Analog front end control circuit and battery management system

Abstract

The application discloses an analog front-end control circuit and a battery management system. The analog front-end control circuit comprises a microcontroller, an analog front-end, a power supply, a voltage dividing circuit and a switch circuit. The microcontroller is used to generate an input signal, and the input signal comprises a first signal and a second signal. The analog front-end is connected with the microcontroller. The power supply is used to output a control voltage. The voltage dividing circuit is connected with the analog front-end and is used to divide the control voltage to generate a voltage dividing signal. The switch circuit is connected with the microcontroller and the voltage dividing circuit, and is used to turn on the voltage dividing circuit to generate a first voltage dividing signal according to the second signal, or turn off the voltage dividing circuit to generate a second voltage dividing signal when the second signal is lost. In the case that the microcontroller generates the input signal and the switch circuit is turned on, the analog front-end is used to shut down according to the first signal. In the case that the microcontroller does not generate the input signal, the analog front-end is used to shut down according to the second voltage dividing signal.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and more specifically, to an analog front-end control circuit and a battery management system. Background Technology

[0002] A Battery Management System (BMS) is an electronic control system that monitors, manages, and protects batteries in real time. In related technologies, a BMS includes devices such as an analog front-end, a microcontroller, and MOSFETs. Generally, when a system fault occurs (e.g., short circuit, overcurrent, overvoltage), the MOSFETs may directly cut off the power supply circuit, causing the microcontroller to shut down. However, since the analog front-end requires a shutdown command from the microcontroller to power off, if a system fault occurs and the microcontroller cannot send a shutdown command to the analog front-end in time, the analog front-end will remain operational and frequently restart the MOSFETs, potentially damaging them and affecting the stability and reliability of the BMS. Utility Model Content

[0003] The embodiments of this application provide a simulated front-end control circuit and a battery management system to solve at least one of the aforementioned technical problems.

[0004] The analog front-end control circuit provided in this application includes a microcontroller, an analog front-end, a power supply, a voltage divider circuit, and a switching circuit. The microcontroller generates an input signal, which includes a first signal and a second signal. The analog front-end is connected to the microcontroller. The power supply outputs a control voltage. The voltage divider circuit is connected to the analog front-end and divides the control voltage to generate a voltage divider signal. The switching circuit is connected to both the microcontroller and the voltage divider circuit and is used to turn on the voltage divider circuit to generate a first voltage divider signal based on the second signal, or to turn off the voltage divider circuit to generate a second voltage divider signal when the second signal is missing. When the microcontroller generates the input signal and the switching circuit is on, the analog front-end is used to power off based on the first signal. When the microcontroller does not generate the input signal, the analog front-end is used to power off based on the second voltage divider signal.

[0005] In some embodiments, the analog front end includes a first pin and a second pin. The first pin is connected to the voltage divider circuit and is used to output the control voltage. The second pin is connected to the microcontroller, the voltage divider circuit, and the switching circuit, and is used to receive the first signal and the voltage divider signal.

[0006] In some embodiments, the voltage divider circuit includes a first resistor and a second resistor connected in series. One end of the first resistor is connected to the first pin, and the other end is connected to one end of the second resistor. The other end of the second resistor is grounded, and the second pin is connected to the intermediate connection point of the first resistor and the second resistor.

[0007] In some implementations, the resistance of the first resistor is less than the resistance of the second resistor.

[0008] In some embodiments, the voltage divider circuit further includes a fifth resistor, which is connected in series with the first resistor and in parallel with the second resistor, and the fifth resistor is connected to ground after being connected to the switching circuit.

[0009] In some embodiments, the resistance value of the fifth resistor is less than the resistance value of the first resistor.

[0010] In some embodiments, the switching circuit includes a field-effect transistor (FET), the drain of which is connected to the fifth resistor, the gate of which receives the second signal, and the source of which is grounded.

[0011] In some implementations, the analog front-end is powered off based on a high-level signal, where the first voltage divider signal is a low-level signal and the second voltage divider signal is a high-level signal.

[0012] In some implementations, when the microcontroller generates the input signal, and the first signal includes a low-level signal and the second signal includes a high-level signal, the analog front-end is in an operational state, and the switching circuit is turned on; when the microcontroller generates the input signal, and the first signal includes a high-level signal, the analog front-end is used to power off according to the first signal; when the microcontroller does not generate the input signal, and the second voltage divider signal includes a high-level signal, the analog front-end is used to power off according to the second voltage divider signal.

[0013] The battery management system provided in this application includes the analog front-end control circuit described in any of the above embodiments.

[0014] In the analog front-end control circuit and battery management system of this application, the microcontroller is used to generate an input signal. The voltage divider circuit is connected to the analog front-end and is used to divide the control voltage to generate a voltage divider signal (including a first voltage divider signal and a second voltage divider signal). When the microcontroller generates an input signal and the switching circuit is turned on, the analog front-end is used to shut down according to the first signal. When the microcontroller does not generate an input signal, the analog front-end is used to shut down according to the second voltage divider signal. That is, when a system fault occurs and the microcontroller is unable to issue a shutdown command (first signal) to the analog front-end in time, the analog front-end can shut down according to the second voltage divider signal. This avoids the analog front-end from frequently restarting the MOSFET while in the working state, which could damage the MOSFET. This extends the service life of the MOSFET and improves the stability and reliability of the analog front-end control circuit and battery management system.

[0015] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:

[0017] Figure 1 This is a block diagram of the module connection of a battery management system according to certain embodiments of this application;

[0018] Figure 2 This is a circuit diagram of the simulated front-end control circuit in a battery management system according to certain embodiments of this application.

[0019] Explanation of key component symbols:

[0020] 100 Battery Management System;

[0021] 10. Analog front-end control circuit;

[0022] 11 Microcontroller; 13 Analog front end; 15 Voltage divider circuit, 151 First resistor, 153 Second resistor, 155 Fifth resistor; 17 Switching circuit, 171 Third resistor, 173 Fourth resistor, 175 Field-effect transistor. Detailed Implementation

[0023] The embodiments of this application are described in detail below. These embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0024] In the description of the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] A Battery Management System (BMS) is an electronic control system that monitors, manages, and protects batteries in real time. In related technologies, a BMS includes devices such as an analog front-end, a microcontroller, and MOSFETs. Generally, when a system fault occurs (e.g., short circuit, overcurrent, overvoltage), the MOSFETs may directly cut off the power supply circuit, causing the microcontroller to shut down. However, since the analog front-end requires a shutdown command from the microcontroller to power off, if a system fault occurs and the microcontroller cannot send a shutdown command to the analog front-end in time, the analog front-end will remain active and frequently restart the MOSFETs, leading to MOSFET damage and affecting the stability and reliability of the BMS. Please refer to [link to relevant documentation]. Figure 1 To address this issue, this application provides an analog front-end control circuit 10 and a battery management system 100.

[0026] Please see Figure 1 This application provides a battery management system 100. The battery management system 100 includes an analog front-end control circuit 10.

[0027] As is understandable, a Battery Management System (BMS) is an electronic system used to monitor, control, and manage batteries. The BMS has functions such as condition monitoring, safety protection, equalization control, and communication and control, ensuring that the battery operates in a safe, efficient, and stable state, and maximizing battery life and performance.

[0028] The analog front-end control circuit 10 is a circuit in the battery management system 100 used to detect signals such as battery voltage, temperature, and current, and is responsible for battery balancing and the shut-off and shut-off of the charging and discharging circuit of the battery management system 100. For example, when the battery management system 100 receives a shutdown command, the analog front-end control circuit 10 can control the battery to stop output; when the battery management system 100 malfunctions, such as when the battery experiences overvoltage, undervoltage, overcurrent, high temperature, or short circuit, the analog front-end control circuit 10 can control the MOSFET to turn off, thereby cutting off the battery's charging and discharging path.

[0029] Since the battery management system 100 in this embodiment includes an analog front-end control circuit 10, it is understood that the battery management system 100 has at least the same beneficial effects as the analog front-end control circuit 10. Therefore, for the beneficial effects of the battery management system 100, please refer to the beneficial effects of the analog front-end control circuit 10 described below.

[0030] Please see Figure 1 and Figure 2 This application provides an analog front-end control circuit 10. The analog front-end control circuit 10 includes a microcontroller 11, an analog front-end 13, a power supply, a voltage divider circuit 15, and a switching circuit 17. The microcontroller 11 generates input signals, including a first signal and a second signal. The analog front-end 13 is connected to the microcontroller 11. The power supply outputs a control voltage. The voltage divider circuit 15 is connected to the analog front-end 13 and divides the control voltage to generate a voltage divider signal. The switching circuit 17 is connected to both the microcontroller 11 and the voltage divider circuit 15, and is used to enable the voltage divider circuit 15 to generate a first voltage divider signal when the second signal is on, or to disable the voltage divider circuit 15 to generate a second voltage divider signal when the second signal is missing. When the microcontroller 11 generates an input signal and the switching circuit 17 is on, the analog front-end 13 is used to power off according to the first signal; when the microcontroller 11 does not generate an input signal, the analog front-end 13 is used to power off according to the second voltage divider signal.

[0031] It is understood that the microcontroller unit (MCU) 11 is a device used to run battery management algorithms (such as SOC / SOH estimation), decision logic (such as charge / discharge control), communication interaction (with the vehicle or charging station), and fault handling. In some embodiments of this application, the microcontroller 11 can be electrically connected to the battery through a MOSFET, so that when the MOSFET is turned on, the battery can supply power to the microcontroller 11 through the MOSFET to maintain the stable operation of the microcontroller 11.

[0032] The Analog Front End (AFE) 13 is a battery signal acquisition and preprocessing unit. It can be directly connected to the battery and is responsible for accurately measuring analog signals such as cell voltage, temperature, and total current, converting them into digital signals for processing by the microcontroller 11. It should be noted that in some embodiments, the Analog Front End 13 can be a BQ769X2 series chip (e.g.,...). Figure 2 The chip U1 in the text can also be other types of chips. Among them, the BQ769X2 series chips include, but are not limited to, BQ76942 and BQ76952.

[0033] The power supply is a device in the analog front-end control circuit 10 used to output a control voltage. In some embodiments, the power supply can be set up independently, that is, the power supply is a separate device capable of outputting a control voltage. For example, during normal operation of the battery management system 100, that is, when the system is not faulty, the battery can supply power to the power supply so that the power supply can output a control voltage.

[0034] In other embodiments, the power supply can be located in the analog front-end 13. For example, the power supply can be an LDO power supply circuit, which can convert a higher input voltage (e.g., battery voltage) into a stable, low-noise low output voltage (i.e., control voltage). The low output voltage value can be 3.3V or 2.5V, etc. Since the analog front-end 13 has an LDO power supply circuit, in the event of a system failure, the power supply can output a control voltage, and the analog front-end 13 can shut down according to the second voltage divider signal generated by the voltage divider circuit 15 dividing the control voltage. That is, in the event of a system failure, the shutdown of the analog front-end 13 depends on its own power supply circuit, thus eliminating the need for an additional power supply circuit in the analog front-end control circuit 10. This simplifies the structure of the analog front-end control circuit 10, reducing structural complexity and production costs.

[0035] For ease of understanding, the following implementation method uses the example of the power supply being located in the analog front end 13.

[0036] In some embodiments of this application, when the system is not malfunctioning, that is, when the battery management system 100 is working normally, the microcontroller 11 can generate an input signal. When the battery management system 100 receives a power-off command, the microcontroller 11 can send an input signal (first signal) to the analog front-end 13 to pull up the voltage of one pin of the analog front-end 13 and make the voltage pull-up time exceed a predetermined time. For example, the microcontroller 11 can send a first signal to the analog front-end 13 to pull up the voltage of one pin of the analog front-end 13 to 3V and make the voltage pull-up time exceed 1 second, thereby realizing the power-down of the analog front-end 13 and the battery management system 100 completes the power-down action. In the event of a system malfunction, such as a short circuit, overcurrent, or overvoltage in the battery, the analog front-end 13 can directly cut off the power supply circuit between the battery and the microcontroller 11. That is, the analog front-end 13 controls the MOSFET between the battery and the microcontroller 11 to disconnect, thereby powering off the microcontroller 11. In this case, the microcontroller 11 does not generate an input signal, and the voltage divider signal can act on a pin of the analog front-end 13 (the same pin that receives the first signal), thereby causing the analog front-end 13 to power down according to the voltage divider signal (the second voltage divider signal).

[0037] It should be noted that when the switching circuit 17 is turned on according to the second signal, the switching circuit 17 is equivalent to a grounded wire. In this case, the pin on the analog front-end 13 connected to the voltage divider circuit 15 can be grounded through the switching circuit 17. The voltage divider circuit 15 divides the control voltage to generate the first voltage divider signal. The analog front-end 13 cannot be shut down according to the first voltage divider signal, thereby ensuring the stability and reliability of the analog front-end control circuit 10 when the system does not malfunction.

[0038] In the analog front-end control circuit 10 of this application embodiment, the microcontroller 11 is used to generate an input signal. The voltage divider circuit 15 is connected to the analog front-end 13 and is used to divide the control voltage to generate a voltage divider signal. When the microcontroller 11 generates an input signal and the switching circuit 17 is turned on, the analog front-end 13 is used to shut down according to the first signal. When the microcontroller 11 does not generate an input signal, the analog front-end 13 is used to shut down according to the second voltage divider signal. That is, when a system fault occurs and the microcontroller 11 is unable to issue a shutdown command (first signal) to the analog front-end 13 in time, the analog front-end 13 can shut down according to the second voltage divider signal. This avoids the analog front-end 13 from being kept in the working state and frequently restarting the MOSFET, which would damage the MOSFET. This can extend the service life of the MOSFET and improve the stability and reliability of the analog front-end control circuit 10 and the battery management system 100.

[0039] The analog front-end control circuit 10 will be further explained below with reference to the accompanying drawings.

[0040] Please see Figure 2 In some implementations, the analog front-end 13 is powered off based on a high-level signal, the first voltage divider signal is a low-level signal, and the second voltage divider signal is a high-level signal.

[0041] Furthermore, in some embodiments, when the microcontroller 11 generates an input signal, and the first signal includes a low-level signal and the second signal includes a high-level signal, the analog front-end 13 is in an operating state, and the switching circuit 17 is turned on; when the first signal includes a high-level signal, the analog front-end 13 is used to power off according to the first signal; when the microcontroller 11 does not generate an input signal, and the second voltage divider signal includes a high-level signal, the analog front-end 13 is used to power off according to the second voltage divider signal. That is, the analog front-end 13 powers off according to the high-level signal; in other words, when the analog front-end 13 receives a high-level signal, the analog front-end 13 can switch from an operating state to a power-off state according to the high-level signal. The switching circuit 17 is turned on under a high-level signal and turned off under a low-level signal or no signal. The high-level signal received by the analog front-end 13 can come from the first signal output by the microcontroller 11; or, the second voltage divider signal generated by the voltage divider circuit 15 dividing the control voltage. It should be noted that in some embodiments, the voltage value of the high-level signal can be greater than or equal to 1.2V.

[0042] It is understood that in some embodiments, when the first signal includes a high-level signal and the analog front-end 13 is used to power off according to the first signal, the second signal can be either a high-level signal or a low-level signal. That is, when the analog front-end 13 powers off according to the first signal, the switching circuit 17 can be either in the on state (when the second signal is a high-level signal) or in the off state (when the second signal is a low-level signal).

[0043] In other embodiments, the analog front-end 13 shuts down based on a low-level signal, and the switching circuit 17 is turned on under a high-level signal and turned off under a low-level signal or no signal; or, the analog front-end 13 shuts down based on a low-level signal, and the switching circuit 17 is turned on under a low-level signal and turned off under a high-level signal; or, the analog front-end 13 shuts down based on a high-level signal, and the switching circuit 17 is turned on under a low-level signal and turned off under a high-level signal.

[0044] For ease of understanding, this application will exemplarily select one of the embodiments for description. That is, in the following embodiment, the analog front end 13 is turned off according to a high-level signal, and the switching circuit 17 is turned on when there is a high-level signal and turned off when there is a low-level signal or no signal.

[0045] Please see Figure 2 In some embodiments, the analog front end 13 includes a first pin and a second pin. The first pin is connected to the voltage divider circuit 15 and is used to output a control voltage. The second pin is connected to the microcontroller 11, the voltage divider circuit 15 and the switching circuit 17 and is used to receive the first signal and the voltage divider signal.

[0046] Specifically, in some embodiments, when the analog front-end 13 is a BQ769X2 series chip U1, the first pin can be PIN "REG1" (hereinafter referred to as REG1 pin), and the second pin can be PIN "RST_SHUT" (hereinafter referred to as RST_SHUT pin). Under fault-free conditions, the first pin outputs a control voltage, and the second pin receives a first signal and a first voltage divider signal. The analog front-end 13 can switch between an operating state and a power-off state based on the first signal. Under system fault conditions, the first pin outputs a control voltage, and the second pin receives a second voltage divider signal. The analog front-end 13 switches from an operating state to a power-off state based on the second voltage divider signal.

[0047] Furthermore, in some embodiments, the voltage divider circuit 15 includes a first resistor 151 and a second resistor 153 connected in series. One end of the first resistor 151 is connected to a first pin, and the other end is connected to one end of the second resistor 153. The other end of the second resistor 153 is grounded (GND), and the second pin is connected to the intermediate connection point of the first resistor 151 and the second resistor 153.

[0048] Specifically, in some embodiments, the second pin is connected to the midpoint between the first resistor 151 and the second resistor 153, that is, the second pin is connected at any position between the first resistor 151 and the second resistor 153. In this case, the voltage V obtained at the second pin is:

[0049]

[0050] Wherein, V1 is the voltage value of the control voltage, R1 is the resistance value of the first resistor 151, and R2 is the resistance value of the second resistor 153.

[0051] More specifically, in some embodiments, the resistance of the first resistor 151 is less than the resistance of the second resistor 153. This ensures that the voltage at the second pin is higher when the switching circuit 17 is open, that is, it ensures that the second voltage divider signal received at the second pin is a high-level signal when the switching circuit 17 is open. This allows the analog front-end 13 to switch from the operating state to the shutdown state according to the second voltage divider signal when a system fault occurs, avoiding the analog front-end 13 remaining in the operating state and frequently restarting the MOSFET, which could damage the MOSFET. This improves the performance of the analog front-end control circuit 10 and the battery management system 100. Figure 1 (As shown) The stability and reliability of the operation.

[0052] For example, the resistance ratio of the first resistor 151 and the second resistor 153 is 1:10. Therefore, when the control voltage is 3.3V, the voltage V obtained at the second pin when the switch circuit 17 is turned off can be 3V, that is, the second voltage divider signal is a high-level signal, thereby enabling the analog front-end 13 to shut down according to the second voltage divider signal.

[0053] In some embodiments, the voltage divider circuit 15 further includes a fifth resistor 155, which is connected in series with the first resistor 151 and in parallel with the second resistor 153. The fifth resistor 155 is connected to the ground after being connected to the switching circuit 17.

[0054] Specifically, in some embodiments, the resistance of the fifth resistor 155 is less than that of the first resistor 151. For example, the resistance ratio of the fifth resistor 155, the first resistor 151, and the second resistor 153 is 1:10:100. This ensures that when the switching circuit 17 is turned on, the second pin can be grounded through the switching circuit 17, at which time the voltage divider 15 generates the first voltage divider signal, and the analog front-end 13 will not shut down based on the first voltage divider signal. On the other hand, it reduces the influence of the fifth resistor 155 on the voltage divider circuit 15, ensuring that the analog front-end 13 can shut down according to the second voltage divider signal when the switching circuit 17 is turned off.

[0055] Please continue reading. Figure 2 In some embodiments, the switching circuit 17 includes an input terminal and an output terminal. The input terminal is connected to the microcontroller 11 and is used to receive the second signal. The output terminal is connected to the intermediate connection point and is connected to the microcontroller 11. When the switching circuit 17 is turned on, the second pin is grounded to GND through the switching circuit 17.

[0056] Specifically, in some embodiments, when the switching circuit 17 is turned on, that is, when the microcontroller 11 can output the first signal and the second signal, and the switching circuit 17 is in the on state according to the second signal, the second pin is grounded to GND through the switching circuit 17. In this case, the potential of the second pin is stabilized at a low level, avoiding false triggering caused by the floating state. In other words, the shutdown control of the analog front-end 13 depends only on the first signal, thereby ensuring that the analog front-end 13 can remain in the working state when the system is fault-free, thereby improving the stability and reliability of the battery management system 100.

[0057] Furthermore, in some embodiments, the switching circuit 17 includes a field-effect transistor 175, the drain d of the field-effect transistor 175 is connected to a fifth resistor 155, the gate g of the field-effect transistor 175 receives a second signal, and the source s of the field-effect transistor 175 is grounded. It should be noted that in some embodiments, the field-effect transistor 175 can be an N-channel enhancement-mode field-effect transistor.

[0058] Specifically, in some embodiments, when the second signal is transmitted to the field-effect transistor 175 and the field-effect transistor 175 is turned on under the action of the second signal, the switching circuit 17 is turned on. In this case, the second pin of the analog front-end 13 can be grounded through the switching circuit 17, and the analog front-end 13 can switch between the working state and the power-off state according to the first signal. When the second signal is transmitted to the field-effect transistor 175 and the field-effect transistor 175 is turned off under the action of the second signal, or when no signal is transmitted to the field-effect transistor 175 and the field-effect transistor 175 is turned off, the switching circuit 17 is turned off. In this case, the analog front-end 13 can be turned off according to the second voltage divider signal, that is, the analog front-end 13 can switch from the working state to the power-off state according to the second voltage divider signal.

[0059] Furthermore, in some embodiments, the switching circuit 17 includes a third resistor 171 and a fourth resistor 173. The drain d of the field-effect transistor 175 is the output terminal of the switching circuit 17, the gate g of the field-effect transistor 175 is the input terminal of the switching circuit 17, and is connected to the microcontroller 11 through the third resistor 171. The source s of the field-effect transistor 175 is grounded to GND. One end of the fourth resistor 173 is connected between the gate g of the field-effect transistor 175 and the third resistor 171, and the other end is grounded to GND.

[0060] It should be noted that, in some embodiments, the third resistor 171 can be a driving resistor, that is, the third resistor 171 is connected in series between the gate g of the field-effect transistor 175 and the microcontroller 11, and is used to control the charging and discharging current of the gate g of the field-effect transistor 175; the fourth resistor 173 can be a voltage divider resistor, which is used to adjust the voltage of the gate g of the field-effect transistor 175. The resistance value of the third resistor 171 is less than the resistance value of the fourth resistor 173; for example, the ratio of the resistance value of the third resistor 171 to the resistance value of the fourth resistor 173 is 1:10.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0063] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An analog front-end control circuit, characterized in that, include: A microcontroller for generating input signals, the input signals including a first signal and a second signal; The analog front end is connected to the microcontroller; Power supply, used to output control voltage; A voltage divider circuit is connected to the analog front end and is used to divide the control voltage to generate a voltage divider signal. and A switching circuit is connected to both the microcontroller and the voltage divider circuit, and is used to turn on the voltage divider circuit according to the second signal to generate a first voltage divider signal, or to turn off the voltage divider circuit to generate a second voltage divider signal when the second signal is missing. When the microcontroller generates the input signal and the switching circuit is turned on, the analog front end is used to power off according to the first signal; When the microcontroller does not generate the input signal, the analog front end is used to shut down based on the second voltage divider signal.

2. The analog front-end control circuit according to claim 1, characterized in that, The analog front end includes a first pin and a second pin. The first pin is connected to the voltage divider circuit and is used to output the control voltage. The second pin is connected to the microcontroller, the voltage divider circuit and the switching circuit, and is used to receive the first signal and the voltage divider signal.

3. The analog front-end control circuit according to claim 2, characterized in that, The voltage divider circuit includes a first resistor and a second resistor connected in series. One end of the first resistor is connected to the first pin, and the other end is connected to one end of the second resistor. The other end of the second resistor is grounded, and the second pin is connected to the midpoint between the first resistor and the second resistor.

4. The analog front-end control circuit according to claim 3, characterized in that, The resistance of the first resistor is less than the resistance of the second resistor.

5. The analog front-end control circuit according to claim 3, characterized in that, The voltage divider circuit also includes a fifth resistor, which is connected in series with the first resistor and in parallel with the second resistor. The fifth resistor is connected to the ground after being connected to the switching circuit.

6. The analog front-end control circuit according to claim 5, characterized in that, The resistance value of the fifth resistor is less than the resistance value of the first resistor.

7. The analog front-end control circuit according to claim 5, characterized in that, The switching circuit includes a field-effect transistor (FET), the drain of which is connected to the fifth resistor, the gate of which receives the second signal, and the source of which is grounded.

8. The analog front-end control circuit according to claim 5, characterized in that, The analog front end is powered off based on a high-level signal, the first voltage divider signal is a low-level signal, and the second voltage divider signal is a high-level signal.

9. The analog front-end control circuit according to any one of claims 1-8, characterized in that, When the microcontroller generates the input signal, and the first signal includes a low-level signal and the second signal includes a high-level signal, the analog front-end is in an operational state, and the switching circuit is turned on; when the microcontroller generates the input signal, and the first signal includes a high-level signal, the analog front-end is used to power off according to the first signal; when the microcontroller does not generate the input signal, and the second voltage divider signal includes a high-level signal, the analog front-end is used to power off according to the second voltage divider signal.

10. A battery management system, characterized in that, include: The analog front-end control circuit according to any one of claims 1-9.

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