Bidirectional current source circuit and channel calibration system for nuclear power units

Abstract

The present application relates to a bidirectional current source circuit and a channel verification system for a nuclear power unit. The bidirectional current source circuit includes: a control circuit for outputting a digital logic signal and a level signal; a differential voltage circuit for converting the digital logic signal provided by the control circuit into a first differential voltage and a second differential voltage, wherein the first differential voltage and the second differential voltage have the same polarity; a switching circuit; and a voltage-current conversion circuit, wherein the four input terminals of the voltage-current conversion circuit are respectively connected to the four second terminals of the switching circuit; wherein the switching circuit is used to select, based on the level signal, a path between the two output terminals of the differential voltage circuit and the two input terminals of the voltage-current conversion circuit, so that the voltage-current conversion circuit outputs a positive current or a negative current based on the received first differential voltage and the second differential voltage, thereby meeting the requirements for the current source amplitude and polarity during the channel verification of the nuclear power unit.

Description

Technical Field

[0001] The present application relates to the field of electronic measurement technology, and in particular to a bidirectional current source circuit and a channel calibration system for a nuclear power unit. Background Art

[0002] During channel verification or inspection of nuclear power units, a signal generator is often required to be inserted into the loop to provide and adjust signals. This signal can be voltage, current, or resistance. Current signals are a common signal used for channel inspection of nuclear power units. The current signal that needs to be inserted into the loop is generally around 0-24mA, but in special cases, a negative current signal may also be required. However, conventional signal generators can only provide specific positive current signals, which can affect the channel verification of the nuclear power unit. Summary of the Invention

[0003] Based on this, it is necessary to provide a bidirectional current source circuit that can provide positive and negative currents and a channel verification system for a nuclear power unit.

[0004] In a first aspect, the present application provides a bidirectional current source circuit, comprising:

[0005] A control circuit for outputting digital logic signals and level signals;

[0006] a differential voltage circuit, connected to the control circuit, and configured to convert a digital logic signal provided by the control circuit into a first differential voltage and a second differential voltage, wherein the first differential voltage and the second differential voltage have the same polarity;

[0007] a switching circuit, wherein two first terminals of the switching circuit are respectively connected to the two output terminals of the differential voltage circuit, and a control terminal of the switching circuit is connected to the control circuit;

[0008] A voltage-current conversion circuit, wherein the four input terminals of the voltage-current conversion circuit are respectively connected to the four second terminals of the switching circuit; wherein,

[0009] The switching circuit is used to select and turn on the paths between the two output ends of the differential voltage circuit corresponding to the two input ends of the voltage-current conversion circuit according to the level signal, so that the voltage-current conversion circuit outputs positive current or negative current according to the received first differential voltage and the second differential voltage.

[0010] In one embodiment, the switching circuit includes a first relay and a second relay, wherein the first end of the first relay is connected to an output end of the differential voltage circuit, the control end of the first relay is connected to the control circuit, and the two second ends of the first relay are respectively connected to the first input end and the second input end of the voltage-current conversion circuit, and the first relay is used to select and output the first differential voltage to one of the two input ends of the voltage-current conversion circuit according to the received level signal;

[0011] The first end of the second relay is connected to the other output end of the differential voltage circuit, the control end of the second relay is connected to the control circuit, the two output ends of the second relay are respectively connected to the third input end and the fourth input end of the voltage-current conversion circuit, and the second relay is used to select one of the two input ends of the voltage-current conversion circuit to output the second differential voltage value according to the received level signal.

[0012] In one embodiment, when the level signal is a high level signal, the first relay outputs the first differential voltage to the first input terminal of the voltage-current conversion circuit, and the second relay outputs the second differential voltage to the fourth input terminal of the voltage-current conversion circuit, so that the voltage-current conversion circuit outputs a negative current;

[0013] When the level signal is a low level signal, the first relay outputs the first differential voltage to the second input terminal of the voltage-current conversion circuit, and the second relay outputs the second differential voltage to the third input terminal of the voltage-current conversion circuit, so that the voltage-current conversion circuit outputs a positive current.

[0014] In one embodiment, the voltage-to-current conversion circuit includes a differential amplifier, a first operational amplifier, and a first resistor;

[0015] The inverting input terminal of the differential amplifier is respectively connected to the first input terminal and the third input terminal of the voltage-current conversion circuit, the non-inverting input terminal of the differential amplifier is respectively connected to the second input terminal, the fourth input terminal, and the output terminal of the first operational amplifier of the voltage-current conversion circuit, the output terminal of the differential amplifier is respectively connected to the inverting input terminal of the first operational amplifier and the first terminal of the first resistor, and the non-inverting input terminal of the first operational amplifier is respectively connected to the second terminal of the first resistor and the load;

[0016] When the inverting input terminal of the differential amplifier receives the first differential voltage and the non-inverting input terminal of the differential amplifier receives the second differential voltage, the first operational amplifier outputs the positive current;

[0017] When the inverting input terminal of the differential amplifier receives the second differential voltage and the non-inverting input terminal of the differential amplifier receives the first differential voltage, the first operational amplifier outputs the negative current.

[0018] In one embodiment, the differential amplifier includes a second resistor, a third resistor, a fourth resistor, a fifth operational amplifier and a second operational amplifier, wherein:

[0019] The first end of the second resistor is connected to the first input end and the third input end of the voltage-current conversion circuit respectively, and the second end of the second resistor is connected to the inverting input end of the second operational amplifier and the first end of the third resistor respectively;

[0020] The second end of the third resistor is connected to the output end of the second operational amplifier and the first end of the first resistor respectively;

[0021] The first end of the fourth resistor is connected to the second input end and the third input end of the voltage-current conversion circuit respectively, the second end of the fourth resistor is connected to the non-inverting input end of the second operational amplifier and the first end of the fifth resistor respectively, and the second end of the fifth resistor is connected to the output end of the first operational amplifier.

[0022] In one embodiment, the first relay and the second relay are high and low level signal controlled relays.

[0023] In one embodiment, the differential voltage circuit includes a DA converter, a first pull-down unit and a second pull-down unit, wherein:

[0024] A first end of the first pull-down unit is connected to an output end of the DA converter, a second end of the first pull-down unit is grounded, and the first pull-down unit is used to clamp the first differential voltage;

[0025] A first end of the second pull-down unit is connected to the other output end of the DA converter, a second end of the second pull-down unit is grounded, and the second pull-down unit is used to clamp the second differential voltage.

[0026] In one embodiment, the first pull-down unit and the second pull-down unit have the same resistance value.

[0027] In one embodiment, the control circuit includes a single chip microcomputer.

[0028] In a second aspect, the present application further provides a channel verification system for a nuclear power unit, comprising a detection circuit and a bidirectional current source circuit as provided in any of the above embodiments, wherein the bidirectional current source circuit is connected to the detection circuit;

[0029] The bidirectional current source circuit is used to provide a current source for the detection circuit.

[0030] In the bidirectional current source circuit and the channel verification system for a nuclear power unit, the bidirectional current source circuit includes a control circuit, a differential voltage circuit, a switching circuit, and a voltage-to-current conversion circuit. The control circuit can output a digital logic signal to the differential voltage circuit, which can convert the digital logic signal into a first differential voltage and a second differential voltage of the same polarity. Specifically, the value of the digital logic signal can be adjusted by adjusting the input of the control circuit, thereby adjusting the value of the first differential voltage and the second differential voltage. The control circuit outputs a level signal to the switching circuit, which can, based on the received level signal, select a path between the two output terminals of the differential voltage circuit and the two input terminals of the voltage-to-current conversion circuit, respectively, so that the voltage-to-current conversion circuit outputs a positive current or a negative current based on the received first differential voltage and the second differential voltage, thereby meeting the current source polarity requirements during nuclear power unit channel verification. Furthermore, by adjusting the value of the digital logic signal output by the control circuit, the values ​​of the first differential voltage and the second differential voltage can be adjusted, thereby adjusting the positive current or the negative current, thereby meeting the current source amplitude requirements during nuclear power unit channel verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 1 is a schematic structural diagram of a bidirectional current source circuit according to an embodiment;

[0033] Figure 2 1 is a schematic structural diagram of a voltage-to-current conversion circuit according to an embodiment;

[0034] Figure 3 is a structural diagram of a switching circuit according to an embodiment;

[0035] Figure 4 A voltage-to-current conversion circuit according to a specific embodiment;

[0036] Figure 5 1 is a schematic structural diagram of a differential voltage circuit according to an embodiment;

[0037] Figure 6 Schematic diagram of the structure of a bidirectional current source circuit according to a specific embodiment.

[0038] Description of reference numerals:

[0039] 100 - control circuit, 200 - differential voltage circuit, 210 - first pull-down unit, 220 - second pull-down unit, 300 - switching circuit, 400 - voltage-current conversion circuit, 500 - load. DETAILED DESCRIPTION

[0040] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0042] It will be understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor without departing from the scope of this application. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0043] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0044] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0045] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0046] In one embodiment, Figure 1As shown, the present application provides a bidirectional current source circuit, including a control circuit 100, a differential voltage circuit 200, a switching circuit 300, and a voltage-to-current conversion circuit 400. The input end of the differential voltage circuit 200 is connected to the control circuit 100, and the two output ends of the differential voltage circuit 200 are respectively connected to the two first ends of the switching circuit 300. The control end of the switching circuit 300 is connected to the control circuit 100, and the four second ends of the switching circuit 300 are respectively connected to the four input ends of the voltage-to-current conversion circuit 400.

[0047] The control circuit 100 can output a digital logic signal to the differential voltage circuit 200 and a level signal to the switching circuit 300. The differential voltage circuit 200 can convert the digital logic signal provided by the control circuit 100 into a first differential voltage and a second differential voltage. The digital logic signal is a digital signal, and the first differential voltage and the second differential voltage are analog signals. The first differential voltage and the second differential voltage have the same polarity. In the embodiment of the present application, both the first differential voltage and the second differential voltage are positive polarity signals.

[0048] The switching circuit 300 can select the paths between the two output ends of the differential voltage circuit 200 corresponding to the two input ends of the voltage-current conversion circuit 400 according to the received level signal, so that the voltage-current conversion circuit 400 outputs the total current or negative current according to the received first differential voltage and second differential voltage.

[0049] It can be understood that the two output terminals of the differential voltage circuit 200 are respectively connected to the two input terminals of the voltage-current conversion circuit 400 through the switching circuit 300. For example, the two output terminals of the differential voltage circuit 200 are connected to the first input terminal and the fourth input terminal of the voltage-current conversion circuit 400 through the switching circuit 300, or the two output terminals of the differential voltage circuit 200 are connected to the second input terminal and the third input terminal of the voltage-current conversion circuit 400 through the switching circuit 300. The switching circuit 300 can select to conduct the path between the two output terminals of the differential voltage circuit 200 and the first input terminal and the fourth input terminal of the voltage-current conversion circuit 400, or select to conduct the path between the two output terminals of the differential voltage circuit 200 and the second input terminal and the third input terminal of the voltage-current conversion circuit 400 based on the received level signal. The voltage-current conversion circuit 400 can output a positive current or a negative current based on the first differential voltage and the second differential voltage received at different input terminals.

[0050] In an embodiment of the present application, a bidirectional current source circuit includes a control circuit 100, a differential voltage circuit 200, a switching circuit 300, and a voltage-to-current conversion circuit 400. The control circuit 100 can output a digital logic signal to the differential voltage circuit 200, and the differential voltage circuit 200 can convert the digital logic signal into a first differential voltage and a second differential voltage of the same polarity. That is, the value of the digital logic signal can be adjusted by adjusting the input of the control circuit 100, thereby adjusting the value of the first differential voltage and the second differential voltage. The control circuit 100 outputs a level signal to the switching circuit 300. The switching circuit 300 can select, based on the received level signal, to conduct the path between the two output terminals of the differential voltage circuit 200 and the two input terminals of the voltage-to-current conversion circuit 400, respectively, so that the voltage-to-current conversion circuit 400 outputs a positive current or a negative current based on the received first differential voltage and the second differential voltage, thereby meeting the current source polarity requirements during channel verification of a nuclear power unit. In addition, by adjusting the value of the digital logic signal output by the control circuit 100, the value of the first differential voltage and the second differential voltage can be adjusted, and then the value of the positive current or negative current can be adjusted, which can meet the amplitude requirement of the current source during the channel calibration of the nuclear power unit.

[0051] In some embodiments, the control circuit may be a single chip microcomputer, FPGA, MCU, etc.

[0052] In one embodiment, Figure 2 As shown, the voltage-to-current conversion circuit 400 includes a differential amplifier U2, a first operational amplifier U1, and a first resistor R1. The inverting input terminal of the differential amplifier U2 is connected to the first input terminal and the third input terminal of the voltage-to-current conversion circuit 400, respectively. The non-inverting input terminal of the differential amplifier U2 is connected to the second input terminal and the fourth input terminal of the voltage-to-current conversion circuit 400, the output terminal and the inverting input terminal of the first operational amplifier U1, respectively. The output terminal of the differential amplifier U2 is connected to the first terminal of the first resistor R1, and the non-inverting input terminal of the first operational amplifier U1 is connected to the second terminal of the first resistor R1 and the load 500.

[0053] The polarity of the output signal of differential amplifier U2 is related to the voltages at its non-inverting and inverting inputs. When the voltage at the non-inverting input of differential amplifier U2 is less than the voltage at the inverting input, a negative polarity signal is output; when the voltage at the non-inverting input of differential amplifier U2 is greater than the voltage at the inverting input, a positive polarity signal is output.

[0054] In the embodiment of the present application, the value of the first differential voltage is greater than the value of the second differential voltage. When the inverting input of the differential amplifier U2 receives the first differential voltage and the non-inverting input of the differential amplifier U2 receives the second differential voltage, the first operational amplifier U1 outputs a negative current. When the inverting input of the differential amplifier U2 receives the second differential voltage and the non-inverting input of the differential amplifier U2 receives the first differential voltage, the first operational amplifier U1 outputs a positive current.

[0055] In one embodiment, Figure 3 As shown, the switching circuit 300 includes a first relay Q1 and a second relay Q2. A first terminal of the first relay Q1 is connected to an output terminal of the differential voltage circuit 200, a control terminal of the first relay Q1 is connected to the control circuit, and two second terminals of the first relay Q1 are connected to the first and second input terminals of the voltage-to-current conversion circuit 400, respectively. A first terminal of the second relay Q2 is connected to the other output terminal of the differential voltage circuit 200, a control terminal of the second relay Q2 is connected to the control circuit, and two output terminals of the second relay Q2 are connected to the third and fourth input terminals of the voltage-to-current conversion circuit 400, respectively.

[0056] The first relay Q1 can select one of the two input terminals of the voltage-current conversion circuit 400 to output the first differential voltage according to the received level signal. The second relay Q2 can select one of the two input terminals of the voltage-current conversion circuit 400 to output the second differential voltage according to the received level signal.

[0057] For example, the first relay Q1 can be connected to the first and second input terminals of the voltage-current conversion circuit 400, and the second relay Q2 can be connected to the third and fourth input terminals of the voltage-current conversion circuit 400. The first relay Q1 can selectively output the first differential voltage to the first or second input terminal of the voltage-current conversion circuit 400 based on a received level signal. The second relay Q2 can selectively output the second differential voltage to the third or fourth input terminal of the voltage-current conversion circuit 400 based on a received level signal.

[0058] Furthermore, when the level signal is a high-level signal, the first relay Q1 outputs a first differential voltage to the first input terminal of the voltage-current conversion circuit 400, and the second relay Q2 outputs a second differential voltage to the fourth input terminal of the voltage-current conversion circuit 400, so that the voltage-current conversion circuit 400 outputs a negative current. When the level signal is a low-level signal, the first relay Q1 outputs a first differential voltage to the second input terminal of the voltage-current conversion circuit 400, and the second relay Q2 outputs a second differential voltage to the third input terminal of the voltage-current conversion circuit 400, so that the voltage-current conversion circuit 400 outputs a positive current.

[0059] Optionally, when the level signal is a low-level signal, the first relay Q1 outputs a first differential voltage to the first input terminal of the voltage-current conversion circuit 400, and the second relay Q2 outputs a second differential voltage to the fourth input terminal of the voltage-current conversion circuit 400, so that the voltage-current conversion circuit 400 outputs a negative current. When the level signal is a high-level signal, the first relay Q1 outputs a first differential voltage to the second input terminal of the voltage-current conversion circuit 400, and the second relay Q2 outputs a second differential voltage to the third input terminal of the voltage-current conversion circuit 400, so that the voltage-current conversion circuit 400 outputs a positive current.

[0060] It should be noted that the control circuit may output one level signal to the first relay Q1 and the second relay Q2, or may output two level signals to the first relay Q1 and the second relay Q2 respectively.

[0061] In an embodiment of the present application, the switching circuit includes a first relay Q1 and a second relay Q2. The first relay Q1 can select to output the first differential voltage to one of the two input terminals of the voltage-current conversion circuit 400 according to the received level signal. The second level signal can also select to output the second differential voltage value to one of the two input terminals of the voltage-current conversion circuit 400 according to the received level signal. By selectively switching the first relay Q1 and the second relay Q2, the voltage-current conversion circuit 400 is controlled to output positive current or negative current, thereby meeting the requirements for current source polarity during channel verification of the nuclear power unit.

[0062] In some embodiments, the first relay and the second relay are high and low level signal controlled relays.

[0063] In one embodiment, Figure 4 As shown, the differential amplifier U2 includes a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a second operational amplifier U3. The first end of the second resistor R2 is respectively connected to the first input terminal and the third input terminal of the voltage-current conversion circuit, the second end of the second resistor R2 is respectively connected to the inverting input terminal of the second operational amplifier U3 and the first end of the third resistor R3, the second end of the third resistor R3 is respectively connected to the output terminal of the second operational amplifier U3 and the first end of the first resistor, the first end of the fourth resistor R4 is respectively connected to the second input terminal and the third input terminal of the voltage-current conversion circuit, the second end of the fourth resistor R4 is respectively connected to the non-inverting input terminal of the second operational amplifier U3 and the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to the output terminal of the first operational amplifier.

[0064] The differential amplifier circuit composed of the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the second operational amplifier U3 can convert the differential voltage into a stable current signal. The first operational amplifier acts as a voltage follower to enhance the positive feedback of the differential amplifier so that all the current flows to the load. Figure 4 The principle of the voltage-to-current conversion circuit of the present application is described below. The second resistor R2, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 have the same resistance value.

[0065] For the first operational amplifier U1, the voltage at its non-inverting input is V I , the output voltage is V O , differential mode input voltage , the common-mode input voltage is ,

[0066] according to and have to:

[0067]

[0068] Arranged as:

[0069]

[0070] in, is the differential mode gain of the first operational amplifier U1, is the differential mode gain of the first operational amplifier U1, is the common mode rejection ratio of the first operational amplifier U1.

[0071] The voltage gain is:

[0072]

[0073] Considering A OD1 >>1 and K CMR1 >>1, then the output error of the first operational amplifier U1 is approximately:

[0074]

[0075] For the second operational amplifier U3, the differential mode input voltage , common mode input voltage ,according to and have to:

[0076]

[0077] Among them, A OD2 is the differential mode gain of the second operational amplifier U3, A OC2is the common mode gain of the second operational amplifier U3, K CMR2 is the common mode rejection ratio of the second operational amplifier U3, and we can get:

[0078]

[0079] Substituting formula (2) into formula (6),

[0080]

[0081] A OD1 and A OD2 Referred to as A1 and A2, K CMR1 and K CMR2 Referred to as K1 and K2, the current on the first resistor R1 is:

[0082]

[0083] K1, K2, A1, and A2 are determined by the model of the operational amplifier. When the resistance of the first resistor is constant and the first differential voltage and the second differential voltage are stable, the current value output by the voltage-current conversion circuit is stable.

[0084] In addition, according to the virtual short circuit, the current at the non-inverting input terminal of the first operational amplifier U1 is approximately zero, so the current flowing through the first resistor R1 will all flow to the load.

[0085] In one embodiment, Figure 5 As shown, the differential voltage circuit includes a DA converter U4, a first pull-down unit 210, and a second pull-down unit 220. A first end of the first pull-down unit 210 is connected to one output end of the DA converter U4, and a second end of the first pull-down unit 210 is grounded. A first end of the second pull-down unit 220 is connected to the other output end of the DA converter U4, and a second end of the second pull-down unit 220 is grounded.

[0086] The first pull-down unit 210 is used to clamp the first differential voltage so that the voltage value of the first differential voltage is maintained within a preset range.

[0087] The second pull-down unit 220 is used to clamp the second differential voltage so that the voltage value of the second differential voltage is maintained within a preset range.

[0088] Furthermore, the first pull-down unit 210 includes a first pull-down resistor R6 , and the second pull-down unit 220 includes a second pull-down resistor R7 . The first pull-down resistor R6 and the second pull-down resistor R7 have the same resistance value.

[0089] For a better understanding, the bidirectional current source circuit of the present application is described with a specific embodiment. Figure 6As shown, the control circuit 100 is a single-chip microcomputer, the differential voltage circuit 200 includes a DA converter U4 of model LTC1666, a first pull-down resistor R6 and a second pull-down resistor R7, the switching circuit 300 includes a first relay Q1 and a second relay Q2, the current-voltage conversion circuit 400 includes a differential amplifier U2 of model INA105, a voltage follower U1 of model OPA602, and a first resistor R1, the resistance values ​​of the first pull-down resistor R6 and the second pull-down resistor R7 are both 52.3Ω, and the resistance value of the first resistor R1 is 1KΩ.

[0090] The control circuit 100 outputs 12-bit data to the DA converter U4. Based on this 12-bit input data, the DA converter U4 outputs a first differential voltage V1 to the first relay Q1 and a second differential voltage V2 to the second relay Q2. The control circuit 100 also outputs high and low level signals to the first relay Q1 and the second relay Q2. Specifically, the control circuit 100 outputs a high level signal to the first relay Q1 and the second relay Q2. The first relay Q1 is connected to terminal ① and outputs the first differential voltage V1 to the inverting input of the differential amplifier U2. The second relay Q2 is connected to terminal ④ and outputs the second differential voltage V2 to the non-inverting input of the differential amplifier U2. The current data obtained by adjusting the value of the first differential voltage is shown in Table 1. The voltage-to-current conversion circuit 400 can output a stable current of 0 to -24 mA. The control circuit 100 outputs a low-level signal to the first relay Q1 and the second relay Q2. The first relay Q1 is connected to terminal ② and outputs a first differential voltage to the non-inverting input of the differential amplifier U2. The second relay Q2 is connected to terminal ③ and outputs a second differential voltage to the inverting input of the differential amplifier U2. The current data obtained by adjusting the value of the first differential voltage is shown in Table 2. The voltage-current conversion circuit 400 can output a stable current of 0-24 mA. It can be understood that using the bidirectional current source circuit of the present application, the values ​​of the first differential voltage and the second differential voltage can be changed by changing the digital logic signal output by the control circuit 100, thereby changing the current value output by the voltage-current conversion circuit 400. By changing the level signal output by the control circuit 100, the switching circuit 300 is connected to different terminals, thereby changing the polarity of the current signal output by the voltage-current conversion circuit 400, meeting the current source requirements for channel verification of nuclear power units.

[0091] Table 1 shows the experimental data of multiple groups of negative current output

[0092] <![CDATA[V1]]> <![CDATA[V2]]> I 11V 10V -1mA 12V 10V -2mA 20V 10V -10mA 30V 10V -20mA 34V 10V -24mA

[0093] Table 2 shows the experimental data of multiple groups of output positive current

[0094] V1 V2 I 11V 10V 1mA 12V 10V 2mA 20V 10V 10mA 30V 10V 20mA 34V 10V 24mA

[0095] In one embodiment, the present application further provides a channel verification system for a nuclear power plant, comprising a detection circuit and a bidirectional current source circuit as provided in any of the above embodiments, wherein the bidirectional current source circuit is connected to the detection circuit. The bidirectional current source circuit can provide a current source for the detection circuit. Because this channel verification system utilizes a bidirectional current source circuit that can stably output positive or negative current, frequent replacement of the current source is not required during channel verification, thereby saving detection time and improving detection efficiency.

[0096] In the description of this specification, reference to the terms "some embodiments" or "other embodiments" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0097] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A bidirectional current source circuit, characterized in that: include: A control circuit for outputting digital logic signals and level signals; a differential voltage circuit, connected to the control circuit, and configured to convert a digital logic signal provided by the control circuit into a first differential voltage and a second differential voltage, wherein the first differential voltage and the second differential voltage have the same polarity and a value of the first differential voltage is greater than a value of the second differential voltage; a switching circuit, wherein two first terminals of the switching circuit are respectively connected to the two output terminals of the differential voltage circuit, and a control terminal of the switching circuit is connected to the control circuit; A voltage-current conversion circuit, wherein the four input terminals of the voltage-current conversion circuit are respectively connected to the four second terminals of the switching circuit; the voltage-current conversion circuit includes a differential amplifier, a first operational amplifier, and a first resistor; the inverting input terminal of the differential amplifier is respectively connected to the first input terminal and the third input terminal of the voltage-current conversion circuit, the non-inverting input terminal of the differential amplifier is respectively connected to the second input terminal, the fourth input terminal, the output terminal, and the inverting input terminal of the voltage-current conversion circuit, the output terminal of the differential amplifier is connected to the first terminal of the first resistor, and the non-inverting input terminal of the first operational amplifier is respectively connected to the second terminal of the first resistor and the load; The switching circuit is used to select and conduct the paths between the two output terminals of the differential voltage circuit and the two input terminals of the voltage-to-current conversion circuit according to the level signal, so that the voltage-to-current conversion circuit outputs a positive current or a negative current according to the received first differential voltage and the second differential voltage; Wherein, when the inverting input terminal of the differential amplifier receives the first differential voltage and the non-inverting input terminal of the differential amplifier receives the second differential voltage, the first operational amplifier outputs the negative current; When the inverting input terminal of the differential amplifier receives the second differential voltage and the non-inverting input terminal of the differential amplifier receives the first differential voltage, the first operational amplifier outputs the positive current.

2. The bidirectional current source circuit according to claim 1, wherein: The switching circuit includes a first relay and a second relay, wherein the first end of the first relay is connected to an output end of the differential voltage circuit, the control end of the first relay is connected to the control circuit, and the two second ends of the first relay are respectively connected to the first input end and the second input end of the voltage-current conversion circuit, and the first relay is used to select and output the first differential voltage to one of the two input ends of the voltage-current conversion circuit according to the received level signal; The first end of the second relay is connected to the other output end of the differential voltage circuit, the control end of the second relay is connected to the control circuit, and the two output ends of the second relay are respectively connected to the third input end and the fourth input end of the voltage-current conversion circuit. The second relay is used to select and output the second differential voltage to one of the two input ends of the voltage-current conversion circuit according to the received level signal.

3. The bidirectional current source circuit according to claim 2, wherein: When the level signal is a high-level signal, the first relay outputs the first differential voltage to the first input terminal of the voltage-current conversion circuit, and the second relay outputs the second differential voltage to the fourth input terminal of the voltage-current conversion circuit, so that the voltage-current conversion circuit outputs a negative current; When the level signal is a low level signal, the first relay outputs the first differential voltage to the second input terminal of the voltage-current conversion circuit, and the second relay outputs the second differential voltage to the third input terminal of the voltage-current conversion circuit, so that the voltage-current conversion circuit outputs a positive current.

4. The bidirectional current source circuit according to claim 1, wherein: The differential amplifier includes a second resistor, a third resistor, a fourth resistor, a fifth resistor and a second operational amplifier, wherein: The first end of the second resistor is connected to the first input end and the third input end of the voltage-current conversion circuit respectively, and the second end of the second resistor is connected to the inverting input end of the second operational amplifier and the first end of the third resistor respectively; The second end of the third resistor is connected to the output end of the second operational amplifier and the first end of the first resistor respectively; The first end of the fourth resistor is connected to the second input end and the third input end of the voltage-current conversion circuit respectively, the second end of the fourth resistor is connected to the non-inverting input end of the second operational amplifier and the first end of the fifth resistor respectively, and the second end of the fifth resistor is connected to the output end of the first operational amplifier.

5. The bidirectional current source circuit according to claim 2, wherein: The first relay and the second relay are high and low level signal controlled relays.

6. The bidirectional current source circuit according to claim 1, wherein: The differential voltage circuit includes a DA converter, a first pull-down unit and a second pull-down unit, wherein: A first end of the first pull-down unit is connected to an output end of the DA converter, a second end of the first pull-down unit is grounded, and the first pull-down unit is used to clamp the first differential voltage; A first end of the second pull-down unit is connected to the other output end of the DA converter, a second end of the second pull-down unit is grounded, and the second pull-down unit is used to clamp the second differential voltage.

7. The bidirectional current source circuit according to claim 6, wherein: The first pull-down unit includes a first pull-down resistor, and the second pull-down unit includes a second pull-down resistor. The resistance value of the first pull-down resistor is the same as the resistance value of the second pull-down resistor.

8. The bidirectional current source circuit according to claim 1, wherein: The control circuit includes a single chip microcomputer.

9. A channel verification system for a nuclear power unit, characterized in that: comprising a detection circuit and the bidirectional current source circuit according to any one of claims 1 to 8, wherein the bidirectional current source circuit is connected to the detection circuit; The bidirectional current source circuit is used to provide a current source for the detection circuit.

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