Charging interface detection circuit and charging device

Abstract

The application relates to the charging technical field and discloses a charging interface detection circuit and a charging device, wherein the charging interface detection circuit comprises a clamping current limiting module configured to be connected with an external power supply device interface, the clamping current limiting module is used for clamping an electric signal accessed by the external power supply device interface; a voltage dividing module connected with the clamping current limiting module, the voltage dividing module is used for voltage dividing an electric signal output by the clamping current limiting module to obtain a voltage dividing signal; and a differential sampling module connected with the voltage dividing module, the differential sampling module is used for differentially sampling the voltage dividing signal to obtain a target voltage, the target voltage is used for inputting into a control module to judge a contact state of the external power supply device interface. The application realizes rapid and accurate identification of a short-circuit fault of the external power supply device interface through the charging interface detection circuit, and improves the safety and reliability of a charging process.

Description

Technical Field

[0001] This application relates to the field of charging technology, and in particular to a charging interface detection circuit and a charging device. Background Technology

[0002] With the development of the new energy vehicle industry, the industry has put forward more stringent technical requirements for the safety, stability, and reliability of power battery systems, battery management systems, charging equipment, and their supporting components. As a key device connecting the power battery and the charging power source, the charging pile is the core infrastructure for realizing fast charging, safe operation, and efficient energy replenishment of new energy vehicles. However, in actual operation, charging piles frequently experience safety hazards such as short circuits. Once a short circuit occurs, the positive and negative terminals of the power battery and the charging pile's power supply are immediately connected, instantly generating a large current, causing the power battery and charging pile to smoke and catch fire, greatly threatening the safety of the surrounding environment. Utility Model Content

[0003] In view of this, the embodiments of this application provide a charging interface detection circuit and a charging device, which can effectively solve the problem of frequent short circuit hazards in charging piles during actual operation.

[0004] In a first aspect, embodiments of this application provide a charging interface detection circuit, including:

[0005] A clamping current limiting module is configured to connect to an external power supply device interface, and the clamping current limiting module is used to clamp the electrical signal connected to the external power supply device interface;

[0006] A voltage divider module is connected to the clamping current limiting module. The voltage divider module is used to divide the electrical signal output by the clamping current limiting module to obtain a voltage divider signal.

[0007] A differential sampling module is connected to the voltage divider module. The differential sampling module is used to perform differential sampling on the voltage divider signal to obtain a target voltage. The target voltage is used to input to the control module to determine the contact status of the external power supply device interface.

[0008] In some embodiments, the charging interface detection circuit further includes:

[0009] A voltage follower module is connected to the voltage divider module and the differential sampling module respectively. The voltage follower module is used to perform voltage following on the voltage divider signal and transmit the resulting follower signal to the differential sampling module for differential sampling.

[0010] In some embodiments, the voltage follower module includes two second-order active low-pass filters, which are connected to the two output terminals of the voltage divider module respectively.

[0011] In some embodiments, the charging interface detection circuit further includes:

[0012] The control module is connected to the differential sampling module. The control module is used to perform analog-to-digital conversion on the target voltage and determine the contact status of the external power supply device interface based on the magnitude of the converted voltage value.

[0013] In some embodiments, the clamping current limiting module includes a clamping unit and a first current limiting unit. The clamping unit is disposed at both ends of the first power supply. The input terminal of the first current limiting unit is connected to the external power supply device interface, and the output terminal of the first current limiting unit is connected to the input terminal of the voltage divider module via the clamping unit.

[0014] In some embodiments, the clamping unit includes two sets of clamping sub-units, and the first current limiting unit includes two sets of current limiting sub-units; one set of clamping sub-units is correspondingly connected to one set of current limiting sub-units.

[0015] One set of the current-limiting subunits is connected to the positive terminal of the external power supply device interface, and the other set of the current-limiting subunits is connected to the negative terminal of the external power supply device interface.

[0016] In some embodiments, each set of clamping subunits includes two clamping diodes connected in series, and each set of current-limiting subunits includes at least one current-limiting resistor;

[0017] In each set of clamping sub-units, two clamping diodes are connected in reverse series between the positive and negative terminals of the first power supply, and the series connection node between the two clamping diodes is connected to the current limiting resistor in the corresponding set of current limiting sub-units.

[0018] In some embodiments, the clamping current limiting module further includes a second current limiting unit, the input of which is connected to the clamping unit and the first current limiting unit respectively, and the output of which is connected to the input of the voltage divider module.

[0019] In some embodiments, the differential sampling module includes an operational amplifier, and the voltage divider module includes three voltage divider resistors connected in series between the positive and negative terminals of the first power supply.

[0020] The non-inverting and inverting input terminals of the operational amplifier are respectively connected to the two ends of the middle voltage divider resistor among the three voltage divider resistors, and the output terminal of the operational amplifier is electrically connected to the control module.

[0021] Secondly, embodiments of this application provide a charging device, which includes the external power supply interface and at least one charging interface detection circuit as described in the first aspect.

[0022] The embodiments of this application have the following beneficial effects:

[0023] The charging interface detection circuit of this application effectively suppresses high-voltage interference that may be introduced when an external power supply device interface is connected by setting a clamping current limiting module, thus protecting the safety of the subsequent circuits. The voltage divider module performs voltage division processing on the clamped signal and extracts voltage characteristics that can be used for detection. The differential sampling module further performs precise sampling on the voltage divider signal to obtain the target voltage reflecting the interface contact state, which facilitates the control module to quickly and accurately determine whether a short circuit has occurred in the charging interface, thereby improving the safety and reliability of the electric vehicle charging process. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A first structural schematic diagram of the charging interface detection circuit according to an embodiment of this application is shown;

[0026] Figure 2 A schematic diagram of the clamping current limiting module according to an embodiment of this application is shown;

[0027] Figure 3 A circuit diagram of the clamping current limiting module according to an embodiment of this application is shown;

[0028] Figure 4 A circuit diagram of the voltage divider module according to an embodiment of this application is shown;

[0029] Figure 5 This paper shows a second structural schematic diagram of the charging interface detection circuit according to an embodiment of the present application;

[0030] Figure 6 A circuit diagram of a voltage follower module according to an embodiment of this application is shown;

[0031] Figure 7 A circuit diagram of the charging interface detection circuit according to an embodiment of this application is shown.

[0032] Explanation of key component symbols:

[0033] 11: Clamping current limiting module; 111: Clamping unit; 112: First current limiting unit; 113: Second current limiting unit; 12: Voltage divider module; 13: Differential sampling module; 14: Voltage follower module; 20: External power supply interface; 30: Control module;

[0034] 40: First power source. Detailed Implementation

[0035] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0036] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] In the following text, the terms "comprising," "having," and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more combinations thereof. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0038] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0039] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] Charging stations are the core component of electric vehicle charging systems. They connect to the vehicle's battery using charging guns to transfer electrical energy. Charging guns can be classified into AC charging guns and DC charging guns according to their current type. AC charging guns can be three-phase or single-phase output and are used for slow charging, while DC charging guns have higher power and are used for fast charging.

[0041] However, the charging interface of existing charging guns is prone to short circuits, causing the power battery and charging pile to smoke and catch fire, which greatly threatens the safety of the surrounding environment. This application provides a charging interface detection circuit and charging equipment, which can effectively improve the safety and reliability of the electric vehicle charging process. The charging interface detection circuit of this application will be described below with reference to some specific embodiments.

[0042] Figure 1 A schematic diagram of a charging interface detection circuit according to an embodiment of this application is shown. It is understood that the charging interface detection circuit of this application can be installed in a battery connected to the external power device interface 20, or in an electronic device connected to the external power device interface 20, such as an electric vehicle, and is not limited thereto.

[0043] Exemplarily, the detection circuit includes: a clamping current limiting module 11, a voltage divider module 12, and a differential sampling module 13. The input terminal of the clamping current limiting module 11 is used to connect to an external power supply interface 20. The output terminal of the clamping current limiting module 11 is connected to the input terminal of the voltage divider module 12. The output terminal of the voltage divider module 12 is connected to the input terminal of the differential sampling module 13. The output terminal of the differential sampling module 13 is used to connect to a control module 30.

[0044] In this embodiment, the clamping current limiting module 11 is used to clamp the electrical signal connected to the external power device interface 20, the voltage divider module 12 is used to divide the electrical signal output by the clamping current limiting module 11 to obtain a voltage divider signal, and the differential sampling module 13 is used to perform differential sampling on the voltage divider signal to obtain a target voltage. The target voltage is used to input to the control module 30 to determine the contact status of the external power device interface 20.

[0045] For example, the external power supply interface 20 can be a charging gun interface, which can be a fast charging interface or a regular charging interface. The interface has two contact states: contact and no contact. If it is in contact, it can be determined that the fast charging interface has a short circuit; if it is in no contact, it can be determined that the fast charging interface is normal. This allows for quick identification of the normal working state and abnormal short circuit state of the fast charging interface.

[0046] For ease of understanding, this application will use the external power device interface 20 as an example of a fast charging interface, where the positive terminal of the fast charging interface is represented by DC+ and the negative terminal by DC-. The various modules will be described in detail below to help understand the charging interface detection circuit of this embodiment.

[0047] As an alternative solution, Figure 2 The diagram shown is a structural schematic of the clamping current limiting module 11. Accordingly, Figure 3 As shown Figure 2A circuit diagram of the clamping current limiting module 11.

[0048] In one embodiment, based on the above embodiments, such as Figure 2 and Figure 3 As shown, the clamping current limiting module 11 includes a clamping unit 111 and a first current limiting unit 112. The clamping unit 111 is located at both ends of the first power supply 40. The input terminal of the first current limiting unit 112 is connected to the external power supply interface 20, and the output terminal of the first current limiting unit 112 is connected to the input terminal of the voltage divider module 12 via the clamping unit 111. It can be understood that the clamping unit 111 and the first current limiting unit 112 can be configured according to actual needs: the clamping unit 111 can clamp only the positive signal of the fast charging interface, or it can clamp both the positive and negative signals of the fast charging interface simultaneously; the first current limiting unit 112 can be located only at the positive terminal of the fast charging interface, or it can be located at both the positive and negative terminals of the fast charging interface. By setting two sets of clamping sub-units at the positive and negative terminals of the fast charging interface, the clamping sub-units can clamp the signal flowing to the voltage divider module 12, preventing excess energy from flowing to subsequent circuits.

[0049] Exemplarily, the clamping unit 111 includes two sets of clamping sub-units, and the first current-limiting unit 112 includes two sets of current-limiting sub-units; one set of current-limiting sub-units is connected to the positive terminal of the external power supply interface 20, and the other set of current-limiting sub-units is connected to the negative terminal of the external power supply interface 20; each set of current-limiting sub-units is connected to a corresponding set of clamping sub-units. Furthermore, a bipolar clamping structure is adopted to avoid device damage caused by reverse power supply due to incorrect insertion or removal, achieving bidirectional protection.

[0050] Each current-limiting subunit includes at least one current-limiting resistor. The number and connection relationship of the current-limiting resistors in the current-limiting subunit can be set according to the actual application. For example, multiple current-limiting resistors can be connected in series between the positive and negative terminals of the fast charging interface to meet the voltage withstand requirements of the circuit. Figure 3 As shown, each current-limiting subunit is equipped with five current-limiting resistors, which are connected in series. These multiple current-limiting resistors limit the maximum current flowing into the voltage divider module 12 in the event of a short circuit, overload, or incorrect connection at the fast charging interface, preventing component damage and improving system reliability.

[0051] Exemplarily, each clamping subunit of the fast charging interface includes two clamping diodes connected in series. Specifically, the two clamping diodes in each clamping subunit are connected in reverse series between the positive and negative terminals of the first power supply 40, and the series connection point between the two clamping diodes is connected to the current-limiting resistor in the corresponding current-limiting subunit. For example, as shown... Figure 3As shown, the clamping subunit connected to the positive terminal of the fast charging interface includes clamping diodes D1 and D4, and the clamping subunit connected to the negative terminal of the fast charging interface includes clamping diodes D2 and D3. The cathode of clamping diode D1 is connected to the anode of clamping diode D4 in series, and the anode of clamping diode D1 is connected to the negative terminal of the first power supply 40. The cathode of clamping diode D4 is connected to the positive terminal of the first power supply 40 in reverse series between the positive and negative terminals of the first power supply 40. The series connection point of clamping diodes D1 and D4 is connected to the current limiting subunit connected to the positive terminal of the fast charging interface. Clamping diode D1 clamps the negative voltage of the positive terminal of the fast charging interface to -0.6V based on its own characteristics, and clamping diode D4 clamps the positive voltage of the positive terminal of the fast charging interface to +5.6V based on its own characteristics, preventing the voltage divider module 12 from being affected by large fluctuations in the voltage of the positive terminal of the fast charging interface.

[0052] The cathode of clamping diode D2 is connected to the anode of clamping diode D3 in series. The anode of clamping diode D2 is connected to the negative terminal of the first power supply 40, and the cathode of clamping diode D3 is connected to the positive terminal of the first power supply 40 in reverse series between the positive and negative terminals of the first power supply 40. The series connection point of clamping diodes D2 and D3 is connected to the current-limiting sub-unit connected to the negative terminal of the fast charging interface. Clamping diode D2 clamps the negative voltage of the fast charging interface to -0.6V based on its characteristics, and clamping diode D3 clamps the positive voltage of the fast charging interface to +5.6V based on its characteristics, preventing large fluctuations in the voltage of the fast charging interface negative terminal from affecting the voltage divider module 12.

[0053] By using four clamping diodes—D1, D2, D3, and D4—the transient high-voltage pulses generated by external electromagnetic interference, surge impacts, or sudden load changes in the fast charging interface during actual use can be avoided, thereby protecting the downstream circuits and improving the system's stability and anti-interference capability.

[0054] Furthermore, the clamping current limiting module 11 also includes a second current limiting unit 113. The input terminal of the second current limiting unit 113 is connected to both the clamping unit 111 and the first current limiting unit 112, and the output terminal of the second current limiting unit 113 is connected to the input terminal of the voltage divider module 12. Specifically, the second current limiting unit 113 includes two high-resistance current limiting resistors, which are connected in series between each current limiting subunit and the series node of the voltage divider module 12. The high resistance of the current limiting resistors in the second current limiting unit 113 limits the current flowing to the voltage divider module 12, preventing negative voltage from entering the voltage divider module 12 and further improving the stability of the system.

[0055] For voltage divider module 12, it can be powered by the power signal from external power supply interface 20, or by other power signals. It is understood that voltage divider module 12 includes voltage dividing resistors, and the number of these resistors can be set according to the actual application. For example, as shown... Figure 4 As shown, the voltage divider module 12 includes components located at the first power supply 40 (e.g., ...). Figure 4 The three voltage divider resistors (V1) shown in the diagram are connected in series between the positive and negative terminals, as indicated by the label V1. Figure 4 Resistors R13, R14, and R15 are shown. The first power supply 40 provides a stable reference voltage to the voltage divider circuit, reducing errors caused by power supply fluctuations and improving circuit stability.

[0056] Understandably, resistor R14 is connected in parallel with the DC+ and DC- of the fast charging interface through clamping current limiting module 11. Clamping current limiting module 11 clamps the signal of the fast charging interface and transmits it to both ends of resistor R14. Differential sampling module 13 is used to collect the voltage across resistor R14. The contact state of the fast charging interface will cause a change in the impedance between the two ends of the interface, thereby affecting the change in the voltage across resistor R14. The controller can judge the contact state of the fast charging interface based on the voltage across resistor R14, identify whether the fast charging interface has a short circuit, and achieve accurate perception of the equivalent impedance change of the fast charging interface. It also avoids the fact that the single-ended voltage cannot truly reflect the real state of the fast charging interface and cause misjudgment, thus enhancing the anti-interference capability and reliability of the detection circuit.

[0057] In one embodiment, the differential sampling module 13 may include an operational amplifier. Exemplarily, the non-inverting and inverting inputs of the operational amplifier are respectively connected to the two ends of the middle voltage divider resistor among three voltage divider resistors, and the output of the operational amplifier is electrically connected to the control module 30. Specifically, the non-inverting input of the operational amplifier is used to connect to the series connection of resistors R13 and R14, and the inverting input is used to connect to the series connection of resistors R15 and R14. The operational amplifier subtracts the voltage across resistor R14 to obtain the voltage across resistor R14, allowing the control module 30 to determine whether a short circuit has occurred at the fast charging interface based on the voltage across resistor R14. Furthermore, resistors and capacitors can be incorporated into the differential sampling module 13 to form a filtering unit, filtering out high-frequency noise and further ensuring the reliability of the system.

[0058] It is understandable that an operational amplifier is set in the differential sampling module 13 for sampling. The operational amplifier has extremely high open-loop gain and input impedance, which can accurately capture minute voltage changes and realize high-precision differential signal acquisition. Moreover, the operational amplifier has high input impedance and low output impedance characteristics, which enables electrical isolation between the voltage divider module 12 and the control module 30, improving the system's anti-interference capability. At the same time, the differential amplifier composed of the operational amplifier has a good common-mode rejection ratio, which can effectively suppress noise signals that change at both input terminals.

[0059] It is understood that the control module 30 of this application may be an existing control module in an electronic device or battery connected to a fast charging interface, or it may be a dedicated control module for charging interface detection settings.

[0060] The control module 30 of this application is a dedicated control module 30 for charging interface detection settings. In one embodiment, the control module 30 is connected to the differential sampling module 13 and is used to perform analog-to-digital conversion on the target voltage generated by the differential sampling module 13, and determine the contact status of the external power device interface 20 based on the magnitude of the converted voltage value.

[0061] Specifically, the contact state of the fast charging interface causes a change in the impedance between its two ends. When the fast charging interfaces are not in contact, the impedance between the two ends is infinite. When the fast charging interfaces are in contact, i.e., a short circuit occurs between the two ends of the fast charging interfaces, the impedance approaches zero ohms. The parameters of each component in the charging interface detection circuit can be set according to the actual application, and corresponding thresholds or threshold ranges can be set in the control module 30 based on the parameters of each component. For example, when the control module 30 detects that the target voltage exceeds the threshold, it determines that a short circuit has occurred between the fast charging interfaces; when the control module 30 detects that the target voltage does not exceed the threshold, it determines that no short circuit has occurred between the fast charging interfaces.

[0062] Furthermore, the system can determine whether the fast charging interface is in a weak short circuit or a short circuit based on the target voltage. Specifically, a weak short circuit refers to an intermediate fault state where the charging interface is not completely short-circuited, but a low-impedance path exists, causing an abnormal increase in current and potentially leading to safety hazards such as localized overheating, fire, or smoke. Compared to a short circuit, the resistance value of a weak short circuit is slightly higher, but still much lower than the insulation resistance under normal conditions. The threshold value for a weak short circuit in the fast charging interface can be set according to the actual application. For example, a first threshold and a second threshold can be set. When the control module 30 detects that the target voltage does not exceed the first threshold, it determines that no short circuit has occurred between the fast charging interfaces; when the control module 30 detects that the target voltage exceeds the first threshold but does not exceed the second threshold, it determines that a weak short circuit has occurred between the fast charging interfaces; when the control module 30 detects that the target voltage exceeds the second threshold, it determines that a short circuit has occurred between the fast charging interfaces.

[0063] Exemplarily, the control module 30 determines whether a short circuit has occurred in the fast charging interface based on the target voltage after differential sampling by the differential sampling module 13. By reasonably setting the voltage threshold, it can distinguish between normal operating conditions and abnormal short circuit conditions, improving the stability of the diagnosis. Furthermore, the control module 30 can complete short circuit detection after the charging gun is inserted but before high-voltage power supply, and quickly trigger protection and conduction mechanisms based on the detection results. For example, if the detection result indicates that the fast charging interface is normal, the circuit connecting the fast charging interface and the battery is connected; if the detection result indicates that the fast charging interface is abnormal, an alarm is issued or the circuit connecting the fast charging interface and the battery is disconnected to protect the battery.

[0064] In one embodiment, based on the above embodiments, such as Figure 5 As shown, the charging interface detection circuit also includes a voltage follower module 14. Specifically, the voltage follower module 14 is used to perform voltage following on the voltage divider signal, and the resulting follower signal is transmitted to the differential sampling module 13 for differential sampling.

[0065] Exemplary, such as Figure 6 As shown, the voltage follower module 14 includes operational amplifier U1, operational amplifier U2, resistors R16, R17, R18, and R19, and capacitors C1, C2, C3, C4, C5, and C6. Specifically, resistors R16 and R17 are connected in series between the voltage divider module and the non-inverting input of operational amplifier U1. One end of capacitor C5 is connected to the series connection of resistors R16 and R17, and the other end is connected to the output of operational amplifier U1. Capacitors C1 and C2 are connected in parallel between the non-inverting input of operational amplifier U1 and ground. The inverting input of operational amplifier U1 is connected to the output of operational amplifier U1.

[0066] In this configuration, resistor R16 and capacitor C5 form an RC filter network, as do resistor R17 and capacitor C1. Resistors R18 and R19 are connected in series between the voltage divider module and the non-inverting input of operational amplifier U2. One end of capacitor C6 is connected to the series connection point of resistors R18 and R19, and the other end is connected to the output of operational amplifier U2. Capacitors C3 and C4 are connected in parallel between the non-inverting input of operational amplifier U2 and ground. The inverting input of operational amplifier U2 is connected to its output. Resistors R19 and C3, and resistors R18 and C6, form another RC filter network.

[0067] The voltage follower module 14 includes two second-order active low-pass filters, which are connected to the two output terminals of the voltage divider module 12. Each second-order active low-pass filter includes an operational amplifier and two RC filter networks. The operational amplifier, as the core component, provides voltage amplification, and its high input impedance and low output impedance characteristics isolate the effect of load changes on filtering performance. Resistors and capacitors form two RC filter networks, and the cutoff frequency and filtering performance can be set by adjusting the resistance and capacitance values. The second-order active low-pass filter is a Saleen-Kay structure. The input signal is divided by resistors and then enters the non-inverting input of the operational amplifier. The output terminal is fed back to the voltage divider node through a capacitor, forming a dual RC filter network.

[0068] It is understandable that the voltage follower module 14 uses two second-order active low-pass filters to transmit the voltage across resistor R14 to the differential sampling module 13, providing high input impedance and low output impedance to ensure that the front and rear stages do not affect each other and to achieve stable signal transmission between the front and rear stages. In addition, the voltage follower module 14 uses second-order active low-pass filters, which have a steeper roll-off characteristic and can better suppress high-frequency interference or noise above the cutoff frequency, ensuring signal quality and detection reliability.

[0069] The following describes the working process of an electric vehicle charging via a charging gun, using the charging interface detection circuit as an example. Figure 7 As shown, the charging interface detection circuit includes two current-limiting sub-units formed by resistors R1, R2, R3, R4, R5 and R7, R8, R9, R10, and R11, which are used to limit the high voltage of the fast charging interface and prevent large current from flowing to the voltage divider module 12. Four clamping diodes, D1, D2, D3 and D4, are used to clamp the positive and negative high voltages on DC+ and DC- to prevent large voltages from entering the voltage divider module 12. The two high-resistance current-limiting resistors R6 and R12 in the second current-limiting unit 113 are used to limit the current while preventing negative voltage from entering the voltage divider module 12.

[0070] The resistor R14 of the voltage divider module 12 is connected in parallel with the circuit between the DC+ and DC- ports of the fast charging interface through resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, and R12. The impedance change between the fast charging interfaces directly affects the voltage change across resistor R14. The non-inverting input terminals of operational amplifiers U1 and U2 of the voltage follower module 14 are connected to the two ends of resistor R14 respectively, which is used to transmit the voltage across resistor R14 to the differential sampling module 13. The differential sampling module 13 is connected to the output terminals of operational amplifiers U1 and U2 through resistors R20 and R14 respectively, and subtracts the voltage across resistor R14 to obtain the voltage across resistor R14, which is then transmitted to the control module 30. The control module 30 determines whether the fast charging interface is short-circuited based on the voltage across resistor R14. Furthermore, capacitors C7 and C8 in the differential sampling module 13 can be used for filtering to ensure the stability of the system.

[0071] This application embodiment also provides a charging device, which includes an external power device interface 20 and the aforementioned charging interface detection circuit. The external power device interface 20 is connected to the charging interface detection circuit. Exemplarily, the external power device interface 20 is a fast charging interface. The charging device is any type of electric vehicle, and the electric vehicle has the following operating states:

[0072] When the electric vehicle is not connected to high voltage, due to the influence of the Y capacitor and X capacitor connected to the power supply, there is a large positive and negative voltage at the charging port of the electric vehicle. In order to prevent this voltage from affecting the voltage divider module 12, four clamping diodes, clamping diodes D1, D2, D3 and D4, and multiple current-limiting resistors are used to limit and clamp the positive and negative voltage, so that the subsequent circuit is not affected by the positive and negative voltage. Under this condition, the charging interface detection circuit meets the safety requirements.

[0073] When an electric vehicle enters fast charging mode, there is a high voltage between the charging ports. The high voltage signal flows into the voltage divider module 12 through multiple current-limiting resistors. The multiple current-limiting resistors limit the current signal to prevent it from affecting the subsequent circuits. The clamping diode D4 clamps the positive high voltage of the charging port to +5.6V. At the same time, the large current signal is discharged using the characteristics of the clamping diode itself to prevent the large current signal from affecting the subsequent circuits. Under this condition, the charging interface detection circuit meets the safety requirements.

[0074] When the fast charging port is plugged into an electric vehicle, the vehicle detects the contact status of the fast charging port. If the detection result indicates that the fast charging port is normal, the circuit connecting the fast charging port and the battery is activated; if the detection result indicates that the fast charging port is abnormal, an alarm is issued or the circuit connecting the fast charging port and the battery is disconnected to protect the battery. The detection circuit of this application can operate stably under various operating conditions, ensuring the stability of the system.

[0075] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, in alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0076] In addition, the functional modules or units in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0077] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A charging interface detection circuit, characterized by, include: A clamping current limiting module (11) is configured to connect to an external power supply device interface (20), and the clamping current limiting module (11) is used to clamp the electrical signal connected to the external power supply device interface (20); The voltage divider module (12) is connected to the clamping current limiting module (11). The voltage divider module (12) is used to divide the electrical signal output by the clamping current limiting module (11) to obtain a voltage divider signal. The differential sampling module (13) is connected to the voltage divider module (12). The differential sampling module (13) is used to perform differential sampling on the voltage divider signal to obtain the target voltage. The target voltage is used to input to the control module (30) to determine the contact status of the external power supply device interface (20).

2. The charging interface detection circuit of claim 1, wherein, Also includes: The voltage follower module (14) is connected to the voltage divider module (12) and the differential sampling module (13) respectively. The voltage follower module (14) is used to perform voltage following on the voltage divider signal and the resulting follower signal is transmitted to the differential sampling module (13) for differential sampling.

3. The charging interface detection circuit of claim 2, wherein, The voltage follower module (14) includes two second-order active low-pass filters, which are connected to the two output terminals of the voltage divider module (12).

4. The charging interface detection circuit of claim 1, wherein, Also includes: The control module (30) is connected to the differential sampling module (13). The control module (30) is used to perform analog-to-digital conversion on the target voltage and determine the contact status of the external power supply device interface (20) based on the magnitude of the converted voltage value.

5. The charging interface detection circuit of claim 1, wherein, The clamping current limiting module (11) includes a clamping unit (111) and a first current limiting unit (112). The clamping unit (111) is located at both ends of the first power supply (40). The input end of the first current limiting unit (112) is connected to the external power supply device interface (20). The output end of the first current limiting unit (112) is connected to the input end of the voltage divider module (12) via the clamping unit (111).

6. The charging interface detection circuit of claim 5, wherein, The clamping unit (111) includes two sets of clamping sub-units, and the first current limiting unit (112) includes two sets of current limiting sub-units; one set of clamping sub-units is correspondingly connected to one set of current limiting sub-units; One set of the current limiting subunits is connected to the positive terminal of the external power supply interface (20), and the other set of the current limiting subunits is connected to the negative terminal of the external power supply interface (20).

7. The charging interface detection circuit of claim 6, wherein, Each set of clamping subunits includes two clamping diodes connected in series, and each set of current-limiting subunits includes at least one current-limiting resistor; In each set of clamping subunits, two clamping diodes are connected in reverse series between the positive and negative terminals of the first power supply (40), and the series connection node between the two clamping diodes is connected to the current limiting resistor in the corresponding set of current limiting subunits.

8. The charging interface detection circuit of claim 5, wherein, The clamping current limiting module (11) further includes a second current limiting unit (113). The input terminal of the second current limiting unit (113) is connected to the clamping unit (111) and the first current limiting unit (112) respectively, and the output terminal of the second current limiting unit (113) is connected to the input terminal of the voltage divider module (12).

9. The charging interface detection circuit of claim 1, wherein, The differential sampling module (13) includes an operational amplifier, and the voltage divider module (12) includes three voltage divider resistors connected in series between the positive and negative terminals of the first power supply (40). The non-inverting and inverting input terminals of the operational amplifier are respectively connected to the two ends of the middle voltage divider resistor among the three voltage divider resistors, and the output terminal of the operational amplifier is electrically connected to the control module (30).

10. A charging device, characterized by The charging device includes the external power supply interface (20) and the charging interface detection circuit as described in any one of claims 1-9.

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