An automobile OBD test system

Abstract

The utility model relates to automobile detection technical field especially, it relates to a kind of automobile OBD test system, including MCU control circuit, OBD diagnosis interface, pin selection circuit, pin display circuit, pin voltage display circuit, output current sampling circuit, output current and battery power display circuit, battery management circuit and power management circuit, each circuit is electrically connected with the MCU control circuit, the MCU control circuit includes the MCU control chip of STC15W408AS-TSSOP20 type.This MCU control chip is responsible for coordinating the work of each circuit module, to realize pin selection, pin display, voltage display, current sampling display and power management and the like functions, and ensure the stable operation of OBD test system.The automobile OBD test system makes up the deficiency of traditional automobile OBD tester in current detection and power supply, significantly improves functional integration, meets increasingly complex diagnostic requirements.

Description

Technical Field

[0001] This utility model relates to the field of automotive testing technology, and in particular to an automotive OBD testing system. Background Technology

[0002] An automotive OBD tester is an electronic tool specifically designed to read and analyze information from a vehicle's On-Board Diagnostics (OBD) system. To achieve this, the vehicle's OBD interface typically uses a standard 16-pin connector, and correspondingly, the OBD diagnostic interface of the automotive OBD tester also uses a standard 16-pin connector. By connecting the OBD diagnostic interface to the vehicle's OBD interface, it is possible to select and monitor the signal status of specific pins and display the corresponding pin number and voltage value in real time, thereby helping technicians determine the operating status of the vehicle's electronic systems. As an important tool for vehicle fault diagnosis, automotive OBD testers play an irreplaceable role in the automotive maintenance field. However, with the continuous development of automotive electronics technology, vehicle electronic systems are becoming increasingly complex, placing higher demands on the functional integration, measurement accuracy, and intelligence level of OBD testers. Currently, most automotive OBD testers on the market primarily measure pin voltage, lacking the ability to detect pin current, and most OBD testers do not have an integrated power supply, requiring external power. This, to some extent, limits their functional diversity and ease of use. Utility Model Content

[0003] In view of this, the present invention proposes an automotive OBD testing system, which aims to solve the problems of existing automotive OBD testers lacking the ability to detect pin current and not integrating a built-in power supply.

[0004] This utility model proposes an automotive OBD testing system, including an MCU control circuit, an OBD diagnostic interface, a pin selection circuit, a pin display circuit, and a pin voltage display circuit. The OBD diagnostic interface, the pin selection circuit, the pin display circuit, and the pin voltage display circuit are all electrically connected to the MCU control circuit. The automotive OBD testing system also includes an output current sampling circuit, an output current and battery level display circuit, a battery management circuit, and a power management circuit. The output current sampling circuit, the output current and battery level display circuit, the battery management circuit, and the power management circuit are all electrically connected to the MCU control circuit. The MCU control circuit includes an STC15W408AS-TSSOP20 type MCU control chip.

[0005] Furthermore, the output current sampling circuit includes an INA226AIDGSR type current monitoring chip.

[0006] Furthermore, the output current and battery power display circuit includes a TM1652 type driver control chip U8, a 3361AS type digital tube, and an LED power display; wherein, pin 1 of the driver control chip U8 is connected to the VCC-5V power supply terminal, pin 10 of the driver control chip U8 is grounded, pin 16 of the driver control chip U8 is connected to the TM1652_SDA terminal, pin 15 of the driver control chip U8 is connected to pin 12 of the digital tube, pin 14 of the driver control chip U8 is connected to pin 9 of the digital tube, pin 13 of the driver control chip U8 is connected to pin 8 of the digital tube, pin 12 of the driver control chip U8 is connected to pin 9 of the LED power display, pin 11 of the driver control chip U8 is left floating, and pin 2 of the driver control chip U8 is connected to pin 11 of the digital tube and the LED power display respectively. The first pin of the power indicator is connected to the 7th pin of the digital tube and the 2nd pin of the LED power indicator, respectively. The 4th pin of the driver control chip U8 is connected to the 4th pin of the digital tube and the 3rd pin of the LED power indicator, respectively. The 5th pin of the driver control chip U8 is connected to the 2nd pin of the digital tube and the 4th pin of the LED power indicator, respectively. The 6th pin of the driver control chip U8 is connected to the 1st pin of the digital tube and the 5th pin of the LED power indicator, respectively. The 7th pin of the driver control chip U8 is connected to the 10th pin of the digital tube and the 6th pin of the LED power indicator, respectively. The 8th pin of the driver control chip U8 is connected to the 5th pin of the digital tube and the 7th pin of the LED power indicator, respectively. The 9th pin of the driver control chip U8 is connected to the 3rd pin of the digital tube and the 8th pin of the LED power indicator, respectively.

[0007] Furthermore, the battery management circuit includes a battery charging / discharging circuit and a battery protection circuit that are electrically connected to each other. The battery charging / discharging circuit includes an SC8815QDER type bidirectional buck-boost charging management chip.

[0008] Furthermore, the battery management circuit includes a battery charging / discharging circuit and a battery protection circuit that are electrically connected to each other, and the battery protection circuit includes a CW1244ALBS type battery protection chip.

[0009] Furthermore, the power management circuit includes a main power supply circuit and an auxiliary power supply circuit that are electrically connected to each other. The main power supply circuit includes a step-down DC-DC converter chip U6 of type XL1509-ADJ, a three-terminal integrated voltage regulator chip U7 of type 78L05, a low dropout linear regulator chip U9 of type ME6209A33M3G, a polarized capacitor C13, a capacitor C15, a diode D18, a resistor R35, a resistor R32, a polarized capacitor C23, an inductor L1, a capacitor C22, a capacitor C17, a polarized capacitor C24, a capacitor C18, a capacitor C19, a capacitor C20, a capacitor C21, a capacitor C27, a capacitor C26, and a capacitor C25.

[0010] Specifically, pin 1 of the buck DC-DC converter chip U6 is connected to the Auxiliary_POWER terminal, the positive terminal of polarized capacitor C13, and one end of capacitor C15. Pin 2 of the buck DC-DC converter chip U6 is connected to one end of inductor L1 and the negative terminal of diode D18. Pin 3 of the buck DC-DC converter chip U6 is connected to one end of resistor R35 and one end of resistor R32. The negative terminal of polarized capacitor C13 is connected to the other end of capacitor C15, pin 4 of the buck DC-DC converter chip U6, pin 5 of the buck DC-DC converter chip U6, pin 6 of the buck DC-DC converter chip U6, pin 7 of the buck DC-DC converter chip U6, pin 8 of the buck DC-DC converter chip U6, the ground terminal, the positive terminal of diode D18, the other end of resistor R35, the negative terminal of polarized capacitor C23, one end of capacitor C22, pin 2 of the three-terminal integrated voltage regulator chip U7, and capacitor C One end of capacitor C17, the negative terminal of polarized capacitor C24, one end of capacitor C18, one end of capacitor C19, one end of capacitor C20, one end of capacitor C21, one end of capacitor C27, pin 1 of low dropout linear regulator chip U9, one end of capacitor C26, and one end of capacitor C25. Pin 3 of the three-terminal integrated regulator chip U7 is connected to the VCC-7.5V power supply terminal, the other end of inductor L1, the other end of resistor R32, the positive terminal of polarized capacitor C23, and the other end of capacitor C22. The first pin of the three-terminal integrated voltage regulator chip U7 is connected to the other end of capacitor C17, the positive terminal of polarized capacitor C24, the other end of capacitor C18, the other end of capacitor C19, the other end of capacitor C20, the other end of capacitor C21, the other end of capacitor C27, the VCC-5V power supply terminal, and the third pin of the low dropout linear regulator chip U9. The second pin of the low dropout linear regulator chip U9 is connected to the other end of capacitor C26, the other end of capacitor C25, and the VCC-3V3 power supply terminal.

[0011] Furthermore, the power management circuit includes a main power supply circuit and an auxiliary power supply circuit electrically connected to each other. The auxiliary power supply circuit includes a 78MXX type linear regulator chip U4, a ME6209A33M3G type low dropout linear regulator chip U2, an SPX3819M5-L-5-0 type low dropout linear regulator chip U8, polarized capacitors C57, C60, C58, C59, and C64, diodes D6 and D5, capacitor C52, and a bidirectional Zener diode. D1, K1, R34, Q8 (AO3401A type P-channel MOSFET), Q16 (2N7002 type N-channel MOSFET), R35, R58, R59, D3 (bidirectional Zener diode), C55, D2, C54, C35, C36, C23, C53, C20, L4 (inductor), C21, C44, C45, C46, ​​C43, and C48;

[0012] In this circuit, pin 1 of the linear regulator chip U4 is connected to the VCC-IN power supply terminal, the positive terminal of polarized capacitor C54, and one end of capacitor C60. Pin 2 of the linear regulator chip U4 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C60, the ground terminal, one end of capacitor C58, one end of capacitor C59, and one end of capacitor C64. Pin 3 of the linear regulator chip U4 is connected to the other end of capacitor C58, the other end of capacitor C59, the other end of capacitor C64, and the positive terminal of diode D6. The negative terminal of diode D6 is connected to the positive terminal of diode D5.

[0013] Pin 1 of the low-dropout linear regulator chip U8 is connected to one end of capacitor C55 and the VBAT terminal, respectively. The other end of capacitor C55 is grounded. Pin 2 of the low-dropout linear regulator chip U8 is grounded. Pin 3 of the low-dropout linear regulator chip U8 is connected to pin 3 of the bidirectional Zener diode D3. Pin 4 of the low-dropout linear regulator chip U8 is left floating. Pin 5 of the low-dropout linear regulator chip U8 is connected to the positive terminal of diode D2. Pins 2 of the bidirectional Zener diode D3 are connected to the VCC-IN power supply terminal through resistor R58 and to the ground terminal through resistor R59, respectively. Pin 1 of the bidirectional Zener diode D3 is connected to the P-channel MOSFET Q8. The drain and source of the P-channel MOSFET Q8 are connected to one end of resistor R34 and the VBAT power supply terminal, respectively. The gate of the P-channel MOSFET Q8 is connected to the other end of resistor R34, the drain of the N-channel MOSFET Q16, and pin 1 of the bidirectional Zener diode D1. Pin 3 of the bidirectional Zener diode D1 is connected to one end of switch K1. The other end of switch K1 is connected to one end of capacitor C52, the ground terminal, the source of the N-channel MOSFET Q16, and one end of resistor R35, respectively. Pin 2 of the bidirectional Zener diode D1 is connected to the POW_KEY terminal and the other end of capacitor C52, respectively. The other end of resistor R35 is connected to the gate of the N-channel MOSFET Q16 and the POW_EN terminal, respectively.

[0014] Pin 3 of the low-dropout linear regulator chip U2 is connected to the negative terminal of diode D5, the VCC power supply terminal, the negative terminal of diode D2, the positive terminal of polarized capacitor C54, one end of capacitor C35, one end of capacitor C36, and one end of capacitor C23. Pin 1 of the low-dropout linear regulator chip U2 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C35, the other end of capacitor C36, the other end of capacitor C23, the ground terminal, the negative terminal of polarized capacitor C53, one end of capacitor C20, and one end of capacitor C21. One end of capacitor C44, one end of capacitor C45, one end of capacitor C46, ​​one end of capacitor C43, and one end of capacitor C48 are connected to the positive terminal of the low dropout linear regulator chip U2, the other end of capacitor C53, and one end of inductor L4, respectively. The other end of inductor L4 is connected to the other end of capacitor C21, the other end of capacitor C44, the other end of capacitor C45, the other end of capacitor C46, ​​the other end of capacitor C43, the other end of capacitor C48, and the VCC-3V3 power supply terminal.

[0015] Furthermore, the automotive OBD testing system also includes an ACC enable switch circuit, which is electrically connected to the MCU control circuit. The ACC enable switch circuit includes an AOD4185 type P-channel MOSFET Q2, a 2N7002 type N-channel MOSFET Q3, resistors R36, R37, and R42. The source of the P-channel MOSFET Q2 is connected to the POWER+ terminal and one end of resistor R36, the gate of the P-channel MOSFET Q2 is connected to the other end of resistor R36 and one end of resistor R37, the drain of the P-channel MOSFET Q2 is connected to the OBD1 terminal, the drain of the N-channel MOSFET Q3 is connected to the other end of resistor R37, the source of the N-channel MOSFET Q3 is connected to the ground terminal and one end of resistor R42, and the gate of the N-channel MOSFET Q3 is connected to the ACC_EN terminal and the other end of resistor R42.

[0016] Furthermore, the automotive OBD testing system also includes a signal matching resistor switch circuit, which is electrically connected to the MCU control circuit. The signal matching resistor switch circuit includes a KAQW212S type optocoupler U6, resistors R33, R28, R60, and R61, a 2N7002 type N-channel MOSFET Q6, a 2N7002 type N-channel MOSFET Q7, resistors R40 and R39. Specifically, pin 1 of optocoupler U6 is connected to both the VCC terminal and pin 3 of optocoupler U6; pin 2 of optocoupler U6 is connected to one end of resistor R33; pin 4 of optocoupler U6 is connected to one end of resistor R28; and pin 5 of optocoupler U6... Pin 6 of the optocoupler U6 is connected to LINE14 via resistor R61. Pin 7 of the optocoupler U6 is connected to LINE11 via resistor R60. Pin 8 of the optocoupler U6 is connected to LINE3. The drain of the N-channel MOSFET Q6 is connected to the other end of resistor R33. The gate of the N-channel MOSFET Q6 is connected to one end of resistor R40 and SW1. The source of the N-channel MOSFET Q6 is connected to the other end of resistor R40 and ground. The drain of the N-channel MOSFET Q7 is connected to the other end of resistor R28. The gate of the N-channel MOSFET Q7 is connected to one end of resistor R39 and SW2. The source of the N-channel MOSFET Q6 is connected to the other end of resistor R39 and ground.

[0017] Furthermore, the automotive OBD testing system also includes a pin expansion port, which is electrically connected to the MCU control circuit.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: An automotive OBD testing system includes an MCU control circuit, an OBD diagnostic interface, a pin selection circuit, a pin display circuit, and a pin voltage display circuit. The OBD diagnostic interface, pin selection circuit, pin display circuit, and pin voltage display circuit are all electrically connected to the MCU control circuit. The automotive OBD testing system also includes an output current sampling circuit, an output current and battery level display circuit, a battery management circuit, and a power management circuit. The output current sampling circuit, output current and battery level display circuit, battery management circuit, and power management circuit are all electrically connected to the MCU control circuit. The MCU control circuit includes an STC15W408AS-TSSOP20 type MCU control chip. Therefore, this automotive OBD testing system uses the STC15W408AS-TSSOP20 type MCU control chip to coordinate the work of each circuit module, thereby realizing functions such as pin selection, pin display, voltage display, current sampling display, and power management, and ensuring the stable operation of the OBD testing system. Specifically, when this automotive OBD testing system is applied to an automotive OBD tester, the output current sampling circuit enables real-time sampling and monitoring of pin current. Combined with the output current and battery power display circuit, it can also intuitively display the current value and remaining battery power, greatly improving the diagnostic accuracy and information richness of the OBD tester. Furthermore, through built-in battery management and power management circuits, efficient management and stable power supply to the built-in power supply are achieved, ensuring that the OBD tester can operate normally in environments without external power, thus significantly improving the ease of use and versatility of the OBD tester. This automotive OBD testing system overcomes the shortcomings of traditional automotive OBD testers in current detection and power supply, significantly improving functional integration and meeting the increasingly complex diagnostic needs of modern automotive electronic systems. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0020] Figure 1 A block diagram of the circuit structure of the automotive OBD testing system provided in this embodiment of the utility model;

[0021] Figure 2 The circuit structure schematic diagram of the output current sampling circuit provided in the embodiment of this utility model;

[0022] Figure 3A circuit diagram illustrating the output current and battery power display circuit provided in this embodiment of the utility model;

[0023] Figure 4 A schematic diagram of the battery charging and discharging circuit provided in this embodiment of the utility model;

[0024] Figure 5 A schematic diagram of the circuit structure of the battery protection circuit provided in this embodiment of the utility model;

[0025] Figure 6 The circuit structure schematic diagram of the main power supply circuit provided in the embodiment of this utility model;

[0026] Figure 7 A schematic diagram of the circuit structure of the auxiliary power supply circuit provided in the embodiment of this utility model;

[0027] Figure 8 The circuit structure schematic diagram of the ACC enable switch circuit provided in the embodiment of this utility model;

[0028] Figure 9 The circuit structure schematic diagram of the signal matching resistor switch circuit provided in the embodiment of this utility model. Detailed Implementation

[0029] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0030] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0032] Please refer to Figure 1 As shown, this utility model proposes an automotive OBD testing system, including an MCU control circuit, an OBD diagnostic interface, a pin selection circuit, a pin display circuit, and a pin voltage display circuit. The OBD diagnostic interface, the pin selection circuit, the pin display circuit, and the pin voltage display circuit are all electrically connected to the MCU control circuit. The automotive OBD testing system also includes an output current sampling circuit, an output current and battery power display circuit, a battery management circuit, and a power management circuit. The output current sampling circuit, the output current and battery power display circuit, the battery management circuit, and the power management circuit are all electrically connected to the MCU control circuit. The MCU control circuit includes an STC15W408AS-TSSOP20 type MCU control chip.

[0033] Specifically, the STC15W408AS-TSSOP20 MCU control chip has high-speed processing capabilities and rich peripheral interfaces, low power consumption and high stability, which can meet the needs of automotive OBD testing systems for real-time data acquisition and control.

[0034] Compared with existing technologies, the automotive OBD testing system proposed in this embodiment uses an STC15W408AS-TSSOP20 MCU control chip to coordinate the operation of various circuit modules, enabling functions such as pin selection, pin display, voltage display, current sampling display, and power management, while ensuring the stable operation of the OBD testing system. Specifically, after applying this automotive OBD testing system to an automotive OBD tester, the output current sampling circuit enables real-time sampling and monitoring of pin current. Combined with the output current and battery power display circuit, the current value and remaining battery power can be displayed intuitively, greatly improving the diagnostic accuracy and information richness of the OBD tester. Furthermore, the built-in battery management and power management circuits achieve efficient management and stable power supply to the built-in power supply, ensuring that the OBD tester can operate normally even without an external power source, thus significantly improving the ease of use and versatility of the OBD tester. This automotive OBD testing system overcomes the shortcomings of traditional automotive OBD testers in current detection and power supply, significantly improving functional integration and meeting the increasingly complex diagnostic needs of modern automotive electronic systems.

[0035] Please refer to Figure 2As shown, in some embodiments of this application, the output current sampling circuit includes an INA226AIDGSR type current monitoring chip U10, a capacitor C28, an inductor L2, a polarized capacitor C26, a resistor R77, a capacitor C27, a capacitor C56, resistors R73, R72, R74, R75, and R76; wherein, the first pin of the current monitoring chip U10 is grounded through resistor R73, the second pin of the current monitoring chip U10 is grounded through resistor R72, the third pin of the current monitoring chip U10 is connected to one end of resistor R74 and the INA226_ALERT terminal, the fourth pin of the current monitoring chip U10 is connected to one end of resistor R75 and the INA226_SDA terminal, the fifth pin of the current monitoring chip U10 is connected to one end of resistor R76 and the INA226_SCL terminal, and the other pin of resistor R74... One end of the resistor R75 and the other end of the resistor R76 are all connected to the VCC-3V3 power supply terminal. The 6th pin of the current monitoring chip U10 is connected to the VCC-3V3 power supply terminal and one end of the capacitor C56. The 7th pin of the current monitoring chip U10 is connected to the ground terminal and the other end of the capacitor C56. The 8th pin of the current monitoring chip U10 is connected to the Auxiliary_POWER terminal, the 10th pin of the current monitoring chip U10, one end of the resistor R77, one end of the inductor L2, and the positive terminal of the polarized capacitor C26. The 9th pin of the current monitoring chip U10 is connected to the other end of the resistor R77, the VBUSOUT terminal, and one end of the capacitor C27. The other end of the capacitor C27 is connected to the ground terminal, the negative terminal of the polarized capacitor C26, and one end of the capacitor C28. The other end of the capacitor C28 is connected to the VBUS terminal and the other end of the inductor L2.

[0036] Specifically, the INA226AIDGSR current monitoring chip features high-precision current and voltage measurement capabilities, supports a digital I2C interface for easy communication with MCU control circuits. Its built-in programmable gain amplifier and 16-bit ADC enable real-time monitoring over a wide dynamic range, and its low power consumption and small size make it suitable for precision power management and current sampling applications.

[0037] Please refer to Figure 3As shown, in some embodiments of this application, the output current and battery power display circuit includes a TM1652 type driver control chip U8, a 3361AS type digital tube, and an LED power display; wherein, pin 1 of the driver control chip U8 is connected to the VCC-5V power supply terminal, pin 10 of the driver control chip U8 is grounded, pin 16 of the driver control chip U8 is connected to the TM1652_SDA terminal, pin 15 of the driver control chip U8 is connected to pin 12 of the digital tube, pin 14 of the driver control chip U8 is connected to pin 9 of the digital tube, pin 13 of the driver control chip U8 is connected to pin 8 of the digital tube, pin 12 of the driver control chip U8 is connected to pin 9 of the LED power display, pin 11 of the driver control chip U8 is left floating, and pin 2 of the driver control chip U8 is connected to pin 11 of the digital tube. The first pin of the driver control chip U8 is connected to the 7th pin of the digital tube and the 2nd pin of the LED power display. The 4th pin of the driver control chip U8 is connected to the 4th pin of the digital tube and the 3rd pin of the LED power display. The 5th pin of the driver control chip U8 is connected to the 2nd pin of the digital tube and the 4th pin of the LED power display. The 6th pin of the driver control chip U8 is connected to the 1st pin of the digital tube and the 5th pin of the LED power display. The 7th pin of the driver control chip U8 is connected to the 10th pin of the digital tube and the 6th pin of the LED power display. The 8th pin of the driver control chip U8 is connected to the 5th pin of the digital tube and the 7th pin of the LED power display. The 9th pin of the driver control chip U8 is connected to the 3rd pin of the digital tube and the 8th pin of the LED power display.

[0038] Specifically, the TM1652 driver control chip features high integration, supporting multi-digit LED displays and LEDs, simplifying circuit structure and reducing the number of external components. The 3361AS model's LED display and power indicator both boast high brightness and excellent viewing angles, clearly and intuitively displaying current values ​​and remaining battery power for convenient real-time monitoring by the user.

[0039] Please refer to Figure 4As shown, in some embodiments of this application, the battery management circuit includes a battery charging / discharging circuit and a battery protection circuit electrically connected to each other. The battery charging / discharging circuit includes an SC8815QDER type bidirectional buck-boost charging management chip U3, a DC socket, a resistor R3, an AOD4185 type P-channel MOSFET Q1, an AOD4185 type P-channel MOSFET Q9, a resistor R67, a bidirectional diode D4, a resistor R8, a resistor R4, a resistor R10, a polarized capacitor C25, a polarized capacitor C6, a capacitor C8, a resistor R1, a capacitor C7, a resistor R7, a VS4620 type N-channel MOSFET Q2, and a VS4620 type N-channel MOSFET Q1. The following components are included: a 0-type N-channel MOSFET Q3, a VS4620-type N-channel MOSFET Q4, a VS4620-type N-channel MOSFET Q5, a resistor R5, a capacitor C9, a resistor R2, a capacitor C5, a polarized capacitor C4, an inductor L1, a resistor R12, a resistor R11, a capacitor C12, a capacitor C13, a capacitor C11, a capacitor C10, a resistor R13, a resistor R14, a capacitor C17, a resistor R78, a 2N7002-type N-channel MOSFET Q19, a resistor R20, a resistor R21, a resistor R22, a capacitor C24, a resistor R19, a capacitor C22, a resistor R17, a resistor R18, a capacitor C18, and a capacitor C19.

[0040] Specifically, pin 1 of the bidirectional buck-boost charging management chip U3 is connected to one end of capacitor C10 and one end of resistor R13; pin 32 of the bidirectional buck-boost charging management chip U3 is connected to the other end of capacitor C10 and one end of resistor R14; pin 29 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R7; pin 30 of the bidirectional buck-boost charging management chip U3 is connected to one end of capacitor C11; pin 28 of the bidirectional buck-boost charging management chip U3 is connected to the other end of capacitor C11, one end of inductor L1, the source of N-channel MOSFET Q2, and the drain of N-channel MOSFET Q5; pin 27 of the bidirectional buck-boost charging management chip U3 is connected to... One end of resistor R11 is connected to one end of capacitor C12, one end of capacitor C13, and the PGND terminal. Pin 25 of the bidirectional buck-boost charging management chip U3 is connected to pin 24 of the bidirectional buck-boost charging management chip U3, the other end of capacitor C12, the other end of capacitor C13, and the VCC-5V power supply terminal. Pin 23 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R12. Pin 22 of the bidirectional buck-boost charging management chip U3 is connected to the drain of N-channel MOSFET Q4, the source of N-channel MOSFET Q3, the other end of inductor L1, and one end of capacitor C18. The bidirectional buck-boost charging management chip... Pin 20 of U3 is connected to the other end of capacitor C18. Pin 21 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R5. Pin 18 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R17 and one end of capacitor C19. Pin 17 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R18 and the other end of capacitor C19. Pin 19 of the bidirectional buck-boost charging management chip U3 is connected to one end of capacitor C22 and the VBAT power supply terminal. The other end of capacitor C22 is connected to the PGND terminal. Pin 16 of the bidirectional buck-boost charging management chip U3 is connected to the VBAT power supply terminal. Pin 5 is grounded sequentially through resistor R19 and capacitor C24. Pin 12 of the bidirectional buck-boost charging management chip U3 is grounded. Pins 3, 4, 5, and 14 of the bidirectional buck-boost charging management chip U3 are all floating. Pin 13 of the bidirectional buck-boost charging management chip U3 is connected to the ADIN terminal. Pin 7 of the bidirectional buck-boost charging management chip U3 is connected to the CE terminal. Pin 8 of the bidirectional buck-boost charging management chip U3 is connected to the PSTOP terminal. Pin 11 of the bidirectional buck-boost charging management chip U3 is connected to the INT terminal and one end of resistor R22. Pin 10 of the bidirectional buck-boost charging management chip U3 is connected to the SDA terminal and one end of resistor R21.Pin 9 of the bidirectional buck-boost charging management chip U3 is connected to the SCL terminal and one end of resistor R20. The other ends of resistors R22, R21, and R20 are all connected to the VCC-3V3 power supply terminal. Pin 33 of the bidirectional buck-boost charging management chip U3 is connected to the PGND terminal. Pin 6 of the bidirectional buck-boost charging management chip U3 is connected to the VCC-IN terminal, one end of resistor R3, the source of P-channel MOSFET Q1, and the positive terminal of the DC socket. Pin 2 of the bidirectional buck-boost charging management chip U3 is connected to one end of resistor R8 and the drain of N-channel MOSFET Q19. The gates of the transistors are connected to the MCUGPO_EN terminal and one end of resistor R78, respectively. The other end of resistor R78 is connected to ground and the source of N-channel MOSFET Q19, respectively. Pin 31 of the bidirectional buck-boost charging management chip U3 is connected to one end of capacitor C17, the positive terminal of polarized capacitor C25, one end of resistor R4, one end of resistor R67, the source of P-channel MOSFET Q9, the positive terminal of polarized capacitor C6, one end of capacitor C8, one end of resistor R1, and one end of resistor R13, respectively. The other end of capacitor C17 is connected to the PGND terminal. The negative terminal of the DC socket is connected to the PGND terminal. The drain of P-channel MOSFET Q9 is connected to the drain of P-channel MOSFET Q1.

[0041] The other end of resistor R3 is connected to the gate of P-channel MOSFET Q1 and pin 1 of bidirectional diode D4. Pin 3 of bidirectional diode D4 is connected to the other end of resistor R8. Pin 2 of bidirectional diode D4 is connected to the other end of resistor R67 and the gate of P-channel MOSFET Q9. The other end of resistor R4 is connected to the ADIN terminal and one end of resistor R10. The other end of resistor R10, the negative terminals of polarized capacitors C25 and C6, and the other end of capacitor C8 are all grounded. The other end of capacitor C8 is connected to the other end of resistor R13. The other end of resistor R1 is connected to the other end of resistor R14. One end of capacitor C7 is connected to the drain of N-channel MOSFET Q2. The other end of resistor R7 is connected to the gate of N-channel MOSFET Q2. The other end of capacitor C7... The gate of N-channel MOSFET Q5 is connected to the other end of resistor R11. The sources of N-channel MOSFET Q5 and N-channel MOSFET Q4 are both connected to the PGND terminal. The source of N-channel MOSFET Q2 is connected to the other end of inductor L1 and the drain of N-channel MOSFET Q5. The gate of N-channel MOSFET Q3 is connected to the other end of resistor R5. The drain of N-channel MOSFET Q3 is connected to one end of capacitor C9, one end of resistor R2, and the other end of resistor R17. The other end of capacitor C9 is grounded. The other end of resistor R2 is connected to the other end of resistor R18, one end of capacitor C5, the positive terminal of polarized capacitor C4, and the VBAT power supply terminal. The other end of capacitor C5 and the negative terminal of polarized capacitor C4 are both connected to the PGND terminal.

[0042] Specifically, the battery management circuit electrically connects the battery charging / discharging circuit and the battery protection circuit to achieve comprehensive monitoring and intelligent management of the battery. This not only effectively prevents abnormal conditions such as overcharging, over-discharging, and short circuits, ensuring battery safety, but also optimizes the charging / discharging process, improves battery life and system stability, and ensures reliable operation of the automotive OBD testing system under various operating conditions. The SC8815QDER bidirectional buck-boost charging management chip features a wide input voltage range and high-efficiency energy conversion capabilities, supporting both boost and buck operating modes to flexibly adapt to different power supply environments.

[0043] Please refer to Figure 5 As shown, in some embodiments of this application, the battery management circuit includes a battery charging / discharging circuit and a battery protection circuit electrically connected to each other. The battery protection circuit includes a CW1244ALBS type battery protection chip U9, resistor R36, capacitor C37, resistor R37, resistor R38, capacitor C38, resistor R41, PBSS5140T type PNP transistor Q10, resistor R43, resistor R47, capacitor C40, resistor R49, PBSS5140T type PNP transistor Q11, resistor R55, resistor R56, and capacitor... C42, resistor R57, PBSS5140T type PNP transistor Q13, resistor R62, resistor R63, resistor R53, capacitor C41, capacitor C39, resistor R42, resistor R44, resistor R46, resistor RT2, resistor RT, resistor R48, resistor R9, resistor R50, resistor R71, BC857 type PNP transistor Q12, resistor R51, resistor R52, resistor R54, NCEP30T12G type N-channel MOSFET Q14 and NCEP30T12G type N-channel MOSFET Q15;

[0044] Specifically, pin 1 of the battery protection chip U9 is connected to one end of capacitor C37 and one end of resistor R36; pin 2 of the battery protection chip U9 is connected to pin 3 of the battery protection chip U9, one end of capacitor C38, one end of resistor R37, and one end of resistor R38; pin 4 of the battery protection chip U9 is connected to one end of capacitor C40, one end of resistor R43, and one end of resistor R47; and pin 5 of the battery protection chip U9 is connected to one end of capacitor C42, one end of resistor R55, and one end of resistor R6. One end of resistor R56 is connected to pin 7 of battery protection chip U9, one end of resistor R62, one end of resistor R63, one end of resistor R57, and ground. Pin 8 of battery protection chip U9 is connected to one end of capacitor C41 and one end of resistor R53. The other ends of capacitors C37, C38, C40, C42, and C41 are all grounded. The emitter of PNP transistor Q10 is also connected to... The P+ discharge port, the other end of resistor R36, the other end of resistor R37, and the 12.6V power input terminal are connected respectively. The base of the PNP transistor Q10 is connected to the other end of resistor R38, and the collector of the PNP transistor Q10 is connected to one end of resistor R41. The other end of resistor R41 is connected to the 8.4V power input terminal, the other end of resistor R43, and the emitter of the PNP transistor Q11. The base of the PNP transistor Q11 is connected to the other end of resistor R47. The collector of transistor Q11 is connected to one end of resistor R49. The other end of resistor R49 is connected to the 4.2V power input terminal, the other end of resistor R55, and the emitter of PNP transistor Q13. The base of PNP transistor Q13 is connected to the other end of resistor R56. The collector of PNP transistor Q13 is connected to the other end of resistor R57. The other end of resistor R53 is connected to the other end of resistor R62, the other end of resistor R63, one end of resistor R71, and the source of N-channel MOSFET Q14.

[0045] Pin 9 of the battery protection chip U9 is connected to one end of resistor R9 and one end of resistor R50. Pin 10 of the battery protection chip U9 is connected to one end of resistor R48. Pin 11 of the battery protection chip U9 is connected to one end of resistor R54. Pin 12 of the battery protection chip U9 is grounded. Pin 13 of the battery protection chip U9 is connected to one end of resistor R46. Pin 14 of the battery protection chip U9 is connected to one end of resistor R44. Pin 15 of the battery protection chip U9 is connected to one end of resistor R42. Pin 16 of the battery protection chip U9 is connected to one end of capacitor C39. The other end of capacitor C39 is connected to one end of resistor RT2, one end of resistor RT, and ground. The other end of resistor RT2... Connect the other ends of resistors R42, R44, R46, and RT respectively. Connect the other end of resistor R54 to the P-discharge port, PGND terminal, one end of resistor R52, and the source of N-channel MOSFET Q15. Connect the drain of N-channel MOSFET Q15 to the drain of N-channel MOSFET Q14. Connect the other end of resistor R52 to the gate of N-channel MOSFET Q15 and the collector of PNP transistor Q12. Connect the emitter of PNP transistor Q12 to the other ends of resistors R48 and R9 respectively. Connect the base of PNP transistor Q12 to ground through resistor R51. Connect the other end of resistor R50 to the other end of resistor R71 and the gate of N-channel MOSFET Q14 respectively.

[0046] Specifically, the CW1244ALBS battery protection chip features precise overcharge, over-discharge, and overcurrent protection functions, effectively ensuring battery safety. It boasts fast response, high stability, and real-time battery status monitoring to prevent abnormal damage. This battery protection chip is highly integrated, compact, and easy to integrate into systems, making it suitable for various lithium battery protection scenarios.

[0047] Please refer to Figure 6 As shown, in some embodiments of this application, the power management circuit includes a main power supply circuit and an auxiliary power supply circuit that are electrically connected to each other. The main power supply circuit includes a step-down DC-DC converter chip U6 of type XL1509-ADJ, a three-terminal integrated voltage regulator chip U7 of type 78L05, a low dropout linear regulator chip U9 of type ME6209A33M3G, a polarized capacitor C13, a capacitor C15, a diode D18, a resistor R35, a resistor R32, a polarized capacitor C23, an inductor L1, a capacitor C22, a capacitor C17, a polarized capacitor C24, a capacitor C18, a capacitor C19, a capacitor C20, a capacitor C21, a capacitor C27, a capacitor C26, and a capacitor C25.

[0048] Specifically, pin 1 of the buck DC-DC converter chip U6 is connected to the Auxiliary_POWER terminal, the positive terminal of polarized capacitor C13, and one end of capacitor C15. Pin 2 of the buck DC-DC converter chip U6 is connected to one end of inductor L1 and the negative terminal of diode D18. Pin 3 of the buck DC-DC converter chip U6 is connected to one end of resistor R35 and one end of resistor R32. The negative terminal of polarized capacitor C13 is connected to the other end of capacitor C15, pin 4 of the buck DC-DC converter chip U6, pin 5 of the buck DC-DC converter chip U6, pin 6 of the buck DC-DC converter chip U6, pin 7 of the buck DC-DC converter chip U6, pin 8 of the buck DC-DC converter chip U6, the ground terminal, the positive terminal of diode D18, the other end of resistor R35, the negative terminal of polarized capacitor C23, one end of capacitor C22, pin 2 of the three-terminal integrated voltage regulator chip U7, and capacitor C One end of capacitor C17, the negative terminal of polarized capacitor C24, one end of capacitor C18, one end of capacitor C19, one end of capacitor C20, one end of capacitor C21, one end of capacitor C27, pin 1 of low dropout linear regulator chip U9, one end of capacitor C26, and one end of capacitor C25. Pin 3 of the three-terminal integrated regulator chip U7 is connected to the VCC-7.5V power supply terminal, the other end of inductor L1, the other end of resistor R32, the positive terminal of polarized capacitor C23, and the other end of capacitor C22. The first pin of the three-terminal integrated voltage regulator chip U7 is connected to the other end of capacitor C17, the positive terminal of polarized capacitor C24, the other end of capacitor C18, the other end of capacitor C19, the other end of capacitor C20, the other end of capacitor C21, the other end of capacitor C27, the VCC-5V power supply terminal, and the third pin of the low dropout linear regulator chip U9. The second pin of the low dropout linear regulator chip U9 is connected to the other end of capacitor C26, the other end of capacitor C25, and the VCC-3V3 power supply terminal.

[0049] Specifically, the main power supply circuit provides the primary power to the automotive OBD testing system, ensuring its efficient and stable operation under normal working conditions. The auxiliary power supply circuit serves as a backup, providing stable voltage during main power circuit malfunctions or startup, preventing the OBD testing system from restarting or failing due to power fluctuations. This dual-power supply circuit helps optimize power consumption management, improves the reliability and anti-interference capabilities of the automotive OBD testing system, and ensures its continuous and stable operation under various conditions. The main power supply circuit uses an XL1509-ADJ step-down DC-DC converter chip for efficient voltage reduction, combined with a 78L05 three-terminal integrated voltage regulator chip and a ME6209A33M3G low-dropout linear regulator chip, providing stable 5V and 3.3V voltage outputs respectively. This multi-stage voltage regulation circuit can meet the power supply requirements of different circuit modules in the automotive OBD testing system, ensuring stable and reliable operation over a wide input voltage range.

[0050] Please refer to Figure 7 As shown, in some embodiments of this application, the power management circuit includes a main power supply circuit and an auxiliary power supply circuit electrically connected to each other. The auxiliary power supply circuit includes a 78MXX type linear regulator chip U4, a ME6209A33M3G type low dropout linear regulator chip U2, an SPX3819M5-L-5-0 type low dropout linear regulator chip U8, polarized capacitors C57, C60, C58, C59, and C64, diodes D6 and D5, capacitor C52, and a dual-phase capacitor. The components are: Zener diode D1, switch K1, resistor R34, AO3401A type P-channel MOSFET Q8, 2N7002 type N-channel MOSFET Q16, resistors R35, R58, R59, bidirectional Zener diode D3, capacitor C55, diode D2, polarized capacitors C54, C35, C36, C23, C53, C20, inductor L4, capacitors C21, C44, C45, C46, ​​C43, and C48;

[0051] In this circuit, pin 1 of the linear regulator chip U4 is connected to the VCC-IN power supply terminal, the positive terminal of polarized capacitor C54, and one end of capacitor C60. Pin 2 of the linear regulator chip U4 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C60, the ground terminal, one end of capacitor C58, one end of capacitor C59, and one end of capacitor C64. Pin 3 of the linear regulator chip U4 is connected to the other end of capacitor C58, the other end of capacitor C59, the other end of capacitor C64, and the positive terminal of diode D6. The negative terminal of diode D6 is connected to the positive terminal of diode D5.

[0052] Pin 1 of the low-dropout linear regulator chip U8 is connected to one end of capacitor C55 and the VBAT terminal, respectively. The other end of capacitor C55 is grounded. Pin 2 of the low-dropout linear regulator chip U8 is grounded. Pin 3 of the low-dropout linear regulator chip U8 is connected to pin 3 of the bidirectional Zener diode D3. Pin 4 of the low-dropout linear regulator chip U8 is left floating. Pin 5 of the low-dropout linear regulator chip U8 is connected to the positive terminal of diode D2. Pins 2 of the bidirectional Zener diode D3 are connected to the VCC-IN power supply terminal through resistor R58 and to the ground terminal through resistor R59, respectively. Pin 1 of the bidirectional Zener diode D3 is connected to the P-channel MOSFET Q8. The drain and source of the P-channel MOSFET Q8 are connected to one end of resistor R34 and the VBAT power supply terminal, respectively. The gate of the P-channel MOSFET Q8 is connected to the other end of resistor R34, the drain of the N-channel MOSFET Q16, and pin 1 of the bidirectional Zener diode D1. Pin 3 of the bidirectional Zener diode D1 is connected to one end of switch K1. The other end of switch K1 is connected to one end of capacitor C52, the ground terminal, the source of the N-channel MOSFET Q16, and one end of resistor R35, respectively. Pin 2 of the bidirectional Zener diode D1 is connected to the POW_KEY terminal and the other end of capacitor C52, respectively. The other end of resistor R35 is connected to the gate of the N-channel MOSFET Q16 and the POW_EN terminal, respectively.

[0053] Pin 3 of the low-dropout linear regulator chip U2 is connected to the negative terminal of diode D5, the VCC power supply terminal, the negative terminal of diode D2, the positive terminal of polarized capacitor C54, one end of capacitor C35, one end of capacitor C36, and one end of capacitor C23. Pin 1 of the low-dropout linear regulator chip U2 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C35, the other end of capacitor C36, the other end of capacitor C23, the ground terminal, the negative terminal of polarized capacitor C53, one end of capacitor C20, and one end of capacitor C21. One end of capacitor C44, one end of capacitor C45, one end of capacitor C46, ​​one end of capacitor C43, and one end of capacitor C48 are connected to the positive terminal of the low dropout linear regulator chip U2, the other end of capacitor C53, and one end of inductor L4, respectively. The other end of inductor L4 is connected to the other end of capacitor C21, the other end of capacitor C44, the other end of capacitor C45, the other end of capacitor C46, ​​the other end of capacitor C43, the other end of capacitor C48, and the VCC-3V3 power supply terminal.

[0054] Specifically, the auxiliary power supply circuit consists of a 78MXX type linear regulator chip, a ME6209A33M3G type low-dropout linear regulator chip, and an SPX3819M5-L-5-0 type low-dropout linear regulator chip, providing stable 5V and 3.3V voltage outputs respectively. This auxiliary power supply circuit ensures stable output voltage through multi-channel low-noise, low-dropout regulation, meeting the different voltage level requirements of the automotive OBD testing system and improving the overall reliability and anti-interference capability of power management.

[0055] Please refer to Figure 8 As shown in some embodiments of this application, the automotive OBD testing system further includes an ACC enable switch circuit, which is electrically connected to the MCU control circuit. The ACC enable switch circuit includes an AOD4185 type P-channel MOSFET Q2, a 2N7002 type N-channel MOSFET Q3, resistors R36, R37, and R42. The source of the P-channel MOSFET Q2 is connected to the POWER+ terminal and one end of resistor R36, the gate of the P-channel MOSFET Q2 is connected to the other end of resistor R36 and one end of resistor R37, the drain of the P-channel MOSFET Q2 is connected to the OBD1 terminal, the drain of the N-channel MOSFET Q3 is connected to the other end of resistor R37, the source of the N-channel MOSFET Q3 is connected to the ground terminal and one end of resistor R42, and the gate of the N-channel MOSFET Q3 is connected to the ACC_EN terminal and the other end of resistor R42.

[0056] Specifically, the ACC enable switch circuit is mainly used to detect the vehicle's ignition status. In conjunction with communication protocols such as CAN and LIN, it can also realize intelligent linkage and data exchange between the automotive OBD test system and the vehicle and external modules, thereby improving its control and communication capabilities.

[0057] Please refer to Figure 9As shown, in some embodiments of this application, the automotive OBD testing system further includes a signal matching resistor switch circuit, which is electrically connected to the MCU control circuit. The signal matching resistor switch circuit includes a KAQW212S type optocoupler U6, resistors R33, R28, R60, R61, a 2N7002 type N-channel MOSFET Q6, a 2N7002 type N-channel MOSFET Q7, resistors R40 and R39. The first pin of the optocoupler U6 is connected to both the VCC terminal and the third pin of the optocoupler U6. The second pin of the optocoupler U6 is connected to one end of resistor R33, and the fourth pin of the optocoupler U6 is connected to one end of resistor R28. Pin 5 of optocoupler U6 is connected to LINE14 via resistor R61. Pin 6 of optocoupler U6 is connected to LINE6. Pin 7 of optocoupler U6 is connected to LINE11 via resistor R60. Pin 8 of optocoupler U6 is connected to LINE3. The drain of N-channel MOSFET Q6 is connected to the other end of resistor R33. The gate of N-channel MOSFET Q6 is connected to one end of resistor R40 and SW1. The source of N-channel MOSFET Q6 is connected to the other end of resistor R40 and ground. The drain of N-channel MOSFET Q7 is connected to the other end of resistor R28. The gate of N-channel MOSFET Q7 is connected to one end of resistor R39 and SW2. The source of N-channel MOSFET Q6 is connected to the other end of resistor R39 and ground.

[0058] Specifically, the signal matching resistor switch circuit provides a constant current by connecting a resistor of appropriate value in parallel with the signal line, ensuring the normal startup and reliable connection of external modules and guaranteeing the stable operation of the automotive OBD test system.

[0059] In some embodiments of this application, the automotive OBD testing system further includes a pin expansion port, which is electrically connected to the MCU control circuit.

[0060] Specifically, the pin expansion port is equivalent to adding an extra OBD diagnostic interface to the automotive OBD testing system, which facilitates the simultaneous connection of multiple vehicles or different types of OBD devices, improves testing efficiency and flexibility, meets the diagnostic needs of multiple scenarios and vehicle models, and enhances the applicability and ease of operation of the automotive OBD testing system.

[0061] It should be noted that other pin connection structures and related component parameters not mentioned in the text description can be found in the attached diagram, and will not be elaborated upon here. Furthermore, the above connection layout is only an example; in actual applications, other connection schemes can be adopted according to specific requirements, and will not be further illustrated here.

[0062] The automotive OBD testing system proposed in this embodiment has functions such as OBD signal acquisition, pin selection and display, voltage and current monitoring, battery management and power control. It can detect and manage vehicle OBD signals, ensure reliable OBD testing and stable power supply, and has strong feasibility.

[0063] It should be noted that the technical solutions of the various embodiments of this utility model can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0064] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. An automotive OBD testing system, comprising an MCU control circuit, an OBD diagnostic interface, a pin selection circuit, a pin display circuit, and a pin voltage display circuit, wherein the OBD diagnostic interface, the pin selection circuit, the pin display circuit, and the pin voltage display circuit are all electrically connected to the MCU control circuit, characterized in that, The automotive OBD testing system also includes an output current sampling circuit, an output current and battery power display circuit, a battery management circuit, and a power management circuit. The output current sampling circuit, the output current and battery power display circuit, the battery management circuit, and the power management circuit are all electrically connected to the MCU control circuit, which includes an STC15W408AS-TSSOP20 MCU control chip.

2. The automotive OBD testing system according to claim 1, characterized in that, The output current sampling circuit includes an INA226AIDGSR type current monitoring chip.

3. The automotive OBD testing system according to claim 1, characterized in that, The output current and battery power display circuit includes a TM1652 type driver control chip U8, a 3361AS type digital tube, and an LED power display. Specifically, pin 1 of the driver control chip U8 is connected to the VCC-5V power supply terminal; pin 10 of the driver control chip U8 is grounded; pin 16 of the driver control chip U8 is connected to the TM1652_SDA terminal; pin 15 of the driver control chip U8 is connected to pin 12 of the digital tube; pin 14 of the driver control chip U8 is connected to pin 9 of the digital tube; pin 13 of the driver control chip U8 is connected to pin 8 of the digital tube; pin 12 of the driver control chip U8 is connected to pin 9 of the LED power display; pin 11 of the driver control chip U8 is left floating; and pin 2 of the driver control chip U8 is connected to both pin 11 of the digital tube and the LED power display. Pin 1 of the display is connected to pin 7 of the digital tube and pin 2 of the LED power display. Pin 4 of the driver control chip U8 is connected to pin 4 of the digital tube and pin 3 of the LED power display. Pin 5 of the driver control chip U8 is connected to pin 2 of the digital tube and pin 4 of the LED power display. Pin 6 of the driver control chip U8 is connected to pin 1 of the digital tube and pin 5 of the LED power display. Pin 7 of the driver control chip U8 is connected to pin 10 of the digital tube and pin 6 of the LED power display. Pin 8 of the driver control chip U8 is connected to pin 5 of the digital tube and pin 7 of the LED power display. Pin 9 of the driver control chip U8 is connected to pin 3 of the digital tube and pin 8 of the LED power display.

4. The automotive OBD testing system according to claim 1, characterized in that, The battery management circuit includes a battery charging / discharging circuit and a battery protection circuit that are electrically connected to each other. The battery charging / discharging circuit includes an SC8815QDER type bidirectional buck-boost charging management chip.

5. The automotive OBD testing system according to claim 1, characterized in that, The battery management circuit includes a battery charging / discharging circuit and a battery protection circuit that are electrically connected to each other. The battery protection circuit includes a CW1244ALBS type battery protection chip.

6. The automotive OBD testing system according to claim 1, characterized in that, The power management circuit includes a main power supply circuit and an auxiliary power supply circuit that are electrically connected to each other. The main power supply circuit includes a step-down DC-DC converter chip U6 of type XL1509-ADJ, a three-terminal integrated voltage regulator chip U7 of type 78L05, a low dropout linear voltage regulator chip U9 of type ME6209A33M3G, a polarized capacitor C13, a capacitor C15, a diode D18, a resistor R35, a resistor R32, a polarized capacitor C23, an inductor L1, a capacitor C22, a capacitor C17, a polarized capacitor C24, a capacitor C18, a capacitor C19, a capacitor C20, a capacitor C21, a capacitor C27, a capacitor C26, and a capacitor C25. Specifically, pin 1 of the buck DC-DC converter chip U6 is connected to the Auxiliary_POWER terminal, the positive terminal of polarized capacitor C13, and one end of capacitor C15. Pin 2 of the buck DC-DC converter chip U6 is connected to one end of inductor L1 and the negative terminal of diode D18. Pin 3 of the buck DC-DC converter chip U6 is connected to one end of resistor R35 and one end of resistor R32. The negative terminal of polarized capacitor C13 is connected to the other end of capacitor C15, pin 4 of the buck DC-DC converter chip U6, pin 5 of the buck DC-DC converter chip U6, pin 6 of the buck DC-DC converter chip U6, pin 7 of the buck DC-DC converter chip U6, pin 8 of the buck DC-DC converter chip U6, the ground terminal, the positive terminal of diode D18, the other end of resistor R35, the negative terminal of polarized capacitor C23, one end of capacitor C22, pin 2 of the three-terminal integrated voltage regulator chip U7, and capacitor C One end of capacitor C17, the negative terminal of polarized capacitor C24, one end of capacitor C18, one end of capacitor C19, one end of capacitor C20, one end of capacitor C21, one end of capacitor C27, pin 1 of low dropout linear regulator chip U9, one end of capacitor C26, and one end of capacitor C25. Pin 3 of the three-terminal integrated regulator chip U7 is connected to the VCC-7.5V power supply terminal, the other end of inductor L1, the other end of resistor R32, the positive terminal of polarized capacitor C23, and the other end of capacitor C22. The first pin of the three-terminal integrated voltage regulator chip U7 is connected to the other end of capacitor C17, the positive terminal of polarized capacitor C24, the other end of capacitor C18, the other end of capacitor C19, the other end of capacitor C20, the other end of capacitor C21, the other end of capacitor C27, the VCC-5V power supply terminal, and the third pin of the low dropout linear regulator chip U9. The second pin of the low dropout linear regulator chip U9 is connected to the other end of capacitor C26, the other end of capacitor C25, and the VCC-3V3 power supply terminal.

7. The automotive OBD testing system according to claim 1, characterized in that, The power management circuit includes a main power supply circuit and an auxiliary power supply circuit that are electrically connected to each other. The auxiliary power supply circuit includes a 78MXX type linear regulator chip U4, a ME6209A33M3G type low dropout linear regulator chip U2, an SPX3819M5-L-5-0 type low dropout linear regulator chip U8, polarized capacitors C57, C60, C58, C59, and C64, diodes D6 and D5, capacitor C52, and a bidirectional Zener diode D.

1. Switch K1, resistor R34, AO3401A type P-channel MOSFET Q8, 2N7002 type N-channel MOSFET Q16, resistor R35, resistor R58, resistor R59, bidirectional Zener diode D3, capacitor C55, diode D2, polarized capacitor C54, capacitor C35, capacitor C36, capacitor C23, polarized capacitor C53, capacitor C20, inductor L4, capacitor C21, capacitor C44, capacitor C45, capacitor C46, ​​capacitor C43 and capacitor C48; In this circuit, pin 1 of the linear regulator chip U4 is connected to the VCC-IN power supply terminal, the positive terminal of polarized capacitor C54, and one end of capacitor C60. Pin 2 of the linear regulator chip U4 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C60, the ground terminal, one end of capacitor C58, one end of capacitor C59, and one end of capacitor C64. Pin 3 of the linear regulator chip U4 is connected to the other end of capacitor C58, the other end of capacitor C59, the other end of capacitor C64, and the positive terminal of diode D6. The negative terminal of diode D6 is connected to the positive terminal of diode D5. Pin 1 of the low-dropout linear regulator chip U8 is connected to one end of capacitor C55 and the VBAT terminal, respectively. The other end of capacitor C55 is grounded. Pin 2 of the low-dropout linear regulator chip U8 is grounded. Pin 3 of the low-dropout linear regulator chip U8 is connected to pin 3 of the bidirectional Zener diode D3. Pin 4 of the low-dropout linear regulator chip U8 is left floating. Pin 5 of the low-dropout linear regulator chip U8 is connected to the positive terminal of diode D2. Pins 2 of the bidirectional Zener diode D3 are connected to the VCC-IN power supply terminal through resistor R58 and to the ground terminal through resistor R59, respectively. Pin 1 of the bidirectional Zener diode D3 is connected to the P-channel MOSFET Q8. The drain and source of the P-channel MOSFET Q8 are connected to one end of resistor R34 and the VBAT power supply terminal, respectively. The gate of the P-channel MOSFET Q8 is connected to the other end of resistor R34, the drain of the N-channel MOSFET Q16, and pin 1 of the bidirectional Zener diode D1. Pin 3 of the bidirectional Zener diode D1 is connected to one end of switch K1. The other end of switch K1 is connected to one end of capacitor C52, the ground terminal, the source of the N-channel MOSFET Q16, and one end of resistor R35, respectively. Pin 2 of the bidirectional Zener diode D1 is connected to the POW_KEY terminal and the other end of capacitor C52, respectively. The other end of resistor R35 is connected to the gate of the N-channel MOSFET Q16 and the POW_EN terminal, respectively. Pin 3 of the low-dropout linear regulator chip U2 is connected to the negative terminal of diode D5, the VCC power supply terminal, the negative terminal of diode D2, the positive terminal of polarized capacitor C54, one end of capacitor C35, one end of capacitor C36, and one end of capacitor C23. Pin 1 of the low-dropout linear regulator chip U2 is connected to the negative terminal of polarized capacitor C54, the other end of capacitor C35, the other end of capacitor C36, the other end of capacitor C23, the ground terminal, the negative terminal of polarized capacitor C53, one end of capacitor C20, and one end of capacitor C21. One end of capacitor C44, one end of capacitor C45, one end of capacitor C46, ​​one end of capacitor C43, and one end of capacitor C48 are connected to the positive terminal of the low dropout linear regulator chip U2, the other end of capacitor C53, and one end of inductor L4, respectively. The other end of inductor L4 is connected to the other end of capacitor C21, the other end of capacitor C44, the other end of capacitor C45, the other end of capacitor C46, ​​the other end of capacitor C43, the other end of capacitor C48, and the VCC-3V3 power supply terminal.

8. The automotive OBD testing system according to claim 1, characterized in that, The automotive OBD testing system also includes an ACC enable switch circuit, which is electrically connected to the MCU control circuit. The ACC enable switch circuit includes an AOD4185 type P-channel MOSFET Q2, a 2N7002 type N-channel MOSFET Q3, resistors R36, R37, and R42. The source of the P-channel MOSFET Q2 is connected to the POWER+ terminal and one end of resistor R36, the gate of the P-channel MOSFET Q2 is connected to the other end of resistor R36 and one end of resistor R37, the drain of the P-channel MOSFET Q2 is connected to the OBD1 terminal, the drain of the N-channel MOSFET Q3 is connected to the other end of resistor R37, the source of the N-channel MOSFET Q3 is connected to the ground terminal and one end of resistor R42, and the gate of the N-channel MOSFET Q3 is connected to the ACC_EN terminal and the other end of resistor R42.

9. The automotive OBD testing system according to claim 1, characterized in that, The automotive OBD testing system also includes a signal matching resistor switch circuit, which is electrically connected to the MCU control circuit. The signal matching resistor switch circuit includes a KAQW212S type optocoupler U6, resistors R33, R28, R60, and R61, a 2N7002 type N-channel MOSFET Q6, a 2N7002 type N-channel MOSFET Q7, resistors R40, and resistor R39. Pin 1 of optocoupler U6 is connected to both the VCC terminal and pin 3 of optocoupler U6. Pin 2 of optocoupler U6 is connected to one end of resistor R33. Pin 4 of optocoupler U6 is connected to one end of resistor R28. Pin 5 of optocoupler U6... The optocoupler U6 is connected to LINE14 via resistor R61. Pin 6 of the optocoupler U6 is connected to LINE6. Pin 7 of the optocoupler U6 is connected to LINE11 via resistor R60. Pin 8 of the optocoupler U6 is connected to LINE3. The drain of the N-channel MOSFET Q6 is connected to the other end of resistor R33. The gate of the N-channel MOSFET Q6 is connected to one end of resistor R40 and SW1. The source of the N-channel MOSFET Q6 is connected to the other end of resistor R40 and ground. The drain of the N-channel MOSFET Q7 is connected to the other end of resistor R28. The gate of the N-channel MOSFET Q7 is connected to one end of resistor R39 and SW2. The source of the N-channel MOSFET Q6 is connected to the other end of resistor R39 and ground.

10. The automotive OBD testing system according to claim 1, characterized in that, The automotive OBD testing system also includes a pin expansion port, which is electrically connected to the MCU control circuit.

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