Connection circuit and charging gun

Abstract

A connection circuit and a charging gun having the connection circuit. The connection circuit is used to connect an external power source and an electrical device to form a charge-discharge loop. The connection circuit includes a power supply circuit, a control circuit, and a relay. The power supply circuit is connected to the external power source and is used to transform the voltage of the external power source to a low voltage using a power frequency transformer. The control circuit is connected to the power supply circuit and is used to obtain the low voltage from the power supply circuit and is configured to generate a control signal. The relay has an input side and an output side, the output side of which is located on the charge-discharge loop, and the input side is connected to the external power source and the control circuit and is configured to drive the output side to turn the charge-discharge loop on or off according to the control signal.

Description

Technical Field

[0001] Cross - reference to related applications This disclosure claims the priority of Chinese Patent Application No. 202310357517.5 filed on March 30, 2023, the document of which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to the field of charging and discharging technologies, and more particularly, to a connection circuit and a charging gun.

Background Art

[0003] A charging gun usually includes a connection circuit for connecting a power source and an electrical device. The connection circuit mainly includes a power supply, a relay, a driver, a chip, and an auxiliary capacitor. Among them, the relay, the driver, etc. are all powered by the power supply in the charging gun.

[0004] Due to high requirements for power transformation, the current connection circuit has a large number of components, resulting in a large volume, heavy weight, and high cost of the charging gun. This is likely to cause poor contact between the charging plug and the power socket during use and is also inconvenient for storage.

Summary of the Invention

[0005] This disclosure is intended to solve at least one of the technical problems existing in the prior art. Therefore, this disclosure provides a connection circuit and a charging gun that reduce the use of corresponding components, lower the cost, and reduce the size.

[0006] In a first aspect, the Disclosure provides a connection circuit for connecting an external power supply and an electrical device to form a charge-discharge circuit, the connection circuit comprising: a power supply circuit connected to the external power supply to transform the voltage of the external power supply to a lower voltage via a power frequency transformer; a control circuit connected to the power supply circuit to receive the lower voltage from the power supply circuit and configured to generate a control signal; and a relay having an input side and an output side, the output side of which is located on the charge-discharge circuit and the input side of which is connected to the external power supply and the control circuit and configured to drive the output side according to the control signal to interrupt or conduct the charge-discharge circuit.

[0007] According to the connection circuit of this disclosure, directly supplying power to the relay from an external power supply allows the power supply circuit to supply power only to the control circuit. This reduces the load on the power supply circuit, decreases the number of components required in the power supply circuit, and results in a lower cost and more compact design.

[0008] According to one embodiment of the present disclosure, the input side of the relay includes a drive circuit and a drive assembly, the drive circuit being connected to a control circuit and the drive assembly being connected to an external power supply.

[0009] According to one embodiment of the present disclosure, an external power supply is used to output alternating current, and the relay is an AC type relay.

[0010] According to one embodiment of the present disclosure, a first terminal of the drive assembly is connected to the live wire of an external power supply, a second end of the drive assembly is connected to the first terminal of a drive circuit, a second terminal of the drive circuit is connected to the neutral wire of an external power supply, and a third terminal of the drive circuit is connected to a control circuit.

[0011] According to one embodiment of the present disclosure, the power supply circuit includes a power frequency transformer, the input terminals of which are connected to an external power supply, and the output terminals of which are connected to a control circuit.

[0012] According to one embodiment of the present disclosure, the power supply circuit further includes a protection circuit, the input terminals of which the protection circuit is connected to an external power supply, and the output terminals of which the protection circuit is connected to the input terminals of a power frequency transformer.

[0013] According to one embodiment of the present disclosure, the protection circuit comprises a thermistor and a TVS tube.

[0014] According to one embodiment of the present disclosure, the power supply circuit further includes a voltage stabilization circuit, the input terminals of which are connected to the output side of a power frequency transformer, and the output terminals of which are connected to a control circuit.

[0015] In a second aspect, the disclosure also provides a charging gun including a connection circuit according to any one of the embodiments described above.

[0016] According to the charging gun of this disclosure, directly supplying power to the relay from an external power supply allows the power supply circuit to supply power only to the control circuit. This reduces the load on the power supply circuit, decreases the number of components required in the power supply circuit, and results in a lower cost and more compact design.

[0017] According to one embodiment of the present disclosure, the charging gun includes a cable, a plug connected to a first end of the cable, and a charging gun head connected to a second end of the cable, the connector being incorporated into the charging gun head.

[0018] Further aspects and advantages of this disclosure are partially presented in the following description, some of which will become apparent from the following description or through the practice of this disclosure.

[0019] The above aspects and advantages of the present disclosure and / or further aspects and advantages will become apparent and will be readily understood from the description of the embodiments in conjunction with the following figures.

Brief Description of the Drawings

[0020] [Figure 1] One of the structural block diagrams of the connection circuit provided in an embodiment of the present disclosure. [Figure 2] It is a second structural block diagram of the connection circuit provided in an embodiment of the present disclosure. [Figure 3] It is a structural block diagram of a connection circuit in the prior art. [Figure 4] It is a schematic structural diagram of a charging gun provided in an embodiment of the present disclosure. [Figure 5] It is a schematic structural diagram of a charging gun in the prior art.

Modes for Carrying Out the Invention

[0021] The following provides a detailed description of embodiments of the present disclosure, examples of which are shown in the accompanying drawings. In the accompanying drawings, throughout, the same or similar reference numerals represent the same or similar elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are merely used to explain the present disclosure and should not be construed as limiting the present disclosure.

[0022] Referring to FIG. 1, FIG. 1 shows a structural block diagram of a connection circuit. One embodiment of the present disclosure provides a connection circuit 100.

[0023] In this embodiment, the connection circuit 100 is used to connect an external power supply (EPS) 200 and an electrical device (ED) 300 to form a charge-discharge circuit. The connection circuit 100 includes a power supply circuit (PSC) 110, a control circuit (CC) 120, and a relay 130. The power supply circuit 110 is connected to the external power supply 200 and used to convert the voltage of the external power supply 200 to a lower voltage via a power frequency transformer. The control circuit 120 is connected to the power supply circuit 110 to receive power from the power supply circuit 110 and is configured to generate control signals. The relay 130 includes an input side (IS) 131 and an output side (OS) 132. The output side 132 is located on the charge-discharge circuit, and the input side 131 is connected to the external power supply 200 and the control circuit 120. The input side 131 is configured to drive the output side 131 according to the control signal to interrupt or conduct the charge-discharge circuit.

[0024] It should be noted that the charge-discharge circuit includes an external power supply 200, an electrical device 300, and wires connected between the external power supply 200 and the electrical device 300. The output side 132 of the relay 130 may be located on the wires, and the output side 132 switches between a connected state and a disconnected state. When the output side 132 is in the connected state, the wires are connected to conduct the charge-discharge circuit, and when the output side 132 is in the disconnected state, the wires are disconnected to interrupt the charge-discharge circuit.

[0025] In this embodiment, the input side 131 of the relay 130 can be connected to the external power supply 200 under the control of a control signal, thereby receiving power, or can be separated from the external power supply 200, thereby losing power. When the input side 131 is in a state of receiving power, the output side 132 is driven in a connected state, and when the input side 131 is in a state of losing power, the output side 132 is driven in a separated state. Alternatively, when the input side 131 is in a state of receiving power, the output side 132 is driven in a separated state, and when the input side 131 is in a state of losing power, the output side 132 is driven in a connected state.

[0026] In some embodiments, the relay 130 can be composed of components such as a coil, a contact, and an armature. Among them, the coil can be used as part of the input side 131, and the contact and the armature can be used as part of the output side 132. The coil can switch between the connected state and the separated state by contacting the armature with different contacts when energized or when power is cut off.

[0027] In other embodiments, the input side 131 of the relay 130 can also include a motor assembly. The motor assembly can switch between the connected state and the separated state by contacting the armature with different contacts when energized or when power is cut off.

[0028] In some embodiments, the power supply circuit 110 may be connected to a wire between the external power supply 200 and the electrical device 300 to receive power from the external power supply 200. The power supply circuit 110 can reduce the voltage of the power supplied by the external power supply 200 and use the reduced power to supply electrical energy to the control circuit 120. The voltage supplied by the external power supply 200 is typically high, such as 220V or 340V, while the control circuit 120 is a low-voltage circuit, and its power supply voltage is typically 12V, 5V, etc. A voltage drop is required to meet the power supply requirements of the control circuit 120. The power supply circuit 110 may include components such as a transformer to achieve the voltage drop function.

[0029] The control circuit 120 can transmit a control signal to the input side 131 of the relay 130 based on a predetermined control logic. Here, the control signal can be either a high-level signal or a low-level signal. If the control signal is high-level, the input side 131 of the relay 130 is connected to the external power supply 200 to receive power, and if the control signal is low-level, the input side 131 of the relay 130 is disconnected from the external power supply 200 and loses power. Alternatively, if the control signal is low-level, the input side 131 of the relay 130 is connected to the external power supply 200 to receive power, and if the control signal is high-level, the input side 131 of the relay 130 is disconnected from the external power supply 200 and loses power.

[0030] In some embodiments, the control circuit 120 can detect and display the state of the charge-discharge circuit. For example, the control circuit 120 may include a temperature detection circuit and a leak detection circuit, etc. Alternatively, the control circuit 120 may include a group of indicator lights that can be used to indicate the normal or abnormal state of the charge-discharge gun.

[0031] In some embodiments, the control circuit 120 can enable the output side 132 of the relay 130 to conduct the charge-discharge circuit by sending a control signal to the input side 131 of the relay 130 after detecting that the connection circuit 100 has been connected to the external power supply 200 and the electrical device 300, respectively. Alternatively, if the control circuit 120 detects an anomaly in the external power supply 200 or the electrical device 300, the control circuit 120 can enable the output side 132 of the relay 130 to shut off the charge-discharge circuit by sending a control signal to the input side 131 of the relay 130. The control principle and circuit structure of the control circuit 120 are based on mature existing technology and are not described in detail herein.

[0032] In conventional technology, the input side 131 of the relay 130 is connected to the power supply circuit 110, and the relay 130 is powered via the power supply circuit 110. In this case, the power supply circuit 110 needs to supply power to both the control circuit 120 and the relay 130 simultaneously, which involves high output requirements (e.g., approximately 1.2W output and 100mA current), resulting in the need for a flyback power supply for the power supply circuit 110. However, since the flyback power supply operates at high frequencies, ensuring proper EMC (electromagnetic compatibility) and product stability requires the addition of various suppression components such as electrolytic capacitors, common-mode chokes, varistors, Y capacitors, and X capacitors. This not only increases the overall size and cost but also compromises product reliability.

[0033] In this embodiment, the load on the power supply circuit 110 is reduced (e.g., 0.025W output and 5mA current) by adjusting the power supply of the relay 130 to use the external power supply 200 directly for power supply. By enabling the power supply circuit 110 to use low-frequency power supply, the structure becomes simpler and the number of components is reduced.

[0034] In this embodiment, the relay 130 needs to have a higher voltage tolerance compared to those used in the prior art. For example, the input side 131 of the relay 130 in this embodiment can receive a higher voltage, such as 220V or 340V. In contrast, the input side 131 of the relay 130 in related art can receive a lower voltage, such as 12V or 24V.

[0035] According to the charging gun of this disclosure, directly supplying power to the relay 130 from the external power supply 200 allows the power supply circuit 110 to supply power only to the control circuit 120. This reduces the load on the power supply circuit 110, reduces the number of components required in the power supply circuit 110, and results in a lower cost and more compact design.

[0036] Referring to Figure 2, in some embodiments, the input side 131 of the relay 130 includes a drive circuit 133 and a drive assembly (DS) 134. The drive circuit (DC) 133 is connected to a control circuit 120, and the drive assembly 134 is connected to an external power supply 200.

[0037] In this embodiment, the drive circuit 133 is connected to the drive assembly 134 and used to control the drive assembly 134 so that it is connected to the external power supply 200 to receive power under a control signal, or so that the drive assembly 134 is disconnected from the external power supply 200 and loses power. When the drive assembly 134 is in a state where it is receiving power, the output side 132 is driven in a connected state, and when the drive assembly 134 is in a state where it is losing power, the output side 132 is driven in a disconnected state. Alternatively, while the drive assembly 134 is in a state where it is receiving power, the output side 132 is driven in a disconnected state, and when the drive assembly 134 is in a state where it is losing power, the output side 132 is driven in a connected state.

[0038] In some embodiments, the drive assembly 134 may be a coil or a motor assembly.

[0039] In some embodiments, the drive circuit 133 may include a switching element connected in series between the drive assembly 134 and the external power supply 200. The switching element can be opened and closed under the control of a control signal. When the switching element is closed, the drive assembly 134 is connected to the external power supply 200 and receives power; when the switching element is disconnected, the drive assembly 134 is disconnected from the external power supply 200 and loses power.

[0040] In some embodiments, the external power supply 200 is used to output alternating current, and the relay 130 is an AC type relay.

[0041] It can be understood that the input side 131 of the AC relay is powered by an AC power source, and the main circuit carries alternating current. Here, the AC voltage may be 220V or 340V, etc.

[0042] In other embodiments, the charge-discharge circuit may also be used to deliver a DC current, and therefore the relay 130 may also be a DC relay. The input side 131 of the DC relay is driven by a DC power supply, and the main circuit carries a DC current. Here, the voltage of the DC power supply may be 220V or 340V, etc.

[0043] In some embodiments, the first terminal of the drive assembly 134 is connected to the live wire L of the external power supply 200, the second terminal of the drive assembly 134 is connected to the first terminal of the drive circuit 133, the second terminal of the drive circuit 133 is connected to the neutral wire N of the external power supply 200, and the third terminal of the drive circuit 133 is connected to the control circuit 120.

[0044] In this embodiment, the drive circuit 133 switches the connected and disconnected states of the first and second terminals according to the control signal received by the third end. For example, when the control signal is at a high level, the first and second terminals are connected, and when the control signal is at a low level, the first and second terminals are disconnected. Alternatively, when the control signal is at a low level, the first and second terminals are connected, and when the control signal is at a high level, the first and second terminals are disconnected.

[0045] In some embodiments, the drive circuit 133 may include a switching element, the first terminal of which acts as the first terminal of the drive circuit 133 connected to the second terminal of the drive assembly 134, and the second terminal of which acts as the second terminal of the drive circuit 133 connected to the neutral wire N of the external power supply 200. When the switching element is closed, the drive assembly 134 is connected to the external power supply 200, and when the switching element is open, the drive assembly 134 is disconnected from the external power supply 200.

[0046] In some embodiments, the switching element may include an optical coupling element, a thyristor, or a combination of both. Both the optical coupling element and the thyristor may be controlled by a relatively low-voltage signal to determine whether the drive assembly 134 is connected to an AC power supply. Furthermore, the optical coupling element can also enhance the stability of the system by providing isolation between strong and weak electricity.

[0047] In some embodiments, the power supply circuit 110 includes a power frequency transformer 111, the input terminals of which are connected to an external power supply 200, and the output terminals of which are connected to a control circuit 120.

[0048] It may be understood that the power frequency transformer 111 is also called a low frequency transformer to distinguish it from high frequency transformers used for switching power supplies. The operating frequency of the power frequency transformer 111 is generally the same as the frequency of the commercial power supply, such as 50 Hz or 60 Hz.

[0049] In some embodiments, the power supply circuit 110 further includes a protection circuit (PC) 112, the input terminals of which are connected to an external power supply 200, and the output terminals of which are connected to the input terminals of a power frequency transformer (PFT) 111.

[0050] The protection circuit 112 may be used to ensure the safety of the power frequency transformer 111 by detecting the power supply connected to the power frequency transformer 111 and preventing overcurrent, overvoltage, or limiting the current.

[0051] In some embodiments, the protection circuit 112 may include an overcurrent protection circuit, an overvoltage protection circuit, or a current limiting circuit. Herein, the specific structure and principles of the overcurrent protection circuit, overvoltage protection circuit, or current limiting circuit are based on mature existing technology and are not described in detail herein.

[0052] In some embodiments, the protection circuit 112 consists of a thermistor and a TVS tube.

[0053] In this embodiment, a thermistor may be used to form an over-temperature detection circuit to provide over-temperature protection for the power frequency transformer 111. A thermistor is a type of sensor resistor whose resistance changes with temperature. Thermistors are classified into positive temperature coefficient thermistors (PTC thermistors) and negative temperature coefficient thermistors (NTC thermistors) depending on their different temperature coefficients. The resistance of a PTC thermistor increases with increasing temperature, while the resistance of an NTC thermistor decreases with increasing temperature.

[0054] A TVS (transient voltage suppressor) transistor may be used to provide overvoltage protection for a power frequency transformer 111. When the two poles of the TVS diode are subjected to a reverse transient high-energy effect, the TVS diode reduces the high impedance between the two poles to 10 -12 The impedance is changed to a low impedance at speed S, and surge power up to several kilowatts is absorbed, thereby clamping the voltage between the two poles to a safe value and effectively protecting the power frequency transformer 111 from damage caused by surge pulses.

[0055] In some embodiments, the power supply circuit 110 further includes a voltage stabilization circuit (VSC) 113, the input terminals of which are connected to the output terminals of the power frequency transformer 111, and the output terminals of which are connected to the control circuit 120.

[0056] The voltage stabilization circuit 113 is used to stabilize the power supply voltage output by the power frequency transformer 111 to a set value in order to ensure the stable operation of the control circuit 120 by ensuring that the control circuit 120 is connected to a stable power supply.

[0057] In some embodiments, the voltage stabilization circuit 113 may use components such as filtering capacitors or voltage regulator chips. The relevant structure and principles of the voltage stabilization circuit 113 are based on mature existing technology and are not described in detail herein.

[0058] In some embodiments, the connection circuit 100 further includes a grounding wire PE, and the control circuit 120 is connected to the grounding wire PE. Since the external power supply 200 is used to transmit high voltage power, the grounding wire PE can prevent leakage current or electrostatic discharge from harming the user during the charging and discharging process.

[0059] Referring to Figure 3, in the prior art, the power supply circuit 110 primarily uses a high-frequency transformer (HFT) 114 due to its considerable load capacity. The input terminals of the high-frequency transformer 114 are equipped with an input protection circuit (IPC) 115, an EMC protection circuit (EPC) 116, and a high-frequency rectified power control circuit (PCC) 117. The output terminals of the high-frequency transformer 114 supply power to both the input side 131 and the control circuit 120 of the relay 130 via an output circuit (OC) 118. As is clear, the power supply circuit 110 has a relatively large number of components.

[0060] In this embodiment, the relay 130 is directly powered by the external power supply 200, so the power supply circuit 110 operates under a reduced load. This allows the use of a low-frequency power transformer 111. Compared to a high-frequency transformer 114, the power transformer 111 exhibits lower radiation and disturbance levels, resulting in increased stability of the charging gun.

[0061] The power supply circuit 110 cannot be designed with EMC (electromagnetic compatibility) circuitry in mind. Due to the low operating frequency and minimal interface of the power supply circuit 110, the practical effectiveness of EMC circuitry should be limited. The power supply circuit 110 can maintain stable operation even without EMC circuitry. This design approach further reduces the number of components, minimizing both physical size and manufacturing costs.

[0062] One embodiment of the present disclosure also provides a charging gun including a connection circuit 100 according to any one of the embodiments described above.

[0063] In this embodiment, the connection circuit 100 is located inside the charging gun. The charging gun is used to connect an external power supply 200 to an electrical device 300, where the external power supply 200 may be a discharge device. The specific structure and principle of the connection circuit 100 can be found in the embodiments described above and are therefore not described in further detail in this embodiment.

[0064] According to the charging gun of this disclosure, directly supplying power from an external power supply 200 to the relay 130 allows the power supply circuit 110 to supply power only to the control circuit 120. This reduces the load on the power supply circuit 110, reduces the number of components required in the power supply circuit 110, and results in a lower cost and more compact design.

[0065] Referring to Figure 4, in some embodiments, the charging gun includes a cable 400, a plug 500 connected to a first end of the cable 400, and a charging gun head 600 connected to a second end of the cable 400. The connection circuit 100 is incorporated into the charging gun head 600.

[0066] It can be understood that the plug 500 and the charging gun head 600 are equipped with internal connectors that connect to the cable 400. The internal connector of the plug 500 is used to connect the external power supply 200, and the internal connector of the charging gun head 600 is used to connect the electrical device 300. The external power supply 200 and the electrical device 300 are connected via the cable 400 to form a charge-discharge circuit.

[0067] In some embodiments, the input side 131 of the power supply circuit 110 and relay 130 is connected to a cable 400 to receive power from an external power supply 200, and the output side 132 of relay 130 is used to conduct or interrupt the cable 400.

[0068] Referring to Figure 5, in the prior art, due to the large number and size of components in the connection circuit 100, the connection circuit 100 is typically housed in a separate control box 700. One end of the control box 700 is connected to the plug 500 via a cable 400, and the other end of the control box 700 is connected to the charging gun head 600 via the cable 400. During use, the weight in the central part of the charging gun can easily cause poor contact between the plug 500 and the socket, and it is also difficult to handle during storage. In this embodiment, the connection circuit 100 is integrated into the charging gun head 600, which simplifies the components, makes it easier to use, and improves space utilization.

[0069] In some embodiments, the charging gun head 600 typically includes a housing and pins, etc. When designing the PCBA (printed circuit board assembly) for the circuit 100, the shape of the circuit board is determined according to the structural design of the charging gun head 600 in order to incorporate the connecting circuit into the charging gun head 600. The fact that the connecting circuit 100 has a small number of components makes it possible to incorporate the connecting circuit 100 into the charging gun head 600.

[0070] The terms “first,” “second,” etc., used in the specification and claims of this disclosure are intended to distinguish similar objects and not to describe a particular order or sequence. The data used in this manner may be interchangeable in appropriate circumstances so that embodiments of this disclosure may be carried out in an order other than that illustrated or described herein, and it should be understood that objects distinguished by “first,” “second,” etc., are usually of the same classification without limiting the number of objects, for example, there may be one or more first objects. Furthermore, in the specification and claims, “and / or” refers to at least one of the connected objects, and the symbol “ / ” generally indicates an “or” relationship between the related objects.

[0071] In this specification, any reference to terms such as “one embodiment,” “several embodiments,” “exemplary embodiments,” “examples,” “specific examples,” or “several examples” means that the specific features, structures, materials, or properties described in relation to that embodiment or example are included in at least one embodiment or example of this disclosure. The exemplary expressions of those terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or properties described may be combined in appropriate manner in any one or more embodiments or examples.

[0072] While embodiments of the Disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations may be made to those embodiments without departing from the principles and purposes of the Disclosure, and that the scope of the Disclosure is limited by the claims and their equivalents. [Explanation of symbols]

[0073] 100 Connect Circuits 110 Power Supply Circuit 111 Power frequency transformer 112 Protection circuit 113 Voltage Stabilization Circuit 114 High-frequency transformer 115 Input protection circuit 116 EMC protection circuit 117 High-frequency rectified power control circuit 118 Output Circuit 120 Control circuits 130 Relay 131 Input side 132 Output side 133 Drive Circuit 134 Drive Components 200 External Power Supply 300 Electrical Devices 400 Cable 500 plug 600 Rechargeable Gun Heads 700 Control Box L live wire N Neutral wire PE ground wire

Claims

1. A connection circuit (100) used to connect an external power supply (200) and an electrical device (300) to form a charge-discharge circuit, A power supply circuit (110) connected to the external power supply (200) and used to transform the voltage of the external power supply (200) to a low voltage via a power frequency transformer, A control circuit (120) connected to the power supply circuit (110), used to receive the low voltage from the power supply circuit (110), and configured to generate a control signal, A relay (130) comprising an input side (131) and an output side (132), wherein the output side (132) is positioned on the charge-discharge circuit, and the input side (131) is connected to the external power supply (200) and the control circuit (120), and is configured to drive the output side (132) according to the control signal to interrupt or conduct the charge-discharge circuit, and A connection circuit (100) comprising the above.

2. The connection circuit (100) according to claim 1, wherein the input side (131) of the relay (130) comprises a drive circuit (133) and a drive assembly (134), the drive circuit (133) being connected to the control circuit (120), and the drive assembly (134) being connected to the external power supply (200).

3. The connection circuit (100) according to claim 2, wherein the external power supply (200) is used to output AC power, and the relay (130) is an AC type relay.

4. The first terminal of the drive assembly (134) is connected to the live line (L) of the external power supply (200), and the second terminal of the drive assembly (134) is connected to the first terminal of the drive circuit (133). The connection circuit (100) according to claim 3, wherein the second terminal of the drive circuit (133) is connected to the neutral wire (N) of the external power supply (200), and the third terminal of the drive circuit (133) is connected to the control circuit (120).

5. The aforementioned power supply circuit (110) A power frequency transformer (111), wherein the input terminal of the power frequency transformer (111) is connected to the external power supply (200), and the output terminal of the power frequency transformer (111) is connected to the control circuit (120). A connection circuit (100) according to any one of claims 1 to 4, comprising:

6. The aforementioned power supply circuit (110) A protection circuit (112), wherein the input terminal of the protection circuit (112) is connected to the external power supply (200), and the output terminal of the protection circuit (112) is connected to the input terminal of the power frequency transformer (111). The connection circuit (100) according to claim 5, further comprising the above.

7. The connection circuit (100) according to claim 6, wherein the protection circuit (112) is composed of a thermistor and a TVS tube.

8. The aforementioned power supply circuit (110) A voltage stabilization circuit (113), wherein the input terminal of the voltage stabilization circuit (113) is connected to the output side (132) of the power frequency transformer (111), and the output terminal of the voltage stabilization circuit (113) is connected to the control circuit (120). The connection circuit (100) according to claim 5, further comprising the above.

9. A charging gun comprising a connection circuit (100) according to any one of claims 1 to 4.

10. The charging gun according to claim 9, comprising a cable (400), a plug (500) connected to a first end of the cable (400), and a charging gun head (600) connected to a second end of the cable (400), wherein the connection circuit (100) is incorporated into the charging gun head (600).

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