement.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1, a schematic diagram of a system for measuring a fly-safe level dc micro-current signal provided by the present invention includes: the device comprises an input interface unit 1, a current-voltage conversion unit 2, a power supply unit 3, an output interface unit 4 and a shielding box unit 5.

The input interface unit 1 is used for receiving a DC micro-current signal of a flying safety level to be detected.

The current-voltage conversion unit 2 is connected with the input interface unit 1 and is used for converting the to-be-detected flying-ampere-level direct-current micro-current signal into a weak voltage signal.

The output interface unit 4 is connected with the current-voltage conversion unit 2 and is used for outputting weak voltage signals.

The current-voltage conversion unit 2 is located inside the shielding box unit 5, and the input interface unit 1 and the output interface unit 4 are respectively connected with the shielding box unit 5.

Fig. 2 is a detailed schematic diagram of the current-voltage conversion unit, and the current-voltage conversion unit 2 includes: the circuit comprises an operational amplifier A, a first capacitor C1, a resistor R1 and a fourth capacitor C4, wherein the model of the operational amplifier A is ADA 4530-1.

The inverting input end of the operational amplifier A is connected with the input interface unit 1 and receives a DC micro-current signal of the flying safety class to be detected, and the non-inverting input end of the operational amplifier A is grounded after passing through a fourth capacitor C4.

The output end of the operational amplifier A is connected with the inverting input end of the operational amplifier A through a first capacitor C1 and a resistor R1; the first capacitor C1 is connected in parallel with the resistor R1. The resistor R1 is a 100G high-value feedback resistor; the capacitance of the first capacitor C1 is a feedback capacitor with 5 pF; the feedback capacitor is used for phase compensation and preventing oscillation.

The output end of the operational amplifier A is connected with the output interface unit 4 and outputs weak direct current voltage signals.

The operational amplifier specifically includes: a positive power supply circuit and a negative power supply circuit.

The positive power supply circuit includes: a first inductor L1, a second capacitor C2, and a third capacitor C3; one end of the first inductor L1 is connected with the positive electrode of the power supply, and the other end of the first inductor L1 is connected with the positive power supply of the operational amplifier A; the other end of the first inductor L1 is further connected to a second capacitor C2 and a third capacitor C3, respectively, and the second capacitor C2 and the third capacitor C3 are grounded in parallel.

The negative power supply circuit includes: a second inductor L2, a fifth capacitor C5, and a sixth capacitor C6; one end of the second inductor L2 is connected with the negative electrode of the power supply, and the other end of the second inductor L2 is connected with the negative power supply of the operational amplifier A; the other end of the second inductor L2 is further connected to a fifth capacitor C5 and a sixth capacitor C6, respectively, and the fifth capacitor C5 and the sixth capacitor C6 are grounded in parallel.

The input interface unit is a triaxial input connector, and the output interface unit is a triaxial output connector; fig. 3 is a schematic diagram of a three-coaxial connector. The three coaxial connectors sequentially comprise from outside to inside: a core wire 101, an inner shield 102 and an outer shield 103.

The output end of the precision operational amplifier is grounded, the output end of the precision operational amplifier is connected to the output triaxial output connector, and finally the microamp level direct current micro current signal is output as a weak direct current voltage signal.

According to the principle that a feedback operational amplifier works in a linear region and two input ends are approximate to virtual short and virtual break, a micro-current test is converted into voltage on a feedback resistor to an output port, the relation between the output voltage and the input current is V-I multiplied by R, and R is 100G. The current-voltage conversion unit processes weak current signals, so special attention needs to be paid to leakage current protection, certain requirements are required on partial PCB layout, and GUARD is required to be used for copper winding at the inverting input end of the operational amplifier and the low ends of the feedback resistor and the feedback capacitor to serve as a protection ring.

The invention also discloses a system for measuring the fly-safe level direct current micro-current signal, which comprises: and the power supply unit 3 is used for supplying power to the current-voltage conversion unit 2. Fig. 5 is a schematic diagram of a power supply unit, which has the following power supply principles: the 18650 lithium battery of rated output 3.3V is converted into the voltage of +/-6V through the boost of power chip ADP5070, then converts into the voltage of high accurate +/-5V through power chip ADP7118 and ADP7182 respectively. As can be seen from the schematic diagram of the current-voltage conversion unit in fig. 2, the voltage of the current-voltage conversion unit is ± 5V.

The shield case unit 5 of the present invention adopts an all-aluminum enclosure structure. Fig. 4 shows the relationship between the input interface unit 1 and the shielding box unit 5 as an example, and it can be known from fig. 4 that the input interface unit 1 is connected to the shielding box unit 5, and the current-voltage conversion process is completely performed in the shielding box unit, so that the whole module has a high anti-electromagnetic interference capability.

The advantages of the present invention over the prior art include:

the input impedance of the conversion circuit is very large by adopting a precise operational amplifier in combination with a high-precision feedback resistor and a feedback capacitor, the flying-safety-level direct-current micro-current signal is converted into a weak direct-current voltage signal which is convenient to measure, the signal conditioning of the flying-safety-level direct-current micro-current is met, and the accurate measurement of the flying-safety-level direct-current micro-current is realized; the shielding box unit adopts an all-aluminum closed design structure, so that the whole module has high electromagnetic interference resistance.

The above description and drawings sufficiently illustrate embodiments of the disclosure to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of the disclosed embodiments includes the full ambit of the claims, as well as all available equivalents of the claims. As used in this application, although the terms "first," "second," etc. may be used in this application to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, unless the meaning of the description changes, so long as all occurrences of the "first element" are renamed consistently and all occurrences of the "second element" are renamed consistently. The first and second elements are both elements, but may not be the same element. Furthermore, the words used in the specification are words of description only and are not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, the terms "comprises" and/or "comprising," when used in this application, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Without further limitation, an element defined by the phrase "comprising an …" does not exclude the presence of other identical elements in a process, method or device comprising the element.

In the embodiments disclosed herein, the disclosed products (including but not limited to devices, apparatuses, etc.) may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit may be merely a division of a logical function, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to implement the present embodiment. In addition, functional units in the embodiments of the present disclosure may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.