CN219592391U - Low-frequency differential signal acquisition circuit based on operational amplifier - Google Patents
Low-frequency differential signal acquisition circuit based on operational amplifier Download PDFInfo
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- CN219592391U CN219592391U CN202223297448.3U CN202223297448U CN219592391U CN 219592391 U CN219592391 U CN 219592391U CN 202223297448 U CN202223297448 U CN 202223297448U CN 219592391 U CN219592391 U CN 219592391U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
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Abstract
The embodiment discloses a low-frequency differential signal acquisition circuit based on an operational amplifier, which adopts an operational amplifier circuit and an ADC conversion circuit, wherein the ADC circuit comprises an ADC front end low-pass filter circuit and an ADC acquisition chip circuit, the input end of the ADC front end low-pass filter circuit is connected with the output end of the operational amplifier circuit, and the output end of the ADC front end low-pass filter circuit is connected with the input end of the ADC acquisition chip circuit. The low-frequency differential signal acquisition circuit based on the operational amplifier has the characteristics of simple circuit structure, high flexibility, easiness in implementation, high stability and good reliability, and is suitable for various circuit designs of low-frequency weak signal acquisition.
Description
Technical Field
The embodiment relates to the technical field of differential signal acquisition circuits requiring high precision, and particularly discloses a low-frequency differential signal acquisition circuit based on an operational amplifier, which relates to underwater weak audio signal acquisition.
Background
In circuit design, the price of a high-end differential signal ADC (Analog-to-digital converter) acquisition chip is often hundreds of times that of a single-end ADC acquisition chip, and the register configuration is complex and the use requirement is high. When such chips are used in large quantities on board, the material and labor costs are high. The traditional ADC acquisition chip has the defects of limited acquisition range, low acquisition precision, large environmental influence on weak signal acquisition and poor acquisition quality under the environments of high noise and complex electromagnetic fields.
Therefore, the existing ADC acquisition chip has a limited acquisition range, low acquisition precision, large environmental influence on weak signal acquisition, and poor acquisition quality under the environment of high noise and complex electromagnetic field, and is a technical problem to be solved urgently at present.
Disclosure of Invention
The embodiment provides a low-frequency differential signal acquisition circuit based on an operational amplifier, which aims to solve the technical problems that the acquisition range of the existing ADC acquisition chip is limited, the acquisition precision is low, the environment influence is large when weak signals are acquired, and the acquisition quality is poor under the environment of high noise and complex electromagnetic fields.
The embodiment relates to a low-frequency differential signal acquisition circuit based on an operational amplifier, which comprises an operational amplifier circuit and an ADC conversion circuit, wherein the ADC circuit comprises an ADC front end low-pass filter circuit and an ADC acquisition chip circuit, the input end of the ADC front end low-pass filter circuit is connected with the output end of the operational amplifier circuit, and the output end of the ADC front end low-pass filter circuit is connected with the input end of the ADC acquisition chip circuit.
Further, the operational amplifier circuit comprises an operational amplifier and a configuration resistor, the 1 st pin of the operational amplifier is connected with the 8 th pin of the operational amplifier through the configuration resistor, and the output end of the operational amplifier is connected with the ADC conversion circuit.
Further, the operational amplifier circuit further comprises a first capacitor and a second capacitor, the positive electrode input end of the operational amplifier is connected with the first capacitor, the negative electrode input end of the operational amplifier is connected with the second capacitor, and the output end of the operational amplifier is connected with the ADC acquisition chip circuit.
Further, the model of the operational amplifier circuit is AD620.
Further, the ADC front end low-pass filter circuit comprises a third capacitor, a first resistor and a second resistor, the output end of the operational amplification circuit is connected with the ADC acquisition chip circuit after passing through the first resistor and the second resistor, one end of the third capacitor is connected with a connection point between the first resistor and the second resistor, and the other end of the third capacitor is grounded.
Further, the ADC acquisition chip circuit comprises an ADC acquisition chip, and a 19 th pin of the ADC acquisition chip is connected with the output end of the ADC front-end low-pass filter circuit.
Further, the model of the ADC acquisition chip is AD7606.
Further, the first capacitor and the second capacitor are both blocking capacitors.
Further, the range of the voltage collected by the ADC collecting chip circuit is 5 mV-10V.
Further, the operational amplifier is used for adjusting the amplification factor by configuring the resistor, and the amplification factor adjusting range is 1-10000 times.
The beneficial effects obtained by the embodiment are as follows:
the embodiment provides a low-frequency differential signal acquisition circuit based on an operational amplifier, which adopts an operational amplification circuit and an ADC conversion circuit, wherein the ADC circuit comprises an ADC front end low-pass filter circuit and an ADC acquisition chip circuit, the input end of the ADC front end low-pass filter circuit is connected with the output end of the operational amplification circuit, the output end of the ADC front end low-pass filter circuit is connected with the input end of the ADC acquisition chip circuit, when the circuit has a requirement on cost and the acquisition of differential signals and single-ended signals is required, the circuit structure can be simplified, unnecessary chip use is reduced, the circuit design is optimized, and the hardware design cost is saved. The low-frequency differential signal acquisition circuit based on the operational amplifier has the characteristics of simple circuit structure, high flexibility, easiness in implementation, high stability and good reliability, and is suitable for various circuit designs of low-frequency weak signal acquisition.
Drawings
FIG. 1 is a functional block diagram of an embodiment of an operational amplifier-based low frequency differential signal acquisition circuit according to the present embodiment;
FIG. 2 is a schematic circuit diagram of an embodiment of the operational amplifier circuit and the ADC front-end low-pass filter circuit shown in FIG. 1;
fig. 3 is a schematic circuit diagram of an embodiment of the ADC front-end low-pass filter circuit and the ADC acquisition chip circuit shown in fig. 1.
Reference numerals illustrate:
10. an operational amplifier circuit; 20. an ADC conversion circuit; 21. a low-pass filter circuit at the front end of the ADC; 22. ADC acquisition chip circuit.
Detailed Description
In order to better understand the above technical solutions, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1 and 2, an embodiment of the present utility model provides a low-frequency differential signal acquisition circuit based on an operational amplifier, which includes an operational amplifier circuit 10 and an ADC conversion circuit 20, wherein the ADC circuit 20 includes an ADC front-end low-pass filter circuit 21 and an ADC acquisition chip circuit 22, an input end of the ADC front-end low-pass filter circuit 21 is connected to an output end of the operational amplifier circuit 10, and an output end of the ADC front-end low-pass filter circuit 21 is connected to an input end of the ADC acquisition chip circuit 22. In this embodiment, the operational amplification circuit 10, the ADC front-end low-pass filter circuit 21 and the ADC acquisition chip circuit 22 may all adopt existing circuits, where the operational amplification circuit 10 is configured to convert the differential double-ended signal into an amplified single-ended signal, and the ADC front-end low-pass filter circuit 21 is configured to filter the single-ended signal amplified by the operational amplification circuit 10 and then convert the single-ended signal into a single-ended dc signal; the ADC acquisition chip circuit 22 is configured to convert the single-ended dc signal converted by the ADC front-end low-pass filter circuit 21 after the filtering process into a digital signal.
Further, please refer to fig. 1 to 3, in the low-frequency differential signal acquisition circuit based on an operational amplifier according to the present embodiment, the operational amplifier circuit 10 includes an operational amplifier U21 and a configuration resistor R143, the 1 st pin of the operational amplifier U21 is connected to the 8 th pin of the operational amplifier U21 through the configuration resistor R143, and the output end of the operational amplifier U21 is connected to the ADC conversion circuit 20. The operational amplifier circuit 10 further includes a first capacitor C13 and a second capacitor C134, an anode input terminal of the operational amplifier is connected to the first capacitor C13, a cathode input terminal of the operational amplifier U21 is connected to the second capacitor C134, and an output terminal of the operational amplifier U21 is connected to the ADC acquisition chip circuit 22. In the present embodiment, the model of the operational amplifier circuit 10 is AD620. The first capacitor C13 and the second capacitor C134 each use a blocking capacitor. The operational amplifier U21 is used for adjusting the amplification factor through the configuration resistor R143, and the amplification factor adjusting range is 1-10000 times. The amplification state of the operational amplifier U21 is controlled by the configuration resistor R143. In this embodiment, the operational amplifier U21 is used as the attribute of the signal amplifying front end, and the configuration resistor R143 is used to collect signals in different situations according to the actual use requirement. As long as the front-end input voltage is between 5mV and 10V, the voltage can be amplified to the range which can be acquired by the operational amplifier U21 through the configuration resistor R143. The first capacitor C13 and the second capacitor C134 are used for removing the direct current component in the signal; the signal after the direct current is cut off is directly connected to the differential input end of the operational amplifier U21, and the input resistance of the operational amplifier U21 is large, so that the signal size requirement of the sensor is greatly reduced.
Preferably, referring to fig. 1 to 3, in the low-frequency differential signal acquisition circuit based on an operational amplifier according to the present embodiment, the ADC front-end low-pass filter circuit 21 includes a third capacitor C263, a first resistor R208 and a second resistor R484, an output end of the operational amplifier circuit 10 is connected to the ADC acquisition chip circuit 22 after passing through the first resistor R208 and the second resistor R484, one end of the third capacitor C263 is connected to a connection point between the first resistor R208 and the second resistor R484, and the other end of the third capacitor C263 is grounded. In this embodiment, the ADC collecting chip circuit 22 includes an ADC collecting chip U55, and a 19 th pin of the ADC collecting chip U55 is connected to an output end of the ADC front-end low-pass filter circuit 21. The model of the ADC acquisition chip is AD7606. The range of the voltage collected by the ADC collecting chip circuit 22 is 5 mV-10V. The ADC front-end low-pass filter circuit 21 adopts a T-type low-pass filter circuit, and is configured to filter the single-ended signal amplified by the operational amplifier circuit 10 and convert the single-ended signal into a single-ended dc signal.
As shown in fig. 1 to 3, the low-frequency differential signal acquisition circuit based on the operational amplifier provided in the present embodiment has the following working principle:
the operational amplification circuit 10 converts the weak differential signal into a single-ended amplified signal. The ADC front-end low-pass filter circuit 21 converts the single-ended signal amplified by the operational amplifier circuit 10 into a direct current signal. The ADC acquisition chip circuit 22 converts the direct current signal output from the ADC front-end low-pass filter circuit 21 into a digital signal.
The amplifying state of the operational amplifier is controlled by the configuration resistor. The low-frequency differential signal acquisition circuit based on the operational amplifier provided by the embodiment utilizes the operational amplifier as the attribute of the signal amplification front end, and the configuration resistor is used for acquiring signals of different occasions according to actual use requirements. As long as the front-end input voltage is between 5mV and 10V, the voltage can be amplified to the range which can be acquired by the operational amplifier U21 through the configuration resistor R143.
Compared with the prior art, the low-frequency differential signal acquisition circuit based on the operational amplifier has the advantages that the operational amplifier circuit and the ADC conversion circuit are adopted, the ADC circuit comprises the ADC front end low-pass filter circuit and the ADC acquisition chip circuit, the input end of the ADC front end low-pass filter circuit is connected with the output end of the operational amplifier circuit, the output end of the ADC front end low-pass filter circuit is connected with the input end of the ADC acquisition chip circuit, when the circuit has requirements on cost and the acquisition of differential signals and single-ended signals is required, the circuit structure can be simplified, unnecessary chip use is reduced, the circuit design is optimized, and the hardware design cost is saved. The low-frequency differential signal acquisition circuit based on the operational amplifier has the characteristics of simple circuit structure, high flexibility, easiness in implementation, high stability and good reliability, and is suitable for various circuit designs of low-frequency weak signal acquisition.
While the preferred embodiments of the present embodiments have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiment. It will be apparent to those skilled in the art that various modifications and variations can be made to the present embodiment without departing from the spirit and scope of the embodiment. Thus, the present embodiment is intended to include such modifications and alterations provided that they come within the scope of the claims of the embodiment and the equivalents thereof.
Claims (10)
1. The low-frequency differential signal acquisition circuit based on the operational amplifier is characterized by comprising an operational amplifier circuit (10) and an ADC conversion circuit (20), wherein the ADC conversion circuit (20) comprises an ADC front end low-pass filter circuit (21) and an ADC acquisition chip circuit (22), the input end of the ADC front end low-pass filter circuit (21) is connected with the output end of the operational amplifier circuit (10), and the output end of the ADC front end low-pass filter circuit (21) is connected with the input end of the ADC acquisition chip circuit (22).
2. The low-frequency differential signal acquisition circuit based on an operational amplifier according to claim 1, wherein the operational amplifier circuit (10) comprises an operational amplifier and a configuration resistor, a 1 st pin of the operational amplifier is connected with an 8 th pin of the operational amplifier through the configuration resistor, and an output end of the operational amplifier is connected with the ADC conversion circuit (20).
3. The low-frequency differential signal acquisition circuit based on an operational amplifier according to claim 2, wherein the operational amplifier circuit (10) further comprises a first capacitor and a second capacitor, the positive input terminal of the operational amplifier is connected with the first capacitor, the negative input terminal of the operational amplifier is connected with the second capacitor, and the output terminal of the operational amplifier is connected with the ADC acquisition chip circuit (22).
4. An operational amplifier based low frequency differential signal acquisition circuit according to claim 3, wherein the operational amplifier circuit (10) is of the type AD620.
5. The low-frequency differential signal acquisition circuit based on an operational amplifier according to claim 2, wherein the ADC front-end low-pass filter circuit (21) comprises a third capacitor, a first resistor and a second resistor, the output end of the operational amplifier circuit (10) is connected with the ADC acquisition chip circuit (22) after passing through the first resistor and the second resistor, one end of the third capacitor is connected with a connection point between the first resistor and the second resistor, and the other end of the third capacitor is grounded.
6. The low-frequency differential signal acquisition circuit based on an operational amplifier according to claim 5, wherein the ADC acquisition chip circuit (22) comprises an ADC acquisition chip, and a 19 th pin of the ADC acquisition chip is connected to an output terminal of the ADC front-end low-pass filter circuit (21).
7. The op-amp based low frequency differential signal acquisition circuit of claim 6 wherein the ADC acquisition chip is model AD7606.
8. The op-amp based low frequency differential signal acquisition circuit as recited in claim 3 wherein said first capacitor and said second capacitor are both dc blocking capacitors.
9. The op-amp based low frequency differential signal acquisition circuit of claim 5 wherein the ADC acquisition chip circuit (22) acquires a voltage in the range of 5 v to 10v.
10. The low-frequency differential signal acquisition circuit based on the operational amplifier according to claim 2, wherein the operational amplifier is used for adjusting the amplification factor through the configuration resistor, and the amplification factor adjustment range is 1-10000 times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223297448.3U CN219592391U (en) | 2022-12-08 | 2022-12-08 | Low-frequency differential signal acquisition circuit based on operational amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223297448.3U CN219592391U (en) | 2022-12-08 | 2022-12-08 | Low-frequency differential signal acquisition circuit based on operational amplifier |
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| Publication Number | Publication Date |
|---|---|
| CN219592391U true CN219592391U (en) | 2023-08-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223297448.3U Active CN219592391U (en) | 2022-12-08 | 2022-12-08 | Low-frequency differential signal acquisition circuit based on operational amplifier |
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| Country | Link |
|---|---|
| CN (1) | CN219592391U (en) |
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2022
- 2022-12-08 CN CN202223297448.3U patent/CN219592391U/en active Active
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