Isolation protection circuit of analog sampling front end, battery management system and energy storage system

Abstract

The present application relates to the field of battery technology, and discloses an isolation protection circuit, a battery management system, and an energy storage system of an analog sampling front end, wherein the isolation protection circuit includes an isolation switch module and an automatic control module; the isolation switch module is used to control whether the voltage signal connected to the charge and discharge interface is output through the receiving side of the isolation switch module according to the enable signal output by the enable end of the microprocessor; the automatic control module is used to control the switch to be turned on when the voltage signal output by the receiving side of the isolation switch module is not greater than the preset voltage value, so that the voltage signal is transmitted to the sampling end of the analog sampling front end; and, when the voltage signal is greater than the preset voltage value, the switch is controlled to switch to a cut-off state to prevent the voltage signal from being transmitted to the sampling end of the analog sampling front end. The present application can prevent the analog sampling front end from being subjected to high voltage risks, and at the same time, the system operates with low power consumption when some applications need to sleep.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an isolation protection circuit of an analog sampling front end, a battery management system, and an energy storage system. Background Art

[0002] Lithium batteries have been widely used in various application areas of life. For example, the energy storage system with a rated voltage of 48V uses a low-voltage battery pack, which is suitable for small households or devices that use electricity alone. In order to improve the safety performance of lithium batteries during use, the battery pack is generally managed and protected by a lithium battery protection board (BMS, battery management system); the battery management system is such as Figure 1 As shown, it generally includes modules such as analog sampling front-end AFE, microcontroller MCU, temperature acquisition and MOS tube driver.

[0003] At present, the connection method between the analog sampling front end AFE and the charging and discharging interface in the battery management system is as follows: Figure 2 As shown, in Figure 2 The PACK / LD pin of the analog sampling front end AFE is connected to the positive electrode of the charge and discharge interface through two series paths formed by a diode and a resistor. In essence, the analog sampling front end AFE directly collects the voltage of the charge and discharge interface. Therefore, it can effectively collect the voltage of the charge and discharge interface; however, when the charge and discharge interface has a high voltage input, the high voltage will be directly introduced into the pin of the AFE, thereby damaging the AFE and even causing the BMS to fail; among them, PACK is the battery detection input pin, and LD is the load detection pin. In addition, when some applications need to sleep, and the positive electrode (P+) of the charging interface is always equal to the total voltage of the home storage battery pack, it will cause the circuit to consume more power. Utility Model Content

[0004] In view of this, the embodiments of the present application provide an isolation protection circuit for an analog sampling front end, a battery management system, and an energy storage system, which can effectively solve the problem that the AFE will be damaged when there is high voltage at the charging and discharging interface.

[0005] In a first aspect, an embodiment of the present application provides an isolation protection circuit of an analog sampling front end, including an isolation switch module and an automatic control module;

[0006] The transmitting side of the isolating switch module is used to electrically connect to the enable end of the microcontroller, and the first end of the receiving side of the isolating switch module is electrically connected to the charging and discharging interface; the isolating switch module is used to control whether the voltage signal connected to the charging and discharging interface is output through the receiving side of the isolating switch module according to the enable signal output by the enable end of the microprocessor;

[0007] The input end of the automatic control module is electrically connected to the second end of the receiving side of the isolation switch module, and the output end of the automatic control module is used to electrically connect to the sampling end of the analog sampling front end;

[0008] The automatic control module is used to control the switch to be turned on so that the voltage signal is transmitted to the sampling end of the analog sampling front end when the voltage signal output from the receiving side of the isolation switch module is not greater than a preset voltage value; and, when the voltage signal is greater than the preset voltage value, control the switch to switch to a cut-off state to prevent the voltage signal from being transmitted to the sampling end of the analog sampling front end.

[0009] In some embodiments, the isolation switch module includes a photocoupler and a transistor; the first end of the transmitting side of the photocoupler is used to access the first working voltage, and the second end of the transmitting side is connected to the collector of the transistor; the base of the transistor is connected to the enable end of the microprocessor;

[0010] The first end of the receiving side of the photoelectric coupler is connected to the charge and discharge interface, and the second end of the receiving side of the photoelectric coupler is connected to the input end of the automatic control module.

[0011] In some embodiments, the automatic control module includes a MOS tube and a voltage regulator tube; the drain of the MOS tube is connected to the second end of the receiving side of the photocoupler; the gate of the MOS tube is connected to one end of the voltage regulator tube, and the other end of the voltage regulator tube is grounded; the source of the MOS tube is connected to the sampling end of the analog sampling front end.

[0012] In some embodiments, the photocoupler includes a light emitting diode and a light sensor; the anode of the light emitting diode serves as the first end of the transmitting side of the photocoupler, and is used to connect the first operating voltage; the cathode of the light emitting diode serves as the second end of the transmitting side of the photocoupler, and is connected to the collector of the transistor; one end of the light sensor is the first end of the receiving side of the photocoupler, and the other end of the light sensor is the second end of the receiving side of the photocoupler.

[0013] In some embodiments, the isolation switch module further includes a first current limiting resistor, one end of which is connected to an enable terminal of a microprocessor; and the other end of which is connected to the base of the transistor.

[0014] In some embodiments, the isolation switch module also includes a first filter capacitor and a matching resistor; one end of the first filter capacitor is connected to the base of the transistor, and one end of the first filter capacitor is connected to the emitter of the transistor; the matching resistor is connected in parallel at both ends of the first filter capacitor.

[0015] In some embodiments, the isolation switch module further includes a second current limiting resistor; one end of the second current limiting resistor is connected to the first operating voltage, and the other end of the second current limiting resistor is connected to the anode of the light-emitting diode in the photoelectric coupler.

[0016] In some embodiments, the MOS tube includes an NMOS tube and a diode; an anode of the diode is connected to a source of the NMOS tube, and a cathode of the diode is connected to a drain of the NMOS tube.

[0017] In a second aspect, an embodiment of the present application provides a battery management system, including an AFE, an MCU, and an isolation protection module;

[0018] The analog sampling front end is used to sample the voltage signal of the charging and discharging interface of the battery pack;

[0019] The microprocessor is used to generate an enable signal;

[0020] The isolation protection module is electrically connected to the analog sampling front end and the microprocessor; the isolation protection module is the isolation protection circuit of the analog sampling front end.

[0021] In a third aspect, an embodiment of the present application provides an energy storage system, including a battery pack and the above-mentioned battery management system; the battery management system is connected to the battery pack.

[0022] The embodiments of the present application have the following beneficial effects:

[0023] The present application proposes an isolation protection circuit, a battery management system and an energy storage system for an analog sampling front end; first, the isolation switch module in the isolation protection circuit of the analog sampling front end can control whether the voltage signal of the charge and discharge interface is output to the isolation switch module according to the enable signal of the microprocessor MCU, so as to achieve low-power operation when some applications enter sleep mode. Secondly, after the automatic control switch module receives the voltage signal output by the isolation switch module, the on or off state of the switch in the automatic control module can be controlled according to the size of the voltage signal, that is, when the voltage signal is greater than the preset voltage value, the automatic control module is in the off state, thereby preventing the voltage signal from being transmitted to the sampling end of the analog sampling front end, which can effectively prevent the BMS from being damaged or functionally failing due to high voltage series connection of the charge and discharge interface, and ensure the safety and reliability of the analog sampling front end AFE. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of an energy storage system in the prior art is shown;

[0026] Figure 2 A schematic diagram of a local connection structure of a BMS in the prior art is shown;

[0027] Figure 3 A schematic diagram of the electrical connection structure of the isolation protection circuit of the analog sampling front end in the present application is shown;

[0028] Figure 4 A schematic diagram of the structure of the battery management system in this application is shown;

[0029] Figure 5 A schematic diagram of the structure of the energy storage system in an embodiment of the present application is shown.

[0030] Description of reference numerals:

[0031] 100-isolating switch module; 200-automatic control module. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0033] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0034] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or increasing the possibility of one or more features, elements, components or combinations of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0035] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0036] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] Since the analog sampling front-end AFE in the current battery management system BMS directly collects the voltage of the charging and discharging interface, there is a risk of high voltage being introduced into the AFE; and the charging and discharging interface P+ is always equal to the total voltage of the low-voltage battery pack, which will result in higher power consumption when some applications need to sleep. Therefore, the present application proposes a method of using the characteristics of the depletion-type MOS tube to set an automatic closing loop to achieve high-voltage protection. At the same time, the isolation switch circuit based on optocoupler components can reduce system power consumption.

[0038] The isolation protection circuit, battery management system and energy storage system of the analog sampling front end are described below in conjunction with some specific embodiments.

[0039] Figure 3 A structural schematic diagram of an isolation protection circuit of an analog sampling front end in an embodiment of the present application is shown.

[0040] Exemplarily, the isolation protection circuit of the analog sampling front end includes an isolation switch module 100 and an automatic control module 200;

[0041] Among them, the transmitting side of the isolation switch module 100 is used to electrically connect to the enable end of the microcontroller MCU, and the first end of the receiving side of the isolation switch module 100 is electrically connected to the voltage signal of the charge and discharge interface P+; the second end of the receiving side of the isolation switch module 100 is connected to the input end of the automatic control module, and the output end of the automatic control module 200 is used to electrically connect to the sampling end of the analog sampling front end AFE.

[0042] The transmitting side of the isolation switch module 100 is used to generate a control signal according to the enable signal of the enable end of the MCU, and the receiving side of the isolation switch module 100 controls whether the voltage signal of the charge and discharge interface P+ is output through the receiving side of the isolation switch module according to the control signal; after the voltage signal of the charge and discharge interface is output to the automatic control module 200 through the receiving side of the isolation switch module, the automatic control module 200 receives the voltage signal output by the isolation switch module, and when the voltage signal is not greater than the preset voltage value, controls the switch to be turned on so that the voltage signal is transmitted to the sampling end of the analog sampling front end AFE; and, when the voltage signal is greater than the preset voltage value, controls the switch to switch to the cut-off state to prevent the voltage signal from being transmitted to the sampling end of the analog sampling front end.

[0043] The isolation protection circuit of the analog sampling front end of the present application receives the enable signal through the isolation switch module. When the enable terminal MCU_P+_EN of the MCU is not set to a high level, the voltage signal of the charge and discharge interface P+ cannot be output to the automatic control module, thereby achieving controllable isolation switch control of the charge and discharge interface P+, ​​and being able to perform low-power operation when some applications need to sleep; if the voltage signal of the charge and discharge interface P+ is output to the automatic control module, if the voltage signal of the charge and discharge interface P+ is not greater than the preset voltage value, the automatic control module will automatically switch to the cut-off state to cut off the electrical connection between the high-voltage signal of the charge and discharge interface P+ and the analog sampling front end AFE, thereby ensuring that the analog sampling front end AFE connected to the output of the automatic control module will no longer be subject to the risk of high voltage.

[0044] In a specific embodiment of the present application, the isolation switch module 100 includes a photocoupler U and a transistor T; the first end of the transmitting side of the photocoupler U is used to access a first working voltage; for example, the first working voltage is a low-voltage power supply such as 3.3V, 5V, etc.; the second end of the transmitting side of the photocoupler U is connected to the collector c of the transistor T; the base b of the transistor T is connected to the enable terminal MCU_P+_EN of the MCU; the first end of the receiving side of the photocoupler (corresponding to Figure 3 The 4th pin in the charging and discharging interface P+ is connected to the second end of the receiving side of the photocoupler U (corresponding to Figure 3 The third pin in the circuit is connected to the input end of the automatic control module 200.

[0045] For the isolation switch module in the above embodiment, when the enable terminal MCU_P+_EN of the microprocessor MCU is at a high level, the transistor T is turned on, and the control end of the photoelectric coupler U controls the voltage of the charge and discharge interface P+ at its input end to be input to the automatic control module. When the enable terminal MCU_P+_EN of the microprocessor MCU is not set to a high level, the transistor T is not turned on, the photoelectric coupler U is in a cut-off state, and the voltage of the charge and discharge interface P+ cannot be output, thereby reducing power consumption.

[0046] In a specific embodiment, the automatic control module 200 includes a MOS tube N and a voltage regulator tube WD; the drain D of the MOS tube N is connected to the second end of the receiving side of the photoelectric coupler U (corresponding to Figure 3 The gate electrode g of the MOS tube N is connected to one end of the voltage regulator tube WD, and the other end of the voltage regulator tube WD is grounded; the source electrode s of the MOS tube N is connected to the sampling end of the analog sampling front end AFE, specifically connected to the battery detection input end PACK of the analog sampling front end AFE.

[0047] The automatic control module in the above embodiment can be automatically closed when the charge and discharge interface P+ outputs high voltage based on the characteristics of the MOS tube and the voltage regulation value of the voltage regulator tube, thereby ensuring that the analog sampling front end AFE connected to the output of the automatic control module will no longer be exposed to the risk of high voltage.

[0048] In the embodiment of the present application, the isolation protection circuit of the analog sampling front end, when the isolation switch module receives a high-level enable signal, realizes outputting the voltage of the charge and discharge interface P+ to the subsequent circuit; when the high-level enable signal is not received and some applications need to sleep, the optocoupler U is in the cut-off state, so that the voltage of the charge and discharge interface P+ cannot be output, thereby achieving the purpose of low power consumption operation.

[0049] In a specific implementation, the photocoupler U includes a light emitting diode and a light sensor. The light emitting diode is a light source commonly used in the photocoupler; the anode of the light emitting diode serves as the first end of the emission side of the photocoupler (corresponding to Figure 3 The first pin in the photocoupler is used to connect the first working voltage, and the cathode of the light-emitting diode serves as the second end of the transmitting side of the photocoupler (corresponding to Figure 3 The second pin in the photocoupler is connected to the collector c of the transistor T; one end of the light sensor is the first end of the receiving side of the photocoupler (corresponding to Figure 3 The other end of the optical sensor is the second end of the receiving side of the photocoupler (corresponding to the 4th pin in Figure 3 3rd pin in the ).

[0050] It should be noted that: the optical sensor can generally be a photoresist, a photodiode, a phototransistor, a silicon controlled rectifier SCR, a bidirectional thyristor or a MOS tube; in the specific embodiment of the present application, the voltage signal of the charge and discharge interface is transmitted through the optical sensor, so the MOS tube is used as the optical sensor in the example of the present application; specifically, in the example Figure 3 In the schematic diagram of the isolation protection circuit of the analog sampling front end shown in FIG. 1 , the photoelectric coupler U includes a light emitting diode and two MOS tubes; the anode of the light emitting diode is connected to the first working voltage, the cathode of the light emitting diode is connected to the collector c of the transistor T, and the two MOS tubes form a series branch, one end of the series branch is the first end 4 of the receiving side of the photoelectric coupler, and the other end of the series branch is the second end of the receiving side of the photoelectric coupler (corresponding to Figure 3 The anode of the light-emitting diode is the first end of the transmitting side of the photocoupler U (corresponding to the third pin in the photocoupler). Figure 3 The cathode of the light-emitting diode is used as the second end of the transmitting side of the photocoupler U (corresponding to the Figure 3 When current flows through the light-emitting diode, the light-emitting diode on the transmitting side of the photocoupler will emit light, turning on the optical sensor on the receiving side of the photocoupler U, thereby outputting the voltage signal of the charge and discharge interface P+ to the automatic control module 200 through the MOS tube on the receiving side of the photocoupler U in the isolation switch module.

[0051] In another specific implementation, the isolation switch module further includes a first current limiting resistor R1, one end of the first current limiting resistor R1 is connected to the enable terminal MCU_P+_EN of the MCU; the other end of the first current limiting resistor R1 is connected to the base b of the transistor T. The present application uses the first current limiting resistor in the isolation module to limit the excessive current between the base b and the emitter e in the transistor T, thereby ensuring the safety of the transistor T.

[0052] In the specific implementation of the present application, the isolation switch module also includes a first filter capacitor C and a matching resistor R4; one end of the first filter capacitor C is connected to the base b of the transistor T, and one end of the first filter capacitor C is connected to the emitter e of the transistor T; the matching resistor R4 is connected in parallel to both ends of the first filter capacitor C. The present application uses the first filter capacitor C in the isolation module to prevent the transistor T from being turned on by mistake; at the same time, under the action of the matching resistor R4, when the enable terminal MCU_P+_EN of the MCU does not output a high level, the base b of the transistor T can maintain an extremely low voltage signal.

[0053] In the specific implementation of the present application, the isolation switch module also includes a second current limiting resistor R2; one end of the second current limiting resistor R2 is connected to the first working voltage, and the other end of the second current limiting resistor R2 is connected to the anode 1 of the light-emitting diode in the photoelectric coupler U. The use of the second current limiting resistor R2 in the isolation module of the present application can ensure that when the transistor T is turned on, the current flowing through the light-emitting diode is limited.

[0054] More specifically, the principle process of achieving low power consumption based on the isolation switch module is as follows:

[0055] When the enable terminal MCU_P+_EN of the MCU is at a high level, the transistor T is turned on, and the first working voltage is input to the anode of the light-emitting diode of the photoelectric coupler U through the second current-limiting resistor R2, so that the light-emitting diode and the transistor T form a loop to the ground; at the same time, when current flows through the light-emitting diode, the light-emitting diode will emit light and turn on the light sensor on the receiving side of the photoelectric coupler U, so that the voltage signal of the charge and discharge interface P+ is transmitted to the automatic control module 200 through the receiving side of the photoelectric coupler U.

[0056] When the enable terminal MCU_P+_EN of the MCU is at a low level, there is no current between the base b and the emitter e of the transistor T, so there is no conduction between the collector c and the emitter e of the transistor T, resulting in the first working voltage being unable to form a ground loop through the second current limiting resistor R2 and the light-emitting diode of the photocoupler U. At this time, the MOS tube of the photocoupler U cannot be turned on and is in a cut-off state, so that the voltage signal of the charge and discharge interface P+ cannot be output by the receiving side of the photocoupler U.

[0057] Therefore, in the present application, the enable terminal MCU_P+_EN of the MCU is not set to a high level, the transistor T is not turned on, and no current passes through the light-emitting diode of the photocoupler U. Correspondingly, the MOS tube of the photocoupler U is in an off state, and the voltage of the charge and discharge interface P+ cannot be output through the receiving side of the photocoupler U, thereby achieving controllable isolation switch control of the voltage signal of the charge and discharge interface P+, ​​thereby enabling low-power operation when some applications need to sleep.

[0058] It should be noted that the present application does not limit the isolating switch module to the contents described in the above records, and other components such as resistors and capacitors or an electrical connection structure composed of multiple components may also be added.

[0059] In the embodiment of the present application, the automatic control module is used to automatically control the disconnection between the charge and discharge interface P+ and the analog sampling front end AFE when receiving the high voltage signal of the charge and discharge interface P+.

[0060] In a specific embodiment of the present application, the MOS tube N includes an NMOS tube and a diode; the anode of the diode is connected to the source s of the NMOS tube, and the cathode of the diode is connected to the drain d of the NMOS tube. Among them, the NMOS tube is a depletion type Nmos. In the present application, when the voltage of the charge and discharge interface P+ is overvoltage, the diode included in the MOS tube first reversely breaks down to prevent the NMOS tube from burning out; at the same time, it can also effectively prevent the NMOS tube from burning out when the source and drain of the NMOS tube are reversely connected.

[0061] In the embodiment of the present application, a MOS tube is formed by directly connecting a diode to an NMOS tube. As another implementation method, a diode may be connected in parallel to parasitize the NMOS tube by means of internal parasitism.

[0062] In the specific implementation of the present application, the automatic control module also includes a voltage-dividing resistor R5; one end of the voltage-dividing resistor R5 is connected to the source s of the NMOS tube, and the other end of the voltage-dividing resistor R5 is connected to the gate g of the NMOS tube.

[0063] In the present application, a voltage-dividing resistor R5 and a voltage-stabilizing diode WD are used in the automatic control module to cooperate with each other to achieve the regulation of the voltage threshold during the high-voltage protection process; wherein, the voltage-dividing resistor R5 is an adjustable resistor, and the voltage-stabilizing value of the voltage-stabilizing diode WD can also be adjusted according to actual conditions.

[0064] More specifically, when the input voltage of the drain d of the MOS tube N is not greater than the voltage regulation value of the voltage regulator WD plus 1.5V (typical value), the MOS tube N is normally turned on, and the voltage of the charge and discharge interface P+ enters the subsequently connected analog sampling front end AFE through the source of the MOS tube N. When the input voltage of the drain d of the MOS tube N is greater than the voltage regulation value of the voltage regulator WD plus 1.5V (typical value), under the action of the voltage regulator WD, the voltage of the gate g of the MOS tube N relative to its source s will be less than 1.5V. Due to the characteristics of the depletion-type NMOS tube in the MOS tube N, the MOS tube N changes from being turned on to being cut off, that is, when the input voltage of the MOS tube N (the voltage of the charge and discharge interface P+) is too large, the subsequently connected analog sampling front end AFE will no longer be subject to the risk of high voltage.

[0065] In the specific implementation of the present application, the automatic control module further includes a third current limiting resistor R3, one end of the third current limiting resistor R3 is connected to the source s of the MOS tube, and the other end of the third current limiting resistor R3 is connected to the analog sampling front end AFE. The present application uses the third current limiting resistor in the automatic control module to further limit the current flowing into the AFE from being too large, thereby ensuring the safety of the analog sampling front end AFE.

[0066] It should be noted that the present application does not limit the automatic control module to the contents described in the above records, as long as the high-voltage automatic closing loop can be realized to prevent the analog sampling front end AFE from being exposed to high-voltage risks.

[0067] The present application also provides a battery management system, Figure 4 A schematic diagram of the structure of a battery management system according to an embodiment of the present application is shown. Exemplarily, the battery management system includes an analog sampling front end AFE, a microprocessor MCU and an isolation protection module;

[0068] The analog sampling front end AFE is used to sample the charge and discharge interface P+ connected to the battery pack;

[0069] The microprocessor MCU is used to generate an enable signal MCU_P+_EN;

[0070] The isolation protection module is electrically connected to the analog sampling front end AFE and the microprocessor MCU; the isolation protection module is the isolation protection circuit of the analog sampling front end described above.

[0071] It can be understood that the options of the isolation protection circuit of the analog sampling front end in the above embodiment are also applicable to this embodiment, so they are not described again here.

[0072] The present application also provides an energy storage system, Figure 5 The schematic diagram of the structure of the energy storage system of the embodiment of the present application is shown. Exemplarily, the energy storage system includes a battery pack and a battery management system; the battery management system is connected to the battery pack; wherein the battery management system manages and protects the battery pack.

[0073] The battery pack includes a plurality of single cells, and the battery management system is the content described in the above embodiment, which is also applicable to the present embodiment, so it will not be described again here.

[0074] In summary, the isolation protection circuit of the analog sampling front end proposed in this application realizes high-voltage protection of the IC port through the conduction mode of the optocoupler and the characteristics of the depletion-type MOS tube, which can effectively prevent the BMS damage or functional failure caused by high voltage series connection of the charging and discharging ports of the low-voltage battery pack, and can automatically shut down the voltage of the P+ port to achieve low-power operation when some applications enter sleep mode. It should be noted that the isolation protection circuit is also suitable for high-voltage protection and low-power design of other interfaces.

[0075] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. An isolation protection circuit for an analog sampling front end, characterized in that: Including isolating switch module and automatic control module; The transmitting side of the isolating switch module is used to electrically connect to the enable end of the microcontroller, and the first end of the receiving side of the isolating switch module is electrically connected to the charging and discharging interface; the isolating switch module is used to control whether the voltage signal connected to the charging and discharging interface is output through the receiving side of the isolating switch module according to the enable signal output by the enable end of the microprocessor; The input end of the automatic control module is electrically connected to the second end of the receiving side of the isolation switch module, and the output end of the automatic control module is used to electrically connect to the sampling end of the analog sampling front end; The automatic control module is used to control the switch to be turned on so that the voltage signal is transmitted to the sampling end of the analog sampling front end when the voltage signal output by the receiving side of the isolation switch module is not greater than the preset voltage value; And, when the voltage signal is greater than the preset voltage value, the switch is controlled to switch to a cut-off state to prevent the voltage signal from being transmitted to the sampling end of the analog sampling front end.

2. The isolation protection circuit of the analog sampling front end according to claim 1, characterized in that: The isolation switch module includes a photocoupler and a transistor; the first end of the transmitting side of the photocoupler is used to access the first working voltage, and the second end of the transmitting side is connected to the collector of the transistor; the base of the transistor is connected to the enable end of the microprocessor; The first end of the receiving side of the photoelectric coupler is connected to the charge and discharge interface, and the second end of the receiving side of the photoelectric coupler is connected to the input end of the automatic control module.

3. The isolation protection circuit of the analog sampling front end according to claim 2, characterized in that: The automatic control module includes a MOS tube and a voltage regulator tube; the drain of the MOS tube is connected to the second end of the receiving side of the photoelectric coupler; the gate of the MOS tube is connected to one end of the voltage regulator tube, and the other end of the voltage regulator tube is grounded; the source of the MOS tube is connected to the sampling end of the analog sampling front end.

4. The isolation protection circuit of the analog sampling front end according to claim 2, characterized in that: The photoelectric coupler includes a light emitting diode and a light sensor; the anode of the light emitting diode serves as the first end of the transmitting side of the photoelectric coupler and is used to connect the first working voltage; the cathode of the light emitting diode serves as the second end of the transmitting side of the photoelectric coupler and is connected to the collector of the transistor; one end of the light sensor serves as the first end of the receiving side of the photoelectric coupler and the other end of the light sensor serves as the second end of the receiving side of the photoelectric coupler.

5. The isolation protection circuit of the analog sampling front end according to claim 2, characterized in that: The isolation switch module further includes a first current limiting resistor, one end of which is connected to an enable terminal of the microprocessor; and the other end of which is connected to the base of the transistor.

6. The isolation protection circuit of the analog sampling front end according to any one of claims 2 to 5, characterized in that: The isolation switch module also includes a first filter capacitor and a matching resistor; one end of the first filter capacitor is connected to the base of the transistor, and one end of the first filter capacitor is connected to the emitter of the transistor; the matching resistor is connected in parallel to both ends of the first filter capacitor.

7. The isolation protection circuit of the analog sampling front end according to claim 2, characterized in that: The isolation switch module further includes a second current limiting resistor; one end of the second current limiting resistor is connected to the first operating voltage, and the other end of the second current limiting resistor is connected to the anode of the light emitting diode in the photoelectric coupler.

8. The isolation protection circuit of the analog sampling front end according to claim 3, characterized in that: The MOS tube includes an NMOS tube and a diode; the anode of the diode is connected to the source of the NMOS tube, and the cathode of the diode is connected to the drain of the NMOS tube.

9. A battery management system, characterized in that: Includes analog sampling front end, microprocessor and isolation protection module; The analog sampling front end is used to sample the voltage signal of the charging and discharging interface of the battery pack; The microprocessor is used to generate an enable signal; The isolation protection module is electrically connected to the analog sampling front end and the microprocessor; the isolation protection module is the isolation protection circuit of the analog sampling front end according to any one of claims 1-8.

10. An energy storage system, characterized in that: It comprises a battery pack and the battery management system as claimed in claim 9; the battery management system is connected to the battery pack.

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