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 priority to Chinese Patent Application No. 202310357517.5, filed on March 30, 2023, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to the field of charging and discharging technology, and in particular to connection circuits and charging guns. [Background technology]

[0003] A charging gun is usually equipped with a connection circuit for connecting a power source to an electrical device. The connection circuit mainly includes a power supply, a relay, a driver, a chip, and an auxiliary capacitor, among which the relay and driver are all powered by the power supply in the charging gun.

[0004] Due to the high requirements for power transformation, the current connection circuit has many components, resulting in a large volume, heavy weight, and high cost of the charging gun, which is prone to poor contact between the charging plug and the power socket during use and is inconvenient to store. Summary of the Invention

[0005] The present disclosure is intended to solve at least one of the technical problems existing in the prior art, and therefore provides a charging gun that reduces the use of connection circuits and corresponding components, lowers costs, and reduces size.

[0006] In a first aspect, the present disclosure provides a connection circuit for connecting an external power supply and an electric device to form a charge-discharge circuit, the connection circuit including: a power supply circuit connected to the external power supply to transform a voltage of the external power supply to a low voltage via a power frequency transformation; a control circuit connected to the power supply circuit to receive the low 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 being disposed on the charge-discharge circuit, the input side being connected to the external power supply and the control circuit, and configured to drive the output side to interrupt or conduct the charge-discharge circuit according to the control signal.

[0007] According to the connection circuitry of the present disclosure, powering the relay directly from an external power supply allows the power supply circuitry to provide power only to the control circuitry, which reduces the load on the power supply circuitry, reduces the number of components required in the power supply circuitry, and allows for 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 connected to a control circuit, and the drive assembly connected to an external power supply.

[0009] According to one embodiment of the present disclosure, the 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 a live conductor of an external power supply, a second end of the drive assembly is connected to a first terminal of a drive circuit, a second terminal of the drive circuit is connected to a neutral conductor of the 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, an input terminal of the power frequency transformer connected to an external power supply, and an output terminal of the power frequency transformer connected to a control circuit.

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

[0013] According to one embodiment of the present disclosure, the protection circuit is composed of 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, an input terminal of the voltage stabilization circuit being connected to the output side of the power frequency transformer, and an output terminal of the voltage stabilization circuit being connected to the control circuit.

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

[0016] According to the charging gun of the present disclosure, powering the relay directly from the external power supply allows the power supply circuit to provide power only to the control circuit, which reduces the load on the power supply circuit, reduces the number of components required in the power supply circuit, and allows for a lower cost and more compact design.

[0017] According to one embodiment of the present disclosure, a 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, wherein the connection portion is incorporated into the charging gun head.

[0018] Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the disclosure.

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

[0020] [Figure 1] FIG. 2 is one of structural block diagrams of a connection circuit provided in an embodiment of the present disclosure. [Figure 2] FIG. 2 is a second structural block diagram of a connection circuit provided in an embodiment of the present disclosure. [Figure 3] FIG. 1 is a structural block diagram of a connection circuit in the prior art; [Figure 4] 1 is a schematic structural diagram of a charging gun provided in an embodiment of the present disclosure; FIG. [Figure 5] FIG. 1 is a schematic structural diagram of a charging gun according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following provides a detailed description of embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements having the same or similar functions throughout. 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 Figure 1, Figure 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, a connection circuit 100 is used to connect an external power supply (EPS) 200 and an electric 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 is used to convert the voltage of the external power supply 200 to a low 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 a control signal. The relay 130 includes an input side (IS) 131 and an output side (OS) 132. The output side 132 is disposed 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 the external power supply 200, the electric device 300, and the wires connected between the external power supply 200 and the electric device 300. The output side 132 of the relay 130 may be disposed 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, thereby receiving power, or can be disconnected from the external power supply 200, thereby losing power, under the control of a control signal. When the input side 131 is in a state to receive power, the output side 132 is driven in a connected state, and when the input side 131 is in a state to lose power, the output side 132 is driven in a disconnected state. Alternatively, when the input side 131 is in a state to receive power, the output side 132 is driven in a disconnected state, and when the input side 131 is in a state to lose power, the output side 132 is driven in a connected state.

[0026] In some embodiments, the relay 130 may be composed of components such as a coil, contacts, and an armature, among which the coil may be used as part of the input side 131, and the contacts and armature may be used as part of the output side 132. The coil may switch between a connected state and a disconnected state by bringing the armature into contact with different contacts when energized or de-energized.

[0027] In other embodiments, the input side 131 of the relay 130 may include a motor assembly that can switch between connected and disconnected states by bringing an armature into contact with different contacts when energized or de-energized.

[0028] In some embodiments, the power supply circuit 110 can be connected to an electrical 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 provided by the external power supply 200 and use the reduced power to provide electrical energy to the control circuit 120. While the voltage provided by the external power supply 200 is typically high, such as 220V or 340V, the control circuit 120 is a low-voltage circuit, and its power supply voltage is typically 12V, 5V, or the like. The voltage drop is required to meet the power supply requirements of the control circuit 120. The power supply circuit 110 can include components such as a transformer to achieve the voltage drop function.

[0029] The control circuit 120 can send a control signal to the input 131 of the relay 130 based on predetermined control logic. Here, the control signal can be either a high-level signal or a low-level signal. When the control signal is high, the input 131 of the relay 130 is connected to the external power supply 200 to receive power, and when the control signal is low, the input 131 of the relay 130 is disconnected from the external power supply 200 and loses power. Alternatively, when the control signal is low, the input 131 of the relay 130 is connected to the external power supply 200 to receive power, and when the control signal is high, the input 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 indicate the status of the charge-discharge circuit. For example, the control circuit 120 can include a temperature detection circuit, a leak detection circuit, etc. Alternatively, the control circuit 120 can include a set of indicator lights that can be used to indicate normal or abnormal conditions of the charge-discharge gun.

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

[0032] In the prior art, the input 131 of the relay 130 is connected to the power supply circuit 110, and the relay 130 is driven via the power supply circuit 110. In this case, the power supply circuit 110 is required to simultaneously power both the control circuit 120 and the relay 130, which entails high output requirements (e.g., approximately 1.2 watts of power and 100 milliamps of current), resulting in the need for a flyback power supply for the power supply circuit 110. However, because the flyback power supply operates at a high frequency, 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 impairs product reliability.

[0033] In this embodiment, by adjusting the power supply of the relay 130 to directly use the external power supply 200 for powering, the load on the power supply circuit 110 is reduced (e.g., 0.025 W output and 5 mA current). By allowing the power supply circuit 110 to use a lower frequency power supply, the construction is simpler and has fewer components.

[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 220 V or 340 V. In contrast, the input side 131 of the relay 130 in the related art can receive a lower voltage, such as 12 V or 24 V.

[0035] In accordance with the charging gun of the present disclosure, powering the relay 130 directly from the external power supply 200 allows the power supply circuit 110 to provide power solely 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 allows for a lower cost and more compact design.

[0036] 2, in some embodiments, the input side 131 of the relay 130 includes a driver circuit 133 and a driver assembly (DS) 134. The driver circuit (DC) 133 is connected to the control circuit 120, and the driver 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 is used to control the drive assembly 134 under a control signal to connect to the external power supply 200 to receive power or to disconnect the drive assembly 134 from the external power supply 200 to lose power. When the drive assembly 134 is in a state to receive power, the output side 132 is driven in the connected state, and when the drive assembly 134 is in a state to lose power, the output side 132 is driven in the disconnected state. Alternatively, while the drive assembly 134 is in a state to receive power, the output side 132 is driven in the disconnected state, and when the drive assembly 134 is in a state to lose power, the output side 132 is driven in the connected state.

[0038] In some embodiments, the drive assembly 134 may be a coil or 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 may be opened or 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 the drive assembly 134 receives power; when the switching element is disconnected, the drive assembly 134 is disconnected from the external power supply 200 and the drive assembly 134 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 type relay is powered by an AC power source, and the main circuit carries an AC current, where the voltage of the AC voltage may be 220V or 340V, etc.

[0042] In other embodiments, the charge-discharge circuit can also be used to transmit direct current, and therefore the relay 130 can also be a DC-type relay. The input side 131 of the DC-type relay is powered by a DC power source, and the main circuit passes direct current. Here, the voltage of the DC power source can be 220V or 340V, etc.

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

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

[0045] In some embodiments, the drive circuit 133 can include a switching element, with a first terminal of the switching element serving as a first terminal of the drive circuit 133 connected to a second terminal of the drive assembly 134, and a second terminal of the switching element serving as a second terminal of the drive circuit 133 connected to the neutral conductor 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 isolated from the external power supply 200.

[0046] In some embodiments, the switching element may include an optocoupler, a thyristor, or a combination of both. Both the optocoupler and the thyristor may be controlled by a relatively small voltage signal to determine whether the drive assembly 134 is connected to an AC power source. Additionally, the optocoupler may also provide isolation between strong and weak electricity, increasing the stability of the system.

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

[0048] It may be appreciated that the power frequency transformer 111 is also referred to as a low frequency transformer to distinguish it from the high frequency transformers used in switching power supplies. The operating frequency of the power frequency transformer 111 is generally the same as the frequency of the utility 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 terminal of which is connected to an external power supply 200, and the output terminal of which is connected to the input terminal of a power frequency transformer (PFT) 111.

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

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

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

[0053] In this embodiment, a thermistor can 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) according to 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 the power frequency transformer 111. When the two poles of the TVS diode are subjected to a reverse transient high energy effect, the TVS diode presents a high impedance between the two poles. -12 The transformer 111 changes its impedance at a rate of S to a low impedance and absorbs surge power up to several kilowatts, thereby clamping the voltage between the two poles to a safe value and effectively protecting the power frequency transformer 111 from damage caused by the surge pulse.

[0055] In some embodiments, the power supply circuit 110 further includes a voltage regulation 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 at a set value to ensure 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 a filtering capacitor or a voltage regulator chip. The related structure and principles of the voltage stabilization circuit 113 are based on mature existing technology and will not be described in detail herein.

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

[0059] 3, in the prior art, a power supply circuit 110 primarily uses a high-frequency transformer (HFT) 114 due to its substantial load capacity. The input terminal of the high-frequency transformer 114 is equipped with an input protection circuit (IPC) 115, an EMC protection circuit (EPC) 116, and a high-frequency rectifier power control circuit (PCC) 117. The output terminal of the high-frequency transformer 114 supplies power to both the input side 131 of a relay 130 and the control circuit 120 via an output circuit (OC) 118. As can be seen, the power supply circuit 110 has a relatively large component count.

[0060] In this embodiment, the relay 130 is powered directly by the external power supply 200, so the power supply circuit 110 operates with a reduced load. This allows the use of a lower frequency power frequency transformer 111. Compared to the high frequency transformer 114, the power frequency 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 power supply circuit 110's low operating frequency and minimal interfacing, the practical effectiveness of EMC circuitry would be limited. The power supply circuit 110 can maintain stable operation without EMC circuitry. This design approach further reduces the component count, minimizing both physical size and manufacturing costs.

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

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

[0064] According to the charging gun of the present disclosure, powering the relay 130 directly from the external power supply 200 allows the power supply circuit 110 to provide 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 allows for a lower cost and more compact design.

[0065] 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 seen that the plug 500 and the charging gun head 600 are provided with connection terminals therein that are connected to the cable 400. The connection terminals inside the plug 500 are used to connect the external power supply 200, and the connection terminals inside the charging gun head 600 are 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 power supply circuit 110 and the input side 131 of the relay 130 are connected to the cable 400 to receive power from the external power supply 200, and the output side 132 of the relay 130 is used to make or break the cable 400.

[0068] Referring to FIG. 5 , in the prior art, due to the large number of components and large size of 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 opposite end of the control box 700 is connected to the charging gun head 600 via the cable 400. During use, the charging gun is prone to poor contact between the plug 500 and the socket due to its weight in the center, 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, facilitates use, and improves space utilization.

[0069] In some embodiments, the charging gun head 600 typically includes a housing, pins, etc. When designing a 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 connection circuit into the charging gun head 600. The fact that the connection circuit 100 has a small number of components makes it possible to incorporate the connection circuit 100 into the charging gun head 600.

[0070] Terms such as "first," "second," and the like, used in the specification and claims of the present disclosure, are intended to distinguish between similar objects and are not intended to describe a particular hierarchy or order. Data used in this manner may be interchanged under appropriate circumstances so that embodiments of the present disclosure may be implemented in an order other than that illustrated or described herein, and it should be understood that objects distinguished by "first," "second," and the like generally refer to the same category of objects without limiting the number of objects; for example, a first object may be one or more. 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 related objects.

[0071] In the description herein, reference to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the disclosure. Exemplary appearances of those terms herein do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

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

[0073] 100 Connect Circuit 110 Power Supply Circuit 111 Power Frequency Transformer 112 Protection circuit 113 Voltage Stabilizer Circuit 114 High Frequency Transformer 115 Input protection circuit 116 EMC protection circuit 117 High-frequency rectification power control circuit 118 Output Circuit 120 control circuit 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 Charging Gun Head 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, comprising: 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 lower voltage via a power frequency transformer; a control circuit (120) connected to the power supply circuit (110), adapted to receive the low voltage from the power supply circuit (110), and configured to generate a control signal; A relay (130) having an input side (131) and an output side (132), the output side (132) being disposed on the charge-discharge circuit, the input side (131) being connected to the external power supply (200) and the control circuit (120), and configured to drive the output side (132) according to the control signal to interrupt or connect the charge-discharge circuit; A connection circuit (100) comprising:

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

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

5. The power supply circuit (110) a power frequency transformer (111), the input terminals of which are connected to the external power supply (200) and the output terminals of which are connected to the control circuit (120); A connection circuit (100) according to any one of claims 1 to 4, comprising:

6. The power supply circuit (110) A protection circuit (112), wherein an input terminal of the protection circuit (112) is connected to the external power supply (200) and an output terminal of the protection circuit (112) is connected to the input terminal of the power frequency transformer (111). The connection circuit (100) of any one of claims 1 to 5, further comprising:

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

8. The power supply circuit (110) A voltage stabilization circuit (113), wherein an input terminal of the voltage stabilization circuit (113) is connected to the output side (132) of the power frequency transformer (111), and an output terminal of the voltage stabilization circuit (113) is connected to the control circuit (120). The connection circuit (100) of any one of claims 1 to 5, further comprising:

9. A charging gun comprising a connection circuit (100) according to any one of claims 1 to 8.

10. 10. The charging gun of 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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