A diagnostic circuit, a diagnostic device, and a diagnostic system

Abstract

This utility model discloses a diagnostic circuit, diagnostic device, and diagnostic system for use in the field of vehicle diagnostic technology. The diagnostic circuit includes: a power supply battery, a diagnostic communication power supply, a diagnostic communication circuit, and a controller; the vehicle's diagnostic connector includes: a diagnostic power supply and a diagnostic data cable; the power supply battery is connected to a first power terminal of the diagnostic communication power supply, and a second power terminal of the diagnostic communication power supply is connected to the diagnostic power supply; the power output terminal of the diagnostic communication power supply is connected to the power input terminal of the controller and the power input terminal of the diagnostic communication circuit; the signal transmission terminal of the controller is connected to the first signal transmission terminal of the diagnostic communication circuit, and the second signal transmission terminal of the diagnostic communication circuit is connected to the diagnostic data cable of the diagnostic connector; this allows the diagnostic device corresponding to the diagnostic circuit to maintain diagnostic communication with the vehicle even when the vehicle is experiencing a power supply abnormality.

Description

Technical Field

[0001] This utility model relates to the field of vehicle diagnostic technology, and in particular to a diagnostic circuit, diagnostic equipment, and diagnostic system. Background Technology

[0002] In existing vehicle diagnostics, external diagnostic equipment is connected to the vehicle's diagnostic connector. When the diagnostic equipment communicates with the vehicle, the vehicle is in an unlocked state with the instrument lights on (for example, the car key is turned to the ON position, or the start button is pressed to turn on the instrument lights). At this time, the vehicle's diagnostic connector is powered, which powers the diagnostic equipment. After the diagnostic equipment is powered on, it communicates with the vehicle to perform diagnostics.

[0003] However, when the vehicle is in a power supply abnormality, such as when the vehicle is locked or the vehicle's battery is faulty, the vehicle's diagnostic connector will not supply power to the diagnostic equipment. In this case, the diagnostic equipment will be unable to communicate with the vehicle and will be unable to perform diagnostics.

[0004] Therefore, there is an urgent need for a solution that can ensure diagnostic communication between the diagnostic equipment and the vehicle when the vehicle is experiencing a power supply failure. Utility Model Content

[0005] This invention provides a diagnostic circuit, diagnostic device, and diagnostic system that ensures the diagnostic device corresponding to the diagnostic circuit can communicate with the vehicle for diagnosis when the vehicle is experiencing a power supply abnormality.

[0006] This utility model provides a diagnostic circuit, which is disposed on the exterior of a vehicle. The diagnostic circuit includes: a power supply battery, a diagnostic communication power supply, a diagnostic communication circuit, and a controller; the vehicle's diagnostic connector includes: a diagnostic power supply and a diagnostic data cable.

[0007] The power supply battery is connected to the first power terminal of the diagnostic communication power supply, and the second power terminal of the diagnostic communication power supply is connected to the diagnostic power supply.

[0008] The power output terminal of the diagnostic communication power supply is connected to the power input terminal of the controller and the power input terminal of the diagnostic communication circuit.

[0009] The controller's signal transmission terminal is connected to the first signal transmission terminal of the diagnostic communication circuit, and the second signal transmission terminal of the diagnostic communication circuit is connected to the diagnostic data line of the diagnostic connector. The controller is used to control the diagnostic communication circuit to perform diagnostic communication with the diagnostic data line of the diagnostic connector after the diagnostic communication circuit is powered on.

[0010] Furthermore, the diagnostic communication circuit includes: a signal transceiver chip, a first resistor, a second resistor, a first bidirectional Zener diode, and a second bidirectional Zener diode;

[0011] The power input terminal of the signal transceiver chip is connected to the power output terminal of the diagnostic communication power supply.

[0012] The signal input terminal of the signal transceiver chip is connected to the signal output terminal of the controller, and the signal output terminal of the signal transceiver chip is connected to the signal input terminal of the controller.

[0013] The differential communication terminal of the signal transceiver chip is connected to the diagnostic data line of the diagnostic connector via a series connection of the first resistor and the second resistor, and via a series connection of the first bidirectional Zener diode and the second bidirectional Zener diode.

[0014] Furthermore, the diagnostic circuit also includes a boost circuit;

[0015] The voltage input terminal of the boost circuit is connected to the power supply battery;

[0016] The voltage output terminal of the boost circuit is connected to the first power supply terminal of the diagnostic communication power supply.

[0017] Furthermore, the boost circuit includes: an inductor, a switching transistor, a diode, and a capacitor;

[0018] One end of the inductor is connected to the positive terminal of the power supply battery, the other end of the inductor is connected to one end of the switching transistor and the anode of the diode, and the cathode of the diode is connected to one end of the capacitor.

[0019] The other end of the capacitor and the other end of the switching transistor are connected to the negative terminal of the power supply battery, and the first power supply terminal of the diagnostic communication power supply is connected in parallel to the two ends of the capacitor.

[0020] Furthermore, the diagnostic circuit also includes: a first electronic switch;

[0021] The first terminal of the first electronic switch is connected to the power supply battery, and the second terminal of the first electronic switch is connected to the voltage input terminal of the boost circuit.

[0022] The conduction control terminal of the first electronic switch is connected to the first signal output terminal of the controller; the controller is used to control the first electronic switch to conduct when the target supply voltage value of the diagnostic communication power input to the power input terminal of the controller is less than a preset voltage threshold.

[0023] Furthermore, the diagnostic circuit also includes: a Schottky diode;

[0024] The anode of the Schottky diode is connected to the power supply battery;

[0025] The cathode of the Schottky diode is connected to the first terminal of the first electronic switch.

[0026] Furthermore, the diagnostic circuit also includes: a second electronic switch;

[0027] The first end of the second electronic switch is connected to the second power supply end of the diagnostic communication power supply, and the second end of the second electronic switch is connected to the diagnostic power supply.

[0028] The conduction control terminal of the second electronic switch is connected to the second signal output terminal of the controller; the controller is used to control the switching states of the first electronic switch and the second electronic switch to switch the power supply mode of the diagnostic communication power supply, and to determine the power supply status of the vehicle and make corresponding prompts based on the target power supply voltage value and the communication status of the diagnostic communication circuit and the diagnostic data line of the diagnostic connector.

[0029] Furthermore, the first electronic switch includes a MOSFET or a transistor; the second electronic switch includes a MOSFET or a transistor.

[0030] This invention also provides a diagnostic device, including the diagnostic circuit described above.

[0031] This invention also provides a diagnostic system, including the diagnostic equipment described above and a diagnostic connector for a vehicle.

[0032] As can be seen from the above technical solutions, this utility model has the following advantages:

[0033] In this invention, the diagnostic circuit is located externally to the vehicle and includes: a power supply battery, a diagnostic communication power supply, a diagnostic communication circuit, and a controller; the vehicle's diagnostic connector includes: a diagnostic power supply and a diagnostic data line; the power supply battery is connected to the first power terminal of the diagnostic communication power supply, and the second power terminal of the diagnostic communication power supply is connected to the diagnostic power supply; the power output terminal of the diagnostic communication power supply is connected to the power input terminal of the controller and the power input terminal of the diagnostic communication circuit; the signal transmission terminal of the controller is connected to the first signal transmission terminal of the diagnostic communication circuit, and the second signal transmission terminal of the diagnostic communication circuit is connected to the diagnostic data line of the diagnostic connector; the controller is used to control the diagnostic communication circuit to perform diagnostic communication with the diagnostic data line of the diagnostic connector after the diagnostic communication circuit is powered on.

[0034] When a vehicle experiences a power supply failure and the diagnostic power supply at the vehicle's diagnostic connector fails to provide power, the diagnostic communication power supply can be powered by the battery in the diagnostic circuit. This power supply then powers the diagnostic communication circuit, which in turn powers the diagnostic communication circuit. Once powered on, the diagnostic communication circuit communicates with the diagnostic data line of the diagnostic connector. This ensures that the diagnostic equipment corresponding to the diagnostic circuit can communicate with the vehicle even when the vehicle is experiencing a power supply failure. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0036] Figure 1 This is a circuit block diagram of a diagnostic circuit disclosed in this utility model;

[0037] Figure 2 This is a circuit diagram of a diagnostic communication circuit disclosed in this utility model;

[0038] Figure 3 Here is a circuit block diagram of another diagnostic circuit disclosed in this utility model;

[0039] Figure 4 This is a circuit diagram of a boost circuit disclosed in this utility model;

[0040] Figure 5 This is a circuit block diagram of a complete diagnostic circuit disclosed in this utility model;

[0041] Figure 6 This is a schematic diagram of a vehicle diagnostic connector disclosed in this utility model;

[0042] Figure 7 This is a control flowchart of a controller disclosed in this utility model. Detailed Implementation

[0043] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0044] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] In vehicle diagnostics, external diagnostic equipment connects to the vehicle's diagnostic connector, which is the connector for the on-board diagnostic (OBD) system. When the external diagnostic equipment communicates with the vehicle, the vehicle is in an unlocked state with the instrument panel lights illuminated. At this time, the vehicle's diagnostic connector is powered, supplying power to the diagnostic communication circuit of the diagnostic equipment. Once the diagnostic communication circuit is powered on, the diagnostic equipment communicates with the vehicle to perform diagnostics. However, when the vehicle is in a power supply abnormality, such as being locked (due to a lost key or the user of the diagnostic equipment not knowing to leave the vehicle unlocked), or the vehicle's battery is faulty, the vehicle's diagnostic connector does not supply power to the diagnostic communication circuit of the diagnostic equipment. The diagnostic equipment will then be unable to communicate with the vehicle and perform diagnostics. This invention provides a diagnostic circuit that ensures that the corresponding diagnostic equipment can communicate with the vehicle when the vehicle is in a power supply abnormality. This diagnostic circuit, for example... Figure 1 As shown, the details are as follows:

[0047] In this invention, the diagnostic circuit is located externally to the vehicle. This external diagnostic circuit communicates with the target diagnostic circuit inside the vehicle via a diagnostic connector to perform vehicle diagnostics. The diagnostic circuit includes a power supply battery 100, a diagnostic communication power supply 200, a diagnostic communication circuit 300, and a controller 400. The vehicle's diagnostic connector includes a diagnostic power supply and a diagnostic data cable. The diagnostic power supply can be understood as the power cable on the vehicle's diagnostic connector, which can supply power to the diagnostic power supply on the vehicle's diagnostic connector and the target diagnostic circuit inside the vehicle via the vehicle's battery. If the vehicle's battery is abnormally damaged, it will be unable to supply power to the diagnostic power supply on the diagnostic connector and the target diagnostic circuit inside the vehicle.

[0048] The power supply battery 100 is connected to the first power terminal of the diagnostic communication power supply 200. The power supply battery 100 can be a 5V or 10V DC power source, which is not specifically limited here. The power supply battery 100 supplies power to the first power terminal of the diagnostic communication power supply 200. The second power terminal of the diagnostic communication power supply 200 is connected to the diagnostic power supply on the diagnostic connector, which can also supply power to the diagnostic communication power supply 200. The power output terminal of the diagnostic communication power supply 200 is connected to the power input terminal of the controller 400 and the power input terminal of the diagnostic communication circuit 300. It is understood that after being powered on, the diagnostic communication power supply 200 can provide the power supply voltage received at the first and second power terminals to the controller 400 and the diagnostic communication circuit 300. The voltage output from the power output terminal of the diagnostic communication power supply 200 has the same amplitude as the received power supply voltage. For example, if it receives a 5V voltage from the power supply battery 100, it provides a 5V voltage to the controller 400 and the diagnostic communication circuit 300.

[0049] The controller 400 can be a DPU or an MCU, which is not specifically limited here. The signal transmission terminal of the controller 400 is connected to the first signal transmission terminal of the diagnostic communication circuit 300, and the second signal transmission terminal of the diagnostic communication circuit 300 is connected to the diagnostic data line of the diagnostic connector. The controller 400 is used to control the diagnostic communication circuit 300 to perform diagnostic communication with the diagnostic data line of the diagnostic connector after the diagnostic communication circuit 300 is powered on. It can be understood that the diagnostic data line of the diagnostic connector is connected to the target diagnostic circuit in the vehicle. By controlling the diagnostic communication circuit 300 to perform diagnostic communication with the diagnostic data line of the diagnostic connector, that is, by controlling the diagnostic communication circuit 300 to perform diagnostic communication with the target diagnostic circuit in the vehicle, vehicle diagnosis can be achieved.

[0050] Understandably, when there is no power supply abnormality in the vehicle (the vehicle is locked or the vehicle's battery is damaged), the vehicle's diagnostic connector provides power to the outside world through the diagnostic power supply, that is, it supplies power to the diagnostic communication power supply 200 of the diagnostic circuit, and the diagnostic communication power supply 200 supplies power to the diagnostic communication circuit 300, thereby enabling the diagnostic communication circuit 300 to be powered on; that is, when there is no power supply abnormality in the vehicle, the diagnostic communication circuit 300 of the diagnostic circuit draws power from the vehicle's diagnostic connector.

[0051] When the vehicle experiences a power supply malfunction, such as when the vehicle is locked or the vehicle's battery is faulty, the vehicle's diagnostic connector cannot provide power to the outside world through the diagnostic power supply. In other words, the diagnostic power supply does not supply power to the diagnostic communication power supply 200 of the diagnostic circuit. In this case, the diagnostic communication power supply 200 can be powered by the battery 100, and the diagnostic communication power supply 200 can then power the diagnostic communication circuit 300, enabling the diagnostic communication circuit to communicate normally with the vehicle.

[0052] As can be seen, in this utility model, the diagnostic circuit is located outside the vehicle and includes: a power supply battery, a diagnostic communication power supply, a diagnostic communication circuit, and a controller; the vehicle's diagnostic connector includes: a diagnostic power supply and a diagnostic data line; the power supply battery is connected to the first power terminal of the diagnostic communication power supply, and the second power terminal of the diagnostic communication power supply is connected to the diagnostic power supply; the power output terminal of the diagnostic communication power supply is connected to the power input terminal of the controller and the power input terminal of the diagnostic communication circuit; the signal transmission terminal of the controller is connected to the first signal transmission terminal of the diagnostic communication circuit, and the second signal transmission terminal of the diagnostic communication circuit is connected to the diagnostic data line of the diagnostic connector; the controller is used to control the diagnostic communication circuit to perform diagnostic communication with the diagnostic data line of the diagnostic connector after the diagnostic communication circuit is powered on.

[0053] When a vehicle experiences a power supply failure and the diagnostic power supply at the vehicle's diagnostic connector fails to provide power, the diagnostic communication power supply can be powered by the battery in the diagnostic circuit. This power supply then powers the diagnostic communication circuit, which in turn powers the diagnostic communication circuit. Once powered on, the diagnostic communication circuit communicates with the diagnostic data line of the diagnostic connector. This ensures that the diagnostic equipment corresponding to the diagnostic circuit can communicate with the vehicle even when the vehicle is experiencing a power supply failure.

[0054] Furthermore, in this invention, the diagnostic communication circuit 300 can use a CAN FD (Controller Area Network Flexible Data Rate) communication system to achieve diagnostic communication, and the corresponding circuit diagram is shown below. Figure 2As shown. The diagnostic communication circuit 300 includes: a signal transceiver chip U1, a first resistor R1, a second resistor R2, a first bidirectional Zener diode D1, and a second bidirectional Zener diode D2; wherein the signal transceiver chip U1 can be a CAN FD transceiver (TCAN3404), and the power input terminal V of the signal transceiver chip U1... cc The signal transceiver chip U1 is connected to the power output terminal of the diagnostic communication power supply 200. The signal input terminal RXD of the transceiver chip U1 is connected to the signal output terminal of the controller 400, and the signal output terminal TXD of the transceiver chip U1 is connected to the signal input terminal of the controller 400. It is understood that the controller 400 has a built-in CAN FD controller, which has signal output and signal input terminals to enable communication with the transceiver chip U1. The transceiver chip U1 may also have a standby terminal STB and a shutdown terminal SHDN connected to the controller 400, allowing the controller 400 to control the transceiver chip U1 to be in standby or off mode.

[0055] The differential communication terminals (CANH and CANL) of the transceiver chip U1 are connected to the diagnostic data lines of the diagnostic connector via a series connection of a first resistor R1 and a second resistor R2, and a series connection of a first bidirectional Zener diode D1 and a second bidirectional Zener diode D2. It is understood that the series connection of the first resistor R1 and the second resistor R2 can cancel CAN bus signal reflections, ensuring signal integrity; the series connection of the first bidirectional Zener diode D1 and the second bidirectional Zener diode D2 can provide surge protection for the transceiver chip U1 and the controller 400.

[0056] Understandably, the diagnostic connectors on the vehicle are specifically as follows: Figure 6 As shown, the diagnostic connector includes: a diagnostic power supply (16 pins), a diagnostic data line, and a ground (4 pins and 5 pins). The diagnostic data line can include data lines for various communication protocols, such as the K-line (7 pins and 15 pins) of the ISO9141 protocol, the CAN bus (6 pins and 14 pins) of the ISO15765 protocol, and the positive signal line (2 pins) and negative signal line (10 pins) of the SAE J1850 protocol. The corresponding communication pins can be selected according to the communication protocol used by the diagnostic communication circuit 300 of the diagnostic circuit. That is, the corresponding diagnostic communication circuit 300 can include various forms, and no specific limitation is made here.

[0057] Furthermore, such as Figure 3As shown, the diagnostic circuit also includes a boost circuit 500; wherein the voltage input terminal of the boost circuit 500 is connected to the power supply battery 100; and the voltage output terminal of the boost circuit 500 is connected to the first power supply terminal of the diagnostic communication power supply 200. By boosting the power supply voltage of the power supply battery 100 through the boost circuit 500 before supplying it to the diagnostic communication power supply 200, the energy utilization efficiency of the power supply battery can be improved, and the diagnostic communication power supply 200 can be effectively adapted.

[0058] Furthermore, such as Figure 4 As shown, the boost circuit includes: an inductor L, a switching transistor S1, a diode D, and a capacitor C; one end of the inductor L is connected to the positive terminal of the power supply battery BAT, and the other end of the inductor L is connected to one end of the switching transistor S1 and the anode of the diode D; the cathode of the diode D is connected to one end of the capacitor C; the other end of the capacitor C and the other end of the switching transistor S1 are connected to the negative terminal of the power supply battery BAT, and the first power supply terminal of the diagnostic communication power supply 200 is connected in parallel across the two ends of the capacitor C.

[0059] Furthermore, in this invention, the diagnostic circuit also includes: a first electronic switch 600; the first terminal of the first electronic switch 600 is connected to the power supply battery 100, the second terminal of the first electronic switch 600 is connected to the voltage input terminal of the boost circuit 500, and the conduction control terminal of the first electronic switch 600 is connected to the first signal output terminal of the controller 400. The first electronic switch 600 can be a MOSFET or a transistor. The controller controls the switching state (on or off) of the MOSFET by outputting a corresponding control signal to the gate of the MOSFET or by outputting a corresponding control signal to the base of the transistor; the specific control is not limited here. For example, the first electronic switch can be a PMOS transistor, with the source of the PMOS transistor connected to the power supply battery 100, the drain of the PMOS transistor connected to the voltage input terminal of the boost circuit 500, and the gate of the PMOS transistor connected to the controller 400. The controller 400 controls the PMOS transistor to conduct by outputting a low-level signal and controls the PMOS transistor to disconnect by outputting a high-level signal.

[0060] The controller 400 is configured to turn on the first electronic switch 600 when the target supply voltage value of the diagnostic communication power supply 200 input to the power input terminal of the controller 400 is less than a preset voltage threshold. This preset voltage threshold can be 0.5V or 1V, and is not specifically limited here. That is, the first electronic switch 600 is initially in the off state, and the diagnostic communication power supply 200 is powered through the diagnostic power supply of the vehicle's diagnostic connector. The controller 400 detects the target supply voltage value of the diagnostic communication power supply 200 input to the controller 400. If the target supply voltage value is less than the preset voltage threshold, it determines that the vehicle has a power supply abnormality, and turns on the first electronic switch 600, allowing the power supply battery 100 to supply power to the diagnostic communication power supply through the boost circuit 500.

[0061] Furthermore, in this invention, the diagnostic circuit also includes: a Schottky diode 700; the anode of the Schottky diode 700 is connected to the power supply battery 100; the cathode of the Schottky diode 700 is connected to the first terminal of the first electronic switch 600. It is understood that the current supplied by the power supply battery 100 is isolated by the Schottky diode 700, which can prevent reverse current flow.

[0062] Furthermore, when the vehicle's diagnostic connector is not supplying power, it does not power the diagnostic equipment, making it difficult for the user to use the equipment to diagnose the vehicle. In this situation, the user cannot determine whether the problem lies with the diagnostic equipment or with an abnormal power supply to the vehicle. Abnormal power supply conditions include the vehicle being locked and a damaged battery. This invention can determine whether the vehicle is locked and the battery status, thus accurately identifying any abnormal power supply conditions.

[0063] In this invention, the diagnostic circuit further includes a second electronic switch 800. This second electronic switch 800 is similar to the first electronic switch 600 described above, and will not be further elaborated here. The first end of the second electronic switch 800 is connected to the second power supply terminal of the diagnostic communication power supply 200, and the second end of the second electronic switch 800 is connected to the diagnostic power supply of the vehicle's diagnostic connector. The conduction control terminal of the second electronic switch 800 is connected to the second signal output terminal of the controller 400. The controller 400 is used to control the switching states of the first electronic switch 600 and the second electronic switch 800 to switch the power supply mode of the diagnostic communication power supply 200, and, based on the target power supply voltage value and the communication status of the diagnostic data line between the diagnostic communication circuit 300 and the diagnostic connector, to determine the vehicle's power supply status and provide corresponding prompts.

[0064] The control flow of controller 400 is as follows Figure 7As shown, specifically, electronic switch A is the first electronic switch 600, and electronic switch B is the second electronic switch 800. First, electronic switch A is turned on and electronic switch B is turned off. At this time, the diagnostic communication power supply draws power from the diagnostic power supply of the vehicle diagnostic connector, and the target diagnostic circuit inside the vehicle also draws power from this diagnostic power supply; all power is supplied by the vehicle. The controller determines whether the power supply is normal based on the target power supply voltage value, which is generally greater than 12V; otherwise, it will affect vehicle starting. That is, the controller can determine whether the target power supply voltage value is less than 12V; if not, it indicates that the vehicle's battery power supply is normal and directly enters the vehicle diagnostic process; if so, it indicates that a voltage below 12V will affect vehicle starting and prompts the controller to charge the battery as soon as possible.

[0065] Next, the controller can determine if the target supply voltage is less than 10V. If not, it determines the target supply voltage is between 10V and 12V, indicating normal communication and prompting a warning that the battery is severely depleted, requiring immediate charging. If yes, it indicates a battery malfunction below 10V, requiring battery replacement. Then, the controller can determine if the target supply voltage is less than 1V. If not, it indicates the battery is damaged and needs replacement; if yes, it indicates the vehicle may be locked.

[0066] Next, the controller can disconnect electronic switch A and open electronic switch B. At this point, the diagnostic communication power supply is powered by the battery, and the vehicle's battery powers the target diagnostic circuit within the vehicle. The controller can then determine if the communication between the diagnostic communication circuit and the diagnostic data line of the diagnostic connector is abnormal. If not, it indicates the vehicle is locked and enters vehicle diagnostic mode; if so, it opens both electronic switches A and B. The battery then powers the diagnostic communication power supply of the diagnostic circuit and also powers the target diagnostic circuit within the vehicle through the diagnostic power supply on the diagnostic connector, all powered by the diagnostic circuit's battery. The controller can again determine if the communication between the diagnostic communication circuit and the diagnostic data line of the diagnostic connector is normal. If yes, it indicates a battery malfunction and inability to provide power, prompting a battery replacement; if no, it indicates the diagnostic circuit is not connected to the vehicle's diagnostic connector, possibly due to a loose connector or a serious vehicle malfunction preventing communication.

[0067] As can be seen, in this utility model, the controller can control the switching states of the first electronic switch and the second electronic switch to switch the power supply mode of the diagnostic communication power supply. By intelligently switching the power supply mode of the diagnostic communication power supply, the requirements for users of diagnostic equipment are reduced, making it easier for users to diagnose the vehicle. Furthermore, based on the target power supply voltage value and the communication status of the diagnostic communication circuit and the diagnostic data line of the diagnostic connector, the power supply status of the vehicle is determined and corresponding prompts are made. This can accurately identify abnormal power supply conditions of the vehicle and facilitate subsequent operation and maintenance when abnormalities occur.

[0068] This invention also provides a diagnostic device, including the diagnostic circuit described above. When a vehicle experiences a power supply abnormality, the diagnostic circuit ensures that the diagnostic device can communicate with the vehicle for diagnosis, thus ensuring the normal progress of vehicle diagnostics.

[0069] This invention also provides a diagnostic system, including the diagnostic equipment described above and a diagnostic connector for a vehicle.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A diagnostic circuit, characterized in that, The diagnostic circuit is located outside the vehicle and includes: a power supply battery, a diagnostic communication power supply, a diagnostic communication circuit, and a controller; the vehicle's diagnostic connector includes: a diagnostic power supply and a diagnostic data cable. The power supply battery is connected to the first power terminal of the diagnostic communication power supply, and the second power terminal of the diagnostic communication power supply is connected to the diagnostic power supply. The power output terminal of the diagnostic communication power supply is connected to the power input terminal of the controller and the power input terminal of the diagnostic communication circuit. The controller's signal transmission terminal is connected to the first signal transmission terminal of the diagnostic communication circuit, and the second signal transmission terminal of the diagnostic communication circuit is connected to the diagnostic data line of the diagnostic connector. The controller is used to control the diagnostic communication circuit to perform diagnostic communication with the diagnostic data line of the diagnostic connector after the diagnostic communication circuit is powered on.

2. The diagnostic circuit according to claim 1, characterized in that, The diagnostic communication circuit includes: a signal transceiver chip, a first resistor, a second resistor, a first bidirectional Zener diode, and a second bidirectional Zener diode; The power input terminal of the signal transceiver chip is connected to the power output terminal of the diagnostic communication power supply. The signal input terminal of the signal transceiver chip is connected to the signal output terminal of the controller, and the signal output terminal of the signal transceiver chip is connected to the signal input terminal of the controller. The differential communication terminal of the signal transceiver chip is connected to the diagnostic data line of the diagnostic connector via a series connection of the first resistor and the second resistor, and via a series connection of the first bidirectional Zener diode and the second bidirectional Zener diode.

3. The diagnostic circuit according to claim 1, characterized in that, The diagnostic circuit also includes: a boost circuit; The voltage input terminal of the boost circuit is connected to the power supply battery; The voltage output terminal of the boost circuit is connected to the first power supply terminal of the diagnostic communication power supply.

4. The diagnostic circuit according to claim 3, characterized in that, The boost circuit includes: an inductor, a switching transistor, a diode, and a capacitor; One end of the inductor is connected to the positive terminal of the power supply battery, the other end of the inductor is connected to one end of the switching transistor and the anode of the diode, and the cathode of the diode is connected to one end of the capacitor. The other end of the capacitor and the other end of the switching transistor are connected to the negative terminal of the power supply battery, and the first power supply terminal of the diagnostic communication power supply is connected in parallel to the two ends of the capacitor.

5. The diagnostic circuit according to claim 3, characterized in that, The diagnostic circuit further includes: a first electronic switch; The first terminal of the first electronic switch is connected to the power supply battery, and the second terminal of the first electronic switch is connected to the voltage input terminal of the boost circuit. The conduction control terminal of the first electronic switch is connected to the first signal output terminal of the controller; the controller is used to control the first electronic switch to conduct when the target supply voltage value of the diagnostic communication power input to the power input terminal of the controller is less than a preset voltage threshold.

6. The diagnostic circuit according to claim 5, characterized in that, The diagnostic circuit also includes: a Schottky diode; The anode of the Schottky diode is connected to the power supply battery; The cathode of the Schottky diode is connected to the first terminal of the first electronic switch.

7. The diagnostic circuit according to claim 5, characterized in that, The diagnostic circuit also includes: a second electronic switch; The first end of the second electronic switch is connected to the second power supply end of the diagnostic communication power supply, and the second end of the second electronic switch is connected to the diagnostic power supply. The conduction control terminal of the second electronic switch is connected to the second signal output terminal of the controller; the controller is used to control the switching states of the first electronic switch and the second electronic switch to switch the power supply mode of the diagnostic communication power supply, and to determine the power supply status of the vehicle and make corresponding prompts based on the target power supply voltage value and the communication status of the diagnostic communication circuit and the diagnostic data line of the diagnostic connector.

8. The diagnostic circuit according to claim 7, characterized in that, The first electronic switch includes a MOSFET or a transistor; the second electronic switch includes a MOSFET or a transistor.

9. A diagnostic device, characterized in that, Includes the diagnostic circuit described in any one of claims 1 to 8.

10. A diagnostic system, characterized in that, This includes the diagnostic device as described in claim 9 and the diagnostic connector for the vehicle.

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