The charging detection circuit is connected with the voltage collection circuit, the battery pack and the electric device

Abstract

The embodiment of the application discloses a charging detection circuit and a voltage collection circuit, a battery pack and a power utilization device. The charging detection circuit comprises a first switch unit, a second switch unit and a control unit. The first switch unit is used for being connected with the positive pole of the battery, a first charging end and a second charging end respectively. The second switch unit is used for being connected with the first switch unit, a first power supply and the control unit respectively. When the first switch unit and the second switch unit are closed, the control unit receives a first level signal. In the above manner, the charging safety can be improved while the cost is reduced.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a charging detection circuit and voltage acquisition circuit, a battery pack, and an electrical device. Background Technology

[0002] In recent years, rechargeable batteries have been widely used in mobile phones, laptops, power banks, electric vehicles, power tools, and other fields, playing an important role in improving people's environmental protection and energy conservation levels, and providing great convenience for people's efficient and convenient lives. At the same time, users' requirements for charging safety are also getting higher and higher.

[0003] In existing technologies, a power switch is typically placed between the positive terminal of the battery and the positive terminal of the charger. The power switch is closed to start charging only when the charger meets the charging requirements (such as confirming that the charger is connected). This can prevent charging abnormalities from damaging the charger or causing accidents, thereby ensuring charging safety.

[0004] However, the above solution requires the installation of power switching transistors, which increases costs. Summary of the Invention

[0005] The embodiments of this application aim to provide a charging detection circuit and voltage acquisition circuit, a battery pack and an electrical device, which can improve charging safety while reducing costs.

[0006] To achieve the above objectives, in a first aspect, this application provides a charging detection circuit, including a first switching unit, a second switching unit, and a control unit. The first switching unit is connected to the positive terminal of the battery, a first charging terminal, and a second charging terminal, respectively. The second switching unit is connected to the first switching unit, a first power supply, and the control unit, respectively. Specifically, when the first switching unit and the second switching unit are closed, the control unit receives a first level signal.

[0007] In this charging detection circuit, the charger can be connected to the first charging terminal and the second charging terminal. When the charger is connected to the charging detection circuit, both the first and second switching units are closed, and the second switching unit outputs a first level signal to the control unit. After receiving the first level signal, the control unit knows that a charger is connected, so it can be set to only perform the charging operation when the charger is connected, which can improve charging safety. At the same time, in this charging detection circuit, there is no need to set a power switching transistor between the positive terminal of the battery and the first charging terminal, thereby achieving the purpose of reducing costs.

[0008] In one alternative embodiment, the first switching unit includes a first switching transistor and a first resistor, wherein a first terminal of the first switching transistor is connected to a first terminal of the first resistor, a second terminal of the first resistor is connected to a second charging terminal, a second terminal of the first switching transistor is connected to the positive terminal of the battery and the first charging terminal, and a third terminal of the first switching transistor is connected to the second switching unit.

[0009] In one alternative embodiment, the first switching unit further includes a first capacitor, with a first terminal connected to the positive terminal of the battery and a second terminal connected to the first terminal of the first switching transistor.

[0010] In one alternative embodiment, the second switching unit includes a second switching transistor, a second resistor, and a third resistor. The first terminal of the second switching transistor is connected to the third terminal of the first switching transistor through the second resistor. The second terminal of the second switching transistor is grounded. The third terminal of the second switching transistor is connected to the first terminal of the third resistor and the control unit. The second terminal of the third resistor is connected to the first power supply.

[0011] In one alternative embodiment, the second switching unit further includes a second capacitor, the first terminal of which is connected to the first terminal of the second switching transistor, and the second terminal of which is grounded.

[0012] In one alternative embodiment, the second switching unit further includes a third capacitor and a fourth resistor, with the first terminal of the third capacitor connected to the first terminal of the fourth resistor and the control unit, the second terminal of the third capacitor grounded, and the second terminal of the fourth resistor connected to the third terminal of the second switching transistor.

[0013] In one alternative embodiment, the first switching transistor is a metal-oxide-semiconductor field-effect transistor, an insulated-gate bipolar transistor, or a transistor, and the second switching transistor is a metal-oxide-semiconductor field-effect transistor, an insulated-gate bipolar transistor, or a transistor.

[0014] In one alternative embodiment, the charging detection circuit further includes a first branch and a second branch. The first branch includes at least two capacitors connected in series, with a first terminal connected to a first charging terminal and a second terminal grounded. The second branch includes at least two capacitors connected in series, with a first terminal connected to the first charging terminal and a second terminal grounded.

[0015] Secondly, embodiments of this application also provide a voltage acquisition circuit, including a resistor branch and a charging detection circuit as provided in the first aspect. The resistor branch includes at least two resistors connected in series, a first end of the resistor branch is connected to a first power supply, a second end of the resistor branch is connected to a second charging terminal, and the connection point between any two of the at least two resistors is connected to a control unit.

[0016] In the voltage acquisition circuit, not only can the charging detection circuit detect whether a charger is connected, but when the control unit detects a charger connected, it can further obtain the charging voltage provided by the connected charger through the resistor branch, and determine whether the charging voltage is within the allowable charging voltage range, and whether the charging voltage exceeds the maximum allowable charging voltage of the battery. Therefore, the battery charging process is only executed if the charging voltage is within the allowable charging voltage range, ensuring that the battery is not damaged by excessive voltage and making battery charging safer.

[0017] In one alternative embodiment, the voltage acquisition circuit further includes a fourth capacitor and a fifth resistor, with the first terminal of the fourth capacitor connected to the first terminal of the fifth resistor and the control unit, the second terminal of the fourth capacitor grounded, and the second terminal of the fifth resistor connected to a connection point.

[0018] In one alternative embodiment, the resistive branch includes a sixth resistor and a seventh resistor, and the voltage V between the first charging terminal and the second charging terminal... CHG The following relationship must be satisfied: Where V2 is the voltage value of the first power supply, V ADC The voltage value at the connection point. R6 is the resistance value of the sixth resistor, R7 is the resistance value of the seventh resistor, V BAT This is the battery voltage value.

[0019] In one alternative approach, the resistance values ​​of the sixth and seventh resistors satisfy the formula: Where V1 is the voltage difference between the battery and the voltage between the first charging terminal and the second charging terminal.

[0020] In one alternative embodiment, the voltage acquisition circuit further includes a first diode, the anode of which is connected to the second end of the resistor branch, and the cathode of which is connected to the second charging terminal.

[0021] In one alternative embodiment, the voltage acquisition circuit further includes a third switch, the first terminal of which is connected to the control unit, the second terminal of which is connected to the second charging terminal, and the third terminal of which is connected to the negative terminal of the battery.

[0022] Thirdly, embodiments of this application also provide a battery pack, including a battery module and the charging detection circuit provided in the first aspect, and / or including a battery module and the voltage acquisition circuit provided in the second aspect. The battery module includes at least one battery.

[0023] Fourthly, embodiments of this application also provide an electrical device, including a load and a battery pack as provided in the second aspect, the battery pack being used to supply power to the load.

[0024] One or more embodiments of this application include the following beneficial effects: The charging detection circuit provided in this application is connected to a charger via a first charging terminal and a second charging terminal. When the charger is connected to the charging detection circuit, the first and second switching units are closed, and a first level signal is output to the control unit through the second switching unit. When the control unit detects that the charger is connected, it can be set to perform the charging operation only when the charger is connected, which can improve charging safety. At the same time, in this circuit, there is no need to set a power switching transistor between the positive terminal of the battery and the first charging terminal, which can reduce costs, thereby achieving the goal of improving charging safety while reducing costs. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1 This is a schematic diagram of a circuit structure using a high-side driving scheme in the prior art;

[0027] Figure 2 This is a schematic diagram of the charging detection circuit provided in an embodiment of this application;

[0028] Figure 3 A schematic diagram of the circuit structure of the charging detection circuit provided in the embodiments of this application;

[0029] Figure 4 A schematic diagram of the circuit structure of a charging detection circuit provided in another embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the voltage acquisition circuit provided in the embodiments of this application;

[0031] Figure 6 A schematic diagram of the circuit structure of the voltage acquisition circuit provided in the embodiments of this application;

[0032] Figure 7 This application provides an equivalent circuit diagram showing how the resistor branch is connected to the battery, the first charging terminal, and the second charging terminal, respectively, in an embodiment. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0034] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a circuit structure using a high-side driving scheme in the prior art. For example... Figure 1 As shown, the high-side drive scheme requires power switch Q11 and power switch Q12 to be placed between the positive terminal B+ of the battery and the positive terminal C+ of the charger, while the negative terminal of the battery is connected to the negative terminal of the charger. Therefore, this scheme makes it easier to realize the presence detection of the charger (i.e., to detect whether the charger is connected to the circuit to charge the battery).

[0035] For example, in Figure 1 In the circuit shown, when no charger is connected to the circuit, the switch Q13 is in the off state. At this time, interface S11 is connected to the power supply V11, and the signal transmitted to the controller through interface S11 is a high-level signal. When a charger is connected to the circuit, the switch Q13 is turned on, and interface S11 is pulled down to ground GND. Therefore, the signal transmitted to the controller through interface S11 is a low-level signal. It is evident that the controller can determine whether a charger is connected to the circuit based on the received signal.

[0036] However, in the high-side drive scheme, power switches Q11 and Q12 need to be set, which leads to higher costs.

[0037] Based on this, this application provides a charging detection circuit that can perform detection based on a low-side driving scheme. That is, it can detect whether the charger is connected even when the negative terminal of the battery is not connected to the negative terminal of the charger. This can improve charging safety and eliminate the need for a power switching transistor, thereby reducing costs.

[0038] like Figure 2 As shown, the charging detection circuit 100 includes a first switching unit 10, a second switching unit 20, and a control unit 30. The first switching unit 10 is connected to the positive terminal BAT+, the first charging terminal CHG+, and the second charging terminal CHG- of the battery, respectively. The second switching unit 20 is connected to the first switching unit 10, the first power supply V21, and the control unit 30, respectively.

[0039] Specifically, the second charging terminal CHG- is connected to the first terminal of the first switching unit 10, the positive terminal BAT+ of the battery and the first charging terminal CHG+ are both connected to the second terminal of the first switching unit 10, the third terminal of the first switching unit 10 is connected to the first terminal of the second switching unit 20, the second terminal of the second switching unit 20 is grounded to GND, and the first power supply V21 and the control unit 30 are both connected to the third terminal of the second switching unit 20.

[0040] Furthermore, the charger can be connected to the charging detection circuit 100 via the first charging terminal CHG+ and the second charging terminal CHG-. After the charger is connected, both the first switching unit 10 and the second switching unit 20 are closed, and the control unit 30 can receive a first level signal and determine that a charger is connected based on the first level signal. Thus, the charging operation can be set to only be performed when the charger is connected, ensuring charging safety. Moreover, in this charging detection circuit 100, a power switching transistor is not required between the positive terminal BAT+ of the battery and the first charging terminal CHG+, as is the case in existing high-side drive schemes, thereby reducing circuit costs.

[0041] To better understand this application, the following will use... Figure 3 The circuit structure of the charging detection circuit shown is used as an example for explanation.

[0042] like Figure 3 As shown, in the charging detection circuit, the first switching unit 10 includes a first switching transistor Q31 (in this case, a transistor Q31) and a first resistor R31. The base of the transistor Q31 is connected to the first end of the first resistor R31, the second end of the first resistor R31 is connected to the second charging terminal CHG-, the emitter of the transistor Q31 is connected to the positive terminal BAT+ of the battery and the first charging terminal CHG+, and the collector of the transistor Q32 is connected to the second switching unit 20.

[0043] Optionally, the second switching unit 20 includes a second switching transistor Q32 (in this case, a triode Q32), a second resistor R32, and a third resistor R33. The base of the triode Q32 is connected to the first end of the second resistor R32, the second end of the second resistor R32 is connected to the collector of the triode Q31 in the first switching unit 10, the collector of the triode Q32 is connected to the first end of the third resistor R33, and the collector of the triode Q32 is also connected to the control unit 30 through the interface S31. The second end of the third resistor R33 is connected to the first power supply V21.

[0044] Specifically, when the first charging terminal CHG+ and the second charging terminal CHG- are connected to the charger, the base of transistor Q31 is connected to the negative terminal of the charger, and the emitter of transistor Q31 is connected to the positive terminal of the charger, thus turning on transistor Q31. The first resistor R31 protects transistor Q31 from damage due to excessive voltage. This is because without the first resistor R31, the voltage between the emitter and base of transistor Q31 would be the same as the voltage across the charger, potentially leading to damage to transistor Q31 due to excessive voltage between its emitter and base.

[0045] Subsequently, after transistor Q31 is turned on, the voltage at the collector of transistor Q31 is the voltage of the positive terminal BAT+ of the battery. This voltage enables transistor Q32 to conduct. At this time, interface S31 is grounded through the collector and emitter of transistor Q32, thus the voltage on interface S31 is forcibly pulled low, and the first level signal received by control unit 30 through interface S31 is a low level signal. The second resistor R32 is used both to limit the current input to the base of transistor Q32 to prevent damage due to excessive current and to protect transistor Q32. Similarly, if the second resistor R32 is not provided, after transistor Q31 is turned on, the voltage between the base and emitter of transistor Q32 is the battery voltage, and transistor Q32 may be damaged due to excessive voltage.

[0046] In summary, when the charging detection circuit 100 is connected to the charger, the control unit 30 receives a low-level signal as the first level signal. When the charging detection circuit 100 is not connected to the charger, the control unit 30 receives a high-level signal. Therefore, the control unit 30 can determine whether the charger is connected to the charging detection circuit 100 simply by receiving the signal.

[0047] It should be understood that, Figure 3 In the illustrated embodiment, both the first and second switching transistors are transistors. However, in other embodiments, the first switching transistor can also be a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), or other switching elements. Similarly, the second switching transistor can also be a MOSFET or an IGBT. Furthermore, the first and second switching transistors can be the same or different; for example, the first switching transistor can be a transistor, while the second switching transistor can be a MOSFET.

[0048] Furthermore, the actual applications of the first and second switching transistors are similar, and we will only use the first switching transistor as an example here. If a transistor is selected as the first switching transistor, then the base of the transistor is the first terminal of the first switching transistor, the emitter of the transistor is the second terminal of the first switching transistor, and the collector of the transistor is the third terminal of the first switching transistor.

[0049] If the first switching transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET), then the gate of the MOSFET is the first terminal of the second switching transistor, the source of the MOSFET is the second terminal of the second switching transistor, and the drain of the MOSFET is the third terminal of the second switching transistor.

[0050] If the first switching transistor is an insulated-gate bipolar transistor (IGBT), then the gate of the IGBT is the first terminal of the first switching transistor, the emitter of the IGBT is the second terminal of the first switching transistor, and the collector of the IGBT is the third terminal of the first switching transistor.

[0051] It should be noted that, as Figure 3 The circuit structure of the charging detection circuit 100 shown is only an example, and the charging detection circuit 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application-specific integrated circuits.

[0052] For example, such as Figure 4 As shown, the first switching unit 10 also includes a first capacitor C41. The first terminal of the first capacitor C41 is connected to the positive terminal BAT+ and the first charging terminal CHG+ of the battery, and the second terminal of the first capacitor C41 is connected to the base of the transistor Q31. The first capacitor C41 mainly serves as a filter to prevent damage to the transistor Q31 caused by possible high-frequency voltage.

[0053] Optionally, the second switching unit 20 further includes a second capacitor C42. The first terminal of the second capacitor C42 is connected to the base of the transistor Q32, and the second terminal of the second capacitor C42 is grounded to GND. The second capacitor C42 is also used for filtering to prevent damage to the transistor Q32 caused by possible high-frequency voltages.

[0054] Optionally, the second switching unit 20 further includes a third capacitor C43 and a fourth resistor R41. The first terminal of the third capacitor C43 is connected to the first terminal of the fourth resistor R41, and the first terminal of the third capacitor C43 is also connected to the control unit 30 via interface S31. The second terminal of the third capacitor C43 is grounded (GND), and the second terminal of the fourth resistor R41 is connected to the collector of the transistor Q32. The fourth resistor R41 is used for current limiting to prevent excessive current input to the control unit 30 from damaging it, and the third capacitor C43 is used for filtering.

[0055] Optionally, the charging detection circuit further includes a first branch 40 and a second branch 50. The first branch 40 includes at least two capacitors connected in series. The first terminal of the first branch 40 is connected to the first charging terminal CHG+, and the second terminal of the first branch 40 is grounded to GND. Figure 4 Taking the first branch 40, which includes the fourth capacitor C44 and the fifth capacitor C45, as an example.

[0056] The second branch 50 includes at least two capacitors connected in series. The first terminal of the second branch 50 is connected to the second charging terminal CHG-, and the second terminal of the second branch 50 is grounded GND. Figure 4 Taking the second branch 50, which includes the sixth capacitor C46 and the seventh capacitor C47, as an example.

[0057] Both the first branch 40 and the second branch 50 serve to eliminate static electricity.

[0058] This application also provides a voltage acquisition circuit, such as Figure 5 As shown, the voltage acquisition circuit includes a charging detection circuit 100 and a resistor branch 200 as described in any of the above embodiments. The resistor branch 200 includes at least two resistors connected in series. The first end of the resistor branch 200 is connected to the first power supply V21, the second end of the resistor branch 200 is connected to the second charging terminal CHG-, and the connection point between any two of the at least two resistors is connected to the control unit 30.

[0059] Specifically, the resistor branch 200 is used to divide the voltage between the first power supply V21 and the second charging terminal CHG- when the charging detection circuit 100 detects that a charger is connected, and outputs the voltage at the connection point to the control unit 30, so that the control unit 30 determines the output voltage of the charger, that is, the charging voltage of the charger to the battery, based on the received voltage.

[0060] Let's take resistor branch 200, which includes two resistors, as an example for illustration. Figure 6 As shown, resistor branch 200 includes a sixth resistor R61 and a seventh resistor R62. The sixth resistor R61 and the seventh resistor R62 are connected in series, and the connection point P1 between the sixth resistor R61 and the seventh resistor R62 is connected to the control unit 30 through interface S61.

[0061] The sixth resistor R61 and the seventh resistor R62 are used to divide the voltage between the first power supply V21 and node P2, and transmit the divided voltage from connection point P1 to control unit 30 through interface S61. Control unit 30 then determines the voltage between the first charging terminal CHG+ and the second charging terminal CHG- based on the received voltage. The voltage of the first power supply V21 can be the voltage from the circuit that provides the operating voltage to control unit 30, or it can be an externally set voltage source; there are no restrictions here.

[0062] Furthermore, to protect the control unit 30 from damage due to excessive voltage, the voltage at connection point P1 must not exceed the normal operating voltage of the control unit 30. Adjusting the voltage at connection point P1 can be achieved by adjusting the resistance values ​​of the sixth resistor R61 and the seventh resistor R62. To facilitate the calculation of the conditions that the resistance values ​​of the sixth resistor R61 and the seventh resistor R62 must meet, the following... Figure 6 The circuit diagram shown can be simplified to obtain the following: Figure 7 The diagram shows the equivalent circuit where the resistor branch is connected to the battery, the first charging terminal, and the second charging terminal, respectively. The equivalent capacitance C71 is... Figure 6 The capacitor formed by connecting the sixth capacitor C46 and the seventh capacitor C47 in series.

[0063] Assume the voltage at connection point P1 is V. ADC The voltage of the first power supply V21 is V2 (which is also the normal operating voltage of the control unit 30), and the battery voltage is V. BAT The voltage between the first charging terminal CHG+ and the second charging terminal CHG- is V. CHG The resistance of the sixth resistor R61 is R6, and the resistance of the seventh resistor R62 is R7. The condition that the resistance values ​​of the sixth resistor R61 and the seventh resistor R62 must satisfy is: 0 ≤ V. ADC ≤V2①.

[0064] like Figure 7 As shown, the voltage at connection point P1 is obtained by subtracting the voltage drop across the sixth resistor R61 from the voltage across the first power supply V21 and node P2. Combining condition ① and formula ②, we can deduce that the resistance values ​​of the sixth resistor R61 and the seventh resistor R62 must satisfy the formula: Where V1 is the battery voltage V BAT The voltage V between the first charging terminal and the second charging terminal CHG The difference, i.e., V1 = V BAT -V CHG Therefore, only when the resistance values ​​of the sixth resistor R61 and the seventh resistor R62 satisfy formula ③ can it be guaranteed that the voltage received by the control unit 30 will not exceed its normal operating voltage, thus achieving protection for the control unit 30.

[0065] Furthermore, simplifying formula ②, we can obtain the relationship between the voltage received by the control unit 30, the battery voltage, and the voltage between the first charging terminal and the second charging terminal as follows: in, Meanwhile, in formula ④, the battery voltage value V BAT The voltage V2 of the first power supply V21, the resistance R6 of the sixth resistor R61, and the resistance R7 of the seventh resistor R62 are all fixed values ​​after the circuit design is completed. Therefore, the control unit 30 calculates the voltage V2 based on the received voltage value at connection point P1. ADC This allows for the accurate determination of the voltage V between the first charging terminal and the second charging terminal. CHG Therefore, the voltage V can be determined. CHG Whether it is within the allowable charging voltage range, and thus whether it can be controlled to only use that voltage V. CHG Charging is only performed within the permissible charging voltage range to ensure greater charging safety.

[0066] Optionally, please refer to [the relevant document / reference]. Figure 6The voltage acquisition circuit also includes a fourth capacitor C61 and a fifth resistor R63. The first end of the fourth capacitor C61 is connected to the first end of the fifth resistor R63, and the first end of the fourth capacitor C61 is also connected to the control unit 30 through interface S61. The second end of the fourth capacitor C61 is grounded to GND, and the second end of the fifth resistor R63 is connected to the connection point P1.

[0067] The fifth resistor R63 is used for current limiting to prevent excessive current input to the control unit 30 from damaging the control unit 30, and the fourth capacitor C61 is used for filtering.

[0068] Optionally, the voltage acquisition circuit also includes a first diode D61, the anode of the first diode D61 being connected to the second terminal of the resistor branch 200, and the cathode of the first diode D61 being connected to the second charging terminal CHG-.

[0069] The first diode D61 can prevent reverse connection to protect the components in the voltage acquisition circuit. For example, when the second charging terminal CHG- is connected to the positive terminal of the charger, the voltage at the positive terminal of the charger will not cause damage to components such as the control unit 30 due to the presence of the first diode D61.

[0070] Optionally, the voltage acquisition circuit also includes a third switching transistor Q61 (which is a MOSFET in this case). The gate of the MOSFET Q61 is connected to the control unit 30 through the interface S62, the source of the MOSFET Q61 is connected to the second charging terminal CHG-, and the drain of the MOSFET Q61 is connected to the negative terminal BAT- of the battery.

[0071] The selection and use of the third switching transistor are similar to those of the first and second switching transistors, and will not be elaborated further here as they are easily understood by those skilled in the art.

[0072] In summary, the control unit 30 outputs a control signal only when the first level signal received by the control unit 30 through interface S31 is a low level signal (i.e., it is determined that a charger is connected), and the control unit 30 determines through interface S61 that the charger's output voltage (i.e., the charging voltage for the battery) is within the allowable charging voltage range. This control signal is input to the gate of the MOSFET Q61 through interface S62, causing the MOSFET Q61 to conduct. At this time, the negative terminal BAT- of the battery is connected to the second charging terminal CHG-. In other words, the charger is only allowed to charge the battery under these conditions. On the one hand, this ensures that the charging voltage for the battery does not exceed the maximum allowable charging voltage of the battery, preventing battery damage and extending battery life. On the other hand, it eliminates the need for a power switch between the positive terminal BAT+ and the first charging terminal CHG+ of the battery, as is done in the prior art, thus reducing circuit costs.

[0073] This application also provides a battery pack, which includes a battery module and a charging detection circuit as described in any of the above embodiments, or the battery pack includes a battery module and a voltage acquisition circuit as described in any of the above embodiments, or the battery pack includes a battery module, a voltage acquisition circuit as described in any of the above embodiments, and a charging detection circuit as described in any of the above embodiments, wherein the battery module includes at least one battery.

[0074] This application also provides an electrical device, which includes a load and a battery pack as described in any of the above embodiments. The battery pack is used to supply power to the load. The electrical device can be an electric bicycle, an electric motorcycle, a power tool, or a drone, etc.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A voltage acquisition circuit, characterized by, The application relates to a voltage acquisition circuit. The voltage acquisition circuit comprises a charging detection circuit, a first switch unit, a second switch unit and a control unit. The first switch unit is connected with a positive electrode of a battery, a first charging end and a second charging end respectively. The second switch unit is connected with the first switch unit, a first power supply and the control unit respectively. When the first switch unit and the second switch unit are closed, the control unit is used for receiving a first level signal. A resistance branch comprises at least two resistors connected in series, a first end of the resistance branch is connected with the first power supply, a second end of the resistance branch is connected with the second charging end, and a connection point between any two resistors of the at least two resistors is connected with the control unit.

2. The voltage acquisition circuit according to claim 1, wherein the first switch unit comprises a first switch tube and a first resistor. A first end of the first switch tube is connected with a first end of the first resistor, a second end of the first resistor is connected with the second charging end, a second end of the first switch tube is connected with the positive electrode of the battery and the first charging end respectively, and a third end of the first switch tube is connected with the second switch unit.

3. The voltage acquisition circuit according to claim 2, wherein the first switch unit further comprises a first capacitor. A first end of the first capacitor is connected with the positive electrode of the battery, and a second end of the first capacitor is connected with the first end of the first switch tube.

4. The voltage acquisition circuit according to claim 2, wherein the second switch unit comprises a second switch tube, a second resistor and a third resistor. A first end of the second switch tube is connected with the third end of the first switch tube through the second resistor, a second end of the second switch tube is grounded, a third end of the second switch tube is connected with a first end of the third resistor and the control unit, and a second end of the third resistor is connected with the first power supply.

5. The voltage acquisition circuit according to claim 4, wherein the second switch unit further comprises a second capacitor. A first end of the second capacitor is connected with the first end of the second switch tube, and a second end of the second capacitor is grounded.

6. The voltage acquisition circuit according to claim 4, wherein the second switch unit further comprises a third capacitor and a fourth resistor. A first end of the third capacitor is connected with the first end of the fourth resistor and the control unit, a second end of the third capacitor is grounded, and a second end of the fourth resistor is connected with the third end of the second switch tube.

7. The voltage acquisition circuit according to claim 4, wherein the first switch tube is a metal-oxide-semiconductor field-effect transistor, an insulated gate bipolar transistor or a triode. The second switch tube is a metal-oxide-semiconductor field-effect transistor, an insulated gate bipolar transistor or a triode.

8. The voltage acquisition circuit according to claim 1, wherein the charging detection circuit further comprises a first branch and a second branch. ​ ​ ​ ​ ​ ​ ​ The first branch includes at least two capacitors connected in series, a first end of the first branch is connected with the first charging end, and a second end of the first branch is grounded. The second branch includes at least two capacitors connected in series, a first end of the second branch is connected with the first charging end, and a second end of the second branch is grounded.

9. The voltage acquisition circuit according to claim 1, wherein, The voltage acquisition circuit further includes a fourth capacitor and a fifth resistor; a first end of the fourth capacitor and a first end of the fifth resistor are connected with the control unit, a second end of the fourth capacitor is grounded, and a second end of the fifth resistor is connected with the connection point.

10. The voltage acquisition circuit according to claim 9, wherein, The resistance branch includes a sixth resistance and a seventh resistance, and a voltage V CHG satisfies the following relationship: wherein V2 is a voltage value of the first power supply, V ADC is a voltage value of the connection point, R6 is a resistance value of the sixth resistance, R7 is a resistance value of the seventh resistance, and V BAT is a voltage value of the battery.

11. The voltage acquisition circuit according to claim 10, wherein, The resistance values of the sixth resistor and the seventh resistor satisfy a formula: wherein V1 is a difference between the voltage of the battery and the voltage between the first charging terminal and the second charging terminal.

12. The voltage acquisition circuit according to any one of claims 1-11, wherein, The voltage acquisition circuit further includes a first diode; an anode of the first diode is connected with the second end of the resistor branch, and a cathode of the first diode is connected with the second charging end.

13. The voltage acquisition circuit according to any one of claims 1-11, wherein, The voltage acquisition circuit further includes a third switch tube; a first end of the third switch tube is connected with the control unit, a second end of the third switch tube is connected with the second charging end, and a third end of the third switch tube is connected with the negative electrode of the battery.

14. A battery pack, characterized by A battery module and the voltage acquisition circuit according to any one of claims 1-13, wherein the battery module includes at least one battery.

15. An electrical device, comprising: A battery pack according to claim 14 and a load, wherein the battery pack is used to supply power for the load.

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