Feedback circuit suitable for direct coupling direct current SQUID

Abstract

The utility model relates to a feedback circuit suitable for a direct coupling direct current SQUID, comprising a control unit, an FB control input unit, an FB feedback unit and an FB probe, an output end of the control unit is connected with an input end of the FB control input unit, an output end of the FB control input unit is connected with an input end of the FB probe, and an output end of the FB probe is connected with an output end of the FB feedback unit. The feedback end of the FB probe is connected with the input end of the FB feedback unit, and the output end of the FB feedback unit is connected with the feedback end of the control unit. According to the utility model, the probe can be monitored in real time, so that corresponding control is adjusted, and the stability of equipment is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to a feedback circuit suitable for direct coupling DC SQUID. BACKGROUND

[0002] The magnetic sensor based on a superconducting quantum interference device (SQUID) is the most sensitive magnetic sensor known at present, wherein the low-temperature superconducting SQUID has a sensitivity better than 10 fT, and the high-temperature superconducting SQUID has a sensitivity better than 100 fT. The SQUID magnetic sensor is an important high-end application sensor, is widely applied to the fields of weak magnetic field detection such as biomagnetism, geophysical detection and extremely low field nuclear magnetic resonance, and has high scientific research and application values. For high-level white noise, the excessive noise is usually caused by external interference or trapped flux in the junction, which suppresses the VF transfer coefficient, causes I0 to change, makes the SQUID no longer optimal or symmetrical, and for the DC SQUID. The excessive low-frequency noise may be the telegraph noise generated by the trapped flux moving in the device. If this noise is very obvious at a very low frequency, the magnetic chain jump will be directly seen at the output end, and a great 1 / f noise will be observed in the FFT spectrum. If the flux jump is too fast to be distinguished in the time domain, the FFT spectrum will present a characteristic Lorentz form. There are several methods to deal with the excessive noise: using the embedded heater on the SQUID chip to heat the SQUID to above Tc, and then recooling to expel the trapped flux

[0003] After retrieval, the patent: a single-channel DC SQUID signal collection device (CN202223119330.1) sets a feedback coil in the superconducting quantum interference device in the liquid nitrogen environment, finds the working point by generating a changing magnetic field through the test circuit; a heating resistor is arranged in the superconducting quantum interference device in the liquid nitrogen environment, the environment of the superconducting quantum interference device is heated through the control switch SW3; the signal processing circuit is connected with the superconducting quantum interference device; a reset switch is arranged to control the superconducting quantum interference device to restore the normal working state; a main controller is arranged, and the switch controller, the signal processing circuit, the heating circuit and the test circuit connected with the reset switch. The above-mentioned circuit does not carry out feedback operation on the equipment, so that the monitoring is not in place.

[0004] In view of the above-mentioned defects, the present design person actively researches and innovates, in order to create a new structure of feedback circuit suitable for direct coupling DC SQUID, so that it has more industrial utilization value. Utility model content

[0005] The utility model discloses a feedback circuit suitable for directly coupled direct current SQUID to solve the above technical problem.

[0006] To realize above object, the utility model adopts the following technical scheme:

[0007] A feedback circuit suitable for directly coupled direct current SQUID, including control unit, FB control input unit, FB feedback unit and FB probe, the output of control unit is connected with the input of FB control input unit, the output of FB control input unit is connected with the input of FB probe, the feedback end of FB probe is connected with the input of FB feedback unit, the output of FB feedback unit is connected with the feedback end of control unit,

[0008] The FB control input unit includes chip IC1A and chip IC1B, the sixth pin of chip IC1B is connected with the output of control unit through resistance R49, the fifth pin of chip IC1B is grounded, the seventh pin of chip IC1B is connected with FB probe through resistance R44, the sixth pin of chip IC1B is connected with the seventh pin of chip IC1B through resistance R42, the first pin of chip IC1A is connected to +2.5V, the fourth pin of chip IC1A is connected to -2.5V, the third pin of chip IC1A is connected with the output of control unit, the second pin of chip IC1A is connected with the first pin of chip IC1A through resistance R43, and the first pin of chip IC1A is connected with FB probe through resistance R45.

[0009] The FB feedback unit includes two same feedback modules, one end of one feedback module is connected with FB probe, the other end of the other feedback module is connected with FB probe, and the output of the two feedback modules is connected with control unit.

[0010] Preferably, the feedback circuit suitable for directly coupled direct current SQUID, the control unit is MCU, and the model thereof is R5F211B4SP.

[0011] Preferably, the feedback circuit suitable for directly coupled direct current SQUID, the chip model of the chip IC1A is AD827.

[0012] Preferably, the feedback circuit suitable for directly coupled direct current SQUID, the chip model of the chip IC1B is AD827.

[0013] Preferably, the feedback circuit suitable for direct coupling DC SQUID includes a feedback module comprising resistors R64, R65, and R69, with R65 and R69 connected in parallel. One end of resistor R65 is connected to one end of resistor R64, the other end of resistor R64 is connected to the FB probe, and the other end of resistor R65 is connected to the control unit.

[0014] By means of the above solution, this utility model has at least the following advantages:

[0015] This invention allows for real-time monitoring of the probe via feedback signals, enabling adjustments to control and ensuring equipment stability.

[0016] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the principle of this utility model;

[0019] Figure 2 This is the actual circuit diagram of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] Example

[0023] likeFigure 1 and Figure 2 As shown, a feedback circuit suitable for directly coupled DC SQUID includes a control unit 1, an FB control input unit 2, an FB feedback unit 3, and an FB probe 4. The output terminal of the control unit 1 is connected to the input terminal of the FB control input unit 2, the output terminal of the FB control input unit 2 is connected to the input terminal of the FB probe 4, the feedback terminal of the FB probe 4 is connected to the input terminal of the FB feedback unit 3, and the output terminal of the FB feedback unit 3 is connected to the feedback terminal of the control unit 1.

[0024] The FB control input unit 2 includes chip IC1A and chip IC1B. The sixth pin of chip IC1B is connected to the output terminal of control unit 1 through resistor R49. The fifth pin of chip IC1B is grounded. The seventh pin of chip IC1B is connected to FB probe 4 through resistor R44. The sixth pin of chip IC1B is connected to the seventh pin of chip IC1B through resistor R42. The first pin of chip IC1A is connected to +2.5V. The fourth pin of chip IC1A is connected to -2.5V. The third pin of chip IC1A is connected to the output terminal of control unit 1. The second pin of chip IC1A is connected to the first pin of chip IC1A through resistor R43. The first pin of chip IC1A is connected to FB probe 4 through resistor R45.

[0025] The FB feedback unit 3 includes two identical feedback modules. One feedback module is connected to one end of the FB probe 4, and the other feedback module is connected to the other end of the FB probe 4. Their outputs are connected to the control unit 1.

[0026] The control unit 1 described in this utility model is an MCU (not shown), model number R5F211B4SP.

[0027] The chip model of IC1A and the chip model of IC1B in this invention are both AD827.

[0028] The feedback module described in this utility model includes resistors R64, R65, and R69. Resistors R65 and R69 are connected in parallel. One end of resistor R65 is connected to one end of resistor R64, the other end of resistor R64 is connected to FB probe 4, and the other end of resistor R65 is connected to control unit 1.

[0029] Among them, the B control input unit 2 is used to adjust the FB input signal.

[0030] FB feedback unit, FB feedback to the magnetic signal output terminal feedback circuit.

[0031] The working principle of this utility model is as follows:

[0032] The control unit (i.e., MCU) is connected to the FB control input unit through resistors R50 and R51. The FB control input unit controls the FB probe, and the FB probe feeds back the signal to the idle unit through the FB feedback unit for monitoring, ensuring the normal operation of the FB probe.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this application, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or vertical, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A feedback circuit suitable for directly coupled DC squuids, characterized in that: It includes a control unit (1), an FB control input unit (2), an FB feedback unit (3), and an FB probe (4). The output terminal of the control unit (1) is connected to the input terminal of the FB control input unit (2), the output terminal of the FB control input unit (2) is connected to the input terminal of the FB probe (4), the feedback terminal of the FB probe (4) is connected to the input terminal of the FB feedback unit (3), and the output terminal of the FB feedback unit (3) is connected to the feedback terminal of the control unit (1). The FB control input unit (2) includes chip IC1A and chip IC1B. The sixth pin of chip IC1B is connected to the output terminal of the control unit (1) through resistor R49. The fifth pin of chip IC1B is grounded. The seventh pin of chip IC1B is connected to the FB probe (4) through resistor R44. The sixth pin of chip IC1B is connected to the seventh pin of chip IC1B through resistor R42. The first pin of chip IC1A is connected to +2.5V. The fourth pin of chip IC1A is connected to -2.5V. The third pin of chip IC1A is connected to the output terminal of the control unit (1). The second pin of chip IC1A is connected to the first pin of chip IC1A through resistor R43. The first pin of chip IC1A is connected to the FB probe (4) through resistor R45. The FB feedback unit (3) includes two identical feedback modules. One feedback module is connected to one end of the FB probe (4), and the other feedback module is connected to the other end of the FB probe (4). Their output terminals are connected to the control unit (1).

2. The feedback circuit suitable for directly coupled DC SQUIDs according to claim 1, characterized in that: The control unit (1) is an MCU with the model number R5F211B4SP.

3. A feedback circuit suitable for directly coupled DC SQUIDs according to claim 1, characterized in that: The chip IC1A has the model number AD827.

4. A feedback circuit suitable for directly coupled DC SQUIDs according to claim 1, characterized in that: The chip model of IC1B is AD827.

5. A feedback circuit suitable for directly coupled DC SQUIDs according to claim 1, characterized in that: The feedback module includes resistors R64, R65 and R69. Resistors R65 and R69 are connected in parallel. One end of resistor R65 is connected to one end of resistor R64. The other end of resistor R64 is connected to the FB probe (4). The other end of resistor R65 is connected to the control unit (1).

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