WO2021051636A1 - Power failure protection circuit and method, data protection method, and electronic product - Google Patents

Abstract

A power failure protection circuit and method, a data protection method, and an electronic product, which specifically relate to a power failure protection circuit, a power failure protection method, a data protection method, and an electronic product employing the circuit and the method. The power failure protection circuit comprises: an energy storage capacitor (C100) configured to be connected to a charging circuit (B100) and a discharging circuit (B200); the charging circuit (B100) disposed between a power supply (A100) and the energy storage capacitor (C100) and configured to charge the energy storage capacitor (C100) in a power-on state; and the discharging circuit (B200) disposed between the power supply (A100) and the energy storage capacitor (C100), and configured to discharge the the power supply (A100) in a power-off state.

Description

Power-off protection circuit and method, data protection method and electronic product

cross reference

The present invention claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 201910878907.0, and the invention title is "A power-off protection circuit and method, data protection method and electronic product" on September 17, 2019. The application The entire content of is incorporated in the present invention by reference.

Technical field

The invention relates to the field of vehicles and electronics, in particular to a power-off protection circuit and method, a data protection method and an electronic product.

Background technique

As automotive applications become more and more widespread, the development of in-vehicle electronic products is also quite rapid, and the dependence on electricity is becoming stronger and stronger, so the impact of abnormal power failure has become a problem that must be solved. Sudden power failure of electronic products may cause product failure, and even cause serious life safety and property losses. Therefore, it is necessary to have a reliable protection plan for abnormal power failure. At present, there are basically two ways to deal with abnormal power outages of in-vehicle electronic products in the industry. The first method is to use pure software, that is, the software opens and closes the dedicated read-only area of the memory to back up important system data in advance. When data is lost, the software restores the data from the read-only area to start. This method has several drawbacks. First, a relatively large storage space is required, which will increase the storage cost; second, the power failure information that cannot be detected, the system cannot follow the normal The power-off sequence may cause damage to the device; the third principle of the so-called read-only memory area is that the system first erases the area and then writes back. When the system is executing the program, an abnormal power failure occurs and the important data of the system is lost. The possibility. The second method is to directly connect large capacitors in parallel with the main power circuit. When the main control system monitors that the main power supply drops below a certain threshold, the protection action is initiated, and the protection action is completed before the voltage of the energy storage capacitor drops to the minimum operating voltage of the electronic system. . This solution requires a large capacity of the energy storage capacitor, not only the cost is high, but also the product is too large, and it is not feasible under the trend of increasing miniaturization of the product.

In view of the above-mentioned abnormal power failure, in-vehicle electronic products need to implement circuit protection to solve problems such as data loss. The existing pure software methods and large capacitor methods cannot store important data in time, and the application of large capacitors is also a limitation.

Summary of the invention

In order to solve the problem in the prior art that electronic products cannot store data in time or need to be equipped with large capacitors when abnormal power failures occur, embodiments of the present invention provide a power failure protection circuit and method, data protection method and electronic product, according to the present invention In one embodiment, a power-off protection circuit is provided, including: an energy storage capacitor, which is set to be connected to a charging circuit and a discharging circuit; the charging circuit is set between the power supply and the energy storage capacitor, the The charging circuit is configured to charge the energy storage capacitor in the power-on state; the discharging circuit is arranged between the power supply and the energy storage capacitor, and the discharging circuit is configured to charge the power supply in the power-off state. Discharge.

According to an embodiment of the present invention, there is provided a power-off protection method. The method for implementing power-off protection using any of the above-mentioned circuits includes: in a power-on state, the constant current switch circuit in the charging circuit receives After the charging enable signal output by the control circuit, the energy storage capacitor is charged; in the power-off state, the step-down switch circuit in the discharging circuit receives the output of the control circuit After the discharge enable signal, perform step-down discharge on the main power circuit; at the same moment, the constant current switch circuit is in the working state, and the step-down switch circuit is in the forbidden state; or, the constant current switch circuit is in the forbidden state , The step-down switch circuit is in a working state.

According to an embodiment of the present invention, there is provided a data protection method. The method for the main control system to realize data protection when the power supply voltage is abnormally cut off includes: when the power supply voltage is abnormally cut off, a power failure detection control circuit Generate a power failure detection signal; after receiving the power failure detection signal, the main control system implements a power failure data protection operation; the power failure data protection operation includes data saving, and/or gradually shutting down each circuit module, and/ Or perform protection actions such as normal power-off and shutdown.

According to an embodiment of the present invention, there is provided an electronic product including the circuit described in any one of the above to perform the method described in any one of the above; the electronic product is used in vehicles or other fields.

Description of the drawings

The drawings described here are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is an example diagram of a power-off protection circuit according to an embodiment of the present invention;

Fig. 2 is an example diagram of a charging and discharging circuit according to an embodiment of the present invention;

Fig. 3 is an example diagram of a control circuit according to an embodiment of the present invention;

Fig. 4 is an exemplary diagram of a power-off protection method according to an embodiment of the present invention;

FIG. 5 is an exemplary diagram of a working method of a power-on state and power-off protection circuit according to an embodiment of the present invention;

6 is an example diagram of a working method of a power-off protection circuit in a power-off state according to an embodiment of the present invention;

Fig. 7 is an exemplary diagram of a data protection method according to an embodiment of the present invention;

FIG. 8 is an exemplary diagram of a data protection method and protection operation after a power failure according to an embodiment of the present invention;

Fig. 9 is a circuit example diagram of an electronic product system according to an embodiment of the present invention.

detailed description

The embodiment of the present invention provides a power-off protection circuit and method, a data protection method, and an electronic product. According to an embodiment of the present invention, a power-off protection circuit is provided. FIG. 1 is a power-off protection circuit according to an embodiment of the present invention. An example diagram of a protection circuit, as shown in Figure 1, the power-off protection circuit includes: an energy storage capacitor C100, which is set to be connected to the charging circuit B100 and the discharging circuit B200; the present invention does not limit the number and capacity of the energy storage capacitors Size; the charging circuit B100 is arranged between the power supply A100 and the energy storage capacitor C100, the charging circuit B100 is configured to charge the energy storage capacitor C100 in the power-on state; the discharging circuit B200 is set Between the power source A100 and the energy storage capacitor C100, the discharging circuit B200 is configured to discharge the power source A100 in a power-off state.

Optionally, in this embodiment, a power-off protection circuit is provided. FIG. 2 is an example diagram of a charging and discharging circuit according to an embodiment of the present invention. As shown in FIG. 2, the charging circuit B100 includes: The control circuit B310 is connected to the power source A100 to control the enabling of the charging circuit B100; the constant current switch circuit B101 is configured to be connected to the power source A100, and the constant current switch circuit B101 is configured to receive the charging enable Signal; wherein, the charging enable signal comes from the boost control circuit B310; the constant current switch circuit B101 uses a boost converter to adjust the voltage; according to an embodiment of the present invention, the boost converter adopts high efficiency The boost BOOST switching boost converter, the high-efficiency boost converters with the functions described above are all adapted to the present invention; two resistors R1/R2 are connected to the constant current switch circuit to adjust the constant current switch The output voltage of the circuit; an overvoltage protection module D100, connected to the resistor, adjusts the output voltage, and then inputs the energy storage capacitor C100.

Optionally, the discharging circuit includes B200: a step-down control circuit B320, which is connected to the power supply A100, and controls the discharging circuit enable B200; a step-down switch circuit B201, which is connected to the power supply A100, and is connected to the power supply. The constant current switch circuit B101 is connected; the buck switch circuit B201 receives a discharge enable signal; the discharge enable signal comes from the buck control circuit B320; the buck switch circuit B201 uses a buck converter to adjust the voltage The buck converter adopts a high-efficiency buck BUCK switching buck converter, and all high-efficiency buck converters with the function are adapted to the present invention; two resistors R3/R4, and the buck switch The circuit B201 is connected to adjust the output voltage of the step-down switch circuit.

Optionally, in this embodiment, a power-off protection circuit is provided. FIG. 3 is an example diagram of a control circuit according to an embodiment of the present invention. As shown in FIG. The voltage control circuit B320 includes: a comparator U1, which is connected to the power supply A100; the power supply is divided by two resistors R5/R6 and then input to the inverting input terminal of the comparator U1; the comparator U1 is positive The phase input terminal inputs the preset network undervoltage protection UVLO undervoltage threshold; the comparator U1 adopts a hysteresis comparator; the boost control circuit B310 and the buck control circuit B320 adopt the same comparator; In the boost control circuit B310, the comparator U1 is connected to an inverter U2, and the inverter U2 outputs the charging enable signal; the charging enable signal is input to the constant current switch circuit; In the step-down control circuit B320, the comparator U1 outputs the discharge enable signal; the discharge enable signal is input to the step-down switch circuit.

According to an embodiment of the present invention, there is provided a power-off protection method, which uses any of the above-mentioned circuits to achieve power-off protection. FIG. 4 is an example diagram of the power-off protection method according to an embodiment of the present invention, as shown in FIG. , Including: S100 judging the power supply status; S210 in the power-on state, after the constant current switch circuit in the charging circuit of S310 receives the charging enable signal output by the control circuit, S410 performs treatment on the energy storage capacitor Perform charging; S220 in the power-off state, after the step-down switch circuit in the discharge circuit of S320 receives the discharge enable signal output by the control circuit, S420 performs step-down discharge on the main power circuit; at the same time Wherein, the constant current switch circuit is in a working state, and the step-down switch circuit is in a prohibited state; or, the constant current switch circuit is in a prohibited state, and the step-down switch circuit is in a working state.

Optionally, in this embodiment, a power-off protection method is provided. FIG. 5 is an example diagram of a working method of a power-on state power-off protection circuit according to an embodiment of the present invention. As shown in FIG. 5, the constant current After the switching circuit receives the charging enable signal output by the control circuit, charging the energy storage capacitor includes: S210 in the power-on state, when the power supply voltage is normal, S311 the comparator inverting input Greater than the positive phase input, the comparator in S311a1 outputs the charging enable signal after being inverted by the inverter; the charging enable signal in S311a2 is input to the constant current switch circuit in the charging circuit; The constant current switch circuit controls the boost converter to charge the energy storage capacitor; the charging enable signal is at a high level; the comparator in S311b1 additionally outputs a low level, and the low level input in S311b2 The step-down switch circuit in the discharge circuit; S311b3, the step-down switch circuit controls the step-down converter to be in a prohibited working state.

Optionally, in this embodiment, a power-off protection method is provided. FIG. 6 is an example diagram of a working method of a power-off protection circuit in a power-off state according to an embodiment of the present invention. As shown in FIG. After the switch circuit receives the discharge enable signal output by the control circuit, it performs step-down and discharge of the main power circuit, including: when the power supply voltage is abnormally cut off in S220, the inverted input of the comparator in S321 is less than Positive phase input, the comparator in S321a1 outputs the discharge enable signal; the discharge enable signal in S321a2 is input to the step-down switch circuit in the discharge circuit; the step-down switch circuit in S321a3 controls the step-down The converter is in a discharging working state; the discharge enable signal is at a high level; the comparator in S321b1 is inverted by the inverter and then outputs a low level, and the low level in S321b2 is input to the charging circuit The constant current switch circuit; S321b3 The constant current switch circuit controls the boost converter to prohibit charging.

Optionally, the constant current switch circuit is in a working state and the step-down switch circuit is in a prohibited state; or, the constant current switch circuit is in a prohibited state and the step-down switch circuit is in a working state, including: When the power supply voltage is normal, the control circuit controls the charging circuit to enable, the constant current switch circuit in the charging circuit is in the working state to perform charging, and the step-down switch circuit in the discharging circuit is in the forbidden operation. State; when the power supply voltage is abnormally cut off, the control circuit controls the discharging circuit to enable, the step-down switch circuit in the discharging circuit is in a discharging state, and the constant current in the charging circuit The switch circuit is in a prohibited working state.

According to an embodiment of the present invention, a data protection method is provided. The main control system realizes data protection when the power supply voltage is abnormally cut off. FIG. 7 is an example diagram of the data protection method according to the embodiment of the present invention, such as As shown in Figure 7, it includes: when the power supply voltage is abnormally cut off in S220, the S500 power failure detection control circuit generates a power failure detection signal; S600 the main control system receives the power failure detection signal, implements power failure data protection Operation; The power-off data protection operation includes data saving, and/or gradually shutting down each circuit module, and/or performing protection actions such as normal power-off and shutdown.

Optionally, in this embodiment, a data protection circuit is provided. FIG. 3 is an example diagram of a control circuit according to an embodiment of the present invention. As shown in FIG. 3, the power failure detection control circuit includes: the comparison The switch U1, the switch tube U3; the power failure detection control circuit, the boost control circuit, and the step-down control circuit use the same comparator; the switch tube U3 uses an enhanced switch tube N-type metal oxide Material semiconductor NMOS transistor, or other enhanced switching tube; the comparator U1 is connected to the switching tube U3; the switching tube is turned on to output a power-down detection signal; the power-down detection signal is input to the main control system E100 .

Optionally, in this embodiment, a data protection method is provided. FIG. 8 is an example diagram of a data protection method and protection operation after a power failure according to an embodiment of the present invention. As shown in FIG. 8, the power supply voltage is abnormal. When the power is off, the power failure detection control circuit generates the power failure detection signal, including: when the power supply voltage is abnormally cut off in S220, the inverting input of the comparator in the power failure detection control circuit S510 is less than the positive Phase input, the comparator in S520 outputs a high level; the high level in S530 drives the switch tube to be turned on to generate the power-down detection signal.

Optionally, after receiving the power failure detection signal, the main control system implements a power failure data protection operation; the power failure data protection operation includes data saving, and/or gradually shutting down each circuit module, and/or executing Protection actions such as normal power-off and shutdown; include: the power-down detection signal generated by the power-down detection control circuit in S610 is input to the main control system; S621-S623 the main control system starts to perform power-off data protection operations, including : After receiving the power failure detection signal, the main control system in S621 executes data storage to complete data protection; the main control system in S622 gradually shuts down the display module and other circuit modules according to the functional importance of each circuit module, such as The interface module circuit, wireless communication subsystem, etc. of the vehicle-machine system communication, and finally only the main control system continues to perform data storage to save power consumption and ensure that the main control system has enough power to complete data storage and realize data protection ; S623 The main control system performs protection actions such as normal power-off and shutdown, to avoid sudden shutdown when abnormal power failure causes data to be stored too late to achieve data protection.

According to an embodiment of the present invention, there is provided an electronic product including the circuit described in any one of the above to perform the method described in any one of the above; the electronic product is used in vehicles or other fields.

Optionally, according to an embodiment of the present invention, a vehicle-mounted electronic product and an abnormal power-off protection circuit thereof are provided. The system is composed of a vehicle-mounted battery, an energy storage control circuit, a wireless communication subsystem, an MCU main control system, and a vehicle machine. The system consists of CAN communication interface and display module.

The present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention, and do not limit the present invention. In the case of no conflict, the embodiments in the application and the features in the embodiments can be combined with each other.

In this embodiment, an electronic product is provided. FIG. 9 is an example circuit diagram of an electronic product system according to an embodiment of the present invention. The A100 main power supply of the example is powered by an on-board battery, and its typical output voltage is 12V through a 3.3V step-down circuit. And 3.6V step-down circuit respectively to supply power to the MCU main control system E100 and the wireless communication subsystem G100 of the microcontroller unit. The MCU main control system E100 exchanges information with the wireless communication subsystem G100 through the universal transmitter UART. In order to prevent the damage to the system caused by abnormal power failure and to solve the problem of excessive energy storage capacitor in the prior art, the present invention proposes to use the energy storage capacitor C100 and the vehicle system to exchange information. A high-efficiency capacitor charging and discharging circuit B100/B200 is added between the main power supply A100, that is, a switching buck-boost converter circuit. Only one of the circuits is effective for charging and discharging at any time, so as to prevent the buck-boost converter from simultaneously causing cycles Work, reducing the discharge time.

Under normal power supply conditions, the capacitor charging and discharging circuit B100/B200 charges the energy storage capacitor through a high-efficiency BOOST switching converter to reduce system power consumption. The maximum charging voltage can be set according to the existing capacitor specifications. When an abnormal power failure occurs, the energy storage control circuit uses a high-efficiency BUCK switching converter time capacitor to step-down and discharge the main power supply A100 circuit to maintain the main power supply A100 stable. At the same time, when the system detects the main power supply A100 power supply drop event, according to the functional importance of each circuit module, the modules are gradually displayed, the interface module circuit of the vehicle system communication, the wireless communication subsystem, etc. are closed, and only the MCU master is retained. The control system E100 minimizes the energy consumption of the energy storage capacitor C100 and prolongs the discharge time of the energy storage capacitor C100 to ensure that the system has enough time to complete important data storage, legal shutdown sequence and other protection actions, and improve system reliability .

In the following, according to an embodiment of the present invention, according to the power-off protection circuit of the present invention, the capacitance required by the present invention is calculated and compared with the capacitance capacity of the prior art solution, thereby embodying the advantages of the present invention.

For the existing technical solution, assuming that the working range of the step-down circuit input voltage is 4-12V, the average input voltage of the step-down circuit during the protection period is (12V+4V)÷2=8V, the time required for the protection work is 50ms, and the maximum operating current of the system 1A, according to energy conservation, 0.5×C×(122-42)=1A×8V×50ms, the required capacitance value for calculation is 6.25mF, so you need to choose a capacitor above 6.25mF/12V to meet the requirements, so Such large capacitors are difficult to find in the market, and a large number of capacitors are required to be used in parallel, which not only increases the cost of the product, but also increases the volume of the product, and the implementation is poor.

For the technical solution of the present invention, it is assumed that the energy storage capacitor is charged to 24V through the charging circuit, the output setting voltage of the discharging circuit is 8V, and the efficiency of the BUCK step-down switching converter is 90%. According to this patent, the power consumption optimization solution after an abnormal power failure occurs , The system load current is reduced from the original 1A to 0.5A. According to the conservation of energy, 0.5×C×(242-42)*0.9=0.5A*8V*50ms, the capacitance required for calculation is 794uF, so 800uF is selected Capacitors above /25V can meet the requirements. If the charging voltage is further increased to 50V, the required capacitance is reduced to 179uF according to the same calculation method. Therefore, choosing a capacitor above 180uF/50V can meet the requirements. If you continue to increase the charging voltage, the required capacitance value will be smaller. In order to prevent the device from being damaged due to excessive voltage, an overvoltage protection module can be added to the output of the charging circuit. Therefore, compared with the prior art solutions, the present invention not only greatly reduces the capacitance value of the energy storage capacitor, but also has a significant cost effect. At the same time, the capacitor charging voltage can be selected at will according to the existing capacitor specifications and prices in the market, the selection is flexible, and the implementation is strong.

A power-off protection circuit and method, a data protection method, and an electronic product provided according to embodiments of the present invention include: a power-off protection circuit, a power-off protection method, a data protection method, and an electronic product using the above-mentioned circuit and method, The above circuits and methods use a control circuit to adjust the charging and discharging circuit enablement to ensure that only one circuit is in working condition at any time, avoiding energy loss, and ensuring the continuous power supply of the main control system after an abnormal power failure. It can accurately detect abnormal power-down signals, shut down unimportant circuit modules in time, maintain the stability of the main control system, and ensure that the main control system has enough residual power to perform data storage, normal power-off and shutdown and other protective actions to avoid abnormal power-off Sudden shutdown causes data to be stored too late to achieve data protection and other problems, alleviating the shortcomings of the existing technology. Compared with the prior art, the present invention has low cost, can greatly reduce the cost of capacitance and product volume, improve the implementability of the product, and has high accuracy and reliability in abnormal power failure detection, good effect, and strong practicability.

The above descriptions are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (13)

1. A power-off protection circuit, wherein the power-off protection circuit includes:

   The energy storage capacitor is set to be connected to the charging circuit and the discharging circuit;

   The charging circuit is arranged between the power supply and the energy storage capacitor, and the charging circuit is configured to charge the energy storage capacitor in a powered-on state;

   The discharging circuit is arranged between the power supply and the energy storage capacitor, and the discharging circuit is configured to discharge the power supply in a power-off state.
2. The circuit of claim 1, wherein the charging circuit comprises:

   A boost control circuit, connected to the power supply, to control the enabling of the charging circuit;

   The constant current switch circuit is configured to be connected to the power supply, and the constant current switch circuit is configured to receive a charging enable signal; wherein the charging enable signal comes from the boost control circuit; the constant current switch circuit Use boost converter to adjust voltage;

   Two resistors connected to the constant current switch circuit to adjust the output voltage of the constant current switch circuit;

   The overvoltage protection module is connected to the resistor, and then inputs the energy storage capacitor after adjusting the output voltage.
3. The circuit of claim 1, wherein the discharge circuit comprises:

   A step-down control circuit, connected to the power supply, to control the discharging circuit to enable;

   The step-down switch circuit is connected to the power supply and is connected to the constant current switch circuit; the step-down switch circuit receives a discharge enable signal; the discharge enable signal comes from the step-down control circuit; The voltage switch circuit adopts a buck converter to adjust the voltage;

   Two resistors are connected with the step-down switch circuit to adjust the output voltage of the step-down switch circuit.
4. The circuit according to claim 2-3, wherein the step-up control circuit and the step-down control circuit comprise:

   A comparator connected to the power supply; the power supply is divided by two resistors and then input to the inverting input terminal of the comparator;

   The non-inverting input terminal of the comparator inputs a preset network undervoltage protection UVLO undervoltage threshold;

   The comparator adopts a hysteresis comparator;

   The step-up control circuit and the step-down control circuit use the same comparator;

   In the boost control circuit, the comparator is connected to an inverter, and the inverter outputs the charging enable signal; the charging enable signal is input to the constant current switch circuit;

   In the step-down control circuit, the comparator outputs the discharge enable signal; the discharge enable signal is input to the step-down switch circuit.
5. A power-off protection method, wherein the method for implementing power-off protection using the circuit described in any one of claims 1 to 4 includes:

   In the power-on state, the constant current switch circuit in the charging circuit charges the energy storage capacitor after receiving the charging enable signal output by the control circuit;

   In the power-off state, after the step-down switch circuit in the discharge circuit receives the discharge enable signal output by the control circuit, perform step-down discharge on the main power circuit;

   At the same moment, the constant current switch circuit is in the working state and the step-down switch circuit is in the prohibited state; or, the constant current switch circuit is in the prohibition state, and the step-down switch circuit is in the work state.
6. The method according to claim 5, wherein after the constant current switch circuit receives the charging enable signal output by the control circuit, charging the energy storage capacitor comprises:

   When the power supply voltage is normal, the inverting input of the comparator is greater than the non-inverting input, and the comparator outputs the charging enable signal after being inverted by the inverter;

   The charging enable signal is input to the constant current switch circuit in the charging circuit;

   The constant current switch circuit controls the boost converter to charge the energy storage capacitor;

   The charging enable signal is at a high level;

   The comparator additionally outputs a low level, and the low level is input to the step-down switch circuit in the discharge circuit;

   The step-down switch circuit controls the step-down converter to be in a prohibited working state.
7. The method according to claim 5, wherein after the step-down switch circuit receives the discharge enable signal output by the control circuit, performing step-down discharge on the main power circuit comprises:

   When the power supply voltage is abnormally cut off, the inverting input of the comparator is smaller than the non-inverting input, and the comparator outputs the discharge enable signal;

   The discharge enable signal is input to the step-down switch circuit in the discharge circuit;

   The step-down switch circuit controls the step-down converter to be in a discharge working state;

   The discharge enable signal is at a high level;

   The comparator outputs a low level after being inverted by the inverter, and the low level is input to the constant current switch circuit in the charging circuit;

   The constant current switch circuit controls the boost converter to prohibit charging.
8. The method according to claim 5, wherein, at the same moment, the constant current switch circuit is in an operating state, and the step-down switch circuit is in a prohibited state; or, the constant current switch circuit is in a prohibited state, and the step-down switch circuit is in a prohibited state. The voltage switch circuit is in working condition, including:

   When the power supply voltage is normal, the control circuit controls the charging circuit to enable, the constant current switch circuit in the charging circuit is in the working state to perform charging, and the step-down switch circuit in the discharging circuit is in Prohibited working status;

   When the power supply voltage is abnormally cut off, the control circuit controls the discharging circuit to enable, the step-down switch circuit in the discharging circuit is in a discharging working state, and the constant current switch circuit in the charging circuit In a state of prohibiting work.
9. A data protection method, wherein the method for the main control system to realize data protection when the power supply voltage is abnormally cut off includes:

   When the power supply voltage is abnormally cut off, the power failure detection control circuit generates a power failure detection signal;

   After the main control system receives the power failure detection signal, implement a power failure data protection operation;

   The power-off data protection operation includes data saving, and/or gradually shutting down each circuit module, and/or performing protection actions such as normal power-off and shutdown, etc.
10. The method according to claim 9, wherein the power-down detection control circuit comprises:

    The comparator, the switch tube;

    The power-down detection control circuit, the step-up control circuit, and the step-down control circuit use the same comparator;

    The switch tube adopts an enhanced switch tube N-type metal oxide semiconductor NMOS transistor or other enhanced switch tube;

    The comparator is connected to the switch tube; the switch tube is turned on to output a power failure detection signal;

    The power failure detection signal is input to the main control system.
11. The method according to claim 9, wherein, when the power supply voltage is abnormally cut off, the power failure detection control circuit generating the power failure detection signal comprises:

    When the power supply voltage is abnormally powered off, the inverting input of the comparator in the power failure detection control circuit is smaller than the non-inverting input, and the comparator outputs a high level;

    The high level drives the switch tube to be turned on to generate the power-down detection signal.
12. The method according to claim 9, wherein after the main control system receives the power failure detection signal, it implements a power failure data protection operation; the power failure data protection operation includes data saving, and/or gradually shutting down each Circuit modules, and/or perform protection actions such as normal power-off and shutdown; including:

    Inputting the power failure detection signal generated by the power failure detection control circuit to the main control system;

    The main control system starts to perform power-off data protection operations, including:

    After the main control system receives the power failure detection signal, execute data storage, etc. to complete data protection;

    The main control system gradually shuts down the display module and other circuit modules, such as the interface module circuit for vehicle system communication, wireless communication subsystem, etc., according to the functional importance of each circuit module, and finally only retains the main control system to continue to perform data storage , In order to save power consumption and ensure that the main control system has enough residual power to complete data storage and realize data protection;

    The main control system executes protection actions such as normal power-off and shutdown, so as to avoid sudden shutdown during abnormal power failure, which may cause data to be stored too late to achieve data protection.
13. An electronic product, including the circuit described in any one of claims 1 to 4 to perform the method described in any one of claims 5 to 12; the electronic product is used in vehicles, or in other fields .

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