Intelligent vehicle-mounted monitoring terminal with 12V or 24V input power supply under-voltage protection

Abstract

The utility model relates to the technical field of vehicle-mounted monitoring terminals, in particular to an intelligent vehicle-mounted monitoring terminal with 12V or 24V input power supply under-voltage protection. The monitoring terminal comprises a microcontroller module which adopts a vehicle gauge level MCU chip and is used for controlling the overall operation of the terminal; the CAN data receiving and transmitting module is used for collecting vehicle information through a CAN bus and uploading the vehicle information to the monitoring platform; the communication module performs data transmission through a 4G network; the GNSS positioning module is used for acquiring and uploading vehicle positioning information; the RTC clock module is used for providing a system time reference; the storage chip is used for storing a vehicle identification number and an upgrading file; the under-voltage protection circuit monitors and protects the power supply voltage of the terminal, and when the voltage is lower than an under-voltage protection threshold value, the internal main power supply is disconnected or disabled; according to the utility model, the chip is taken as a core to replace a discrete device, so that the integration level and the maintainability of the circuit are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle-mounted monitoring terminals, in particular to an intelligent vehicle-mounted monitoring terminal with 12V or 24V input power undervoltage protection. Background Art

[0002] The low-voltage battery of new energy vehicles provides power for the vehicle control system, which is generally 12V or 24V, and the power battery provides a charging source for it. When the vehicle is in a power-off state, all high-voltage contactors of the power battery control system are disconnected, the low-voltage control power supply does not work, the battery provides power for the monitoring terminal, and the system enters a dormant state. At this time, when the battery voltage is too low, the monitoring terminal hardware needs to be disconnected to prevent the battery from over-discharging, so the monitoring terminal needs to have undervoltage protection capabilities.

[0003] like Figure 3 As shown, the existing undervoltage protection is mostly constructed by discrete devices such as voltage regulator diodes, optocouplers, MOS tubes, triodes and resistors. The optocoupler is used for power enable control, and the MOS tube controls the power supply circuit. Such undervoltage protection has the problems of high power consumption and difficulty in analyzing the failure of discrete devices due to low integration. Utility Model Content

[0004] The utility model provides an intelligent vehicle-mounted monitoring terminal with 12V or 24V input power supply undervoltage protection to solve the technical problems of high power consumption and low integration of the existing undervoltage protection circuit.

[0005] The technical solution of the utility model to solve the above technical problems is as follows:

[0006] Provided is an intelligent vehicle-mounted monitoring terminal with 12V or 24V input power undervoltage protection, the monitoring terminal comprising:

[0007] The microcontroller module uses an automotive-grade MCU chip to control the overall operation of the terminal;

[0008] CAN data transceiver module collects vehicle information through the CAN bus and uploads it to the monitoring platform;

[0009] Communication module, data transmission through 4G network;

[0010] GNSS positioning module, to obtain and upload vehicle positioning information;

[0011] RTC clock module, providing system time reference;

[0012] A memory chip for storing the vehicle identification number and upgrade files; and

[0013] The undervoltage protection circuit monitors and protects the terminal power supply voltage. When the voltage is lower than the undervoltage protection threshold, the internal main power supply is disconnected or disabled.

[0014] Furthermore, the undervoltage protection circuit includes:

[0015] an operational amplifier (U112) for comparing the input power supply voltage and outputting a control signal;

[0016] A voltage regulator (D156) is used to provide an accurate reference voltage (Vref) for the inverting input terminal of the operational amplifier;

[0017] Resistor (R917), used to limit current and reduce static power consumption;

[0018] A voltage divider resistor (R915) and a resistor (R916) for sensing the input power supply voltage and providing a voltage to the positive input terminal of the operational amplifier; and

[0019] Positive feedback resistor (R918) is used to set the hysteresis voltage value;

[0020] The positive input end of the operational amplifier (U112) is connected to the voltage dividing point of the voltage dividing resistor (R915) and the resistor (R916), and the negative input end is connected to the output end of the voltage regulator tube (D156);

[0021] The positive feedback resistor (R918) is connected between the positive input terminal and the output terminal of the operational amplifier (U112);

[0022] The output end of the operational amplifier (U112) is connected to the enable end (EN) of the power chip. When the input power voltage is lower than the undervoltage protection threshold, the operational amplifier (U112) outputs a low-level signal to control the power chip to be disabled.

[0023] Furthermore, the microcontroller module adopts NXP's automotive-grade MCU chip S32K, with a maximum main frequency of 112MHz, 512KB of FLASH and 64KB of RAM.

[0024] Furthermore, the CAN data transceiver module includes a CAN transceiver, an interface protection circuit and a matching circuit.

[0025] Furthermore, the communication module includes a 4G module, a module power supply circuit, a module startup circuit, a traffic card chip circuit and an antenna interface circuit.

[0026] Furthermore, the RTC clock module is integrated inside the MCU to provide a time reference and realize time, calendar, alarm and device sleep and wake-up functions.

[0027] Furthermore, the storage chip is in the form of an external NOR FLASH and an eMMC, the NOR FLASH is used to store the vehicle identification number and the upgrade file, and the eMMC is used for local message storage.

[0028] Furthermore, the undervoltage protection circuit supports input voltages of 12V and 24V.

[0029] Furthermore, the undervoltage protection circuit uses a three-terminal voltage regulator as a reference voltage source.

[0030] The beneficial effects of the utility model are:

[0031] The utility model uses the chip as the core to replace the discrete device, which improves the integration and maintainability of the circuit. The power consumption can be reduced from mA level to uA level by eliminating the triode switch mode, thereby reducing the power consumption. In addition, the hysteresis voltage can be adjusted by the k value, and the threshold voltage accuracy is improved by using a three-terminal voltage regulator as a reference voltage source. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a hardware block diagram of the utility model;

[0033] Figure 2 This is the schematic diagram of the undervoltage protection circuit of the utility model;

[0034] Figure 3 This is the design circuit diagram of the existing undervoltage. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the utility model, and cannot be understood as limiting the utility model. In addition, it should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0036] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0037] The disclosure below provides many different embodiments or examples for realizing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the utility model. In addition, the utility model may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the utility model provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0038] The utility model provides the following preferred embodiments:

[0039] The utility model intends to design an intelligent vehicle-mounted monitoring terminal with input power undervoltage protection function, which can improve the performance of the existing undervoltage protection circuit. The types and quantities of components are selected as few as possible, and an integrated chip solution is adopted. Circuit-related parameters such as protection voltage threshold and hysteresis voltage range can be configured through single or multiple resistors. The main purpose is to reduce power consumption after the power is turned off.

[0040] refer to Figure 1 As shown in the figure, the intelligent vehicle monitoring terminal uses the CAN bus to collect vehicle information and status, and uploads it to the monitoring platform through the 4G network. The monitoring terminal integrates a high-precision positioning module, which can accurately obtain vehicle positioning information and upload it to the monitoring platform. When the vehicle battery voltage is lower than the undervoltage protection threshold, the monitoring terminal enters the low-voltage protection state, and the internal main power supply is disconnected or disabled; when the battery voltage rises to a certain value higher than the undervoltage protection threshold, the monitoring terminal should be awakened and enter the normal power supply state, and the device power supply voltage is higher than the minimum working voltage. The device will resume awakening and enter the working state, and report the latest working status to the server.

[0041] The intelligent vehicle-mounted monitoring terminal with input power undervoltage protection function of the utility model includes the following main modules:

[0042] 1) The microcontroller module is mainly composed of NXP's automotive-grade MCU chip S32K and peripheral circuits. The main frequency can reach up to 112MHz, the FLASH size is 512KB, and the RAM size is 64KB. One of the three CAN channels supports CANFD, and the ISO26262 functional safety level reaches ASIL-B to ensure system safety and reliability. Other interfaces include UART, LIN, SPI, I2C, etc.

[0043] 2) The CAN data transceiver module is mainly composed of a CAN transceiver, an interface protection circuit, a matching circuit, etc. The main function is to receive vehicle CAN messages, parse them, and upload them to the monitoring platform in accordance with the protocol. This ensures the real-time collection and transmission of vehicle data and the accuracy and timeliness of the monitoring platform.

[0044] 3) The communication module is mainly composed of 4G module, module power supply circuit, module startup circuit, flow card chip circuit, antenna interface circuit, etc. The main functions of 4G are to register for networking, log in to the platform, and send messages to the platform at regular intervals. Ensure stable communication between the monitoring terminal and the remote monitoring platform, and support real-time data upload and remote control.

[0045] 4) The main function of the GNSS positioning module is to obtain satellite positioning information and support all constellation positioning and navigation systems such as GPS, Beidou, and GLONASS. It can obtain and upload the precise positioning information of the vehicle and support vehicle trajectory tracking and positioning services.

[0046] 4) The RTC clock uses an integrated module inside the MCU. Its main function is to provide a time reference for the system and realize functions such as time, calendar, alarm, and device sleep and wake-up.

[0047] 5) The storage chip adopts the form of external NOR FLASH + eMMC. FLASH is used to store the vehicle identification number and upgrade files, and eMMC can be used as a local message storage medium. It ensures reliable storage and fast access to data, and supports system firmware upgrades and data backup.

[0048] refer to Figure 2 As shown, the undervoltage protection circuit of the utility model is used for power undervoltage protection of an intelligent vehicle-mounted monitoring terminal, and its composition is as follows:

[0049] Operational Amplifier (U112):

[0050] As the core of the circuit, it compares the input signal and outputs the control signal. It compares the signal at its positive and negative input terminals and outputs the corresponding result.

[0051] Zener diode (D156):

[0052] Provides accurate reference voltage (Vref) to the inverting input of the operational amplifier to ensure the stability and accuracy of the undervoltage protection circuit.

[0053] Current limiting resistor (R917):

[0054] Used to limit current, usually with a larger resistance value to reduce static power consumption and ensure that the circuit runs stably in a low power state.

[0055] Resistor divider network (R915 and R916):

[0056] It is used to detect the input power supply voltage and provide the positive input voltage of the operational amplifier. When the input power supply voltage changes, the output voltage of the voltage divider network changes accordingly.

[0057] Positive feedback resistor (R918):

[0058] Connected between the positive input and output of the operational amplifier. Used to set the hysteresis voltage value (Vh) to ensure the stability of the system in the undervoltage protection state.

[0059] The specific connection relationship is as follows:

[0060] The non-inverting input terminal of the operational amplifier (U112) is connected to the voltage dividing point of the voltage dividing resistor network (R915 and R916). The inverting input terminal of the operational amplifier (U112) is connected to the output terminal of the voltage regulator (D156).

[0061] The output of the operational amplifier (U112) is connected to the enable terminal (EN) of the power control chip. When the input power voltage is lower than the undervoltage protection threshold, the operational amplifier outputs a low-level signal to disable the control power chip.

[0062] Through the above technical scheme, the intelligent vehicle-mounted monitoring terminal of the utility model has the advantages of high integration, flexible undervoltage protection threshold setting, low power consumption and high precision, and can effectively protect the vehicle battery and ensure the stable operation of the system.

[0063] It can be understood that U112 is an operational amplifier, which outputs the corresponding result by comparing the signals at its forward and reverse input terminals. The external input power supply VCC_IN is stabilized by the voltage regulator D156 to provide an accurate reference voltage Vref for the reverse terminal of the operational amplifier. R917 is a current limiting resistor, and the resistance value is usually selected to be larger to reduce static power consumption. R915 and R916 form a resistor divider network. When the input power supply VCC_IN changes, the ratio of the two changes accordingly, and the voltage value U+ at the positive terminal of the operational amplifier also changes accordingly. When Vp is greater than Vref, the operational amplifier outputs a high level; when Vp is less than Vref, the operational amplifier outputs a low level. After VCC_IN reaches the undervoltage protection threshold, the output terminal of the operational amplifier will output a low level signal, thereby controlling the subsequent power chip EN.

[0064] In actual situations, after the system enters the hardware undervoltage protection, it needs to reach a certain hysteresis voltage before starting the system to ensure the normal use of the battery. Add a positive feedback resistor R918 to the positive phase terminal and output terminal of the operational amplifier to set the hysteresis voltage value Vh, using the formula:

[0065] (Vt+)=Voh*k+Vref / (1-k) Formula 1

[0066] (Vt-)=Voh*k+Vref / (1-k) Formula 2

[0067] as well as:

[0068] Vh=(Vt+)-(Vt-) Formula 3

[0069] The hysteresis voltage value Vh can be calculated by combining Formula 1 to Formula 3, where k is the positive feedback coefficient.

[0070] Furthermore, the utility model uses a three-terminal voltage regulator to provide a reverse terminal reference voltage for the operational amplifier; sets the undervoltage threshold and hysteresis voltage value through a resistor voltage divider network and a positive feedback resistor; uses an operational amplifier as the circuit core to compare input signals and output control signals; and supports undervoltage protection functions for input voltages of 12V and 24V.

[0071] The utility model solves the problem of undervoltage protection of the intelligent vehicle monitoring terminal for the previous power supply such as a battery. Compared with the existing undervoltage protection technology, the chip is used as the core to replace discrete devices, which improves the integration and maintainability of the circuit. The undervoltage protection threshold setting is more flexible, and the parameter adjustment can be achieved by simply changing the corresponding resistance value without modifying the circuit.

[0072] The beneficial effects of the present invention are specifically embodied in that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection, characterized in that: The monitoring terminal comprises: The microcontroller module uses an automotive-grade MCU chip to control the overall operation of the terminal; CAN data transceiver module collects vehicle information through the CAN bus and uploads it to the monitoring platform; Communication module, data transmission through 4G network; GNSS positioning module, to obtain and upload vehicle positioning information; RTC clock module, providing system time reference; A memory chip for storing the vehicle identification number and upgrade files; and The undervoltage protection circuit monitors and protects the terminal power supply voltage. When the voltage is lower than the undervoltage protection threshold, the internal main power supply is disconnected or disabled.

2. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The undervoltage protection circuit comprises: an operational amplifier (U112) for comparing the input power supply voltage and outputting a control signal; A voltage regulator (D156) is used to provide an accurate reference voltage (Vref) for the inverting input terminal of the operational amplifier; Resistor (R917), used to limit current and reduce static power consumption; A voltage divider resistor (R915) and a resistor (R916) for sensing the input power supply voltage and providing a voltage to the positive input terminal of the operational amplifier; and Positive feedback resistor (R918) is used to set the hysteresis voltage value; The positive input end of the operational amplifier (U112) is connected to the voltage dividing point of the voltage dividing resistor (R915) and the resistor (R916), and the negative input end is connected to the output end of the voltage regulator tube (D156); The positive feedback resistor (R918) is connected between the positive input terminal and the output terminal of the operational amplifier (U112); The output end of the operational amplifier (U112) is connected to the enable end (EN) of the power chip. When the input power voltage is lower than the undervoltage protection threshold, the operational amplifier (U112) outputs a low-level signal to control the power chip to be disabled.

3. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The microcontroller module uses NXP's automotive-grade MCU chip S32K, with a maximum main frequency of 112MHz, 512KB of FLASH and 64KB of RAM.

4. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The CAN data transceiver module includes a CAN transceiver, an interface protection circuit and a matching circuit.

5. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The communication module includes a 4G module, a module power supply circuit, a module startup circuit, a flow card chip circuit and an antenna interface circuit.

6. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The RTC clock module is integrated inside the MCU to provide a time reference and implement time, calendar, alarm and device sleep and wake-up functions.

7. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The storage chip is in the form of an external NOR FLASH and an eMMC. The NOR FLASH is used to store the vehicle identification number and upgrade files, and the eMMC is used for local message storage.

8. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The undervoltage protection circuit supports input voltages of 12V and 24V.

9. The intelligent vehicle monitoring terminal with 12V or 24V input power undervoltage protection as claimed in claim 1, characterized in that: The undervoltage protection circuit uses a three-terminal voltage regulator as a reference voltage source.

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