Charging Detection Circuit and Device, Battery Management System, Battery Pack, and Electrical Equipment

Abstract

In an embodiment of the present application, a charging detection circuit, a charging device, a battery management system, a battery pack, and an electrical device are provided, including a first voltage dividing branch, a second voltage dividing branch, a third voltage dividing branch, and a comparator. Each voltage dividing branch includes at least two resistors connected in series with each other, and both ends of each voltage dividing branch are electrically connected between the output terminals of the first voltage input source and the isolated ground respectively. Different input pins of the comparator are respectively connected to the voltage dividing branches, the first output pin is configured to output a first signal based on the voltage of the first input pin and the voltage of the third input pin, and the second output pin is configured to output a second signal based on the voltage of the second input pin and the voltage of the fourth input pin. In this charging detection circuit, by setting three voltage dividing branches and a comparator, different access states of the resistors in the external charging device can be identified, thereby improving the reliability of charging device access identification.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of charging, and particularly to a charging detection circuit and device, a battery management system, a battery pack, and an electrical device. Background Art

[0002] With the increasing popularity of new energy technologies, users' demand for battery charging is constantly increasing. And with the development of battery technologies, the charging efficiency of secondary batteries is getting higher and higher at present. However, the existing methods for identifying the connection of charging devices have low reliability. Summary of the Invention

[0003] The embodiments of the present application provide a charging detection circuit and device, a battery management system, a battery pack, and an electrical device, which can improve the reliability of identifying the connection of charging devices.

[0004] In a first aspect, the embodiments of the present application provide a charging detection circuit. The charging detection circuit is used to detect the connection state of an external charging device. The charging detection circuit includes: a first voltage division branch, a second voltage division branch, a third voltage division branch, and a comparator. Each voltage division branch includes at least two resistors connected in series with each other, and both ends of each voltage division branch are respectively electrically connected between the output terminals of a first voltage input source and an isolated ground. The first input pin and the second input pin of the comparator are respectively electrically connected to the nodes between the resistors connected in series in the first voltage division branch. The third input pin of the comparator is electrically connected to the node between the resistors connected in series in the second voltage division branch. The fourth input pin of the comparator is electrically connected to the node between the resistors connected in series in the third voltage division branch. The first output pin of the comparator is configured to output a first signal based on the voltage of the first input pin and the voltage of the third input pin. The second output pin of the comparator is configured to output a second signal based on the voltage of the second input pin and the voltage of the fourth input pin.

[0005] In this charging detection circuit, by setting three voltage division branches and a comparator, the connection state of the resistors in the external charging device can be identified, thereby improving the reliability of identifying the connection of the charging device.

[0006] In some embodiments, the first voltage division branch includes a first resistor and a second resistor, the second voltage division branch includes a third resistor and a fourth resistor, and the third voltage division branch includes a fifth resistor and a sixth resistor. Among them, the resistance value of the second resistor is greater than the resistance value of the first resistor, the resistance value of the third resistor is greater than the resistance value of the fourth resistor, and the resistance value of the sixth resistor is greater than the resistance value of the fifth resistor. By setting the magnitude relationship of each resistor, the voltages output by each voltage division branch to the comparator can be made different, so that the comparator can output different first signals and second signals when the connection states of the resistors in the charging device are different, thereby different connection states of the charging device can be identified.

[0007] In some embodiments, the charging detection circuit further includes a first isolation element, and the first isolation element includes an input terminal and an output terminal. The input terminal of the first isolation element is electrically connected between the output terminal of the first voltage input source and the first output pin of the comparator, and the output terminal of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the first pin of the control unit. By providing the first isolation element, electrical isolation can be achieved.

[0008] In some embodiments, at least two resistors are connected in series between the output terminal of the first voltage input source and the first output pin of the comparator. One end of the input terminal of the first isolation element is electrically connected to the node between the series resistors, and the other end of the input terminal of the first isolation element is electrically connected to the first output pin of the comparator. At least two resistors are connected in series between the output terminal of the second voltage input source and the first pin of the control unit. One end of the output terminal of the first isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the first isolation element is grounded. Through the above arrangements, the first isolation element and the control unit can be protected.

[0009] In some embodiments, the charging detection circuit further includes a second isolation element, and the second isolation element includes an input terminal and an output terminal. The input terminal of the second isolation element is electrically connected between the output terminal of the first voltage input source and the second output pin of the comparator, and the output terminal of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the second pin of the control unit. By providing the second isolation element, electrical isolation can be achieved.

[0010] In some embodiments, at least two resistors are connected in series between the output terminal of the first voltage input source and the second output pin of the comparator. One end of the input terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the input terminal of the second isolation element is electrically connected to the second output pin of the comparator. At least two resistors are connected in series between the output terminal of the second voltage input source and the second pin of the control unit. One end of the output terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the second isolation element is grounded. Through the above arrangements, the second isolation element and the control unit can be protected.

[0011] In some embodiments, the charging detection circuit further includes a third isolation element, and the third isolation element includes an input terminal and an output terminal. The input terminal of the third isolation element is used for electrical connection with an external charging device, and the output terminal of the third isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the third pin of the control unit. By providing the second isolation element, electrical isolation can be achieved.

[0012] In some embodiments, the charging detection circuit further includes a fourth voltage dividing branch. The fourth voltage dividing branch includes at least two resistors connected in series with each other. One end of the input terminal of the third isolation element is electrically connected to the node of the resistors connected in series in the fourth voltage dividing branch, and the other end of the input terminal of the third isolation element is used to be electrically connected to an external charging device. At least two resistors are connected in series between the output terminal of the second voltage input source and the third pin of the control unit. One end of the output terminal of the third isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the third isolation element is grounded. Through the above arrangement, the third isolation element and the control unit can be protected.

[0013] In some embodiments, the first isolation element, the second isolation element, and the third isolation element are respectively at least one of an optocoupler, an optoelectronic field effect transistor, and an optotriac. By providing a variety of isolation elements, the design freedom of the charging detection circuit can be improved.

[0014] In some embodiments, the first voltage input source includes a DCDC module with isolation characteristics to supply power to the charging detection circuit. The second voltage input source is electrically connected to the first voltage input source and is used to step down the output voltage of the first voltage input source to supply power to the control unit. By setting the DCDC module and the second voltage input source, the high-voltage part and the low-voltage part can be isolated, the anti-interference ability of the circuit can be improved, and the control unit can be powered.

[0015] In a second aspect, an embodiment of the present invention further provides a charging device, including an electrical connection terminal, and the electrical connection terminal is used to be electrically connected to the charging detection circuit according to any one of the first aspect. The access states in the charging device include: a) the resistor in the charging device is not connected between the electrical connection terminal and the isolated ground of the charging detection circuit; b) the resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit; c) the resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit in a short-circuit form. Subsequently, the charging detection circuit provided in the present application can be used to identify different access states of the resistor in the charging device, improving the reliability of charging device access identification.

[0016] In a third aspect, an embodiment of the present invention further provides a battery management system, including the charging detection circuit according to any one of the first aspect. The battery management system can identify different access states of the resistor in the charging device, improving the reliability of charging device access identification.

[0017] In a fourth aspect, an embodiment of the present invention further includes a battery pack, including the battery management system according to the third aspect. The battery pack can identify different access states of the resistor in the charging device, improving the reliability of charging device access identification.

[0018] Fifth aspect, an embodiment of the present invention further provides an electrical device, which includes an electrical load and the battery pack as described in the fourth aspect, wherein the battery pack supplies power to the electrical load. The electrical device can identify different access states of the resistor in the charging device, improving the reliability of charging device access identification.

[0019] Compared with the prior art, the beneficial effects of one or more embodiments of the present application include: Different from the prior art, embodiments of the present application provide a charging detection circuit, a charging device, a battery management system, a battery pack and an electrical device, including a first voltage division branch, a second voltage division branch, a third voltage division branch and a comparator. Each voltage division branch includes at least two resistors connected in series with each other, and both ends of each voltage division branch are respectively electrically connected between the output terminals of the first voltage input source and the isolated ground. The first input pin and the second input pin of the comparator are respectively electrically connected to the nodes between the resistors connected in series in the first voltage division branch, the third input pin is electrically connected to the node between the resistors connected in series in the second voltage division branch, the fourth input pin is electrically connected to the node between the resistors connected in series in the third voltage division branch, the first output pin is configured to output a first signal based on the voltage of the first input pin and the voltage of the third input pin, and the second output pin is configured to output a second signal based on the voltage of the second input pin and the voltage of the fourth input pin. In this charging detection circuit, by setting three voltage division branches and a comparator, different access states of the resistor in the external charging device can be identified, thereby improving the reliability of charging device access identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Elements / modules and steps with the same reference numerals in the drawings represent similar elements / modules and steps, unless otherwise stated, the figures in the drawings do not constitute a proportional limitation.

[0021] Figure 1 is a schematic circuit diagram of a charging detection circuit provided by an embodiment of the present application;

[0022] Figure 2 is a schematic circuit diagram of a DCDC module provided by an embodiment of the present application;

[0023] Figure 3 is a schematic circuit connection diagram of a charging detection circuit provided by an embodiment of the present application;

[0024] Figure 4 is a schematic partial circuit diagram of a charging detection circuit provided by an embodiment of the present application;

[0025] Figure 5It is a schematic diagram of another part of the circuit structure of a charging detection circuit provided by an embodiment of the present application;

[0026] Figure 6 It is a schematic diagram of yet another part of the circuit structure of a charging detection circuit provided by an embodiment of the present application;

[0027] Figure 7 It is a schematic diagram of the circuit connection of another charging detection circuit provided by an embodiment of the present application;

[0028] Figure 8 It is a schematic diagram of the circuit connection of yet another charging detection circuit provided by an embodiment of the present application. Detailed implementation manners

[0029] The present application will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made. These all fall within the protection scope of the present application.

[0030] For the convenience of understanding the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0031] It should be noted that if there is no conflict, the various features in the embodiments of the present application can be combined with each other, and all are within the protection scope of the present application. In addition, although the functional modules are divided in the device schematic diagram, in some cases, it can be different from the module division in the device. In addition, the terms "first", "second", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0032] In recent years, battery charging technology has developed rapidly. In the existing charging methods, when identifying whether a charging device is connected to a battery pack, the first solution is to perform communication handshakes between the battery pack and the charging device. However, this method of simply relying on communication handshakes for identification will perform fast charging when the charging port connection is unstable. Due to the large contact resistance, large currents can cause accidents such as fires and explosions. The second solution is to combine a linear optocoupler and a control unit for charging identification. However, in this method, various connection situations of the resistors in the charging device cannot be identified.

[0033] It can be seen that the current solution has the defect of low reliability in identifying whether the charging device is effectively connected to the battery pack. Based on this, the embodiments of the present application provide a charging detection circuit, which can detect the connection state of an external charging device, identify the connection state of the charging device, and improve the reliability of the charging device connected to the battery pack.

[0034] Please refer to Figure 1 , the charging detection circuit is used to detect the connection state of an external charging device, and the charging detection circuit includes: a first voltage dividing branch 10, a second voltage dividing branch 20, a third voltage dividing branch 30, and a comparator.

[0035] The first voltage dividing branch 10, the second voltage dividing branch 20, and the third voltage dividing branch 30 each include at least two resistors connected in series, and both ends of the first voltage dividing branch 10, both ends of the second voltage dividing branch 20, and both ends of the third voltage dividing branch 30 are respectively electrically connected between the output terminal V1 of the first voltage input source and the isolated ground PE. It can be understood that the voltage of the isolated ground PE of the first voltage input source relative to the output terminal V1 is 0V.

[0036] The first input pin -INA of the comparator U1 is electrically connected to the node between the resistors connected in series in the first voltage dividing branch 10, the second input pin +INB of the comparator U1 is also electrically connected to the node between the resistors connected in series in the first voltage dividing branch 10, the third input pin +INA of the comparator U1 is electrically connected to the node between the resistors connected in series in the second voltage dividing branch 20, and the fourth input pin -INB of the comparator U1 is electrically connected to the node between the resistors connected in series in the third voltage dividing branch 30. The first output pin OUTA of the comparator U1 is configured to output a first signal based on the voltage of the first input pin -INA and the voltage of the third input pin +INA, and the second output pin OUTB of the comparator U1 is configured to output a second signal based on the voltage of the second input pin +INB and the voltage of the fourth input pin -INB.

[0037] Among them, the charging device can be a charging pile, a charging gun, a charger, or other charging devices that can be used to charge the battery. The charging detection circuit can be arranged on the circuit board of the battery management system (BMS) in the battery pack. Since the charging device is external to the battery pack and the BMS circuit board is a part of the battery pack, the charging device is external to the charging detection circuit.

[0038] In some embodiments, since the voltage output by the external charging device and the resistance in the external charging device are not directly electrically connected to the BMS circuit board of the battery pack, a first voltage input source is required to achieve electrical isolation between the external charging device and the BMS circuit board of the battery pack.

[0039] In a specific implementation, as Figure 2 shown, the first voltage input source can be a DCDC module U5 with isolation characteristics, and the DCDC module U5 can supply power to the charging detection circuit. The DCDC module U5 can be a buck module with isolation function, which can step down the voltage of the first input terminal VIN and output the stepped-down voltage V1 through the first output terminal +V0. For example, the voltage of the first input terminal VIN of the DCDC module U5 can be that after stepping down the voltage output by the battery pack, the voltage value is close to 12V. The second input terminal GND of the DCDC module U5 is grounded. The first output terminal +V0 of the DCDC module U5 is the output terminal V1 of the first voltage input source described in the embodiments of the present application. The output terminal V1 of this first voltage input source can output a +5V voltage. The second output terminal 0V of the DCDC module U5 is the isolated ground PE described in the embodiments of the present application. Among them, the voltage of the second input terminal GND of the DCDC module U5 can be understood as 0V relative to the voltage VIN of the first input terminal VIN, and the voltage of the second output terminal 0V of the DCDC module U5, that is, the isolated ground PE mentioned above, can be understood as 0V relative to the voltage V1 of the first output terminal +VO.

[0040] When this charging detection circuit is applied to the BMS, it can achieve that the ground in the charging device is different from the ground in the BMS. The DCDC module U5 isolates the external charging device from the BMS circuit board of the battery pack, reducing the risk that the BMS circuit board will also be short-circuited due to a failure of the external charging device, such as a short circuit of the external charging device. By using the DCDC module U5 with isolation characteristics to isolate the external charging device and the BMS circuit board of the battery pack, the safety performance of the BMS circuit board can be improved.

[0041] In addition, the comparator U1 can compare the voltage of the first input pin -INA and the voltage of the third input pin +INA, and output a first signal through the first output pin OUTA, and compare the voltage of the second input pin +INB and the voltage of the fourth input pin -INB, and output a second signal through the second output pin OUTB.

[0042] Specifically, in Figure 1In the comparator U1 shown, the comparator U1 is a comparator with two channels. When the voltage of the first input pin -INA is greater than the voltage of the third input pin +INA, the comparator U1 outputs a low-level signal through the first output pin OUTA. When the voltage of the first input pin -INA is less than the voltage of the third input pin +INA, the comparator U1 outputs a high-level signal through the first output pin OUTA. Also, when the voltage of the second input pin +INB is greater than the voltage of the fourth input pin -INB, the comparator U1 outputs a high-level signal through the second output pin OUTB. When the voltage of the second input pin +INB is less than the voltage of the fourth input pin -INB, the comparator U1 outputs a low-level signal through the second output pin OUTB. In this way, the comparator U1 can compare the voltage output by the first voltage-dividing branch 10 with the voltage output by the second voltage-dividing branch 20 through different input pins, and output a first signal through the first output pin OUTA. Also, it can compare the voltage output by the first voltage-dividing branch 10 with the voltage output by the third voltage-dividing branch 30, and output a second signal through the second output pin OUTB. In practical applications, the way the comparator U1 outputs signals is not limited to the above way. For example, the comparator U1 can be configured to output a high-level signal through the first output pin OUTA when the voltage of the first input pin -INA is greater than the voltage of the third input pin +INA, and output a low-level signal through the second output pin OUTB when the voltage of the second input pin +INB is greater than the voltage of the fourth input pin -INB. It should be noted that the comparator U1 can also use two single-channel comparators to compare the voltages of the three voltage-dividing branches, and this way should also fall within the scope protected by this application.

[0043] In this charging detection circuit, the node between the resistors connected in series in the first voltage-dividing branch 10 can be used to connect an external charging device. Usually, a resistor, denoted as the CC2 resistor, is often provided in the external charging device. Then, when the resistor in the external charging device is connected to this charging detection circuit in different connection ways, the voltage output from the node between the resistors connected in series in the first voltage-dividing branch 10 to the comparator U1 will change, thereby changing the first signal and the second signal output by the comparator U1. Subsequently, the connection state of the resistor in the external charging device can be identified through the first signal and the second signal. By identifying the connection state of the charging device in this way, the reliability of the identification can be improved, and subsequently, the safety of the charging device charging the electrical load can be improved.

[0044] In some embodiments, please continue to refer to Figure 1, the first voltage dividing branch 10 includes a first resistor R1 and a second resistor R2, the second voltage dividing branch 20 includes a third resistor R3 and a fourth resistor R4, and the third voltage dividing branch 30 includes a fifth resistor R5 and a sixth resistor R6. Among them, the resistance value of the second resistor R2 is greater than that of the first resistor R1, the resistance value of the third resistor R3 is greater than that of the fourth resistor R4, and the resistance value of the sixth resistor R6 is greater than that of the fifth resistor R5.

[0045] In the first voltage dividing branch 10, the first resistor R1 and the second resistor R2 are connected in series with each other, and the first end of the first resistor R1 is connected to the output terminal V1 of the first voltage input source. The second end of the first resistor R1 is respectively connected to the first end of the second resistor R2, the first input pin -INA of the comparator U1, and the second input pin +INB of the comparator U1. The second end of the second resistor R2 is connected to the isolated ground PE.

[0046] In the second voltage dividing branch 20, the third resistor R3 and the fourth resistor R4 are connected in series with each other, and the first end of the third resistor R3 is connected to the output terminal V1 of the first voltage input source. The second end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4 and the third input pin +INA of the comparator U1. The second end of the fourth resistor R4 is connected to the isolated ground PE.

[0047] In the third voltage dividing branch 30, the fifth resistor R5 and the sixth resistor R6 are connected in series with each other, and the first end of the fifth resistor R5 is connected to the output terminal V1 of the first voltage input source. The second end of the fifth resistor R5 is respectively connected to the first end of the sixth resistor R6 and the fourth input pin -INB of the comparator U1. The second end of the fourth resistor R4 is connected to the isolated ground PE.

[0048] In this way, subsequently, by setting the resistance values of each resistor, in the charging detection circuit, when the resistor in the charging device is normally connected, the voltage value input to the comparator U1 by the second voltage division branch 20 is less than the voltage value input to the comparator U1 by the first voltage division branch 10. The first output pin OUTA of the comparator U1 is a low-level signal. The voltage value input to the comparator U1 by the third voltage division branch 30 is greater than the voltage value input to the comparator U1 by the first voltage division branch 10. The second output pin OUTB of the comparator U1 is a low-level signal. When the resistor in the charging device is not connected, the voltage value input to the comparator U1 by the second voltage division branch 20 is less than the voltage value input to the comparator U1 by the first voltage division branch 10. The first output pin OUTA of the comparator U1 is a low-level signal. The voltage value input to the comparator U1 by the third voltage division branch 30 is less than the voltage value input to the comparator U1 by the first voltage division branch 10. The second output pin OUTB of the comparator U1 is a high-level signal. When the resistor in the charging device is connected in a short-circuit form, the voltage value input to the comparator U1 by the second voltage division branch 20 is greater than the voltage value input to the comparator U1 by the first voltage division branch 10. The first output pin OUTA of the comparator U1 is a high-level signal. The voltage value input to the comparator U1 by the third voltage division branch 30 is greater than the voltage value input to the comparator U1 by the first voltage division branch 10. The second output pin OUTB of the comparator U1 is a low-level signal.

[0049] It can be seen that by setting the resistance values of each resistor, the comparator U1 can output different first signals and second signals in different connection states of the resistor in the charging device. Subsequently, the connection state of the external charging device can be determined according to the first signal and the second signal of the comparator U1, improving the reliability of identifying the connection of the external charging device. In practical applications, the number of resistors included in the first voltage division branch 10, the second voltage division branch 20, and the third voltage division branch 30 can be set according to actual needs.

[0050] In one specific embodiment, the resistance value of the second resistor R2 is much larger than that of the first resistor R1. In this way, when the second terminal of the first resistor R1 is not connected to the resistor in the external charging device, for example, when the connection state of the resistor in the charging device is open, the voltage across the second resistor R2 is close to the output voltage value of the first voltage input source, that is, the voltages of the first input pin -INA of the comparator U1 and the second input pin +INB of the comparator U1 are close to the output voltage value of the first voltage input source. When the second terminal of the first resistor R1 is connected to the resistor in the external charging device, at this time, since the resistor in the external charging device, the first resistor R1, and the second resistor R2 divide the output voltage of the first voltage input source simultaneously, the voltage across the second resistor R2 will change, thereby causing the voltages of the first input pin -INA of the comparator U1 and the second input pin +INB of the comparator U1 to change, ultimately affecting the first signal and the second signal output by the comparator U1. When the resistance value of the second resistor R2 is set much larger than that of the first resistor R1, the reliability of the access recognition of the external charging device can be further improved.

[0051] In some embodiments, please refer to Figure 3 , the charging detection circuit further includes a first capacitor C1. The first capacitor C1 is connected between the output terminal V1 of the first voltage input source and the isolated ground PE. The first capacitor C1 can be used to filter the power supply output by the output terminal V1 of the first voltage input source, making the power supply output smooth and stable.

[0052] In some embodiments, please continue to refer to Figure 3 , the charging detection circuit further includes a first transient suppression diode D11. The first transient suppression diode D11 is connected in parallel with the second resistor R2. When the two poles of the first transient suppression diode D11 are subjected to a reverse transient high-energy impact, it can change the high impedance between its two poles into a low impedance, clamp the voltage between its two poles to a predetermined value, and absorb the surge pulse, thereby effectively protecting each device in the circuit.

[0053] In some embodiments, please refer to Figure 3 , the charging detection circuit further includes a first fuse PTC1. The first fuse PTC1 is connected between the first electrical connection terminal CC2 and the first end of the second resistor R2. Among them, the first electrical connection terminal CC2 is used to connect the resistor Rw in the external charging device. Specifically, the first fuse can be a positive temperature coefficient (PTC) thermistor or other fuses. By setting the first fuse, the connection between the external charging device and the charging detection circuit can be disconnected when the temperature is too high, thereby improving the safety of the circuit.

[0054] In some of these embodiments, the charging detection circuit further includes a first isolation element, which includes an input terminal and an output terminal. Among them, the input terminal of the first isolation element is electrically connected between the output terminal of the first voltage input source and the first output pin of the comparator, and the output terminal of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the first pin of the control unit. In this charging detection circuit, by setting the first isolation element, electrical isolation between the input terminal and the output terminal of the first isolation element can be achieved, which can avoid interference between the first output pin of the comparator and the control unit, improve the anti-interference ability of the circuit, and can also prevent high-voltage pulse signals from being transmitted to the control unit, thereby protecting the control unit.

[0055] Specifically, in some of these embodiments, refer to Figure 4 , the first isolation element includes a first optocoupler U2. Among them, the first optocoupler U2 includes a light-emitting device and a photosensitive device. In Figure 4 the illustrated embodiment, the light-emitting device is a light-emitting diode, and the photosensitive device is an NPN transistor. The anode of the light-emitting diode of the first optocoupler U2 is connected to the output terminal V1 of the first voltage input source, the cathode of the light-emitting diode of the first optocoupler U2 is connected to the first output pin OUTA of the comparator U1, the collector of the NPN transistor of the first optocoupler U2 is respectively connected to the output terminal V2 of the second voltage input source and the first pin MCU1 of the control unit, and the emitter of the NPN transistor of the first optocoupler U2 is grounded to GND.

[0056] In this first isolation element, when the first output pin OUTA of the comparator U1 outputs a low-level signal, the voltage difference between the anode and the cathode of the light-emitting diode of the first optocoupler U2 is greater than the conduction voltage, and the light-emitting diode of the first optocoupler U2 will conduct and emit a light signal. After the base of the NPN transistor of the first optocoupler U2 receives the light signal, it will conduct, causing the first pin MCU1 of the control unit to be grounded to GND, that is, the first pin MCU1 of the control unit will be a low-level signal at this time. When the first output pin OUTA of the comparator U1 outputs a high-level signal, the light-emitting diode of the first optocoupler U2 cannot conduct. At this time, the NPN transistor of the first optocoupler U2 will also be disconnected, and the first pin MCU1 of the control unit will be pulled high to a high-level signal by the voltage of the output terminal V2 of the second voltage input source. It can be seen that in this charging detection circuit, the signal of the first output pin OUTA of the comparator U1 can be in-phase output to the control unit, and electrical isolation is achieved through the first optocoupler U2.

[0057] In some other embodiments, the first isolation element may also be at least one of a photoelectric field effect transistor and a photoelectric thyristor. In this way, in practical applications, a suitable first isolation element can be selected according to needs, thereby increasing the design freedom of the charging detection circuit.

[0058] In some of the embodiments, the control unit may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of these components. The control unit may be configured to determine the access state of an external charging device according to the first signal and the second signal output by the comparator, so as to control the charging process of a subsequent electrical device or remind a user.

[0059] In some of the embodiments, at least two resistors are connected in series between the output terminal of the first voltage input source and the first output pin of the comparator. One end of the input terminal of the first isolation element is electrically connected to the node between the series resistors, and the other end of the input terminal of the first isolation element is electrically connected to the first output pin of the comparator.

[0060] Specifically, in some of the embodiments, please refer to Figure 4 , the charging detection circuit includes a seventh resistor R7 and an eighth resistor R8. Wherein, the first end of the seventh resistor R7 is connected to the output terminal V1 of the first voltage input source, the second end of the seventh resistor R7 is respectively connected to the first end of the eighth resistor R8 and the anode of the light-emitting diode of the first optocoupler U2, and the second end of the eighth resistor R8 is respectively connected to the cathode of the light-emitting diode of the first optocoupler U2 and the first output pin OUTA of the comparator U1. In this charging detection circuit, by setting the seventh resistor R7, when the light-emitting diode of the first optocoupler U2 is turned on, the magnitude of the current flowing through the light-emitting diode of the first optocoupler U2 can be limited, thereby protecting the first optocoupler U2. At the same time, by setting the eighth resistor R8, it can cooperate with the seventh resistor R7 to divide the voltage difference between the output terminal V1 of the first voltage input source and the first output pin OUTA of the comparator U1, preventing the voltage across the light-emitting diode of the first optocoupler U2 from being too large, thereby protecting the first optocoupler U2. In addition, when the first optocoupler U2 is turned off, the eighth resistor R8 can also provide a discharge path for the light-emitting diode of the first optocoupler U2, improving the turn-off speed of the first optocoupler U2. Moreover, the eighth resistor R8 can also provide a path for weak currents (such as currents generated by static electricity) in the case of weak currents, avoiding mis-turning on the light-emitting diode of the first optocoupler U2 and improving the anti-interference ability of the first optocoupler U2.

[0061] In some of these embodiments, at least two resistors are connected in series between the output terminal of the second voltage input source and the first pin of the control unit. One end of the output terminal of the first isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the first isolation element is grounded.

[0062] Specifically, in some of these embodiments, refer to Figure 4 , the charging detection circuit includes a ninth resistor R9 and a tenth resistor R10. Among them, the first end of the ninth resistor R9 is connected to the output terminal V2 of the second voltage input source, the second end of the ninth resistor R9 is respectively connected to the collector of the NPN triode of the first optocoupler U2 and the first end of the tenth resistor R10, and the second end of the tenth resistor R10 is connected to the first pin MCU1 of the control unit. In this charging detection circuit, by setting the ninth resistor R9, when the NPN triode of the first optocoupler U2 conducts, the magnitude of the current flowing through the NPN triode of the first optocoupler U2 can be limited, thereby protecting the first optocoupler U2. In addition, by setting the tenth resistor R10, the magnitude of the current output from the collector of the NPN triode of the first optocoupler U2 to the first input pin MCU1 of the control unit can be limited, thereby protecting the control unit.

[0063] In some of these embodiments, continue to refer to Figure 4 , the charging detection circuit further includes a first diode D1. The cathode of the first diode D1 is connected to the anode of the light-emitting diode of the first optocoupler U2, and the anode of the first diode D1 is connected to the cathode of the light-emitting diode of the first optocoupler U2. By setting the first diode D1, the light-emitting diode of the first optocoupler U2 can be prevented from being broken down by the reverse high voltage, thereby protecting the first optocoupler U2.

[0064] In some of these embodiments, continue to refer to Figure 4 , the charging detection circuit further includes a second capacitor C2. The second capacitor C2 is connected between the first pin MCU1 of the control unit and the ground GND. By setting the second capacitor C2, the signal input from the first isolation element to the first pin of the control unit can be filtered, the noise can be reduced, and the anti-interference ability of the circuit can be improved. In addition, when the tenth resistor R10 is provided in the charging detection circuit, the tenth resistor R10 and the second capacitor C2 together form an RC filter circuit to further improve the anti-interference ability of the circuit.

[0065] In some of these embodiments, the charging detection circuit further includes a second isolation element, which includes an input terminal and an output terminal. The input terminal of the second isolation element is electrically connected between the output terminal of the first voltage input source and the second output pin of the comparator, and the output terminal of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the second pin of the control unit. In this charging detection circuit, by providing the second isolation element, electrical isolation between the input terminal and the output terminal of the second isolation element can be achieved, avoiding interference between the second output pin of the comparator and the control unit, improving the anti-interference ability of the circuit, and also preventing high-voltage pulse signals from reaching the control unit, thereby protecting the control unit.

[0066] Specifically, in some of these embodiments, refer to Figure 5 , the second isolation element includes a second optocoupler U3. Among them, the second optocoupler U3 includes a light-emitting device and a photosensitive device. In Figure 5 the illustrated embodiment, the light-emitting device is a light-emitting diode, and the photosensitive device is an NPN transistor. The anode of the light-emitting diode of the second optocoupler U3 is connected to the output terminal V1 of the first voltage input source, the cathode of the light-emitting diode of the second optocoupler U3 is connected to the second output pin OUTB of the comparator U1, the collector of the NPN transistor of the second optocoupler U3 is respectively connected to the output terminal V2 of the second voltage input source and the second pin MCU2 of the control unit, and the emitter of the NPN transistor of the second optocoupler U3 is grounded to GND.

[0067] In this second isolation element, when the second output pin OUTB of the comparator U1 outputs a low-level signal, the voltage difference between the anode and the cathode of the light-emitting diode of the second optocoupler U3 is greater than the conduction voltage, and the light-emitting diode of the second optocoupler U3 will conduct and emit a light signal. After the base of the NPN transistor of the second optocoupler U3 receives the light signal, it will conduct, causing the second pin MCU2 of the control unit to be grounded to GND, that is, the second pin MCU2 of the control unit will be at a low-level signal at this time. When the second output pin OUTB of the comparator U1 outputs a high-level signal, the light-emitting diode of the second optocoupler U3 cannot conduct. At this time, the NPN transistor of the second optocoupler U3 will also be disconnected, and the second pin MCU2 of the control unit will be pulled high to a high-level signal by the voltage of the output terminal V2 of the second voltage input source. It can be seen that in this charging detection circuit, the signal of the second output pin OUTB of the comparator U1 can be in-phase output to the control unit, and electrical isolation is achieved through the second optocoupler U3.

[0068] In some other embodiments, the second isolation element may also be at least one of an optoelectronic field effect transistor and an optoelectronic thyristor. In this way, in practical applications, a suitable second isolation element can be selected according to needs, thereby improving the design freedom of the charging detection circuit.

[0069] In some of these embodiments, at least two resistors are connected in series between the output terminal of the first voltage input source and the second output pin of the comparator. One end of the input terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the input terminal of the second isolation element is electrically connected to the second output pin of the comparator.

[0070] Specifically, in some of these embodiments, please refer to Figure 5 , the charging detection circuit includes an eleventh resistor R11 and a twelfth resistor R12. Among them, the first end of the eleventh resistor R11 is connected to the output terminal V1 of the first voltage input source, and the second end of the eleventh resistor R11 is respectively connected to the first end of the twelfth resistor R12 and the anode of the light-emitting diode of the second optocoupler U3. The second end of the twelfth resistor R12 is respectively connected to the cathode of the light-emitting diode of the second optocoupler U3 and the second output pin OUTB of the comparator U1. In this charging detection circuit, by setting the eleventh resistor R11, when the light-emitting diode of the second optocoupler U3 is turned on, the magnitude of the current flowing through the light-emitting diode of the second optocoupler U3 can be limited, thereby protecting the second optocoupler U3. At the same time, by setting the twelfth resistor R12, it can, together with the eleventh resistor R11, divide the voltage difference between the output terminal V1 of the first voltage input source and the first output pin OUTA of the comparator U1, preventing the voltage across the two ends of the light-emitting diode of the second optocoupler U3 from being too large, thereby protecting the second optocoupler U3. In addition, when the second optocoupler U3 is turned off, the twelfth resistor R12 can also provide a discharge path for the light-emitting diode of the second optocoupler U3, improving the turn-off speed of the second optocoupler U3. Moreover, the twelfth resistor R12 can also provide a path for weak currents (such as currents generated by static electricity) in the case of weak currents, avoiding the mis-turn-on of the light-emitting diode of the second optocoupler U3 and improving the anti-interference ability of the second optocoupler U3.

[0071] In some of these embodiments, at least two resistors are connected in series between the output terminal of the second voltage input source and the second pin of the control unit. One end of the output terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the second isolation element is grounded.

[0072] Specifically, in some of these embodiments, please refer to Figure 5, the charging detection circuit includes a thirteenth resistor R13 and a fourteenth resistor R14. Among them, the first end of the thirteenth resistor R13 is connected to the output terminal V2 of the second voltage input source, and the second end of the thirteenth resistor R13 is respectively connected to the collector of the NPN triode of the second optocoupler U3 and the first end of the fourteenth resistor R14. The second end of the fourteenth resistor R14 is connected to the second pin MCU2 of the control unit. In this charging detection circuit, by setting the thirteenth resistor R13, when the NPN triode of the second optocoupler U3 is turned on, the magnitude of the current flowing through the NPN triode of the second optocoupler U3 can be limited, thereby protecting the second optocoupler U3. In addition, by setting the fourteenth resistor R14, the magnitude of the current output from the collector of the NPN triode of the first optocoupler U2 to the first input pin MCU1 of the control unit can be limited, thereby protecting the control unit.

[0073] In some of these embodiments, please continue to refer to Figure 5 , the charging detection circuit further includes a second diode D2. The cathode of the second diode D2 is connected to the anode of the light-emitting diode of the second optocoupler U3, and the anode of the second diode D2 is connected to the cathode of the light-emitting diode of the second optocoupler U3. By setting the second diode D2, the light-emitting diode of the second optocoupler U3 can be prevented from being broken down by the reverse high voltage, thereby protecting the second optocoupler U3.

[0074] In some of these embodiments, please continue to refer to Figure 5 , the charging detection circuit further includes a third capacitor C3. The third capacitor C3 is connected between the second pin MCU2 of the control unit and the ground GND. By setting the third capacitor C3, the signal input from the first isolation element to the first pin of the control unit can be filtered, reducing noise and improving the anti-interference ability of the circuit. In addition, when the charging detection circuit is provided with the fourteenth resistor R14, the fourteenth resistor R14 and the third capacitor C3 together form an RC filter circuit to further improve the anti-interference ability of the circuit.

[0075] In some of these embodiments, the charging detection circuit further includes a third isolation element. The third isolation element includes an input end and an output end. The input end of the third isolation element is used for electrical connection with an external charging device, and the output end of the third isolation element is electrically connected between the output terminal of the second voltage input source and the ground and is also electrically connected to the third pin of the control unit. In this charging detection circuit, by setting the second isolation element, electrical isolation can be achieved, and high-voltage pulse signals can be prevented from being transmitted to the control unit, thereby protecting the control unit.

[0076] Specifically, in some of these embodiments, please refer to Figure 6 , the third isolation element is a third optocoupler U4. Among them, the third optocoupler U4 includes a light-emitting device and a photosensitive device. InFigure 6 In the illustrated embodiment, the light-emitting device is a light-emitting diode, the photosensitive device is an NPN transistor, the anode of the light-emitting diode of the third optocoupler U4 is connected to the first end of the external charging device, the cathode of the light-emitting diode of the third optocoupler U4 is connected to the second end of the external charging device, the collector of the NPN transistor of the third optocoupler U4 is respectively connected to the output terminal V2 of the second voltage input source and the third pin MCU3 of the control unit, and the emitter of the NPN transistor of the third optocoupler U4 is grounded to GND.

[0077] In this charging detection circuit, the first end of the external charging device may be the positive terminal of the auxiliary power supply in the charging device, and the second end of the external charging device may be the negative terminal of the auxiliary power supply in the charging device, where the auxiliary power supply can output a voltage of 12V through the first end and the second end. Then, in this charging detection circuit, when the charging detection circuit is connected to the auxiliary power supply in the external charging device, the voltage difference between the anode and the cathode of the light-emitting diode of the third optocoupler U4 is greater than the conduction voltage, and the light-emitting diode of the third optocoupler U4 will conduct and emit a light signal. After the base of the NPN transistor of the third optocoupler U4 receives the light signal, it will conduct, causing the third pin MCU3 of the control unit to be grounded to GND, that is, the third pin MCU3 of the control unit will be a low-level signal at this time. When the connection between the external charging device and the charging detection circuit is disconnected, the light-emitting diode of the third optocoupler U4 cannot conduct. At this time, the NPN transistor of the third optocoupler U4 will also be disconnected, and the third pin MCU3 of the control unit will be pulled high to a high-level signal by the voltage of the output terminal V2 of the second voltage input source. It can be seen that in this charging detection circuit, the control unit can determine the access state of the auxiliary power supply in the external charging device through the signal of the third pin.

[0078] In some other embodiments, the third isolation element may also be at least one of an optoelectronic field effect transistor and an opto-thyristor. In this way, in practical applications, a suitable third isolation element can be selected according to needs, thereby improving the design freedom of the charging detection circuit.

[0079] In some of the embodiments, please refer to Figure 6 , the charging detection circuit further includes a fourth voltage dividing branch 40; the fourth voltage dividing branch 40 includes at least two resistors connected in series, one end of the input terminal of the third isolation element is electrically connected to the node of the resistors connected in series, and the other end of the input terminal of the third isolation element is used to be electrically connected to the external charging device.

[0080] Specifically, in some of the embodiments, please refer to Figure 6, the fourth voltage-dividing branch 40 includes a fifteenth resistor R15 and a sixteenth resistor R16. Among them, the first end of the fifteenth resistor R15 is connected to the first end of the external device, and the second end of the fifteenth resistor R15 is respectively connected to the first end of the sixteenth resistor R16 and the anode of the light-emitting diode of the third optocoupler U4. The second end of the sixteenth resistor R16 is respectively connected to the cathode of the light-emitting diode of the third optocoupler U4 and the second end of the external device. In this charging detection circuit, by setting the fifteenth resistor R15 and the sixteenth resistor R16, the auxiliary power supply can be voltage-divided when the auxiliary power supply in the charging device is connected. Subsequently, by setting the resistance values of the fifteenth resistor R15 and the sixteenth resistor R16, it is possible to avoid damage caused by excessive voltage across the light-emitting diode of the third optocoupler U4, thereby protecting the third optocoupler U4. In addition, the fifteenth resistor R15 can also limit the magnitude of the current flowing through the light-emitting diode of the third optocoupler U4 when the light-emitting diode of the third optocoupler U4 is turned on, thereby protecting the third optocoupler U4. In addition, the sixteenth resistor R16 can provide a discharge path for the light-emitting diode of the third optocoupler U4 when the third optocoupler U4 is turned off, improving the turn-off speed of the third optocoupler U4. Moreover, the sixteenth resistor R16 can also provide a path for weak current (such as the current generated by static electricity) in the case of weak current, avoiding mis-turning on the light-emitting diode of the third optocoupler U4 and improving the anti-interference ability of the third optocoupler U4.

[0081] In some embodiments, at least two resistors are connected in series between the output terminal of the second voltage input source and the third pin of the control unit, and one end of the output terminal of the third isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the third isolation element is grounded.

[0082] Specifically, in some embodiments, please refer to Figure 6 , the charging detection circuit includes a seventeenth resistor R17 and an eighteenth resistor R18. Among them, the first end of the seventeenth resistor R17 is connected to the output terminal of the second voltage input source, the second end of the seventeenth resistor R17 is respectively connected to the collector of the NPN triode of the third optocoupler U4 and the first end of the eighteenth resistor R18, and the second end of the eighteenth resistor R18 is connected to the third pin MCU3 of the control unit. In this charging detection circuit, by setting the seventeenth resistor R17, the magnitude of the current flowing through the NPN triode of the third optocoupler U4 can be limited when the NPN triode of the third optocoupler U4 is turned on, thereby protecting the third optocoupler U4. In addition, the eighteenth resistor R18 can limit the magnitude of the current output from the collector of the NPN triode of the first optocoupler U2 to the first input pin MCU1 of the control unit, thereby protecting the control unit.

[0083] In some embodiments, please refer toFigure 6 , the charging detection circuit further includes a third diode D3. The cathode of the third diode D3 is connected to the anode of the light-emitting diode of the third optocoupler U4, and the anode of the third diode D3 is connected to the cathode of the light-emitting diode of the third optocoupler U4. By providing the third diode D3, the light-emitting diode of the third optocoupler U4 can be prevented from being broken down by the reverse high voltage, thereby protecting the third optocoupler U4.

[0084] In some embodiments, please refer to Figure 6 , the charging detection circuit further includes a fourth capacitor C4. The fourth capacitor C4 is connected between the third pin MCU3 of the control unit and the ground GND. By providing the fourth capacitor C4, the signal input from the third isolation element to the third pin of the control unit can be filtered, reducing noise and improving the anti-interference ability of the circuit. Additionally, when the charging detection circuit is provided with an eighteenth resistor R18, the eighteenth resistor R18 and the fourth capacitor C4 together form an RC filter circuit to further improve the anti-interference ability of the circuit.

[0085] In some embodiments, please continue to refer to Figure 6 , the charging detection circuit further includes a second transient suppression diode D21. The second transient suppression diode D21 is connected in parallel with the second voltage division branch 40. The second transient suppression diode D21 can change the high impedance between its two poles to a low impedance when the two poles are subjected to a reverse transient high-energy impact, clamp the voltage between the two poles to a predetermined value, and absorb the surge pulse, thereby effectively protecting each device in the circuit.

[0086] In some embodiments, please refer to Figure 6 , the charging detection circuit further includes a second fuse PTC2. The second fuse PTC2 is connected between the second electrical connection terminal AP+ and the first end of the fifteenth resistor R15, where the second electrical connection terminal AP+ is used to connect to the first end of the auxiliary power supply in the external charging device. Specifically, the second fuse can be a PTC thermistor or other fuse. By providing the second fuse, the connection between the external charging device and the charging detection circuit can be disconnected when the temperature is too high, thereby improving the safety of the circuit.

[0087] In some of these embodiments, the second voltage input source is electrically connected to the first voltage input source and is used to step down the output voltage of the first voltage input source to supply power to the control unit. Specifically, an LDO step-down module can be set. The input end of the LDO step-down module is connected to the first output end of the above-mentioned DCDC module U5, and the output end of the LDO step-down module can be the output end V2 of the second voltage input source described in the embodiments of the present application. For example, the LDO step-down module can receive 5V output by the DCDC module U5 and output 3.3V through the output end, and this 3.3V can supply power to the control unit.

[0088] The following will Figures 2 - 6 elaborate in detail the specific working process of the charging detection circuit provided by the embodiments of the present application in combination with the embodiments shown.

[0089] In this charging detection circuit, it includes a first electrical connection terminal CC2, a second electrical connection terminal AP+, and a third electrical connection terminal AP-. Among them, the first electrical connection terminal CC2 is used to connect the first electrical connection terminal in an external charging device, the second electrical connection terminal AP+ is used to connect the second electrical connection terminal in the external charging device, and the third electrical connection terminal AP- is used to connect the third electrical connection terminal in the external charging device. The first electrical connection terminal in the external charging device is connected to the first end of the CC2 resistor, the second electrical connection terminal is connected to the positive extreme of the auxiliary power supply, and the third electrical connection terminal is connected to the negative extreme of the auxiliary power supply. Usually, the auxiliary power supply is a DC power supply.

[0090] Among them, the voltage of the output terminal V1 of the first voltage input source is selected as 5V, the voltage of the output terminal V2 of the second voltage input source is selected as 3.3V, the resistance value of the second resistor R2 is much larger than the resistance value of the first resistor R1. The resistance value of the first resistor R1 is selected as 1kΩ, the resistance value of the third resistor R3 is selected as 10kΩ, the resistance value of the fourth resistor R4 is selected as 4.7kΩ, the resistance value of the fifth resistor R5 is selected as 10kΩ, the resistance value of the sixth resistor R6 is selected as 24kΩ, and the resistance value of the CC2 resistor Rw in the external charging device is selected as 1kΩ. Then, the voltage input to the third input pin +INA of the comparator U1 at the second end of the third resistor R3 is approximately 1.6V, and the voltage input to the fourth input pin -INB of the comparator U1 at the second end of the fifth resistor R5 is approximately 3.53V. It should be noted that the values selected here are only for facilitating the description of the operation of the charging detection circuit and do not serve as a limitation of the present application.

[0091] In this charging detection circuit, when the auxiliary power supply in the charging device is not connected to the second electrical connection terminal AP+ and the third electrical connection terminal AP-, the light-emitting diode of the third optocoupler U4 is not turned on, that is, the NPN triode of the third optocoupler U4 is disconnected. At this time, the third pin MCU3 of the control unit is pulled up to 3.3V by the output terminal V2 of the second voltage input source, that is, the third pin MCU3 of the control unit is a high-level signal.

[0092] When the positive terminal of the auxiliary power supply in the charging device is connected to the second electrical connection terminal AP+ and the negative terminal of the auxiliary power supply is connected to the third electrical connection terminal AP-, the fifteenth resistor R15 and the sixteenth resistor R16 divide the voltage of the auxiliary power supply. The voltage across the light-emitting diode of the third optocoupler U4 is greater than the conduction voltage, and the light-emitting diode of the third optocoupler U4 conducts and emits light, causing the NPN transistor of the third optocoupler U4 to also conduct. At this time, the third pin MCU3 of the control unit will change from a high-level signal to a low-level signal, and subsequently, it can be recognized by the control unit that the auxiliary power supply in the charging device has been connected.

[0093] When the auxiliary power supply in the charging device has been connected, if the CC2 resistor Rw in the charging device is not connected between the first electrical connection terminal CC2 and the isolated ground PE of the charging detection circuit, as Figure 3 shown, at this time, since the resistance value of the second resistor R2 is much larger than the resistance value of the first resistor R1, the voltage at the second end of the first resistor R1 is close to 5V. Then, the voltage of the first input pin -INA of the comparator U1 is greater than the voltage of the third input pin +INA, and the first output pin OUTA of the comparator U1 will output a low-level signal, and the NPN transistor of the first optocoupler U2 will conduct, and the first pin MCU1 of the control unit will be pulled down to the ground, that is, the first pin MCU1 of the control unit is a low-level signal. And the voltage of the second input pin +INB of the comparator U1 is greater than the voltage of the fourth input pin -INB, and the second output pin OUTB of the comparator U2 will output a high-level signal, and the NPN transistor of the second optocoupler U3 will be disconnected, and the second pin MCU2 of the control unit will be pulled up to 3.3V by the output terminal V2 of the second voltage input source, that is, the second pin MCU2 of the control unit is a high-level signal.

[0094] If the CC2 resistor Rw in the charging device is connected between the first electrical connection terminal CC2 and the isolated ground PE of the charging detection circuit, as Figure 7 shown, at this time, the voltage at the second end of the first resistor R1 is about 2.5V, and the voltage at the second end of the third resistor R3 is still about 1.6V, and the voltage at the second end of the fifth resistor R5 is still about 3.53V. Then, the voltage of the first input pin -INA of the comparator U1 is greater than the voltage of the third input pin +INA, and the first output pin OUTA of the comparator U1 still outputs a low-level signal, and the first pin MCU1 of the control unit is still a low-level signal. And the voltage of the third input pin +INB of the comparator U1 is less than the voltage of the fourth input pin -INB, and the second output pin OUTB of the comparator U2 will output a low-level signal, and the NPN transistor of the second optocoupler U3 will conduct, and the second pin MCU2 of the control unit will be pulled down to the ground, that is, the second pin MCU2 of the control unit is a low-level signal.

[0095] If the CC2 resistor Rw in the charging device is connected between the first electrical connection terminal CC2 and the isolated ground PE of the charging detection circuit in a short - circuit form, as Figure 8 shown, at this time, the voltage at the second terminal of the first resistor R1 is approximately 0V, while the voltage at the second terminal of the third resistor R3 is still approximately 1.6V, and the voltage at the second terminal of the fifth resistor R5 is still approximately 3.53V. Then, the voltage at the first input pin - INA of the comparator U1 is less than the voltage at the third input pin + INA, and the first output pin OUTA of the comparator U1 outputs a high - level signal. The NPN triode of the first optocoupler U2 will be disconnected, and the first pin MCU1 of the control unit will be pulled up to 3.3V by the output terminal V2 of the second voltage input source, that is, the first pin MCU1 of the control unit is a high - level signal. And the voltage at the third input pin + INB of the comparator U1 is also less than the voltage at the fourth input pin - INB, and the second output pin OUTB of the comparator U2 still outputs a low - level signal, that is, the second pin MCU2 of the control unit is still a low - level signal.

[0096] In summary, when the third pin MCU3 of the control unit is a high - level signal, the auxiliary power supply in the charging device is not connected to the charging detection circuit; when the third pin MCU3, the second pin MCU2, and the first pin MCU1 of the control unit are all low - level signals, it indicates that the auxiliary power supply in the charging device has been connected to the charging detection circuit, and the CC2 resistor in the charging device has also been connected between the first electrical connection terminal and the isolated ground; when the third pin MCU3 and the first pin MCU1 of the control unit are low - level signals, while the second pin MCU2 is a high - level signal, it indicates that the auxiliary power supply in the charging device has been connected to the charging detection circuit, and the CC2 resistor in the charging device is not connected between the first electrical connection terminal and the isolated ground; when the third pin MCU3 and the second pin MCU1 of the control unit are low - level signals, while the first pin MCU1 is a high - level signal, it indicates that the auxiliary power supply in the charging device has been connected to the charging detection circuit, and the CC2 resistor in the charging device is connected between the first electrical connection terminal and the isolated ground in a short - circuit form.

[0097] It can be seen that through the above - mentioned method, the reliability of identifying the access state of the charging device can be improved, and the circuit topology is simple and the circuit cost is low.

[0098] Second aspect: An embodiment of the present application further provides a charging device, including an electrical connection terminal for electrically connecting to the charging detection circuit in any one of the first aspect. Among them, the access states in the charging device include: a) the resistor in the charging device is not connected between the electrical connection terminal and the isolated ground of the charging detection circuit; b) the resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit; c) the resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit in a short-circuit form.

[0099] In this embodiment, the charging detection circuit has the same structure and function as the charging detection circuit in any of the above embodiments, and will not be elaborated here one by one.

[0100] Third aspect: An embodiment of the present application further provides a battery management system, including the charging detection circuit in any one of the first aspect. In this embodiment, the charging detection circuit has the same structure and function as the charging detection circuit in any of the first aspect embodiments, and will not be elaborated here one by one.

[0101] Fourth aspect: An embodiment of the present application further provides a battery pack, which includes the battery management system as described in the third aspect. In this embodiment, the battery management system has the same structure and function as the battery management system in any of the above embodiments, and will not be elaborated here one by one.

[0102] Fifth aspect: An embodiment of the present application further provides an electrical device, which includes an electrical load and the battery pack as described in the fourth aspect, where the battery pack supplies power to the electrical load. In this embodiment, the battery pack has the same structure and function as the battery pack in the above embodiments, and will not be elaborated here one by one. In addition, the battery pack may include only one battery cell, or may include at least two battery cells connected in series and / or in parallel.

[0103] In some embodiments, the electrical load includes but is not limited to energy storage products, drones, power tools, and electric vehicles.

[0104] It should be noted that the device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above. For the sake of brevity, they are not provided in detail; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present application.

Claims

1. A charging detection circuit for detecting the access state of an external charging device, the charging detection circuit comprising: A first voltage dividing branch, a second voltage dividing branch and a third voltage dividing branch, each voltage dividing branch includes at least two resistors connected in series with each other, and both ends of each voltage dividing branch are respectively electrically connected between the output terminals of a first voltage input source and an isolated ground. Among them, the first voltage dividing branch includes a first resistor and a second resistor, the second voltage dividing branch includes a third resistor and a fourth resistor, the third voltage dividing branch includes a fifth resistor and a sixth resistor, the resistance value of the second resistor is greater than that of the first resistor, the resistance value of the third resistor is greater than that of the fourth resistor, and the resistance value of the sixth resistor is greater than that of the fifth resistor; A comparator, the first input pin and the second input pin of the comparator are respectively electrically connected to the nodes between the resistors connected in series in the first voltage dividing branch, the third input pin of the comparator is electrically connected to the node between the resistors connected in series in the second voltage dividing branch, the fourth input pin of the comparator is electrically connected to the node between the resistors connected in series in the third voltage dividing branch, the first output pin of the comparator is configured to output a first signal based on the voltage of the first input pin and the voltage of the third input pin, and the second output pin of the comparator is configured to output a second signal based on the voltage of the second input pin and the voltage of the fourth input pin.

2. The charging detection circuit according to claim 1, wherein, The charging detection circuit further includes a first isolation element, the first isolation element includes an input end and an output end; The input end of the first isolation element is electrically connected between the output terminal of the first voltage input source and the first output pin of the comparator, and the output end of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is electrically connected to the first pin of the control unit.

3. The charging detection circuit according to claim 2, wherein, At least two resistors are connected in series between the output terminal of the first voltage input source and the first output pin of the comparator, one end of the input end of the first isolation element is electrically connected to the node between the series resistors, and the other end of the input end of the first isolation element is electrically connected to the first output pin of the comparator; At least two resistors are connected in series between the output terminal of the second voltage input source and the first pin of the control unit, one end of the output end of the first isolation element is electrically connected to the node between the series resistors, and the other end of the output end of the first isolation element is grounded.

4. The charging detection circuit according to claim 2, wherein, The charging detection circuit further includes a second isolation element, the second isolation element includes an input end and an output end; The input end of the second isolation element is electrically connected between the output terminal of the first voltage input source and the second output pin of the comparator, and the output end of the first isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is electrically connected to the second pin of the control unit.

5. The charging detection circuit according to claim 4, wherein, At least two resistors are connected in series between the output terminal of the first voltage input source and the second output pin of the comparator. One end of the input terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the input terminal of the second isolation element is electrically connected to the second output pin of the comparator; At least two resistors are connected in series between the output terminal of the second voltage input source and the second pin of the control unit. One end of the output terminal of the second isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the second isolation element is grounded.

6. The charging detection circuit according to claim 4, wherein, The charging detection circuit further includes a third isolation element, and the third isolation element includes an input terminal and an output terminal; The input terminal of the third isolation element is used for electrical connection with an external charging device. The output terminal of the third isolation element is electrically connected between the output terminal of the second voltage input source and the ground, and is also electrically connected to the third pin of the control unit.

7. The charging detection circuit according to claim 6, wherein The charging detection circuit further includes a fourth voltage dividing branch; The fourth voltage dividing branch includes at least two resistors connected in series with each other. One end of the input terminal of the third isolation element is electrically connected to the node of the resistors connected in series in the fourth voltage dividing branch, and the other end of the input terminal of the third isolation element is used for electrical connection with an external charging device; At least two resistors are connected in series between the output terminal of the second voltage input source and the third pin of the control unit. One end of the output terminal of the third isolation element is electrically connected to the node between the series resistors, and the other end of the output terminal of the third isolation element is grounded.

8. The charging detection circuit according to claim 6, wherein, The first isolation element, the second isolation element and the third isolation element are respectively at least one of an optocoupler, an optoelectronic field effect transistor, and an optotriac.

9. The charging detection circuit according to claim 2, wherein, The first voltage input source includes a DCDC module with isolation characteristics to supply power to the charging detection circuit; The second voltage input source is electrically connected to the first voltage input source and is used for step-down processing of the output voltage of the first voltage input source to supply power to the control unit.

10. A charging device, comprising an electrical connection terminal, the electrical connection terminal being used for electrically connecting with the charging detection circuit described in any one of claims 1 to 9, wherein, The access states in the charging device include: a) The resistor in the charging device is not connected between the electrical connection terminal and the isolated ground of the charging detection circuit; b) The resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit; c) The resistor in the external charging device is connected between the electrical connection terminal and the isolated ground of the charging detection circuit in a short-circuit form.

11. A battery management system includes the charging detection circuit according to any one of claims 1 to 9.

12. A battery pack includes the battery management system according to claim 11.

13. An electrical device, comprising an electrical load and the battery pack as described in claim 12, wherein, The battery pack supplies power to the electrical load.

Images