Automatic cut-off type power-off circuit of vehicle-mounted OBD terminal

Abstract

The utility model discloses an automatic cut-off type power-off circuit of a vehicle-mounted OBD terminal, which comprises a power supply circuit, an MCU power supply circuit, a module power supply circuit, an MCU circuit and a module circuit, and the power supply circuit, the MCU power supply circuit, the module power supply circuit, the MCU circuit and the module circuit are connected through the power-off circuit. According to the utility model, the external power supply provided by the power supply circuit is conducted through the power-off circuit, so that the MCU circuit and the module circuit can respectively obtain current required by starting, the MCU circuit and the module circuit are activated to work, and after the whole circuit enters normal work, the input current is switched to the battery for power supply, so that the continuous working power demand is met. When the equipment is in an abnormal state and high power consumption abnormity is caused, the MCU circuit and the module circuit can be quickly powered off in an automatic cut-off manner, so that the safety protection capability of the system is ensured not to be weakened, and potential electrical risks and data security vulnerabilities are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to an automatic cut-off power-off circuit of an on-vehicle OBD terminal. Background Art

[0002] With the rapid development of mobile Internet, OBD terminal devices are facing the challenge of high integration, especially in terms of rich functionality and compact device layout. With the rapid development of mobile Internet technology, OBD terminal devices are facing the challenge of unprecedented high integration, especially in terms of rich functionality and compact device layout. Users' growing demands not only require devices to be compact, easy to carry and install, but also expect them to have comprehensive peripheral function support.

[0003] In this context, the selection and application of microcontroller chips are crucial to meeting market expectations for both compactness and powerful functionality. Designers strive to achieve highly integrated chip solutions, using a small number of powerful core components to power the entire device. This not only tests the limits of technology but also places higher demands on cost control and energy efficiency. However, this process is not without its obstacles. The pursuit of miniaturization and multi-functional integration while ensuring the system's security capabilities and avoiding potential electrical risks and data security vulnerabilities remains a major challenge on the road to innovation.

[0004] Therefore, the existing technology has defects and needs to be improved. Utility Model Content

[0005] The purpose of the utility model is to overcome the deficiencies of the prior art and provide an automatic cut-off power-off circuit for an on-board OBD terminal.

[0006] The technical solution of the utility model is as follows: an automatic cut-off power-off circuit of a vehicle-mounted OBD terminal is provided, comprising: a power supply circuit, an MCU power supply circuit, a module power supply circuit, an MCU circuit and a module circuit, the power supply circuit is electrically connected to the MCU power supply circuit and the module power supply circuit, the MCU power supply circuit is electrically connected to the module power supply circuit, the MCU circuit and the module circuit, the module power supply circuit is electrically connected to the module circuit, the MCU circuit is electrically connected to the module circuit, and the power supply circuit, the MCU power supply circuit, the module power supply circuit, the MCU circuit and the module circuit are connected through the power-off circuit.

[0007] Furthermore, the power-off circuit includes: transistor Q1, transistor Q2, transistor Q3, transistor Q5, transistor Q6, transistor Q7, transistor Q8, MOS tube Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, and resistor R6. The emitter of the transistor Q1 is connected to the input segment of the MCU circuit, the collector of the transistor Q1 is connected to the MCU power supply circuit, the base of the transistor Q1 is connected to the base of the transistor Q3, the collector of the transistor Q2, and one end of the resistor R1, the base of the transistor Q2 is connected to the collector of the transistor Q8 and one end of the resistor R2, the collector of the transistor Q3 is connected to the input end of the module circuit, the emitter of the transistor Q3 is connected to the module power supply circuit, the base of the transistor Q8 is connected to the output end of the MCU circuit, and the MO The drain of the MOS transistor Q4 is connected to the other end of the resistor R1, the other end of the resistor R2, one end of the resistor R3, and the emitter of the transistor Q6, and is connected to the output end of the power supply circuit and the MCU circuit. The source of the MOS transistor Q4 is connected to the output end of the module circuit. The other end of the resistor R3 is connected to the emitter of the transistor Q5. The base and collector of the transistor Q5 are connected to the base of the transistor Q6 and one end of the resistor R4. The collector of the transistor Q6 is connected to one end of the resistor R6 and one end of the resistor R5. The other end of the resistor R6 is connected to the base of the transistor Q7. The collector of the transistor Q7 is connected to the enable end of the module circuit. The emitter of the transistor Q7, the other end of the resistor R5, the other end of the resistor R4, the gate of the MOS transistor Q4, the emitter of the transistor Q8, and the emitter of the transistor Q2 are grounded respectively.

[0008] Furthermore, the transistor Q3, the transistor Q5 and the transistor Q6 are PNP transistors.

[0009] Furthermore, the transistor Q1 , the transistor Q2 , the transistor Q7 and the triode Q8 are NPN transistors.

[0010] Furthermore, the MOS tube Q4 is an N-type field effect tube.

[0011] Using this solution, the present invention connects the external power provided by the power supply circuit via the power-off circuit, allowing the MCU circuit and module circuit to each receive the current required for startup, activating the MCU circuit and module circuit respectively. Once the entire circuit enters normal operation, the input current is switched to battery power to meet continued operational power requirements. When an abnormal device state causes high power consumption, the MCU circuit and module circuit can be automatically powered off quickly, ensuring that the system's safety protection capabilities are not weakened and avoiding potential electrical risks and data security vulnerabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a circuit block diagram of the utility model.

[0013] Figure 2 This is a circuit connection diagram for the power-off circuit. DETAILED DESCRIPTION

[0014] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] See also Figure 1 The present invention provides an automatic cut-off power-off circuit for an on-board OBD terminal, comprising: a power supply circuit, an MCU power supply circuit, a module power supply circuit, an MCU circuit, and a module circuit. The power supply circuit is electrically connected to the MCU power supply circuit and the module power supply circuit, the MCU power supply circuit is electrically connected to the module power supply circuit, the MCU circuit, and the module circuit, the module power supply circuit is electrically connected to the module circuit, and the MCU circuit is electrically connected to the module circuit. The power supply circuit, the MCU power supply circuit, the module power supply circuit, the MCU circuit, and the module circuit are connected via the power-off circuit. The MCU used in the MCU circuit refers to a microcontroller unit, which is a chip that integrates a microprocessor, a memory, and a peripheral interface; the module circuit refers to a mature kit that includes a microcontroller unit and its peripheral circuits. Compared with the MCU, the module circuit has a higher degree of integration, adaptability to scenarios, and development level.

[0016] In some embodiments, see Figure 2The power-off circuit includes: transistor Q1, transistor Q2, transistor Q3, transistor Q5, transistor Q6, transistor Q7, transistor Q8, MOS transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, and resistor R6. The emitter of the transistor Q1 is connected to the input section of the MCU circuit, the collector of the transistor Q1 is connected to the MCU power supply circuit, the base of the transistor Q1 is connected to the base of the transistor Q3, the collector of the transistor Q2, and one end of the resistor R1, the base of the transistor Q2 is connected to the collector of the transistor Q8 and one end of the resistor R2, the collector of the transistor Q3 is connected to the input end of the module circuit, the emitter of the transistor Q3 is connected to the module power supply circuit, the base of the transistor Q8 is connected to the output end of the MCU circuit, and the MOS transistor The drain of Q4 is connected to the other end of the resistor R1, the other end of the resistor R2, one end of the resistor R3, and the emitter of the transistor Q6, and is connected to the output end of the power supply circuit and the MCU circuit. The source of the MOS transistor Q4 is connected to the output end of the module circuit. The other end of the resistor R3 is connected to the emitter of the transistor Q5. The base and collector of the transistor Q5 are connected to the base of the transistor Q6 and one end of the resistor R4. The collector of the transistor Q6 is connected to one end of the resistor R6 and one end of the resistor R5. The other end of the resistor R6 is connected to the base of the transistor Q7. The collector of the transistor Q7 is connected to the enable end of the module circuit. The emitter of the transistor Q7, the other end of the resistor R5, the other end of the resistor R4, the gate of the MOS transistor Q4, the emitter of the transistor Q8, and the emitter of the transistor Q2 are grounded respectively.

[0017] In some embodiments, the transistors Q3, Q5, and Q6 are PNP transistors, the transistors Q1, Q2, Q7, and Q8 are NPN transistors, and the MOS transistor Q4 is an N-type field effect transistor.

[0018] The power-off circuit operates as follows: When no external power is input, transistors Q1, Q2, and Q7 are off. At this point, no power is supplied to the MCU and module circuits. When external power is supplied to the power-off circuit through the power supply circuit, current flows through resistor R1 and turns on transistor Q1. The external power input then flows through a linear regulator and serves as the input to the MCU power supply circuit, thereby supplying power to the MCU circuit. The external power input then flows through resistor R2 and turns on transistor Q2. This causes the base of transistor Q3 to go low, turning on transistor Q3. The external power input then serves as the module power supply circuit, providing power to the module circuit.

[0019] After the MCU circuit is powered on, it outputs a pulse wave. Since transistor Q6 is conducting, the MCU circuit's output passes through transistor Q6 and resistor R6, applying a high level to the base of transistor Q7, turning on transistor Q7. This causes a low pulse potential to be applied to the module circuit's enable terminal, thereby starting the module circuit. The module circuit's output passes through MOS transistor Q4 and its parasitic diode. Due to the characteristics of N-type MOS transistors, the external power input cannot flow current through MOS transistor Q4 to the module circuit's output port. At this time, the external power input is disconnected, and the battery supplies power to the MCU power supply circuit and the module power supply circuit in the circuit.

[0020] The module circuit output passes through the MOS tube Q4 and the resistor R1 to turn on the transistor Q1. The MCU power supply circuit supplies power to the input end of the MCU circuit through the transistor Q1. The module circuit output passes through the MOS tube Q4 and the resistor R2 and turns on the transistor Q2. At this time, the base of the transistor Q3 is pulled low due to the conduction of the transistor Q2, thereby turning on the transistor Q3. The module power supply circuit supplies power to the input end of the module circuit through the transistor Q3.

[0021] If the module circuit resets abnormally, transistors Q1, Q2, and Q3 become non-conductive, and the MCU circuit and the module circuit are powered off together. The battery cannot supply power to the MCU circuit and the module circuit through transistors Q1 and Q3, achieving automatic power-off.

[0022] Alternatively, when the output end of the MCU circuit sends a high level, transistor Q8 is turned on, and the base potential of transistor Q2 is pulled low. At this time, transistor Q2 and transistor Q3 are not turned on, and the module power supply circuit cannot supply power to the input end of the module circuit through transistor Q3, thereby powering off the module circuit, transistor Q1 is not turned on, and the MCU circuit is powered off.

[0023] The functions of resistors R3, R4, R5, transistor Q5, and Q6 are to prevent MOS transistor Q4 and transistor Q1 from entering an incomplete conduction state after the external power input is disconnected and power is supplied by the power supply, thereby ensuring the safety and stability of the overall power-off circuit.

[0024] In summary, the present invention uses a power-off circuit to conduct the external power provided by the power supply circuit, allowing the MCU circuit and module circuit to obtain the current required for startup, activating the operation of the MCU circuit and module circuit, and after the entire circuit enters normal operation, switching the input current to the battery power supply to meet the continuous working power demand. When the device enters an abnormal state causing high power consumption, the MCU circuit and module circuit can be automatically shut off and powered off quickly, ensuring that the system's safety protection capabilities are not weakened and avoiding potential electrical risks and data security vulnerabilities.

[0025] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An automatic cut-off power-off circuit for an on-board OBD terminal, characterized in that: include: The power supply circuit, the MCU power supply circuit, the module power supply circuit, the MCU circuit and the module circuit, the power supply circuit is electrically connected to the MCU power supply circuit and the module power supply circuit, the MCU power supply circuit is electrically connected to the module power supply circuit, the MCU circuit and the module circuit, the module power supply circuit is electrically connected to the module circuit, the MCU circuit is electrically connected to the module circuit, and the power supply circuit, the MCU power supply circuit, the module power supply circuit, the MCU circuit and the module circuit are connected through the power-off circuit.

2. The automatic shut-off power-off circuit of the vehicle-mounted OBD terminal according to claim 1, characterized in that: The power-off circuit includes: transistor Q1, transistor Q2, transistor Q3, transistor Q5, transistor Q6, transistor Q7, transistor Q8, MOS transistor Q4, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, and resistor R6. The emitter of the transistor Q1 is connected to the input section of the MCU circuit, the collector of the transistor Q1 is connected to the MCU power supply circuit, the base of the transistor Q1 is connected to the base of the transistor Q3, the collector of the transistor Q2, and one end of the resistor R1, the base of the transistor Q2 is connected to the collector of the transistor Q8 and one end of the resistor R2, the collector of the transistor Q3 is connected to the input end of the module circuit, the emitter of the transistor Q3 is connected to the module power supply circuit, the base of the transistor Q8 is connected to the output end of the MCU circuit, and the MOS transistor Q The drain of MOSFET Q4 is connected to the other end of the resistor R1, the other end of the resistor R2, one end of the resistor R3, and the emitter of the transistor Q6, and is connected to the output end of the power supply circuit and the MCU circuit. The source of the MOS transistor Q4 is connected to the output end of the module circuit. The other end of the resistor R3 is connected to the emitter of the transistor Q5. The base and collector of the transistor Q5 are connected to the base of the transistor Q6 and one end of the resistor R4. The collector of the transistor Q6 is connected to one end of the resistor R6 and one end of the resistor R5. The other end of the resistor R6 is connected to the base of the transistor Q7. The collector of the transistor Q7 is connected to the enable end of the module circuit. The emitter of the transistor Q7, the other end of the resistor R5, the other end of the resistor R4, the gate of the MOS transistor Q4, the emitter of the transistor Q8, and the emitter of the transistor Q2 are grounded respectively.

3. The automatic shut-off power-off circuit of the vehicle-mounted OBD terminal according to claim 2, characterized in that: The transistor Q3 , the transistor Q5 and the transistor Q6 are PNP transistors.

4. The automatic shut-off power-off circuit of the vehicle-mounted OBD terminal according to claim 2, characterized in that: The transistor Q1 , the transistor Q2 , the transistor Q7 and the triode Q8 are NPN transistors.

5. The automatic shut-off power-off circuit of the vehicle-mounted OBD terminal according to claim 2, characterized in that: The MOS tube Q4 is an N-type field effect tube.

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