Weak current signal acquisition system

Abstract

The utility model relates to a weak current signal acquisition system, and relates to the technical field of weak current signal detection. The system comprises an isolation module, a current-voltage conversion module and a filtering isolation module, the isolation module is connected with the current-voltage conversion module, and the current-voltage conversion module is connected with the filtering isolation module; the isolation module is used for isolation and noise reduction; the current and voltage conversion module is used for converting the current signal into a voltage signal; and the filtering isolation module is used for amplifying the converted voltage and further reducing noise. In a weak current signal acquisition system, isolation of interference in the environment is realized through an isolation module, signal conversion is carried out in combination with a current and voltage conversion module, and noise reduction and signal output are realized through an isolation filtering module. And the three assemblies are combined to work cooperatively, so that sensitive and efficient acquisition of weak current signals is realized.

Description

Technical Field

[0001] This utility model relates to the field of weak current signal detection technology, and in particular to a weak current signal acquisition system. Background Technology

[0002] Weak current is a physical quantity with a magnitude below the microampere (µA) level. Its detection is widely used in fields such as analytical chemistry, physics, testing and measurement, biomedicine, and geography. Examples include spacecraft in the aerospace industry, ionization chamber output current detection instruments in the nuclear industry, bioelectrical detection instruments in the biomedical field, and leakage current testing in the semiconductor industry. Weak current plays a crucial role in all these applications. Therefore, research on weak current measurement methods is essential.

[0003] In the aerospace field, there is a significant demand for the measurement of weak currents. For example, an ion fire detector is a detector that uses the generation and movement of cations (signal ions) and electrons (charge carriers) to detect ionized gas (ion) signals, characterized by high sensitivity and rapid response. Therefore, the detection of ion fire detector signals requires both high sensitivity and rapid response, and detecting weak signals has always been a challenge.

[0004] However, there is no reliable method for acquiring weak current signals in the relevant technologies. Summary of the Invention

[0005] This utility model relates to a weak current signal acquisition system, which can reliably acquire weak current signals. The system includes an isolation module, a current-to-voltage conversion module, and a filtering and isolation module.

[0006] The isolation module is connected to the current-to-voltage conversion module, and the current-to-voltage conversion module is connected to the filter isolation module.

[0007] The isolation module is used for noise reduction and isolation.

[0008] The current-to-voltage conversion module is used to convert current signals into voltage signals;

[0009] The filter isolation module is used to amplify the converted voltage and further reduce noise.

[0010] In one possible implementation, the isolation module includes a high-voltage power supply chip and a first filter circuit;

[0011] The first filter circuit is connected to the high-voltage power supply chip, and the high-voltage power supply chip is connected to the current-to-voltage conversion module.

[0012] In one possible implementation, the high-voltage power supply chip is an ISO124 isolation chip.

[0013] In one possible implementation, the first filter circuit is a resistor-capacitor (RC) filter circuit.

[0014] In one possible implementation, please refer to Figure 2 as well as Figure 4 The current-to-voltage conversion module includes a first operational amplifier, a fourth resistor R4, a transistor, a diode, a capacitor array, a first resistor R1, a fifth resistor R5, an eighth resistor R8, a seventh resistor R7, a sixth resistor R6, and a seventh capacitor C7. The first operational amplifier is connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to the base of the transistor and one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to one end of the seventh capacitor C7 and one end of the seventh resistor R7. The other end of the seventh capacitor C7 is connected to the first operational amplifier. The other end of R7 is connected to one end of the eighth resistor R8, and one end of the eighth resistor R8 is connected to the capacitor array; the other end of the eighth resistor R8 is connected to the other end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the emitter of the transistor; the collector of the transistor is connected to the connector XP8, the connector XP8 is connected to the negative terminal of the diode, and the positive terminal of the diode is connected to the capacitor array (23); one end of the first resistor R1 is connected to the capacitor array, the other end of the first resistor R1 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected to the capacitor array, and is connected to the filter isolation module through the capacitor array.

[0015] In one possible implementation, the filter isolation module includes a second operational amplifier, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, an isolation chip, a twelfth resistor R12, a thirteenth resistor R13, a ninth capacitor C9, a fourteenth capacitor C14, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-second capacitor C22, and a second filter circuit; one end of the twentieth capacitor C20 is connected to one end of the ninth resistor R9, and the other end of the twentieth capacitor C20 is grounded; the other end of the ninth resistor R9 is sequentially connected to one end of the ninth capacitor C9 and one end of the eleventh resistor R11, and one end of the eleventh resistor R11 is connected to the isolation chip; the other end of the eleventh resistor R11 is connected to the second operational amplifier; the other end of the ninth capacitor C9 is connected to one end of the tenth resistor R10, and the tenth resistor R12 is connected to the isolation chip; the other end of the eleventh resistor R11 is connected to the second operational amplifier; the other end of the ninth capacitor C9 is connected to one end of the tenth resistor R10, and the tenth resistor R11 is connected to the isolation chip; the other end of the eleventh resistor R11 is connected to the second operational amplifier; the other end of the ninth capacitor C9 is connected to one end of the tenth resistor R10, and the other end of the eleven ... The other end of resistor R10 is connected to one end of capacitor C21 (the twenty-first capacitor), and the other end of capacitor C21 is grounded. One end of resistor R10 is also connected to the second operational amplifier. One end of capacitor C14 is connected to the second operational amplifier (31), and the other end of capacitor C14 is grounded. One end of resistor R13 is connected to the second operational amplifier, and the other end of resistor R13 is connected to the other end of capacitor C21 (the twenty-first capacitor) and grounded. One end of capacitor C22 (the twenty-second capacitor) is connected to the second operational amplifier, and the other end of capacitor C22 is grounded. One end of resistor R12 is connected to the isolation chip, and the other end of resistor R12 is connected to one end of capacitor C19 (the nineteenth capacitor), and the other end of capacitor C19 is connected to the isolation chip and grounded. The isolation chip is connected to the output of the second filter circuit and the weak current signal acquisition system.

[0016] The beneficial effects of the technical solution provided by this utility model include at least the following:

[0017] In a weak current signal acquisition system, an isolation module isolates the signal from environmental interference, a current-to-voltage conversion module performs signal conversion, and an isolation filter module reduces noise and outputs the signal. The coordinated operation of these three components enables sensitive and efficient acquisition of weak current signals. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A block diagram of a weak current signal acquisition system is shown.

[0020] Figure 2A block diagram of a weak current signal acquisition system is shown.

[0021] Figure 3 The diagram shows a circuit diagram of an isolation module.

[0022] Figure 4 A circuit diagram of a current-to-voltage conversion module is shown.

[0023] Figure 5 A circuit diagram of a filter isolation module is shown.

[0024] The labels in the attached diagram are as follows:

[0025] 1-Isolation module, 2-Current-to-voltage conversion module, 3-Filtering and isolation module;

[0026] 11-High voltage power supply chip, 12-First filter circuit;

[0027] 21-First operational amplifier, 22-Transistor, 23-Capacitor array;

[0028] 31-Second operational amplifier, 32-Isolation chip, 33-Second filter circuit. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0030] Figure 1 This diagram illustrates a structural block diagram of a weak current signal acquisition system according to an exemplary embodiment of the present invention. The system includes an isolation module 1, a current-to-voltage conversion module 2, and a filtering and isolation module 3. The isolation module is connected to the current-to-voltage conversion module, and the current-to-voltage conversion module is connected to the filtering and isolation module. The isolation module is used for noise isolation and reduction. The current-to-voltage conversion module is used to convert the current signal into a voltage signal. The filtering and isolation module is used to amplify the converted voltage and further reduce noise.

[0031] Figure 2 This diagram illustrates another structural block diagram of a weak current signal acquisition system provided by an exemplary embodiment of the present invention. Figure 3 A circuit diagram of an isolation module is shown. Figure 4 A circuit diagram of a current-to-voltage conversion module is shown. Figure 5 A circuit diagram of a filter isolation module is shown. Next, in conjunction with... Figures 2 to 5 The following describes each part of the weak current acquisition system in the embodiments of this utility model.

[0032] In one possible implementation, please refer to the reference. Figure 2 as well as Figure 3 The isolation module 1 includes a high-voltage power supply chip 11 and a first filter circuit 12. The first filter circuit 12 is connected to the high-voltage power supply chip 11, and the high-voltage power supply chip 11 is connected to the current-to-voltage conversion module 2. In this case, the high-voltage power supply chip 11 is an ISO124 isolation chip. That is, in this embodiment of the present invention, the isolation module 1 serves as front-end and back-end isolation to prevent mutual influence between front-end and back-end circuit faults. Using the ISO124 isolation chip as the high-voltage power supply chip 11 can effectively reduce power supply noise, and the front-end using an RC filter circuit can effectively reduce input source noise. Correspondingly, the first filter circuit 12 is an RC filter circuit. The first filter circuit 12 is composed of a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17, and an eighteenth capacitor C18 connected together; it also includes a second resistor R2 and an eighth capacitor C8. The second resistor R2 is connected to one end of the eighth capacitor C8 and the high-voltage power supply chip 11, and the other end of the eighth capacitor C8 is grounded.

[0033] In one possible implementation, the current-to-voltage conversion module 2 includes a first operational amplifier 21, a fourth resistor R4, a transistor 22, a diode, a capacitor array 23, a first resistor R1, a fifth resistor R5, an eighth resistor R8, a seventh resistor R7, a sixth resistor R6, and a seventh capacitor C7. The first operational amplifier 21 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to the base of the transistor and one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to one end of the seventh capacitor C7 and one end of the seventh resistor R7, and the other end of the seventh capacitor C7 is connected to the first operational amplifier 21. The other end of the seventh resistor R7 is connected to one end of the eighth resistor R8, and one end of the eighth resistor R8 is connected in parallel to the capacitor array 23; the other end of the eighth resistor R8 is connected to the other end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the emitter of the transistor; the collector of the transistor is connected to the connector XP8, the connector XP8 is connected to the negative terminal of the diode, and the positive terminal of the diode is connected to the capacitor array 23; one end of the first resistor R1 is connected to the capacitor array 23, the other end of the first resistor R1 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected to the capacitor array 23, and then connected to the filter isolation module 3 through the capacitor array 23. In this case, the first operational amplifier is implemented as an OP200 operational amplifier.

[0034] In other words, in this embodiment of the invention, the current-to-voltage conversion module converts the current signal into a voltage signal. It consists of an OP200 operational amplifier and transistors, reducing cost and featuring high input impedance and low output impedance. The circuit, designed with operational amplifiers, introduces feedback, providing sufficient accuracy and adjustability. An RC filter circuit at the front end effectively reduces front-end noise; numerous capacitors are added to the transistor terminals to provide high voltage withstand capability and noise reduction.

[0035] In one possible implementation, please refer to Figure 2 as well as Figure 5 The filter isolation module 3 includes a second operational amplifier 31, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, an isolation chip 32, a twelfth resistor R12, a thirteenth resistor R13, a ninth capacitor C9, a fourteenth capacitor C14, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-second capacitor C22, and a second filter circuit 33. One end of the twentieth capacitor C20 is connected to one end of the ninth resistor R9, and the other end of the twentieth capacitor C20 is grounded. The other end of the ninth resistor R9 is connected to one end of the ninth capacitor C9 and one end of the eleventh resistor R11, and one end of the eleventh resistor R11 is connected to the isolation chip 32. The other end of the eleventh resistor R11 is connected to the second operational amplifier 31. The other end of the ninth capacitor C9 is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to one end of the twenty-first capacitor C21, and the other end of the twenty-first capacitor C21 is grounded. One end of the tenth resistor R10 is also connected to the second operational amplifier 31. One end of the fourteenth capacitor C14 is connected to the second operational amplifier 33. Operational amplifier 31 has its fourteenth capacitor 14 connected to ground at one end; one end of the thirteenth resistor R13 is connected to the second operational amplifier 31, and the other end of the thirteenth resistor R13 is connected to the other end of the twenty-first capacitor C21 and grounded; one end of the twenty-second capacitor C22 is connected to the second operational amplifier 31, and the other end of the twenty-second capacitor C22 is grounded; one end of the twelfth resistor R12 is connected to the isolation chip 32, and the other end of the twelfth resistor R12 is connected to one end of the nineteenth capacitor C19, and the other end of the nineteenth capacitor C19 is connected to the isolation chip 32 and grounded; the isolation chip 32 is connected to the second filter circuit 33 and the output terminal of the weak current signal acquisition system. In this case, the isolation chip is implemented as an ISO124 isolation chip.

[0036] The second filter circuit 33 is composed of capacitors C23 (twenty-third), C24 (twenty-fourth), C25 (twenty-fifth), C26 (twenty-sixth), C27 (twenty-seventh), C28 (twenty-eighth), C29 (twenty-ninth), and C30 (thirtieth).

[0037] In this embodiment of the invention, the filter isolation module 3 functions as an amplification and filtering module, isolating the front and back ends to prevent mutual interference between faults in the front and back circuits. It is composed of an OP200 operational amplifier, an ISO124 isolation chip, and an RC filter circuit.

[0038] It should be noted that in some embodiments of this utility model, the weak current signal acquisition system is used to connect to a host computer device. That is, during the entire signal processing process, the weak current signal output by the detector is isolated, converted into a voltage signal by a current-to-voltage conversion module, and then filtered and removed by a two-stage amplification and filtering to remove high-frequency noise mixed in the voltage signal. The effective signal is then amplified to the maximum input range of the AD device, isolated, and then converted into a digital signal by an A / D device to generate the corresponding digital signal. This signal is then transmitted to the data processing section for data processing and arrangement, and finally uploaded to the host computer for data processing and analysis.

[0039] The above are merely optional embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A weak current signal acquisition system, characterized in that, The weak current signal acquisition system comprises an isolation module (1), a current-voltage conversion module (2) and a filter isolation module (3); The isolation module (1) is connected with the current-voltage conversion module (2), and the current-voltage conversion module (2) is connected with the filter isolation module (3); The isolation module (1) is used for isolating and reducing noise. The current-voltage conversion module (2) is used for converting a current signal into a voltage signal. The filter isolation module (3) is used for amplifying the converted voltage and further reducing noise.

2. The weak current signal acquisition system according to claim 1, characterized in that, The isolation module (1) comprises a high-voltage power supply chip (11) and a first filter circuit (12). The first filter circuit (12) is connected with the high-voltage power supply chip (11), and the high-voltage power supply chip (11) is connected to the current-voltage conversion module (2).

3. The weak current signal acquisition system according to claim 2, characterized in that, The high-voltage power supply chip (11) is an ISO124 isolation chip.

4. The weak current signal acquisition system according to claim 2, characterized in that, The first filter circuit (12) is an RC filter circuit.

5. The weak current signal acquisition system according to claim 1, wherein, The current-voltage conversion module (2) comprises a first operational amplifier (21), a fourth resistor R4, a triode (22), a diode, a capacitor array (23), a first resistor R1, a fifth resistor R5, an eighth resistor R8, a seventh resistor R7, a sixth resistor R6 and a seventh capacitor C7; one end of the fourth resistor R4 is connected with the first operational amplifier (21), the other end of the fourth resistor R4 is connected with the base of the triode and one end of the sixth resistor R6 respectively, the other end of the sixth resistor R6 is connected with one end of the seventh capacitor C7 and one end of the seventh resistor R7 respectively; the other end of the seventh capacitor C7 is connected with the first operational amplifier (21); the other end of the seventh resistor R7 is connected with one end of the eighth resistor R8, and one end of the eighth resistor R8 is connected with the capacitor array (23); the other end of the eighth resistor R8 is connected with the other end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected with the emitter of the triode; the collector of the triode is connected with a power strip XP8, the power strip XP8 is connected with the negative electrode of the diode, and the positive electrode of the diode is connected with the capacitor array (23); one end of the first resistor R1 is connected with the capacitor array (23), the other end of the first resistor R1 is connected with one end of the fifth resistor R5, the other end of the fifth resistor R5 is connected with the capacitor array (23), and the capacitor array (23) is connected to the filter isolation module (3).

6. The weak current signal acquisition system according to claim 5, wherein, The first operational amplifier (21) is implemented as an OP200 operational amplifier.

7. The weak current signal acquisition system according to claim 1, wherein, The filter isolation module (3) comprises a second operational amplifier (31), a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, an isolation chip (32), a twelfth resistor R12, a thirteenth resistor R13, a ninth capacitor C9, a fourteenth capacitor C14, a nineteenth capacitor C19, a twentieth capacitor C20, a twenty-first capacitor C21, a twenty-second capacitor C22, and a second filter circuit (33); one end of the twentieth capacitor C20 is connected with one end of the ninth resistor R9, and the other end of the twentieth capacitor C20 is grounded; the other end of the ninth resistor R9 is sequentially connected with one end of the ninth capacitor C9 and one end of the eleventh resistor R11, and one end of the eleventh resistor R11 is connected with the isolation chip (32); the other end of the eleventh resistor R11 is connected with the second operational amplifier (31); the other end of the ninth capacitor C9 is connected with one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected with one end of the twenty-first capacitor C21, and the other end of the twenty-first capacitor C21 is grounded; one end of the tenth resistor R10 is also connected with the second operational amplifier (31); one end of the fourteenth capacitor C14 is connected with the second operational amplifier (31), and the other end of the fourteenth capacitor C14 is grounded; one end of the thirteenth resistor R13 is connected with the second operational amplifier (31), and the other end of the thirteenth resistor R13 is connected with the other end of the twenty-first capacitor C21 and grounded; one end of the twenty-second capacitor C22 is connected with the second operational amplifier (31), and the other end of the twenty-second capacitor C22 is grounded; one end of the twelfth resistor R12 is connected with the isolation chip (32), and the other end of the twelfth resistor R12 is connected with one end of the nineteenth capacitor C19, and the other end of the nineteenth capacitor C19 is connected with the isolation chip (32) and grounded; the isolation chip (32) is connected with the second filter circuit (33) and an output end of the weak current signal acquisition system.

8. The weak current signal acquisition system according to claim 3, wherein, The isolation chip (32) is implemented as an ISO124 isolation chip.

9. The weak current signal acquisition system according to claim 1, wherein, The weak current signal acquisition system is used to be connected with a host computer device.

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