Switching state detection circuit, battery management system, charging machine and electric device

Abstract

The application discloses a switch state detection circuit, a battery management system, a charging machine and a power utilization device. The circuit comprises a first voltage division module, a comparison module and an identification module; a first end of the first voltage division module is electrically connected with a first power supply, a second end of the first voltage division module is electrically connected with a first end of a first switch, a first voltage division node of the first voltage division module is electrically connected with a first input end of the comparison module, and a second end of the first switch is electrically connected with a grounding end. According to the embodiment of the application, the voltage at the first voltage division node is different under the condition that the first switch is in different states, so that the output signal of the comparison module is different, and then the state of the first switch is represented by different identification results, so that the switch state detection is achieved, and the technical effect of improving the safety of the circuit where the switch is located is further realized.

Description

Technical Field

[0001] This application belongs to the technical field of battery management, and particularly relates to a switch state detection circuit, a battery management system, a charger, and an electrical device. Background Technology

[0002] With the widespread application of new energy technologies, battery management systems (BMS) for driving these technologies have become a popular research topic. Relay and other switch status detection is a crucial component of a BMS. By detecting the status of these switches, it determines whether the battery is supplying power to the load, providing important information for load control and battery management safety.

[0003] Currently, the switches that need to be controlled and monitored in battery management systems are located in different positions within the high-voltage system, and may experience different faults during application. For example, relays often stick together due to excessive current caused by abnormal high-voltage control, and there are also issues where relays cannot close due to drive failures. Therefore, relay status detection is crucial. Typically, the status of a relay or other switch connected to the positive terminal of the battery can be detected by measuring the voltage difference across the positive relay after the relay or switch connected to the negative terminal is closed. However, the status detection of the negative relay cannot be achieved using high-voltage detection methods, and surge impacts at the negative relay sampling port can damage the sampling circuit and chip, significantly increasing the difficulty of switch status detection. Therefore, switch status detection has become a problem that centralized procurement aims to address. Utility Model Content

[0004] This application provides a switch state detection circuit, a battery management system, a charger, and an electrical device. By utilizing the different output voltages of a first switch to the first voltage divider node through a first voltage divider module under different states, the signals output by the comparison module differ. The identification module identifies the different states of the first switch based on these different signals. This achieves the purpose of switch state detection and improves circuit safety.

[0005] In a first aspect, embodiments of this application provide a switch state detection circuit, including a first voltage divider module, a comparison module, and an identification module; a first terminal of the first voltage divider module is electrically connected to a first power supply, a second terminal of the first voltage divider module is electrically connected to a first terminal of a first switch, a first voltage divider node of the first voltage divider module is electrically connected to a first input terminal of the comparison module, and a second terminal of the first switch is electrically connected to a ground terminal; a second input terminal of the comparison module is electrically connected to a second power supply, and an output terminal of the comparison module is electrically connected to an input terminal of the identification module; when the state of the first switch is different, the comparison module is used to output different signals, and the identification module is used to identify the state of the first switch based on the signals output by the comparison module.

[0006] In one possible implementation, the first voltage divider module includes a first resistor network, a second resistor network, and a diode network; a first end of the first resistor network is electrically connected to the first power supply, a second end of the first resistor network is electrically connected to the first voltage divider node, and the second resistor network and the diode network are connected in series between the first voltage divider node and the first end of the first switch.

[0007] In one possible implementation, the first resistor network includes at least one first resistor; and / or, the second resistor network includes a plurality of second resistors connected in series; and / or, the diode network includes at least one diode, the anode of which is electrically connected to the first voltage divider node, and the cathode of which is electrically connected to the first terminal of the first switch.

[0008] In one possible implementation, the comparison module includes a comparator; the non-inverting input of the comparator is the first input of the comparison module, and the inverting input of the comparator is the second input of the comparison module; or, the inverting input of the comparator is the first input of the comparison module, and the non-inverting input of the comparator is the second input of the comparison module.

[0009] In one possible implementation, the switch state detection circuit further includes a second voltage divider module, the first end of which is electrically connected to the second power supply, the second end of which is electrically connected to the ground terminal, and the second voltage divider node of which is electrically connected to the second input terminal of the comparison module.

[0010] In one possible implementation, the second voltage divider module includes a third resistor and a fourth resistor; one end of the third resistor is electrically connected to the second power supply, and the other end of the third resistor is electrically connected to one end of the fourth resistor and the second voltage divider node; the other end of the fourth resistor is electrically connected to the ground terminal.

[0011] In one possible implementation, the switch state detection circuit further includes a first filtering module; one end of the first filtering module is electrically connected to the second end of the first voltage divider module, and the other end of the first filtering module is electrically connected to the first end of the first switch; and / or, the switch state detection circuit further includes a second filtering module, one end of the second filtering module is electrically connected to the first voltage divider node, and the other end of the second filtering module is electrically connected to the first input end of the comparison module; and / or, the switch state detection circuit further includes a fifth resistor, one end of the fifth resistor is electrically connected to the output end of the comparison module and the input end of the identification module, and the other end of the fifth resistor is electrically connected to the second end of the identification module and the third power supply.

[0012] Secondly, embodiments of this application provide a battery management system, the system including a switch state detection circuit as described in any one of the first aspects.

[0013] Thirdly, embodiments of this application provide a charger, including a switch state detection circuit as described in any one of the first aspects.

[0014] Fourthly, embodiments of this application provide an electrical device, the electrical device including the battery management system as described in the second aspect.

[0015] The switch state detection circuit, battery management system, charger, and power device provided in this application embodiment, when the first switch is in different states, result in different output voltages to the first voltage divider node through the first voltage divider module, causing different signals output by the comparison module. The identification module identifies the different states of the first switch based on the different signals output by the comparison module. This achieves the purpose of switch state detection and improves the technical effect of circuit safety. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a switch state detection circuit provided in the prior art;

[0018] Figure 2 This is a schematic diagram of a switch state detection circuit provided in Embodiment 1 of this application;

[0019] Figure 3a This is a schematic diagram of a switch state detection circuit provided in Embodiment 2 of this application;

[0020] Figure 3b This is a schematic diagram of another switch state detection circuit provided in Embodiment 2 of this application;

[0021] Figure 4a This is a schematic diagram of a switch state detection circuit provided in Embodiment 3 of this application;

[0022] Figure 4b This is a schematic diagram of another switch state detection circuit provided in Embodiment 3 of this application;

[0023] Figure 5 This is a schematic diagram of the structure of a battery management system provided in Embodiment 4 of this application;

[0024] Figure 6 This is a schematic diagram of the structure of an electrical device provided in Embodiment 5 of this application. Detailed Implementation

[0025] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0027] In applications of switch status detection, relay status detection is the primary method. With the widespread adoption of new energy vehicles, relays have become a crucial component of the high-voltage systems in these vehicles, and relay status diagnostics has become an important technology in high-voltage systems. Relays often experience sticking due to excessive current caused by abnormal high-voltage control, and there are also issues where drive faults prevent the relay from closing. Therefore, relay status detection is extremely important.

[0028] Typically, positive relays are detected by checking the high voltage outside the positive relay after the negative relay is closed. However, since negative relays are usually required to close first and then open later in most applications, and cannot be detected by high voltage after the control command is issued, and surge impacts often occur at the negative relay sampling port, the detection of the negative relay status has always been one of the key technologies of the power system of new energy vehicles.

[0029] Figure 1 This is a schematic diagram of a switch state detection circuit provided in the prior art. According to... Figure 1 The provided diagram shows a positive relay K1 connected between the positive terminals of DC power supplies DC1 and DC2, and a negative relay K2 connected between their negative terminals. The state of the negative relay K2 is detected by the detection circuit shown in the dashed box. When the negative relay K2 is closed, the voltage sampled by the MCU port is the voltage drop across the power supply VCC after passing through resistors RR1, RR2, and RR3 in parallel, specifically the voltage divided by the parallel connection of RR2 and RR3. When the negative relay K2 is open, the voltage sampled by the MCU port is the voltage across RR2 after passing through resistors RR1 and RR2 in series. The different voltage values ​​sampled by the MCU distinguish between the on and off states of the negative relay K2. Combined with the issued relay control commands, this determines whether the negative relay K2 is in a faulty state.

[0030] pass Figure 1 The method of adding an external power supply and directly sampling the voltage through the port of the MCU chip can distinguish the open and closed states of the negative relay. The two states of the relay are distinguished by the different voltage values ​​collected by the chip, and then it can be determined whether the relay is in a fault state. In this case, when the relay is open and a surge voltage is generated at the port, the high voltage will cause the chip to burn out.

[0031] To address the aforementioned problems, this application proposes a switch state detection circuit. By adding switch state detection structures on both sides of the switch, the voltage output to the first voltage divider node through the first voltage divider module differs when the switch is closed and open. This, in turn, causes different electrical signals output by the comparator, allowing the identification of signals of different magnitudes to characterize the corresponding switch state, thereby achieving the purpose of switch state detection. This results in a novel switch state detection circuit. The switch state detection circuit provided in the embodiments of this application will be described below.

[0032] Example 1

[0033] Figure 2 This is a schematic diagram of a switch state detection circuit provided in Embodiment 1 of this application. Figure 2 The provided diagram shows that the structure of the switch state detection circuit 100 specifically includes:

[0034] The first voltage divider module 10, the comparison module 20, and the identification module 30.

[0035] The first end of the first voltage divider module 10 is electrically connected to the first power supply V1, the second end of the first voltage divider module 10 is electrically connected to the first end of the first switch KK1, the first voltage divider node N1 of the first voltage divider module 10 is electrically connected to the first input end of the comparator module 20, and the second end of the first switch KK1 is electrically connected to the ground terminal.

[0036] The second input terminal of the comparison module 20 is electrically connected to the second power supply V2, and the output terminal of the comparison module 20 is electrically connected to the input terminal of the identification module 30.

[0037] When the state of the first switch KK1 is different, the comparison module 20 outputs different signals. The identification module 30 identifies the state of the first switch KK1 based on the signal output by the comparison module 20.

[0038] The first switch mentioned here can be understood as a switching device that has the function of turning on or off, such as a negative relay, a transistor, or other switching devices.

[0039] The second power supply mentioned here is the reference power supply of the comparator module.

[0040] according to Figure 1The provided diagram shows that when the first switch KK1 is closed, the voltage division at the first voltage divider node N1 is VIN1 after voltage division calculation by the first voltage divider module. The comparison module 20 compares the input voltage VIN with the second power supply V2 and outputs a voltage signal representing the input terminal of the second power supply V2. When the first switch KK1 is open, the voltage division at the first voltage divider node N1 is VIN2 after voltage division calculation by the first voltage divider module 10. Since the first switch KK1 is open, the voltage value of VIN2 is high. The comparison module 20 compares the input voltage VIN with the second power supply V2 and outputs a voltage signal representing the first voltage divider node N1. Then, the identification module 30 identifies the magnitude of different electrical signals to determine the corresponding state of the first switch KK1, thus achieving the purpose of switch state detection. At the same time, the comparison module 20 and the second power supply V2 convert the impact of the large voltage at the first voltage divider node N1 when the first switch KK1 is open into a safe electrical signal, preventing the identification module 30 from being burned out due to the large voltage signal, thereby improving the safety of the circuit.

[0041] The switch state detection circuit provided in this application detects different voltages at the first voltage divider node output by the first voltage divider module under different switch states, thereby changing the voltage signal input to the comparison module. This signal is then compared with a reference power supply corresponding to the second power supply. The comparison module outputs different comparison results based on the different switch states of the first switch KK1, thus identifying different electrical signals. The switch state of the first switch is distinguished by the magnitude of these different electrical signals, achieving switch state detection. Simultaneously, by using the second power supply as a reference power supply, the comparison module can output a safety electrical signal when the voltage signal at the first voltage divider node changes, preventing damage to the identification module from high voltage caused by the opening of the first switch, thereby improving circuit safety.

[0042] Example 2

[0043] Figure 3a This is a schematic diagram of a switch state detection circuit provided in Embodiment 2 of this application. Figure 3a This is based on the previous embodiment. Figure 3a The provided diagram shows the specific structure of the switch state detection circuit, including:

[0044] The first voltage divider module 10, the comparison module 20, and the identification module 30.

[0045] according to Figure 3a The provided diagram shows that the first voltage divider module 10 in the switch state detection circuit 100 includes a first resistor network 110, a second resistor network 120, and a diode network 130.

[0046] The first end of the first resistor network 110 is electrically connected to the first power supply V1, the second end of the first resistor network 110 is electrically connected to the first voltage divider node N1, and the second resistor network 120 and the diode network 130 are connected in series between the first voltage divider node N1 and the first end of the first switch KK1.

[0047] The first resistor network mentioned here can be understood as a voltage divider network with resistive characteristics. The second resistor network can be understood as a network with high-resistivity resistive characteristics, which can block the impact of high-voltage signals. The diode network can be understood as a unidirectional conduction structure with reverse blocking capability, ensuring that when the first switch is open, the input voltage of the comparator module remains within a safe voltage range due to excessive voltage entering the first voltage divider module. The identification module can be understood as a digital signal identification device such as an MCU or DSP with identification characteristics. The first power supply V1 supplies power to the first voltage divider module. The comparator module can convert changes in the input voltage signal into high and low level signals that can be recognized by identification devices such as MCUs.

[0048] according to Figure 3a The provided diagram shows that when the first switch KK1 is closed, the second resistor network 120 and the first resistor network 110 divide the voltage in the circuit, adjusting the voltage at the input terminal of the comparator module 20. The voltage signal at the first voltage divider node N1 is compared with the reference voltage corresponding to the second power supply V2, and the comparator module 20 outputs an electrical signal indicating that the first switch KK1 is closed. When the first switch KK1 is open, under the influence of a surge voltage impacting the second resistor network 120 and the diode network 130, the reverse conduction of the diode network 130 and the high-resistance value of the second resistor network 120 can reduce the surge voltage to a safe range that can be recognized by the input terminal of the comparator module 20 and the second power supply V2. This allows the comparison result to represent different states of the first switch KK1, while simultaneously protecting the identification module 30 from damage by large voltage signals, thus improving circuit safety.

[0049] In one possible example scenario, according to Figure 3a The provided diagram shows that the comparison module 20 in the switch state detection circuit 100 includes a comparator A.

[0050] The non-inverting input of comparator A is the first input of comparator module 20, and the inverting input of comparator A is the second input of comparator module 20.

[0051] Depending on the input connections of the comparator, the logic for determining the state of the first switch KK1 may differ. When the first voltage divider node N1, where the second resistor network 120 and the first resistor network 110 are connected, is connected to the non-inverting input of comparator A, and the inverting input of comparator A is directly connected to the reference voltage source (i.e., the second power supply V2), when the first switch KK1 is open, since the first resistor network and diode network are disconnected, the voltage at the first voltage divider node is the voltage of the first power supply V1, and the voltage at the inverting input of comparator A is equal to the voltage of the second power supply V2. By setting the first voltage to be greater than the reference voltage source, comparator A outputs the voltage of the second power supply V2. When the first switch KK1 is closed, the current flows from the first power supply V1 through the first resistor network, the second resistor network, and the diode network to the ground terminal GND. At this time, the voltage input to the first voltage divider node of comparator A is the voltage divided by the second resistor network and the diode network in the first voltage divider module circuit. When the reference voltage source value corresponding to the second power supply V2 is set to be greater than the aforementioned voltage divider value and less than the voltage of the first power supply V1, when the first switch KK1 is open, the non-inverting input terminal of comparator A is greater than the inverting input terminal, resulting in a high-level signal at the output terminal of comparator A. When the first switch KK1 is closed, the non-inverting input terminal of comparator A is less than the inverting input terminal, resulting in a low-level signal at the output terminal of comparator A. The switching state of the first switch KK1 is distinguished by the high and low level states, thereby achieving the purpose of switch state detection. By setting a high-impedance second resistor network and diode network, a voltage divider is used to block the surge voltage that occurs when the first switch is open, ensuring that the electrical signal input to the comparator is within the safe processing range of the comparator, thereby preventing damage to the identification module due to surge voltage and improving the safety of the circuit.

[0052] In one possible example scenario, according to Figure 3a The provided diagram shows that the switch state detection circuit 100 also includes a second voltage divider module 40. The first end of the second voltage divider module 40 is electrically connected to the second power supply V2, the second end of the second voltage divider module 40 is electrically connected to the ground terminal, and the second voltage divider node N2 of the second voltage divider module 40 is electrically connected to the second input terminal of the comparison module 20.

[0053] The reference voltage of the comparator can be supplied by the second power supply V2, or the reference voltage value can be obtained by adjusting the voltage of the second voltage divider node through the second voltage divider module.

[0054] By adding a second voltage divider module, when comparator A compares the voltages at the non-inverting and inverting input terminals, the second voltage divider module is powered by the second power supply. Under the control of the second voltage divider module on the voltage division of the second power supply, the potential of the second voltage divider node is changed, thereby achieving the purpose of adjusting the reference voltage source. When the first power supply and the second power supply are the same, the output voltage of the second voltage divider node can be adjusted to achieve the purpose of the second voltage divider node being less than the first power supply and greater than the voltage division potential of the first node when the first switch is closed, thus achieving the purpose of flexibly adjusting the reference voltage source.

[0055] Or, in one possible example scenario, Figure 3b This is a schematic diagram of another switch state detection circuit provided in Embodiment 2 of this application. According to... Figure 3b The provided illustrations, and Figure 3a In contrast, the difference lies in that the inverting input of comparator A is the first input of comparator module 20, and the non-inverting input of comparator A is the second input of comparator module 20.

[0056] The input terminals of comparator A are swapped, thereby changing the judgment logic. With the first voltage divider node N1, connecting the second resistor network 120 and the first resistor network 110, connected to the inverting input terminal of comparator A, and the non-inverting input terminal of comparator A directly connected to the reference voltage source (i.e., the second power supply V2), when the reference voltage source is set to be greater than the voltage division value of the first voltage divider node N1 when the first switch KK1 is closed, but less than the voltage of the first power supply V1, when the first switch KK1 is open, the non-inverting input terminal of comparator A is lower than the inverting input terminal, resulting in a low-level signal at the output terminal of comparator A; when the first switch KK1 is closed, the non-inverting input terminal of comparator A is higher than the inverting input terminal, resulting in a high-level signal at the output terminal of comparator A. The switching state of the first switch KK1 is distinguished by the high and low level states, thus achieving the purpose of switch state detection.

[0057] This application provides a switch state detection circuit. By connecting a reference voltage source and a second resistor network with a high impedance state to the input of a comparator, the potential of the first voltage divider node is changed when the first switch is in different states, thereby causing the comparator to output electrical signals with different high and low levels, thus achieving the purpose of identifying the first switch state. Simultaneously, by setting the second resistor network and diode network with a high impedance state, in the event of a surge voltage caused by the first switch being open, the high voltage can be blocked by the second resistor network and diode network, ensuring that the identification module is not damaged by the high voltage and improving circuit safety.

[0058] Example 3

[0059] Figure 4a This is a schematic diagram of a switch state detection circuit provided in Embodiment 3 of this application. Figure 4aThis is based on the previous embodiment. Figure 4a The provided diagram shows the specific structure of the switch state detection circuit, including:

[0060] First resistor network 110, second resistor network 120, diode network 130, second voltage divider module 40.

[0061] In one possible example scenario, according to Figure 4a The provided diagram shows that the first resistor network 1110 in the switch state detection circuit 100 includes at least one first resistor R1.

[0062] And / or, the second resistor network 120 includes a plurality of second resistors R2 connected in series.

[0063] And / or, diode network 130 includes at least one diode D, the positive terminal of diode D is electrically connected to the first voltage divider node N1, and the negative terminal of diode D is electrically connected to the first terminal of the first switch KK1.

[0064] The diode network uses diodes with high reverse breakdown voltages. When a large voltage appears at the negative terminal of the diode, it cannot reach the positive terminal of the diode or the second resistor network, thus blocking and protecting the first voltage divider module and the first power supply. The multiple second resistors R2 in the second resistor network are high-resistance, high-voltage resistors connected in series. By connecting these high-voltage resistors in series, when a surge voltage occurs due to the first switch being open, the high-resistance resistors can reduce the impact of the large voltage on the comparator and identification module, weakening the influence of the surge voltage on the circuit. The position of the diodes in the series resistors is not restricted.

[0065] When there are no high surge protection requirements in the circuit, the use of high voltage resistors for diodes and second resistors can be reduced or their parameters adjusted.

[0066] When the first switch KK1 is closed, the voltage at the first voltage divider node is the voltage divided by the diode and multiple second resistors. When the first switch KK1 is open, the potential of the first voltage divider node is the voltage value of the first power supply. By setting the potential of the second voltage divider node in the second voltage divider module to be greater than the first voltage divider node's potential when the first switch is closed, but less than the first power supply voltage value, the voltage input to the comparator is different when the first switch KK1 is in different states, resulting in different electrical signals output by the comparator, thereby achieving the purpose of identifying the state of the first switch.

[0067] In one possible example scenario, according to Figure 4a The provided diagram shows that the second voltage divider module 40 in the switch state detection circuit 100 includes a third resistor R3 and a fourth resistor R4.

[0068] One end of the third resistor R3 is electrically connected to the second power supply V2, and the other end of the third resistor R3 is electrically connected to one end of the fourth resistor R4 and the second voltage divider node N2.

[0069] The other end of the fourth resistor R4 is electrically connected to the ground terminal.

[0070] In one implementation, the digital signal recognition terminal interface corresponding to the recognition module can receive digital signals with a high-level voltage of 5V and a low-level voltage of 0V. The comparator or operational amplifier in the comparator module uses a 15V power supply voltage to ensure that the voltage can be output on the rail when the comparator outputs a high level, thus ensuring that a recognizable 5V is provided to the recognition module.

[0071] In one possible example scenario, the first power supply V1 in the first voltage divider module 10 used to distinguish the switching state is set to be 5V, the second power supply V2 is set to be 5V, the third resistor R3 and the fourth resistor R4 are divided by the second power supply V2, and the reference voltage is set to be connected to the second input terminal of the comparator through the second voltage divider node.

[0072] In one possible scenario, by adjusting the values ​​of the third resistor R3 and the fourth resistor R4, the reference voltage corresponding to the second voltage divider node at the inverting input of the comparator is set to 3V. Furthermore, by adjusting the ratio of the first resistor R1 and the multiple second resistors R2, when the first switch KK1 is closed, the voltage divided between the first resistor R1 and the multiple second resistors R2 is 2V, and the voltage at the non-inverting input of the comparator is also 2V. This makes the voltage at the non-inverting input less than the voltage at the inverting input, thus causing the comparator output to be a low-level signal of 0V.

[0073] When the first switch KK1 is open, the non-inverting input of the comparator is 5V. Since the voltage at the non-inverting input is greater than the voltage at the inverting input, the comparator outputs a high-level signal of 5V. This 5V output signal can be identified by the recognition module, and the corresponding digital signal recognition device can then distinguish the switching state of the first switch, thus achieving the purpose of switch state detection.

[0074] In one embodiment, according to Figure 4a The provided diagram shows that the switch state detection circuit 100 also includes a first filter module 50. One end of the first filter module 50 is electrically connected to the second end of the first voltage divider module 10, and the other end of the first filter module 50 is electrically connected to the first end of the first switch KK1.

[0075] And / or, the switch state detection circuit 100 further includes a second filter module 60, one end of which is electrically connected to the first voltage divider node N1, and the other end of which is electrically connected to the first input terminal of the comparison module 20.

[0076] And / or, the switch state detection circuit 100 further includes a fifth resistor R5, one end of which is electrically connected to the output terminal of the comparison module 20 and the input terminal of the identification module 30, and the other end of which is electrically connected to the second terminal of the identification module 30 and the third power supply V3.

[0077] The fifth resistor mentioned here can be understood as a protection mechanism used to prevent the comparator's output voltage from exceeding the rated voltage detected by the identification module. Through voltage division or pull-up, the fifth resistor ensures that the input voltage detected by the identification module remains within a safe range. For example, if the third power supply V3 is set to 5V, and the comparator's internal power supply voltage is set to 15V due to internal structural requirements, the output voltage might exceed 5V. The pull-up effect of the fifth resistor divides this excess output voltage. By designing the value of the fifth resistor, the voltage input to the identification module can be adjusted to a safe voltage within 5V, thus ensuring the normal operation of the identification module.

[0078] according to Figure 4a The provided diagram shows that when the first switch KK1 is open, the high voltage across the first switch KK1 is first filtered by the first filter module 50. The filtered, stable high voltage is then output to the branch containing diode D and multiple second resistors R2. The voltage in the branch containing diode D and multiple second resistors R2 increases. Under the voltage division effect of the multiple second resistors R2 in their high-impedance state and the unidirectional conduction effect of diode D, the potential of the first voltage divider node N1 is reduced to a voltage range that comparator A can safely handle. At the same time, the voltage at the first voltage divider node N1 is filtered by the second filter module 60 to ensure that the voltage input to the first input terminal of comparator A is a stable voltage signal, unaffected by external factors. This further ensures that the digital signal strength output by comparator A remains at a high / low level that the recognition module can recognize.

[0079] In one possible embodiment, the comparator in this application includes, but is not limited to, a comparator circuit with or without hysteresis built using a comparator chip or an operational amplifier chip.

[0080] In this application, the comparator reference voltage is not limited to being connected to either the non-inverting or inverting input of the comparator. The digital signal level logic corresponding to the identification module that determines whether the first switch is closed or open is not limited to one state. The comparator supply voltage and pull-up level are not limited. The comparator reference voltage value is not limited, and the reference voltage form is not limited to resistor divider or reference voltage.

[0081] In one possible embodiment, the first filtering module includes a first inductor L1 and a first capacitor C1, and the second filtering module includes a sixth resistor R6 and a second capacitor C2.

[0082] One end of the first inductor is electrically connected to the first terminal of the first switch KK1, and the other end of the first inductor L1 is electrically connected to the negative terminal of the diode D and one end of the first capacitor C1.

[0083] The other end of the first capacitor C1 is electrically connected to the ground terminal GND.

[0084] One end of the sixth resistor R6 is electrically connected to the first voltage divider node N1, and the other end of the sixth resistor R6 is electrically connected to one end of the second capacitor C2 and the first input terminal of comparator A.

[0085] The other end of the second capacitor C2 is electrically connected to the ground terminal GND.

[0086] The filter structure formed by the first inductor L1 and the first capacitor C1 in the circuit can attenuate and filter out high-frequency interference. The filter structure formed by the resistor R6 and the second capacitor C2 filters the electrical signal output from the first voltage divider node.

[0087] By adding multiple filtering modules, the voltage input to the diode and the second resistor is filtered when the first switch is in different states, and the electrical signal output from the first voltage divider node to the comparator is also filtered to ensure that the voltage signal is not affected by high-frequency interference and improve the stability of the switch state detection circuit.

[0088] In one possible example scenario, Figure 4b This is a schematic diagram of another switch state detection circuit provided in Embodiment 3 of this application. Figure 4a In comparison, the difference lies in the reversed connection of the first and second input terminals of comparator A. According to... Figure 4b The provided diagram shows the control process and Figure 3b Similarly, the relevant work process will not be described in detail here.

[0089] Example 4

[0090] In one possible example scenario, Figure 5 This is a schematic diagram of a battery management system provided in Embodiment 4 of this application. Figure 5 The provided diagram shows that the battery management system (BMS) includes a switch state detection circuit 100, a first switch KK1, and a battery module 200, thus constituting the battery management system (BMS). The second terminal of the first switch KK1 is connected to the negative terminal of the battery module 200.

[0091] In one possible example scenario, the first switch is a negative relay, and the status of the negative relay connected to the negative terminal of the battery module 200 is detected by the switch status detection circuit 100 in the battery management system (BMS).

[0092] The battery management system can detect various states of internal switches, thus enhancing the safety of the battery management system.

[0093] Example 5

[0094] In one possible example scenario, Figure 6 This is a schematic diagram of the structure of an electrical device provided in Embodiment 5 of this application. According to... Figure 6 The provided diagram shows that the electrical device includes a battery management system (BMS) and a charger 300.

[0095] In one possible example scenario, the electrical device is applied to the electric vehicle control unit, the battery module in the battery management system is applied to the high-voltage electrical structure of the electric vehicle, and the charger is applied to the off-board charger structure.

[0096] The negative terminal of the battery management system is connected to the negative terminal of the charger 300 through the internal first switch KK1. The negative terminal of the charger is equipped with a second switch KK2, the positive terminal of the charger is equipped with a third switch KK3, and the positive terminal of the battery management system is equipped with a fourth switch KK4. A switch status detection structure can be set inside the charging terminal to realize the status detection of the internal switches of the charger.

[0097] The first, second, third, and fourth switches mentioned here are all relay switches. Among them, the first and second switches are negative relays, while the third and fourth switches are positive relays.

[0098] In one possible scenario, employing a multi-level protection scheme using diodes, resistors, and other components can improve the reliability of the switch detection circuit. However, due to the limited high-voltage side port resources and the increased sampling requirements from dual-gun charging, adding additional isolation increases costs. Adding a comparator to the switch state detection circuit allows for circuit detection via the high-voltage side digital port, reducing the resource requirements of the scarce high-voltage side analog port sampling and lowering overall costs. Simultaneously, diodes and high-voltage resistors protect the switch state detection circuit module and sampling port from surge voltages, while the comparator converts the analog signal into a digital signal recognizable by the identification module, protecting the digital device chip within the identification module from damage and improving circuit reliability and safety.

[0099] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A switch state detection circuit, characterized in that, It includes a first voltage divider module, a comparison module, and an identification module; The first terminal of the first voltage divider module is electrically connected to the first power supply, the second terminal of the first voltage divider module is electrically connected to the first terminal of the first switch, the first voltage divider node of the first voltage divider module is electrically connected to the first input terminal of the comparator module, and the second terminal of the first switch is electrically connected to the ground terminal. The second input terminal of the comparison module is electrically connected to the second power supply, and the output terminal of the comparison module is electrically connected to the input terminal of the identification module. When the state of the first switch is different, the comparison module is used to output different signals, and the identification module is used to identify the state of the first switch based on the signals output by the comparison module.

2. The switch state detection circuit according to claim 1, characterized in that, The first voltage divider module includes a first resistor network, a second resistor network, and a diode network; The first end of the first resistor network is electrically connected to the first power supply, the second end of the first resistor network is electrically connected to the first voltage divider node, and the second resistor network and the diode network are connected in series between the first voltage divider node and the first end of the first switch.

3. The switch state detection circuit according to claim 2, characterized in that, The first resistor network includes at least one first resistor; And / or, the second resistor network includes a plurality of second resistors connected in series; And / or, the diode network includes at least one diode, the anode of which is electrically connected to the first voltage divider node, and the cathode of which is electrically connected to the first terminal of the first switch.

4. The switch state detection circuit according to claim 1, characterized in that, The comparison module includes a comparator; The non-inverting input of the comparator is the first input of the comparison module, and the inverting input of the comparator is the second input of the comparison module. Alternatively, the inverting input of the comparator can be the first input of the comparison module, and the non-inverting input of the comparator can be the second input of the comparison module.

5. The switch state detection circuit according to claim 1, characterized in that, The switch state detection circuit further includes a second voltage divider module. The first end of the second voltage divider module is electrically connected to the second power supply, the second end of the second voltage divider module is electrically connected to the ground terminal, and the second voltage divider node of the second voltage divider module is electrically connected to the second input terminal of the comparison module.

6. The switch state detection circuit according to claim 5, characterized in that, The second voltage divider module includes a third resistor and a fourth resistor; One end of the third resistor is electrically connected to the second power supply, and the other end of the third resistor is electrically connected to one end of the fourth resistor and the second voltage divider node. The other end of the fourth resistor is electrically connected to the ground terminal.

7. The switch state detection circuit according to claim 1, characterized in that, The switch state detection circuit further includes a first filtering module; one end of the first filtering module is electrically connected to the second end of the first voltage divider module, and the other end of the first filtering module is electrically connected to the first end of the first switch. And / or, the switch state detection circuit further includes a second filtering module, one end of which is electrically connected to the first voltage divider node, and the other end of which is electrically connected to the first input terminal of the comparison module; And / or, the switch state detection circuit further includes a fifth resistor, one end of which is electrically connected to the output terminal of the comparison module and the input terminal of the identification module, and the other end of which is electrically connected to the second terminal of the identification module and the third power supply.

8. A battery management system, characterized in that, The system includes a switch state detection circuit as described in any one of claims 1 to 7.

9. A charger, characterized in that, Includes the switch state detection circuit as described in any one of claims 1 to 7.

10. An electrical device, characterized in that, The electrical device includes the battery management system as described in claim 8.

Images