Current detection device, circuit board, power conversion equipment and air conditioner

Abstract

The utility model discloses a current detection device, a circuit board, a power conversion device and an air conditioner, the current detection device is applied to the circuit board, the circuit board is provided with a power device, a pin of the power device passes through the circuit board, and the current detection device comprises an induction coil unit and a control unit, the induction coil unit is printed on the circuit board around a pin of the power device; and the current detection unit is connected with the induction coil unit and is configured to detect the electrical parameters passing through the induction coil unit so as to obtain the working current of the power device. According to the current detection device, the space of a circuit board at the bottom of the device can be fully utilized, the space of the circuit board is basically not occupied, and current detection and short-circuit protection without cost and real objects are realized, so that the cost is reduced, the space of the circuit board is saved, passive isolation sampling can be realized, and current detection is more convenient and safer.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, in particular to a current detection device, a circuit board, a power conversion device and an air conditioner. Background Art

[0002] In the related art, current detection and short-circuit protection both require using current transformers, resistors or Hall sensors to sample current. These devices are expensive and occupy a large amount of space. In addition, there are certain parameter differences between different manufacturers, and the sampling devices are likely to be damaged by inrush current. Summary of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the first object of the utility model is to provide a current detection device, which can make full use of the bottom circuit board space of the device, hardly occupies the circuit board space, realizes current detection and short-circuit protection without cost and physical objects, thus reducing the cost, saving the circuit board space, and can realize passive isolation sampling, making the current detection more convenient and safer.

[0004] The second object of the utility model is to provide a circuit board.

[0005] The third object of the utility model is to provide a power conversion device.

[0006] The fourth object of the utility model is to provide an air conditioner.

[0007] To achieve the above object, an embodiment of the first aspect of the utility model provides a current detection device, which is applied to a circuit board. A power device is arranged on the circuit board, and the pins of the power device pass through the circuit board. The current detection device includes: an induction coil unit, which is printed on the circuit board around the pins of the power device; a current detection unit connected to the induction coil unit, which is configured to detect the electrical parameters passing through the induction coil unit to obtain the working current of the power device.

[0008] According to the current detection device of the embodiments of the present utility model, during the operation of the circuit, according to the principle of electromagnetic induction, the induction coil unit can generate electrical parameters such as current and voltage corresponding to the power device, and the current detection unit detects the electrical parameters passing through the induction coil unit to obtain the operating current of the power device. Thus, the device can make full use of the bottom circuit board space of the device, hardly occupy the circuit board space, realize current detection and short-circuit protection without cost and physical objects, thereby reducing costs, saving the circuit board space, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0009] In addition, the current detection device according to the above embodiments of the present utility model may further have the following additional technical features:

[0010] Specifically, the induction coil unit includes a first induction coil, the first induction coil is printed on the top layer of the circuit board, and the number of turns of the first induction coil is greater than 1.

[0011] Specifically, the induction coil unit further includes a second induction coil, the second induction coil is printed on the bottom layer of the circuit board, and the number of turns of the second induction coil is greater than or equal to 1.

[0012] Specifically, the above current detection device further includes: a voltage dividing unit, the voltage dividing unit is connected to the induction coil unit to boost the induced voltage signal of the induction coil unit.

[0013] Specifically, the voltage dividing unit includes: a first resistor, one end of the first resistor is adapted to be connected to a reference power supply; a second resistor, one end of the second resistor is connected to the other end of the first resistor and has a first node, the other end of the second resistor is grounded, and the first node is connected to the induction coil unit.

[0014] Specifically, the voltage dividing unit includes: a third resistor, one end of the third resistor is adapted to be connected to a reference power supply; a fourth resistor, one end of the fourth resistor is connected to the other end of the third resistor and has a second node, the other end of the fourth resistor is grounded; a fifth resistor, one end of the fifth resistor is connected to the second node, and the other end of the fifth resistor is grounded after being connected to the induction coil unit.

[0015] Specifically, the above current detection device further includes: a sixth resistor, one end of the sixth resistor is connected to the induction coil unit; a first amplifier, the negative input terminal of the first amplifier is connected to the other end of the sixth resistor, the positive input terminal of the first amplifier is connected to the second node, and the output terminal of the first amplifier is connected to the current detection unit; a seventh resistor, the seventh resistor is connected between the negative input terminal and the output terminal of the first amplifier.

[0016] Specifically, the current detection unit includes: an eighth resistor, one end of the eighth resistor is connected to one end of the induction coil unit, and the other end of the induction coil unit is grounded; a ninth resistor, one end of the ninth resistor is adapted to be connected to a reference power supply; a tenth resistor, one end of the tenth resistor is connected to the other end of the ninth resistor and has a third node, and the other end of the tenth resistor is grounded; a first comparator, the negative input terminal of the first comparator is connected to the other end of the eighth resistor, and the positive input terminal of the first comparator is connected to the third node; a controller, the sampling terminal of the controller is connected to the output terminal of the first comparator, and is configured to determine whether the operating current of the power device is overcurrent according to the comparison signal output by the first comparator.

[0017] To achieve the above object, an embodiment of the second aspect of the present invention provides a circuit board, including: a board body; a power device disposed on the board body, and pins of the power device penetrate through the board body; the above-mentioned current detection device, configured to detect the operating current of the power device.

[0018] According to the circuit board of the embodiment of the present invention, through the above-mentioned current detection device, the bottom circuit board space of the device can be fully utilized, and the circuit board space is basically not occupied, realizing current detection and short-circuit protection without cost and without physical objects, thereby reducing costs, saving the circuit board space, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0019] To achieve the above object, a power conversion device provided by an embodiment of the third aspect of the present invention includes the above-mentioned circuit board.

[0020] According to the power conversion device of the embodiment of the present invention, through the above-mentioned circuit board, current detection and short-circuit protection can be realized without cost and without physical objects, thereby reducing costs, saving the circuit board space, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0021] To achieve the above object, an embodiment of the fourth aspect of the present invention provides an air conditioner, including the above-mentioned power conversion device.

[0022] According to the air conditioner of the embodiment of the present invention, through the above-mentioned power conversion device, current detection and short-circuit protection can be realized without cost and without physical objects, thereby reducing costs, saving the circuit board space, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0023] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. Brief Description of the Drawings

[0024] Figure 1 It is a block diagram of a current detection device according to an embodiment of the present utility model;

[0025] Figure 2 It is a schematic structural diagram of a circuit board according to an embodiment of the present utility model;

[0026] Figure 3 It is a schematic structural diagram of an induction coil unit according to an embodiment of the present utility model;

[0027] Figure 4 It is a schematic structural diagram of an induction coil unit according to an embodiment of the present utility model;

[0028] Figure 5 It is a waveform diagram of the detected current according to an embodiment of the present utility model;

[0029] Figure 6 It is a waveform diagram of the detected current under a short - circuit condition according to an embodiment of the present utility model;

[0030] Figure 7 It is a block diagram of a current detection device according to an embodiment of the present utility model;

[0031] Figure 8 It is a topological circuit diagram of a voltage - dividing unit according to an embodiment of the present utility model;

[0032] Figure 9 It is a topological circuit diagram of a voltage - dividing unit according to another embodiment of the present utility model;

[0033] Figure 10 It is a topological circuit diagram of a current detection unit according to an embodiment of the present utility model;

[0034] Figure 11 It is a schematic structural diagram of a circuit board according to an embodiment of the present utility model;

[0035] Figure 12 It is a block diagram of a power change device according to an embodiment of the present utility model;

[0036] Figure 13 It is a topological schematic diagram of a totem - pole circuit in a power change device according to an embodiment of the present utility model;

[0037] Figure 14 It is a block diagram of an air conditioner according to an embodiment of the present utility model. Detailed Embodiments

[0038] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present utility model, and should not be construed as a limitation to the present utility model.

[0039] The current detection device, circuit board, power conversion device, and air conditioner proposed according to the embodiments of the present utility model will be described below with reference to the accompanying drawings.

[0040] Figure 1 It is a block diagram of a current detection device according to an embodiment of the present utility model.

[0041] As Figure 1 shown, the current detection device 100 according to an embodiment of the present utility model is applied to a circuit board. The current detection device 100 includes: an induction coil unit 110 and a current detection unit 120.

[0042] Among them, the induction coil unit 110 is printed around the lead of the power device on the circuit board. The current detection unit 120 is connected to the induction coil unit 110 and is configured to detect the electrical parameters passing through the induction coil unit 110 to obtain the operating current of the power device. Among them, the electrical parameters include parameters such as current and voltage. It should be noted that the power device can be a plug-in power device such as a toroidal inductor, electrolytic capacitor, solid-state capacitor, etc. Hereinafter, the power device is taken as an inductor for example.

[0043] For example, as Figure 2 shown, an inductor L is provided on the circuit board 200. The lead of the inductor L passes through the board body of the circuit board 210. The induction coil unit 110 is arranged below the inductor L. Thus, the bottom circuit board space of the device is fully utilized, and the circuit board space is hardly occupied. And, as Figure 3 shown, the induction coil unit 110 is printed around the lead of the inductor on the circuit board, where the central black dot is the lead of the inductor. Thus, the inductor and the induction coil unit 110 form a current transformer, and the current detection unit 120 can obtain the operating current of the inductor through corresponding calculations based on the electrical parameters of the induction coil unit 110.

[0044] It should be understood that when the circuit is working normally, the induction coil unit 110 will generate a square wave consistent with the operating frequency of the inductor. As Figure 5 shown, the duty cycle of the square wave is consistent with the duty cycle of the control signal of the circuit. Among them, the relationship between the voltage amplitude U of the square wave, the current i of the inductor, and the mutual inductance M between the induction coil unit 110 and the inductor lead is as follows:

[0045] U = M * di / dt

[0046] Among them, the mutual inductance M between the induction coil unit 110 and the inductive pin is a fixed value.

[0047] Specifically, after the circuit starts to work, the current detection unit 120 can perform edge detection on the square-wave voltage of the induction coil unit 110, start timing after detecting the rising edge, detect the voltage value U of the waveform after the rising voltage stabilizes, and stop timing when detecting the falling edge of the waveform to obtain the time t. Then, the rising current i of the inductor in this stage is i = U * t / M, where the mutual inductance M is detected by the device and recorded in the current detection unit 120, thereby obtaining the working current of the inductor. When a short-circuit occurs during the operation of the circuit, such as Figure 6 as shown, the working current flowing through the inductor suddenly increases, and the induction coil unit 110 will correspondingly output an instantaneous pulse voltage. When the current detection unit 120 detects the pulse voltage, it can turn off the circuit operation to protect the circuit.

[0048] In addition, since the inductor and the induction coil unit 110 form a current transformer, the ratio of the inductor current to the current of the induction coil unit 110, that is, the current ratio of the current transformer, can also be obtained through the detection device. After the circuit starts to work, the current detection unit 120 can detect and obtain the current in the induction coil unit 110, and multiply the current in the induction coil unit 110 by the current ratio to obtain the working current of the inductor.

[0049] It should be understood that when the power device is an electrolytic capacitor, a solid capacitor, etc., the induction coil unit 110 is printed on the circuit board around the pin of the power device, and the current detection unit 120 can calculate the working current of the power device according to the electrical parameters of the induction coil unit 110. For the convenience of understanding, when describing the following embodiments, the power device is described as an inductor.

[0050] According to an embodiment of the present invention, as Figure 2 and Figure 3 shown, the induction coil unit 110 includes a first induction coil 111, the first induction coil 111 is printed on the top layer of the circuit board, and the number of turns of the first induction coil 111 is greater than 1.

[0051] Specifically, as Figure 2 shown, the first induction coil 111 is printed on the top layer of the circuit board, as Figure 3 shown, the first induction coil 111 is printed on the circuit board around the pin of the inductor. Among them, the central black dot is the pin of the inductor. Thus, by using the characteristic that the inductor pin passes through the circuit board, the current passing through the inductor pin (i.e., through the inductor) can be detected by detecting the electrical parameters of the first induction coil 111 to obtain the working current of the inductor.

[0052] According to an embodiment of the present utility model, as Figure 2 and Figure 4 shown, the induction coil unit 110 further includes a second induction coil 112, the second induction coil 112 is printed on the bottom layer of the circuit board, and the number of turns of the second induction coil 112 is greater than or equal to 1.

[0053] Specifically, as Figure 2 shown, the second induction coil 112 is printed on the bottom layer of the circuit board. As Figure 4 shown, when the induction intensity of only using the inductive pin is too small, the induction intensity can be enhanced by the second induction coil 112.

[0054] According to an embodiment of the present utility model, as Figure 7 shown, the above-mentioned current detection device 100 further includes: a voltage dividing unit 130, the voltage dividing unit 130 is connected to the induction coil unit 110 to boost the induction voltage signal of the induction coil unit 110.

[0055] That is to say, when the inductive output voltage is small or it is necessary to detect the falling current stage, the voltage dividing unit 130 can boost the induction voltage signal of the induction coil unit 110 to facilitate the detection by the current detection unit 120.

[0056] According to an embodiment of the present utility model, as Figure 8 shown, the voltage dividing unit 130 includes: a first resistor R1, one end of the first resistor R1 is adapted to be connected to a reference power supply; a second resistor R2, one end of the second resistor R2 is connected to the other end of the first resistor R1 and has a first node, the other end of the second resistor R2 is grounded, and the first node is connected to the induction coil unit 110.

[0057] Specifically, as Figure 8 shown, let the voltage value of the reference power supply be V0 and the voltage value of the first node be V1. Then the voltage of the first node is the voltage divided by the second resistor R2, that is, V1 = R2 / (R1 + R2)*V0. When the inductive output voltage is small or it is necessary to detect the falling current stage, the induction voltage signal of the induction coil unit 110 is superimposed on the voltage of the first node, and the voltage value obtained by the current detection unit 120 is the sum of the induction voltage signal and the voltage value of the first node. Thus, the voltage dividing unit 130 realizes the boosting of the induction voltage signal of the induction coil unit 110.

[0058] According to another embodiment of the present utility model, as Figure 9As shown, the voltage dividing unit 130 includes: a third resistor R3, one end of the third resistor R3 being adapted to be connected to a reference power supply; a fourth resistor R4, one end of the fourth resistor R4 being connected to the other end of the third resistor R3 and having a second node, the other end of the fourth resistor R4 being grounded; a fifth resistor R5, one end of the fifth resistor R5 being connected to the second node, and the other end of the fifth resistor R5 being connected to the induction coil unit 110 and then grounded.

[0059] Further, as Figure 9 shown, the above-mentioned current detection device 100 further includes: a sixth resistor R6, one end of the sixth resistor R6 being connected to the induction coil unit 110; a first amplifier M1, the negative input terminal of the first amplifier M1 being connected to the other end of the sixth resistor R6, the positive input terminal of the first amplifier M1 being connected to the second node, and the output terminal of the first amplifier M1 being connected to the current detection unit 120; a seventh resistor R7, the seventh resistor R7 being connected between the negative input terminal and the output terminal of the first amplifier M1.

[0060] Specifically, when the inductive output signal value is too small, the induced voltage signal generated on the induction coil unit 110 is also small. Therefore, the Figure 9 circuit shown can be adopted to first boost the induced voltage signal and then amplify the boosted induced voltage signal. As Figure 9 shown, the induced voltage signal of the induction coil unit 110 is superimposed on the voltage of the second node and sent to the negative input terminal of the first amplifier M1 through the sixth resistor R6. The first amplifier M1 can amplify the voltage signal and send the amplified voltage signal to the current detection unit 120 through the output terminal. Thus, the voltage dividing unit 130 realizes boosting the too small induced voltage signal of the induction coil unit 110 while amplifying the voltage signal.

[0061] According to an embodiment of the present invention, as Figure 10 shown, the current detection unit 120 includes: an eighth resistor R8, one end of the eighth resistor R8 being connected to one end of the induction coil unit 110, and the other end of the induction coil unit 110 being grounded; a ninth resistor R9, one end of the ninth resistor R9 being adapted to be connected to a reference power supply; a tenth resistor R10, one end of the tenth resistor R10 being connected to the other end of the ninth resistor R9 and having a third node, the other end of the tenth resistor R10 being grounded; a first comparator T1, the negative input terminal of the first comparator T1 being connected to the other end of the eighth resistor R8, and the positive input terminal of the first comparator T1 being connected to the third node; a controller 121, the sampling terminal of the controller 121 being connected to the output terminal of the first comparator T1 and being configured to determine whether the working current of the power device is overcurrent according to the comparison signal output by the first comparator T1.

[0062] Specifically, as Figure 10As shown in the figure, the voltage of the reference power supply is divided by the ninth resistor R9 and the tenth resistor R10. The voltage divided by the tenth resistor R10 is the voltage of the third node, and the voltage of the third node is provided to the positive input terminal of the first comparator T1 as the reference voltage. The input voltage signal at the negative input terminal of the first comparator T1 is the sum of the induced voltage value in the induction coil unit 110 and the voltage value on the eighth resistor R8 (the current in the induction coil unit 110 passes through the eighth resistor R8 to generate a voltage on the eighth resistor R8).

[0063] Specifically, during the normal operation of the circuit, the current in the coil of the induction coil unit 110 is small, making the input voltage signal at the negative input terminal of the first comparator T1 less than the voltage value at the positive input terminal of the first comparator T1. The output terminal of the first comparator T1 outputs a high-level comparison signal to the controller 121, and the controller 121 can determine that the working current of the inductor is not overcurrent based on the high-level comparison signal. When a short circuit occurs during the operation of the circuit, as Figure 6 shown in the figure, the working current flowing through the inductor suddenly increases, and the induction coil unit 110 will correspondingly output an instantaneous pulse voltage, making the input voltage signal at the negative input terminal of the first comparator T1 greater than the voltage value at the positive input terminal of the first comparator T1. The output terminal of the first comparator T1 outputs a low-level comparison signal to the controller 121, and the controller 121 can determine that the working current of the inductor is overcurrent based on the low-level comparison signal. When it is detected that the working current of the inductor is overcurrent, the controller 121 can turn off the circuit operation to protect the circuit against overcurrent. Thus, the purpose of automatic protection against circuit short circuits can be achieved.

[0064] In summary, according to the current detection device of the embodiment of the present invention, during the operation of the circuit, based on the principle of electromagnetic induction, the induction coil unit can generate electrical parameters such as current and voltage corresponding to the power device, and the current detection unit detects the electrical parameters passing through the induction coil unit to obtain the working current of the power device. Thus, the device can make full use of the bottom circuit board space of the device, basically does not occupy the circuit board space, realizes current detection and short-circuit protection without cost and physical objects, thereby reducing costs, saving the circuit board space, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0065] Corresponding to the above embodiments, the present invention also proposes a circuit board.

[0066] Figure 11 It is a schematic structural diagram of the circuit board according to the embodiment of the present invention.

[0067] As Figure 11As shown in the figure, the 200 circuit board of the embodiment of the present utility model includes: a board body 210; a power device 220 disposed on the board body 210, and the pins of the power device 220 pass through the board body 210; the above-mentioned current detection device 100 is configured to detect the working current of the power device 220. It should be noted that the power device 220 can be a plug-in power device such as a toroidal inductor, an electrolytic capacitor, a solid capacitor, etc. Figure 11 The power device 220 shown is exemplified by a toroidal inductor, and it should not be construed as a limitation to the present utility model.

[0068] According to the circuit board of the embodiment of the present utility model, through the above-mentioned current detection device, the bottom circuit board space of the device can be fully utilized, and the circuit board space is basically not occupied. The current detection and short-circuit protection are realized without cost and physical objects, thereby reducing the cost, saving the circuit board space, and being able to realize passive isolation sampling, making the current detection more convenient and safer.

[0069] Corresponding to the above embodiment, the present utility model also proposes a power change device.

[0070] Figure 12 It is a block diagram of the power change device according to the embodiment of the present utility model.

[0071] As Figure 12 shown, the power conversion device 300 of the embodiment of the present utility model includes the above-mentioned circuit board 200.

[0072] According to the power conversion device of the embodiment of the present utility model, through the above-mentioned circuit board, the current detection and short-circuit protection can be realized without cost and physical objects, thereby reducing the cost, saving the circuit board space, and being able to realize passive isolation sampling, making the current detection more convenient and safer.

[0073] For example, when the power conversion device 300 has Figure 13 the totem pole circuit shown, the PFC inductor L1 serves as the inductor L on the circuit board 200, and its pins pass through the board body 210. Thus, through the circuit board 200, passive isolation sampling can be realized, making the current detection more convenient and safer, and being able to reduce the cost.

[0074] Corresponding to the above embodiment, the present utility model also proposes an air conditioner.

[0075] Figure 14 It is a block diagram of the air conditioner according to the embodiment of the present utility model.

[0076] As Figure 14 shown, the air conditioner 400 of the embodiment of the present utility model includes the above-mentioned power conversion device 300.

[0077] According to the air conditioner of the embodiment of the present utility model, through the above-mentioned power conversion device, it is possible to perform current detection and short-circuit protection without cost and physical objects, thereby reducing costs, saving the space of the circuit board, and being able to achieve passive isolation sampling, making the current detection more convenient and safer.

[0078] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0079] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0080] In the present utility model, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected to", "fixed" etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0081] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present utility model.

Claims

1. A current detection device, characterized in that: Applied to a circuit board, the circuit board is provided with a power device, the pins of the power device pass through the circuit board, and the current detection device comprises: An induction coil unit, wherein the induction coil unit is printed on the circuit board around the pins of the power device; The current detection unit connected to the induction coil unit is configured to detect the electrical parameters passing through the induction coil unit to obtain the operating current of the power device.

2. The current detection device according to claim 1, characterized in that: The induction coil unit includes a first induction coil, which is printed on a top layer of the circuit board and has a number of turns greater than one.

3. The current detection device according to claim 1, characterized in that: The induction coil unit further includes a second induction coil, which is printed on the bottom layer of the circuit board, and the number of turns of the second induction coil is greater than or equal to one.

4. The current detection device according to claim 1, characterized in that: Also includes: A voltage dividing unit is connected to the induction coil unit to increase the induced voltage signal of the induction coil unit.

5. The current detection device according to claim 4, characterized in that: The voltage dividing unit comprises: a first resistor, one end of which is suitable for connecting to a reference power supply; A second resistor, one end of the second resistor is connected to the other end of the first resistor and has a first node, the other end of the second resistor is grounded, and the first node is connected to the induction coil unit.

6. The current detection device according to claim 4, characterized in that: The voltage dividing unit comprises: a third resistor, one end of which is suitable for connecting to a reference power supply; a fourth resistor, one end of the fourth resistor being connected to the other end of the third resistor and having a second node, and the other end of the fourth resistor being grounded; a fifth resistor, one end of the fifth resistor being connected to the second node, and the other end of the fifth resistor being connected to the induction coil unit and then grounded.

7. The current detection device according to claim 6, characterized in that: Also includes: a sixth resistor, one end of which is connected to the induction coil unit; a first amplifier, wherein a negative input terminal of the first amplifier is connected to the other end of the sixth resistor, a positive input terminal of the first amplifier is connected to the second node, and an output terminal of the first amplifier is connected to the current detection unit; A seventh resistor is connected between the negative input terminal and the output terminal of the first amplifier.

8. The current detection device according to claim 1, characterized in that: The current detection unit comprises: an eighth resistor, one end of the eighth resistor being connected to one end of the induction coil unit, and the other end of the induction coil unit being grounded; a ninth resistor, one end of which is suitable for being connected to a reference power supply; a tenth resistor, one end of the tenth resistor being connected to the other end of the ninth resistor and having a third node, and the other end of the tenth resistor being grounded; a first comparator, wherein a negative input terminal of the first comparator is connected to the other end of the eighth resistor, and a positive input terminal of the first comparator is connected to the third node; A controller, wherein a sampling terminal of the controller is connected to an output terminal of the first comparator, and is configured to determine whether an operating current of the power device is overcurrent according to a comparison signal output by the first comparator.

9. A circuit board, characterized in that: include: plate body; A power device is arranged on the board, and a pin of the power device passes through the board; The current detection device according to any one of claims 1 to 8 is configured to detect the operating current of the power device.

10. A power conversion device, characterized in that: Comprising the circuit board according to claim 9.

11. An air conditioner, characterized in that: Comprising the power conversion device according to claim 10.

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