Signal transmission processing circuit for an eddy current position sensor

Abstract

The utility model discloses a signal transmission processing circuit for electric eddy current position sensor, include: first operational amplifier, first negative feedback branch, positive feedback branch, first output unit, second operational amplifier, second negative feedback branch, second output unit, first negative feedback branch links with the noninverting input end, output end of first operational amplifier, and first output unit links with the output end of first operational amplifier, and positive feedback branch links with the noninverting input end of first operational amplifier, first output unit, second negative feedback branch links with the noninverting input end, second end, output end of second operational amplifier, the utility model discloses a signal transmission processing circuit for electric eddy current position sensor, through with the voltage of differential signal converts for the transmission of current, utilizes the low sensitivity of current signal to common mode interference, effectively reduces the generation of common mode current to reduce common mode radiation.

Description

Technical Field

[0001] This utility model belongs to the field of sensor technology, specifically relating to a signal transmission and processing circuit for an eddy current position sensor. Background Technology

[0002] In the cutting-edge fields of intelligent manufacturing and precision measurement, eddy current displacement sensors, with their non-contact measurement, high-sensitivity response, and rapid dynamic capture capabilities, have become core components for industrial equipment health monitoring and precision displacement detection. However, the high-precision displacement signals acquired by eddy current sensors face challenges such as interference from complex electromagnetic environments and long-distance attenuation during transmission. Traditional single-ended signal transmission modes are no longer sufficient to meet the stringent requirements of modern industry for the reliability and integrity of measurement data.

[0003] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0004] The purpose of this invention is to provide a signal transmission and processing circuit for an eddy current position sensor, which can improve the suppression of electromagnetic interference and crosstalk.

[0005] To achieve the above objectives, a specific embodiment of this utility model provides the following technical solution: a signal transmission and processing circuit for an eddy current position sensor, comprising: a first operational amplifier, a first negative feedback branch, a positive feedback branch, a first output unit, a second operational amplifier, a second negative feedback branch, and a second output unit;

[0006] The first negative feedback branch is connected to the inverting input terminal and the output terminal of the first operational amplifier. The first terminal of the first output unit is connected to the output terminal of the first operational amplifier. The positive feedback branch is connected to the non-inverting input terminal of the first operational amplifier and is used to receive voltage input signals. The positive feedback branch is connected to the second terminal of the first output unit and outputs current signals. The second negative feedback branch is connected to the inverting input terminal of the second operational amplifier and the second terminal of the first output unit to receive current signals. The second negative feedback branch is connected to the output terminal of the second operational amplifier and the second output unit to output voltage output signals.

[0007] In one or more embodiments of the present invention, the first negative feedback branch includes a first resistor and a second resistor. The first end of the first resistor is connected to ground voltage, the second end of the first resistor is connected to the first end of the second resistor and the inverting input terminal of the first operational amplifier, and the second end of the second resistor is connected to the output terminal of the first operational amplifier.

[0008] In one or more embodiments of this utility model, the positive feedback branch includes a third resistor, a fourth resistor, and a third operational amplifier. The first end of the third resistor is used to receive a voltage input signal. The second end of the third resistor is connected to the first end of the fourth resistor and the non-inverting input of the first operational amplifier. The second end of the fourth resistor is connected to the output of the third operational amplifier. The output of the third operational amplifier is connected to the inverting input of the third operational amplifier. The non-inverting input of the third operational amplifier is connected to the second end of the first output unit.

[0009] In one or more embodiments of the present invention, the first output unit includes an output resistor, the first end of which is connected to the output terminal of the first operational amplifier, and the second end of which is connected to a positive feedback branch for outputting a current signal.

[0010] In one or more embodiments of the present invention, the first output unit further includes a capacitor, the first end of which is connected to the first end of the output resistor, and the second end of which is connected to the second end of the output resistor.

[0011] In one or more embodiments of the present invention, the signal transmission processing circuit further includes a load resistor, the first end of which is connected to the second end of the first output unit, and the second end of which is connected to ground voltage.

[0012] In one or more embodiments of the present invention, the second negative feedback branch includes a sixth resistor, the first end of which is connected to the inverting input terminal of the second operational amplifier, and the second end of which is connected to the output terminal of the second operational amplifier.

[0013] In one or more embodiments of the present invention, the second output unit includes a seventh resistor, the first end of which is connected to the output terminal of the second operational amplifier, and the second end of which is connected to ground voltage.

[0014] In one or more embodiments of the present invention, the signal transmission processing circuit further includes a fifth resistor, the first end of which is connected to the inverting input terminal of the second operational amplifier, and the second end of which is connected to ground voltage.

[0015] In one or more embodiments of the present invention, the signal transmission processing circuit further includes an eighth resistor, the first end of which is connected to the non-inverting input terminal of the second operational amplifier, and the second end of which is connected to ground voltage.

[0016] Compared with existing technologies, the signal transmission processing circuit for eddy current position sensors of this invention converts the voltage of differential signals into current for transmission. Utilizing the low sensitivity of current signals to common-mode interference, it effectively reduces the generation of common-mode current, thereby lowering common-mode radiation. Simultaneously, under current-mode transmission, the signal loop area is easier to control, further weakening differential-mode radiation and significantly reducing the overall electromagnetic interference radiation level. The rate of change of the current signal can be effectively controlled, reducing inductive crosstalk. Furthermore, using a transmission line with characteristic impedance matching can reduce the impact of capacitive crosstalk, improving the anti-crosstalk capability of differential signals in long-distance transmission. The technical solution of this invention can effectively improve the signal integrity of eddy current sensor signals in long-distance transmission, reduce signal distortion and bit error rate, and improve the reliability and stability of signal transmission in electronic systems. It is suitable for various fields with high requirements for signal transmission quality, such as industrial control, high-speed data communication, and automotive electronics. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a partial circuit diagram of a signal transmission and processing circuit for an eddy current position sensor according to one embodiment of the present invention.

[0019] Figure 2 This is a circuit diagram of another part of the signal transmission and processing circuit for an eddy current position sensor in one embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0021] The terms "coupled," "connected," or "linked" in the specification include both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as an electrical conduction medium, which may have parasitic inductance or capacitance. Indirect connections may also include connections made through other active or passive devices to achieve the same or similar functional purpose, such as connections through switches, follower circuits, or other circuits or components. Furthermore, in the invention, terms such as "first" and "second" are primarily used to distinguish one technical feature from another, and do not necessarily require or imply any actual relationship, quantity, or order between these technical features.

[0022] In the detailed description of this specification, reference is made to the accompanying drawings, which form a part thereof, wherein like reference numerals always denote like parts, and wherein exemplary embodiments are shown by way of example that may be implemented. It should be understood that other embodiments may be utilized, and structural or logical changes may be made, without departing from the scope of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0023] The various operations in the specification may be described sequentially as multiple discrete actions or operations in a manner most conducive to understanding the claimed subject matter. However, the order of description should not be construed as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. Various additional operations may be performed in additional embodiments and / or the described operations may be omitted.

[0024] For the purposes of this disclosure, the phrase “A and / or B” means (A), (B), or (A and B). For the purposes of this disclosure, the phrase “A, B and / or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0025] Various components and devices may be referred to or shown in the singular (e.g., “transistor”, “transistor”, “switch”, etc.) in this document, but only for the convenience of discussion, and any element referred to in the singular may include multiple such elements as taught herein.

[0026] The description uses the phrases "in one embodiment," "in other embodiments," or "in some embodiments," each of which may refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," etc., used with respect to embodiments of this disclosure are synonymous.

[0027] like Figure 1As shown, a signal transmission and processing circuit for an eddy current position sensor according to one embodiment of the present invention includes: a first operational amplifier U1, a first negative feedback branch 10, a positive feedback branch 20, and a first output unit 30.

[0028] The first negative feedback branch 10 is connected to the inverting input terminal and the output terminal of the first operational amplifier U1. The first terminal of the first output unit 30 is connected to the output terminal of the first operational amplifier U1. The positive feedback branch 20 is connected to the non-inverting input terminal of the first operational amplifier U1 and is also used to receive the voltage input signal UI. The positive feedback branch 20 is connected to the second terminal of the first output unit 30 and is also used to output the current signal I1.

[0029] The first negative feedback branch 10 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the ground voltage, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the inverting input terminal of the first operational amplifier U1, and the second end of the second resistor R2 is connected to the output terminal of the first operational amplifier U1.

[0030] The positive feedback branch 20 includes a third resistor R3, a fourth resistor R4, and a third operational amplifier U3. The first end of the third resistor R3 is used to receive the voltage input signal UI. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the non-inverting input of the first operational amplifier U1. The second end of the fourth resistor R4 is connected to the output of the third operational amplifier U3. The output of the third operational amplifier U3 is connected to the inverting input of the third operational amplifier U3. The non-inverting input of the third operational amplifier U3 is connected to the second end of the first output unit 30.

[0031] The first output unit 30 includes an output resistor Ro. The first end of the output resistor Ro forms the first end of the first output unit 30 and is connected to the output end of the first operational amplifier U1. The second end of the output resistor Ro forms the second end of the first output unit 30 and is connected to the non-inverting input end of the third operational amplifier U3 of the positive feedback branch 20 for outputting the current signal I1.

[0032] The first output unit 30 also includes a capacitor C1, the first end of which is connected to the first end of the output resistor Ro, and the second end of which is connected to the second end of the output resistor Ro.

[0033] The signal transmission and processing circuit also includes a load resistor RL. The first end of the load resistor RL is connected to the second end of the first output unit 30, and the second end of the load resistor RL is connected to the ground voltage.

[0034] The output resistor Ro and capacitor C1 form an RC hysteresis compensation to cancel the high-frequency phase hysteresis of the operational amplifier, improve the loop phase margin, avoid high-frequency self-oscillation, and adapt to scenarios such as pulse signals and capacitive loads.

[0035] The first operational amplifier U1 and the third operational amplifier U3 preferably use the AD8628, which utilizes its low offset and low noise characteristics to adapt to weak signal processing. The first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 form a symmetrical differential network, which, together with the first operational amplifier U1, realizes high-precision differential conditioning and amplification of the voltage input signal UI and suppresses common-mode noise, with an ideal gain of approximately 1.

[0036] The first operational amplifier U1, in conjunction with the first negative feedback branch 10, the positive feedback branch 20, and the first output unit 30, converts the voltage input signal UI into a constant current signal I1, adapting to long-distance anti-interference transmission. The current signal I1 is: ,in, This is the output voltage of the first operational amplifier U1.

[0037] like Figure 2 As shown, the signal transmission and processing circuit for the eddy current position sensor also includes: a second operational amplifier U2, a second negative feedback branch 40, and a second output unit 50.

[0038] The second negative feedback branch 40 is connected to the inverting input terminal of the second operational amplifier U2 and the second terminal of the first output unit 30 to receive the current signal I1. The second negative feedback branch 40 is connected to the output terminal of the second operational amplifier U2 and the second output unit 50 to output the voltage output signal UO.

[0039] The second negative feedback branch 40 includes a sixth resistor R6. The first end of the sixth resistor R6 is connected to the inverting input terminal of the second operational amplifier U2, and the second end of the sixth resistor R6 is connected to the output terminal of the second operational amplifier U2.

[0040] The second output unit 50 includes a seventh resistor R7. The first end of the seventh resistor R7 is connected to the output terminal of the second operational amplifier U2, and the second end of the seventh resistor R7 is connected to ground voltage.

[0041] The signal transmission and processing circuit also includes a fifth resistor R5. The first end of the fifth resistor R5 is connected to the inverting input of the second operational amplifier U2, and the second end of the fifth resistor R5 is connected to ground.

[0042] The signal transmission and processing circuit also includes an eighth resistor R8. The first end of the eighth resistor R8 is connected to the non-inverting input of the second operational amplifier U2, and the second end of the eighth resistor R8 is connected to ground voltage.

[0043] The second operational amplifier U2 is preferably an AD8628 to achieve high-precision recovery and conditioning of the current signal. The voltage output signal UO is: If the sixth resistor R6 is set to be equal to the output resistor Ro, then This enables linear conversion from current to voltage, while suppressing common-mode noise during transmission, restoring high-precision voltage signals, and ensuring signal processability.

[0044] In one embodiment, the resistance values ​​of all resistors are preferably equal, such as 100Ω, and the capacitance value of capacitor C1 is preferably 100pF. In other embodiments, the resistance values ​​of each resistor can be changed as needed, and other capacitance values ​​can also be selected for capacitor C1.

[0045] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A signal transmission and processing circuit for an eddy current position sensor, characterized in that, include: First operational amplifier, first negative feedback branch, positive feedback branch, first output unit, second operational amplifier, second negative feedback branch, second output unit; The first negative feedback branch is connected to the inverting input terminal and the output terminal of the first operational amplifier. The first terminal of the first output unit is connected to the output terminal of the first operational amplifier. The positive feedback branch is connected to the non-inverting input terminal of the first operational amplifier and is used to receive voltage input signals. The positive feedback branch is connected to the second terminal of the first output unit and outputs current signals. The second negative feedback branch is connected to the inverting input terminal of the second operational amplifier and the second terminal of the first output unit to receive current signals. The second negative feedback branch is connected to the output terminal of the second operational amplifier and the second output unit to output voltage output signals.

2. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The first negative feedback branch includes a first resistor and a second resistor. The first end of the first resistor is connected to ground voltage. The second end of the first resistor is connected to the first end of the second resistor and the inverting input terminal of the first operational amplifier. The second end of the second resistor is connected to the output terminal of the first operational amplifier.

3. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The positive feedback branch includes a third resistor, a fourth resistor, and a third operational amplifier. The first end of the third resistor is used to receive a voltage input signal. The second end of the third resistor is connected to the first end of the fourth resistor and the non-inverting input of the first operational amplifier. The second end of the fourth resistor is connected to the output of the third operational amplifier. The output of the third operational amplifier is connected to the inverting input of the third operational amplifier. The non-inverting input of the third operational amplifier is connected to the second end of the first output unit.

4. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The first output unit includes an output resistor, the first end of which is connected to the output terminal of the first operational amplifier, and the second end of which is connected to the positive feedback branch for outputting a current signal.

5. The signal transmission and processing circuit for an eddy current position sensor according to claim 4, characterized in that, The first output unit further includes a capacitor, the first end of which is connected to the first end of the output resistor, and the second end of which is connected to the second end of the output resistor.

6. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The signal transmission processing circuit further includes a load resistor, the first end of which is connected to the second end of the first output unit, and the second end of which is connected to ground voltage.

7. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The second negative feedback branch includes a sixth resistor, the first end of which is connected to the inverting input of the second operational amplifier, and the second end of which is connected to the output of the second operational amplifier.

8. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The second output unit includes a seventh resistor, the first end of which is connected to the output terminal of the second operational amplifier, and the second end of which is connected to ground.

9. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The signal transmission processing circuit also includes a fifth resistor, the first end of which is connected to the inverting input of the second operational amplifier, and the second end of which is connected to ground voltage.

10. The signal transmission and processing circuit for an eddy current position sensor according to claim 1, characterized in that, The signal transmission processing circuit also includes an eighth resistor, the first end of which is connected to the non-inverting input of the second operational amplifier, and the second end of which is connected to ground voltage.

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