Low voltage detection control circuit, method and electronic equipment

Abstract

The embodiment of the present application relates to the field of electronic technology, and discloses a low voltage detection control circuit, method and electronic device. The above-mentioned low voltage detection control circuit includes a voltage comparison module and a voltage control module, the voltage comparison module includes an external voltage input terminal and a threshold voltage input terminal, the external voltage input terminal is electrically connected to the output terminal of the external power supply module, the first input terminal of the voltage control module is electrically connected to the output terminal of the voltage comparison module, the threshold voltage output terminal of the voltage control module is electrically connected to the threshold voltage input terminal, and the signal output terminal of the voltage control module is electrically connected to the external system module; the voltage comparison module compares the voltage of the external voltage input terminal with the voltage of the threshold voltage input terminal, obtains a comparison result, and sends the comparison result to the voltage control module. The low voltage detection control circuit provided by the embodiment of the present application solves the problem that the system is prone to system abnormality or freeze under low voltage.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of electronic technology, and in particular to a low voltage detection control circuit, method and electronic device. Background Art

[0002] Narrow Band Internet of Things (NBIoT) is an important branch of the wide area Internet of Things based on cellular networks. In the NBIoT communication system, a system on chip (SoC) integrated circuit is usually used, wherein the system on chip SoC includes a narrow band (NB) subsystem and a microcontroller (MCU) subsystem integrated on the chip. When the system on chip SoC is working, when the power supply voltage suddenly drops, the board-level energy storage capacitor will continue to power the system on chip SoC. However, if the NB subsystem is transmitting data at this time, the current consumption is very large. At this time, the power of the board-level energy storage capacitor will be quickly consumed, causing the system voltage to drop quickly, and the system will not have time to process it, causing a crash. In addition, if the system is in sleep mode, when the power supply voltage suddenly drops, the system will not be able to perceive the behavior, causing the system to behave abnormally or crash. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a low voltage detection control circuit, method and electronic device to solve the problem that the system is prone to system abnormality or crash under low voltage.

[0004] To solve the above technical problems, an embodiment of the present application provides a low voltage detection control circuit, including: a voltage comparison module and a voltage control module, the voltage comparison module includes an external voltage input terminal and a threshold voltage input terminal, the external voltage input terminal is electrically connected to the output terminal of an external power supply module; the first input terminal of the voltage control module is electrically connected to the output terminal of the voltage comparison module, the threshold voltage output terminal of the voltage control module is electrically connected to the threshold voltage input terminal, and the signal output terminal of the voltage control module is electrically connected to an external system module; wherein the voltage comparison module compares the voltage of the external voltage input terminal with the voltage of the threshold voltage input terminal, obtains a comparison result, and sends the comparison result to the voltage control module; when the voltage of the external voltage input terminal is less than the voltage of the threshold voltage input terminal, the voltage control module sends a control signal to the external system module.

[0005] In addition, the voltage control module includes: a threshold control module, a mode setting module and a state machine module; wherein the output end of the threshold control module is electrically connected to the threshold voltage input end, the first input end of the threshold control module is electrically connected to the first output end of the mode setting module, and the second input end of the threshold control module is electrically connected to the first output end of the state machine module; the second output end of the mode setting module is electrically connected to the first input end of the state machine module, and the control signal output end of the state machine module is electrically connected to the external system module.

[0006] In addition, the voltage control module also includes: a filtering module, a first input end of the filtering module is electrically connected to the output end of the voltage comparison module, a second input end of the filtering module is electrically connected to the third output end of the mode setting module, and an output end of the filtering module is electrically connected to the second input end of the state machine module.

[0007] In addition, the external system module includes a NB subsystem and an MCU subsystem, the first signal output end of the voltage control module is electrically connected to the input end of the NB subsystem, the second signal output end of the voltage control module is electrically connected to the first input end of the MCU subsystem, and the third signal output end of the voltage control module is electrically connected to the second input end of the MCU subsystem.

[0008] In addition, the first signal output end of the voltage control module is electrically connected to the input end of the NB subsystem through the first end of the first key switch, and the second end of the first key switch is grounded; the second signal output end of the voltage control module is electrically connected to the first input end of the MCU subsystem through the first end of the second key switch, and the second end of the second key switch is grounded.

[0009] In addition, when the external voltage is less than a first threshold voltage, the voltage control module sends a control signal to the NB subsystem to control the power of the NB subsystem to be turned off; when the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the voltage control module sends a control signal to the MCU subsystem to control the power of the MCU subsystem to be turned off; when the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module sends an interrupt signal to the MCU subsystem.

[0010] In addition, the low voltage detection control circuit further includes: a voltage stabilizer, the input end of the voltage stabilizer is electrically connected to the output end of the external power supply module, and the output end of the voltage stabilizer is electrically connected to the external voltage input end.

[0011] In addition, the low voltage detection control circuit further includes: a backup power supply module, and the output end of the backup power supply module is electrically connected to the second input end of the voltage control module.

[0012] An embodiment of the present application further provides an electronic device, comprising any of the low voltage detection control circuits described above.

[0013] An embodiment of the present application also provides a low voltage detection control method, which is applied to any of the above-mentioned low voltage detection control circuits, and the method includes: when it is detected that the external voltage is less than a first threshold voltage, the voltage control module sends a control signal to the NB subsystem to control the power of the NB subsystem to be turned off; when it is detected that the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the voltage control module sends a control signal to the MCU subsystem to control the power of the MCU subsystem to be turned off; when it is detected that the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when it is detected that the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module sends an interrupt signal to the MCU subsystem.

[0014] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0015] The low voltage detection control circuit provided by the embodiment of the present application can monitor the system voltage during the system sleep mode, and set different threshold voltage values ​​and corresponding threshold settings for different behaviors to protect the system and improve the safety of the system. The low voltage detection control circuit provided by the present application is provided with a voltage comparison module and a voltage control module. The voltage comparison module compares the external voltage with the threshold voltage and sends the comparison result to the voltage control module. The voltage control module sends a corresponding control signal to the external system module according to the comparison result to protect the system; the embodiment of the present application can monitor the system voltage at all times through the voltage comparison module and the voltage control module, and when the external voltage is less than the threshold voltage, the voltage control module can output a control signal to the external system module to turn off the system power supply, reduce the power consumption of the system, extend the external power supply time, and prevent the system from abnormal or freezing when the voltage is low, so as to protect the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by the pictures in the corresponding drawings, and these exemplary descriptions do not constitute limitations on the embodiments.

[0017] Figure 1 Schematic diagram of the module structure of the low voltage detection control circuit of the embodiment of the present application;

[0018] Figure 2 is a schematic diagram of a low voltage detection control circuit according to an embodiment of the present application;

[0019] Figure 3 is a schematic diagram of a voltage control module according to an embodiment of the present application;

[0020] Figure 4 It is a flow chart of the low voltage detection control method of an embodiment of the present application. DETAILED DESCRIPTION

[0021] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not be construed as any limitation, and the various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0022] The embodiment of the present application relates to a low voltage detection control circuit, which is applied to an electronic device; wherein the electronic device can be a terminal or a server, and this embodiment and the following embodiments are described by taking an electronic device integrated with a SoC system as an example. The implementation details of the low voltage detection control circuit of this embodiment are described in detail below, and the following content is only for the convenience of understanding the implementation details provided, and is not necessary for the implementation of this solution.

[0023] An embodiment of the present application provides a low voltage detection control circuit, including: a voltage comparison module 101 and a voltage control module 102, wherein the voltage comparison module 101 includes an external voltage input terminal and a threshold voltage input terminal, and the external voltage input terminal is electrically connected to the output terminal of an external power supply module 103; a first input terminal of the voltage control module 102 is electrically connected to the output terminal of the voltage comparison module 101, a threshold voltage output terminal of the voltage control module 102 is electrically connected to the threshold voltage input terminal, and a signal output terminal of the voltage control module 102 is electrically connected to an external system module 104; wherein the voltage comparison module 101 compares the voltage of the external voltage input terminal with the voltage of the threshold voltage input terminal to obtain a comparison result, and sends the comparison result to the voltage control module 102; when the voltage of the external voltage input terminal is less than the voltage of the threshold voltage input terminal, the voltage control module 102 sends a control signal to the external system module 104.

[0024] See also Figure 1In the NBIoT communication system, the external power module 103 usually provides power for the system on chip SoC, and the external power module 103 can be, for example, a battery. The output end of the external power module 103 is electrically connected to the external voltage input end of the voltage comparison module 101, the threshold voltage input end of the voltage comparison module 101 is electrically connected to the voltage control module 102, the output end of the voltage comparison module 101 is electrically connected to the first input end of the voltage control module 102, and the signal output end of the voltage control module 102 is electrically connected to the external system module 104. The low voltage detection control circuit provided in the embodiment of the present application is provided with a voltage comparison module 101 and a voltage control module 102. The voltage comparison module 101 compares the external voltage with the threshold voltage and sends the comparison result to the voltage control module 102. The voltage control module 102 sends a corresponding control signal to the external system module 104 according to the comparison result to protect the system.

[0025] See also Figure 2 , the external system module 104 includes an NB subsystem and an MCU subsystem integrated on the chip to form a system-on-chip SoC. The system-on-chip SoC can realize functions such as data storage, processing, logic and interface through the NB subsystem and the MCU subsystem, and can realize faster and safer data transmission between the NB subsystem and the MCU subsystem, with higher overall system speed, lower power consumption, smaller physical size and better reliability. Usually, the NB subsystem of the system-on-chip SoC is used for data transmission, and the current consumption is relatively large, about 200 to 300mA. Therefore, when the system-on-chip SoC is in a low voltage state, the high-power NB subsystem should be turned off first to reduce the power consumption of the system and extend the external power supply time, and then turn off the MCU subsystem to put the system into sleep mode to further reduce power consumption. Usually, the MCU subsystem includes one or more MCU processors, as well as peripheral interfaces such as memory, counter (timer), USB, A / D conversion, etc. As a chip-level computer, it is mainly used in measurement and control systems, intelligent instruments, mechatronics products, intelligent interfaces, etc., and performs different combination controls for different application scenarios.

[0026] In response to the problem that the system voltage drops rapidly and the system is in sleep mode, and the system does not have time to handle the abnormality, resulting in a crash, etc., the embodiment of the present application provides a low voltage detection control circuit, which can monitor the system voltage at all times through the voltage comparison module 101 and the voltage control module 102, and when the external voltage is less than the threshold voltage, the voltage control module 102 can output a control signal to the external system module 104 to shut down the system power supply, reduce the power consumption of the system, extend the external power supply time, and prevent the system from abnormalities or crashes when the voltage is low, so as to protect the system and improve the safety of the system.

[0027] like Figure 3 As shown, the voltage control module 102 includes: a threshold control module 1021, a mode setting module 1022 and a state machine module 1023; wherein, the output end of the threshold control module 1021 is electrically connected to the threshold voltage input end, the first input end of the threshold control module 1021 is electrically connected to the first output end of the mode setting module 1022, and the second input end of the threshold control module 1021 is electrically connected to the first output end of the state machine module 1023; the second output end of the mode setting module 1022 is electrically connected to the first input end of the state machine module 1023, and the control signal output end of the state machine module 1023 is electrically connected to the external system module 104.

[0028] In some embodiments, the mode setting module 1022 includes a time setting module, a threshold setting module and a signal setting module. By setting different times, threshold voltages and state machine output signal modes corresponding to different comparison results, the mode setting module 1022 sends the set time and threshold voltage to the threshold control module 1021. The threshold control module 1021 can be, for example, a threshold controller. The threshold controller sends different threshold voltages to the voltage comparison module 101. The threshold voltages include a first threshold voltage (threshold 1), a second threshold voltage (threshold 2), a third threshold voltage (threshold 3) and a fourth threshold voltage (threshold 4). The mode setting module 1022 sends the state machine output signal corresponding to different comparison results to the state machine module 1023. The state machine module 1023 sends different control signals according to different comparison results to trigger different behaviors of the system. Of course, other numbers of threshold voltages can also be set as needed. The threshold control module 1021 sends different threshold voltages to the voltage comparison module 101 for voltage comparison to obtain comparison results; the state machine module 1023 sends a control signal to the external system module 104 according to the comparison results to protect the system.

[0029] It should be noted that the voltage comparison module 101 can be, for example, a voltage comparator, which compares the external voltage with the threshold voltage and sends the comparison result to the state machine module 1023. The state machine module 1023 generates different signals according to the comparison result to control the behavior of the system. For example, when the external voltage is less than the first threshold voltage, the state machine module 1023 generates an nb_pd signal to control the power switch of the NB subsystem, automatically turns off the power of the NB subsystem, reduces the power consumption of the system, and extends the external power supply time; when the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the state machine module 1023 generates an mcu_pd signal to control the power switch of the MCU subsystem, turns off the power of the MCU subsystem, and the system enters a sleep state to further reduce the power consumption of the system; when the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the state machine module 1023 generates an interrupt signal and sends it to the MCU subsystem, so that the MCU subsystem determines the behavior of the system. In the embodiment of the present application, the threshold control module 1021 sends different preset threshold voltages to the voltage comparison module 101. The voltage comparison module 101 compares the threshold voltage with the external voltage. The state machine module 1023 sends different control signals to the external system module 104 according to the comparison result between the external voltage and the threshold voltage. This not only realizes real-time monitoring of the system voltage, but also can output control signals to the external system module to trigger corresponding behaviors when the system voltage is low, thereby improving the safety of the system.

[0030] In some embodiments, the voltage control module 102 also includes: a filtering module 1024, a first input terminal of the filtering module 1024 is electrically connected to the output terminal of the voltage comparison module 101, a second input terminal of the filtering module 1024 is electrically connected to the third output terminal of the mode setting module 1022, and an output terminal of the filtering module 1024 is electrically connected to the second input terminal of the state machine module 1023.

[0031] Please continue to see Figure 3, after the voltage comparison module 101 compares the external voltage with the threshold voltage, it obtains a comparison result, and sends the comparison result to the filter module 1024, and sends the comparison result to the state machine module 1023 after filtering. The state machine module 1023 generates different signals to control the behavior of the system. In addition, the mode setting module 1022 sends the set time and threshold voltage to the filter module 1024, and sends it to the threshold control module 1021 after filtering; the mode setting module 1022 sends the state machine output signal corresponding to different comparison results to the filter module 1024, and sends it to the state machine module 1023 after filtering, so as to send different signals to trigger different behaviors. The filter module 1024 can be, for example, a filter, which is used to filter out interference signals and prevent detection errors caused by voltage jitter.

[0032] In some embodiments, the external system module 104 includes a NB subsystem and an MCU subsystem, the first signal output end of the voltage control module 102 is electrically connected to the input end of the NB subsystem, the second signal output end of the voltage control module 102 is electrically connected to the first input end of the MCU subsystem, and the third signal output end of the voltage control module 102 is electrically connected to the second input end of the MCU subsystem.

[0033] like Figure 2 As shown, the first signal output terminal of the voltage control module 102 outputs the nb_pd signal and sends it to the NB subsystem to control the power switch of the NB subsystem; the second signal output terminal of the voltage control module 102 outputs the mcu_pd signal and sends it to the MCU subsystem to control the power switch of the MCU subsystem; the third signal output terminal of the voltage control module 102 outputs the interrupt signal and sends it to the MCU subsystem, so that the MCU subsystem determines the behavior of the system. By monitoring the external power supply voltage, the embodiment of the present invention can timely control the behavior of the system when the external power supply voltage is lower than the threshold voltage, prevent the system from abnormal behavior, and improve the safety of the system.

[0034] Please continue to see Figure 2 , the first signal output end of the voltage control module 102 is electrically connected to the input end of the NB subsystem through the first end of the first key switch S1, and the second end of the first key switch S1 is grounded; the second signal output end of the voltage control module 102 is electrically connected to the first input end of the MCU subsystem through the first end of the second key switch S2, and the second end of the second key switch S2 is grounded. In the embodiment of the present invention, the voltage control module and the NB subsystem are turned on or off through the first key switch S1; and the voltage control module and the MCU subsystem are turned on or off through the second key switch S2.

[0035] In some embodiments, when the external voltage is less than a first threshold voltage, the voltage control module 102 sends a control signal to the NB subsystem to control the power of the NB subsystem to be turned off; when the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the voltage control module 102 sends a control signal to the MCU subsystem to control the power of the MCU subsystem to be turned off; when the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module 102 sends an interrupt signal to the MCU subsystem.

[0036] The low voltage detection control circuit provided in the embodiment of the present application can not only monitor the system voltage at all times, but also set different voltage thresholds, and the system automatically performs different processing according to different voltage thresholds. This device can set 4 different voltage thresholds: a first threshold voltage (threshold 1), a second threshold voltage (threshold 2), a third threshold voltage (threshold 3) and a fourth threshold voltage (threshold 4). For typical application scenarios, the voltage of threshold 1 can be set to control whether the NB subsystem is turned off, and the voltage of threshold 2 can be set to control whether different MCU subsystems are turned off. At the same time, the settings of all thresholds are transmitted to the MCU subsystem through the mode setting module 1022, and the behavior of the system is determined by the MCU.

[0037] like Figure 2 As shown, the low voltage detection control circuit also includes: a voltage regulator 105, the input end of the voltage regulator 105 is electrically connected to the output end of the external power module 104, and the output end of the voltage regulator 105 is electrically connected to the external voltage input end. The voltage regulator 105 can be, for example, a low dropout linear regulator (Low Dropout Regulator, LDO), the external voltage output by the external power module 104 is adjusted to a stable output voltage by the voltage regulator 105, and then the stabilized external voltage is output to the external voltage input end of the voltage comparison module, and the voltage comparison module 101 compares the voltage of the external voltage input end with the voltage of the threshold voltage input end.

[0038] like Figure 2 As shown, the low voltage detection control circuit also includes: a backup power module 106, the output end of the backup power module 106 is electrically connected to the second input end of the voltage control module 102. The backup power module 106 is used to maintain the system's minimum power consumption mode and protect the system when the external power supply 103 is removed or the system voltage is reduced. Specifically, when there is no external power supply 103 or the system voltage is reduced, the working power supply of the voltage control module 102 is switched to the backup power module 106, and after the high energy consumption 104 is turned off, the system's minimum power consumption mode is maintained.

[0039] The low voltage detection control circuit provided in the embodiment of the present application compares the external voltage and the threshold voltage through the voltage comparison module 101, and sends the comparison result to the voltage control module. The voltage control module 102 sends a corresponding control signal to the external system module according to the comparison result to protect the system. The present invention can monitor the system voltage at all times through the voltage comparison module 101 and the voltage control module 102, and when the external voltage is less than the threshold voltage, the voltage control module 102 outputs a control signal to the external system module 104 to shut down the system power supply, reduce the power consumption of the system, extend the external power supply time, and prevent the system from abnormal or freezing behavior when the voltage is low, so as to protect the system.

[0040] The embodiment of the present application also provides an electronic device, including any of the low voltage detection control circuits described above. The electronic device may be a terminal, a server, or an IoT electric meter, water meter, and gas meter based on NBIoT communication technology. When the external battery is out of power or removed, the voltage is monitored at all times in the sleep mode of the electronic device through the low voltage detection control circuit to prevent the electronic device from having system abnormalities, freezing, and other problems due to a decrease in external voltage.

[0041] See also Figure 4 , an embodiment of the present application further provides a low voltage detection control method, which is applied to any of the above-mentioned low voltage detection control circuits, and the method comprises:

[0042] Step S1: when it is detected that the external voltage is less than the first threshold voltage, the voltage control module 102 sends a control signal to the NB subsystem to control the power supply of the NB subsystem to be turned off;

[0043] Step S2: when it is detected that the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the voltage control module 102 sends a control signal to the MCU subsystem to control the power supply of the MCU subsystem to be turned off;

[0044] Step S3: When it is detected that the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when it is detected that the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module 102 sends an interrupt signal to the MCU subsystem.

[0045] The embodiment of the present application sets different threshold voltages and corresponding threshold settings for different system behaviors, so that the system can always detect the system voltage when the system is in low voltage or sleep mode. According to the comparison result between the external voltage and the threshold voltage, the voltage control module 102 sends different control signals to the NB subsystem and the MCU subsystem to trigger corresponding behaviors and improve the safety of the system.

[0046] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0047] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A low voltage detection control circuit is applied to a system on chip, wherein the system on chip includes a NB subsystem and an MCU subsystem integrated on a chip, characterized in that: include: A voltage comparison module; the voltage comparison module comprises an external voltage input terminal and a threshold voltage input terminal, the external voltage input terminal is electrically connected to the output terminal of the external power supply module; A voltage control module; a first input terminal of the voltage control module is electrically connected to an output terminal of the voltage comparison module, a threshold voltage output terminal of the voltage control module is electrically connected to the threshold voltage input terminal, and a signal output terminal of the voltage control module is electrically connected to an external system module; The voltage comparison module compares the voltage of the external voltage input terminal with the voltage of the threshold voltage input terminal to obtain a comparison result, and sends the comparison result to the voltage control module; when the voltage of the external voltage input terminal is less than the voltage of the threshold voltage input terminal, the voltage control module sends a control signal to the external system module; The voltage control module comprises: a threshold control module, a mode setting module and a state machine module; wherein the output end of the threshold control module is electrically connected to the threshold voltage input end, the first input end of the threshold control module is electrically connected to the first output end of the mode setting module, the second input end of the threshold control module is electrically connected to the first output end of the state machine module; the second output end of the mode setting module is electrically connected to the first input end of the state machine module, and the control signal output end of the state machine module is electrically connected to the external system module; The external system module includes a NB subsystem and an MCU subsystem, the first signal output end of the voltage control module is electrically connected to the input end of the NB subsystem, the second signal output end of the voltage control module is electrically connected to the first input end of the MCU subsystem, and the third signal output end of the voltage control module is electrically connected to the second input end of the MCU subsystem.

2. The low voltage detection control circuit according to claim 1, characterized in that: The voltage control module further includes: A filtering module, wherein a first input terminal of the filtering module is electrically connected to an output terminal of the voltage comparison module, a second input terminal of the filtering module is electrically connected to a third output terminal of the mode setting module, and an output terminal of the filtering module is electrically connected to a second input terminal of the state machine module.

3. The low voltage detection control circuit according to claim 1, characterized in that: The first signal output end of the voltage control module is electrically connected to the input end of the NB subsystem through the first end of the first key switch, and the second end of the first key switch is grounded; the second signal output end of the voltage control module is electrically connected to the first input end of the MCU subsystem through the first end of the second key switch, and the second end of the second key switch is grounded.

4. The low voltage detection control circuit according to claim 1 or 3, characterized in that: When the external voltage is less than a first threshold voltage, the voltage control module sends a control signal to the NB subsystem to control the power supply of the NB subsystem to be turned off; When the external voltage is greater than a first threshold voltage and less than a second threshold voltage, the voltage control module sends a control signal to the MCU subsystem to control the power supply of the MCU subsystem to be turned off; When the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module sends an interrupt signal to the MCU subsystem.

5. The low voltage detection control circuit according to claim 1, characterized in that: Also includes: A voltage stabilizer, wherein the input end of the voltage stabilizer is electrically connected to the output end of the external power supply module, and the output end of the voltage stabilizer is electrically connected to the external voltage input end.

6. The low voltage detection control circuit according to claim 1, characterized in that: Also includes: A backup power supply module, wherein the output end of the backup power supply module is electrically connected to the second input end of the voltage control module.

7. An electronic device, characterized in that: The invention comprises a low voltage detection control circuit as claimed in any one of claims 1 to 6.

8. A low voltage detection control method, characterized in that: Applied to the low voltage detection control circuit according to any one of claims 1 to 6, the method comprising: When it is detected that the external voltage is less than the first threshold voltage, the voltage control module sends a control signal to the NB subsystem to control the power supply of the NB subsystem to be turned off; When it is detected that the external voltage is greater than the first threshold voltage and less than the second threshold voltage, the voltage control module sends a control signal to the MCU subsystem to control the power supply of the MCU subsystem to be turned off; When it is detected that the external voltage is greater than the second threshold voltage and less than the third threshold voltage, or when it is detected that the external voltage is greater than the second threshold voltage and less than the fourth threshold voltage, the voltage control module sends an interrupt signal to the MCU subsystem.

Images