CN113690966A

CN113690966A - Switch circuit, battery management system, battery pack, electric equipment and control method

Info

Publication number: CN113690966A
Application number: CN202110922004.5A
Authority: CN
Inventors: 陈勇; 雷雨
Original assignee: Dongguan Poweramp Technology Ltd
Current assignee: Dongguan Poweramp Technology Ltd
Priority date: 2021-08-11
Filing date: 2021-08-11
Publication date: 2021-11-23
Also published as: WO2023016574A1

Abstract

The application provides a switching circuit, including first switch tube, control module and discharge module. The first switch tube is arranged in the main circuit loop and is respectively and electrically connected with the control module and the discharge module. The control module comprises a first pin, and the control module is configured to output a voltage signal through the first pin, wherein the voltage signal is used for indicating the first switch tube to be switched on or switched off. The voltage signal comprises a first voltage signal, the first voltage signal is used for indicating the first switch tube to be turned off, and when the first pin outputs the first voltage signal, the first switch tube discharges through the discharging module. The application also provides a battery management system, a battery pack, electric equipment and a switch circuit control method. The application can improve the turn-off speed of the switch tube.

Description

Switch circuit, battery management system, battery pack, electric equipment and control method

Technical Field

The application relates to the technical field of batteries, in particular to a switch circuit, a battery management system, a battery pack, electric equipment and a switch circuit control method.

Background

A Battery Management System (BMS) is a System for managing charging and discharging of a Battery. In the battery management system, a driving circuit controls a switching tube such as an MOS tube to serve as a battery anode switch to output battery voltage, and when the switching tube is turned off, the switching tube needs to be turned off as fast as possible, so that the switching tube is prevented from working in an over-power state for a long time and being damaged. In the related art, when the switching tube is turned off by using the driving circuit, it is difficult to rapidly turn off the switching tube.

Disclosure of Invention

In view of this, the present application provides a switching circuit, a battery management system, a battery pack, an electric device, and a switching circuit control method to improve the turn-off speed of a switching tube.

One aspect of the present application provides a switching circuit including a first switching tube, a control module, and a discharge module. The first switch tube is arranged in the main circuit loop and is respectively and electrically connected with the control module and the discharge module. The control module comprises a first pin, and the control module is configured to output a voltage signal through the first pin, wherein the voltage signal is used for indicating the first switch tube to be switched on or switched off. The voltage signal comprises a first voltage signal, the first voltage signal is used for indicating the first switch tube to be turned off, and when the first pin outputs the first voltage signal, the first switch tube discharges through the discharging module.

In the above embodiment, by providing the discharging module, when the first switching tube is turned off, the discharging module discharges the first switching tube, so that the charge stored in the first switching tube is quickly discharged, and the turn-off speed of the first switching tube is increased.

In some embodiments of the present application, the discharge module includes a primary discharge loop. And two ends of the primary discharge circuit are respectively and electrically connected with the first end of the first switch tube and the second end of the first switch tube. The first end of the first switch tube is electrically connected with the first pin and used for receiving the voltage signal, and the third end of the first switch tube is electrically connected with the first end of the battery. The primary discharge circuit comprises a second switch tube, the second switch tube is electrically connected with the first pin and used for receiving the voltage signal, and when the second switch tube is conducted, the first switch tube discharges through the primary discharge circuit.

In the above embodiment, the primary discharge circuit is configured to accelerate the discharge of the charge between the first end and the second end of the first switch tube. In the process of turning off the first switching tube, the first switching tube is discharged through the primary discharging loop, so that the turning-off speed of the first switching tube can be increased.

In some embodiments of the present application, the primary discharge circuit further includes a first resistor and a second resistor, and the first resistor, the second resistor and the second switch tube are connected in series between the first end of the first switch tube and the second end of the first switch tube.

In the above embodiment, the first resistor is used to reduce the speed of driving the first switching tube to turn on and off, so as to avoid oscillation. The second resistor is a bleeder resistor of the first switching tube, and is used for discharging electric charges between the first end of the first switching tube and the second end of the second switching tube so as to improve the turn-off speed of the first switching tube.

In some embodiments of the present application, the discharge module further includes a secondary discharge loop, and two ends of the secondary discharge loop are electrically connected to the first end of the first switch tube and the second end of the first switch tube, respectively. The second-stage discharge circuit comprises a third switching tube, a first end of the third switching tube is electrically connected with a third end of the first switching tube, a second end of the third switching tube is electrically connected with a second end of the first switching tube, and when the third switching tube is conducted, the first switching tube discharges through the second-stage discharge circuit.

In the above embodiment, the secondary discharge circuit is configured to discharge the first switching tube, so as to accelerate discharge of charges between the first end of the first switching tube and the second end of the first switching tube. In the process of turning off the first switching tube, the first switching tube is discharged through the secondary discharge loop, so that the turning-off speed of the first switching tube can be further increased.

In some embodiments of the present application, the secondary discharge circuit further includes a first resistor and a third resistor, and the first resistor, the third resistor and the third switching tube are connected in series between the first end of the first switching tube and the second end of the first switching tube.

In the above embodiment, the third resistor is a bleeding resistor of the first switching tube, and is configured to bleed off charges between the first end of the first switching tube and the second end of the second switching tube, so as to further increase the turn-off speed of the first switching tube.

In some embodiments of the present application, the switch further includes a fourth switching tube and a fourth resistor, and the fourth switching tube and the fourth resistor are connected in series between the third terminal of the first switching tube and the first terminal of the third switching tube.

In the above embodiment, the fourth resistor is configured to provide a driving current for the first end of the third switching tube.

In some embodiments of the present application, the battery further comprises a charging module, wherein the charging module comprises a fifth resistor and capacitor unit. The fifth resistor and the capacitor unit are connected in series between the first end of the fourth switching tube and the second end of the third switching tube.

In the above embodiment, the fifth resistor is configured to provide a driving current for the first end of the fourth switching tube. The capacitor unit is used for providing driving current for the fourth switching tube.

In some embodiments of the present application, the switch further comprises a first diode, an anode of the first diode is electrically connected to the first end of the fourth switch tube, and a cathode of the first diode is electrically connected to the third end of the first switch tube and the second end of the fourth switch tube, respectively.

In the above embodiment, the first diode is used to provide a bleeder circuit for the capacitor unit, and at the same time, it is ensured that the fourth switching tube is not reversely broken down when the capacitor unit is discharged.

In some embodiments of the present application, the discharge module further comprises a three-stage discharge circuit. The three-stage discharge loop comprises a first resistor and a sixth resistor. The first resistor and the sixth resistor are connected in series between the first end of the first switch tube and the second end of the first switch tube, and the first switch tube discharges through the three-stage discharge loop.

In the above embodiment, the first switch tube may discharge through a three-stage discharge circuit, so as to further increase the turn-off speed of the first switch tube. The sixth resistor is a bleeder resistor of the first switch tube, and when the first pin outputs the first voltage signal to indicate that the first switch tube is turned off, the voltage between the first end of the first switch tube and the second end of the first switch tube can be fixed at a low level, so that the level is more stable, and the instability of a circuit caused by the suspension of the voltage can be avoided.

In some embodiments of the present application, the switch further includes a second diode, an anode of the second diode is electrically connected to the first pin, and a cathode of the second diode is electrically connected to the first end of the first switch tube.

In the above embodiment, the second diode is an anti-reverse diode, which has an anti-reverse function, and can prevent a high voltage pulse of the external battery equipment from directly impacting the first pin when coming in, so that the first pin has sufficient high voltage pulse protection capability.

In some embodiments of the present application, the switch further includes a seventh resistor and an eighth resistor, a first end of the seventh resistor is electrically connected to the first pin, a second end of the seventh resistor is electrically connected to an anode of the second diode, a first end of the second switch tube, and a first end of the eighth resistor, respectively, and a second end of the eighth resistor is electrically connected to a second end of the first switch tube.

In the above embodiment, the seventh resistor and the eighth resistor are used as the bleeder resistor of the second switching tube, and the seventh resistor may also be used as a current limiting resistor to limit the magnitude of the current of the branch where the seventh resistor is located, so as to prevent the first pin from outputting an excessive current at the moment of outputting the excessive current, which results in the first pin outputting an excessive rated current. The eighth resistor can also be used as a pull-down resistor at the first end of the second switch tube to prevent the second switch tube from being conducted by mistake.

One aspect of the present application provides a battery management system, including: the controller, and the switching circuit that this application provided. The controller is electrically connected with the control module, the control module acquires a first signal of the controller, and the first signal is configured to instruct the control module to output a first voltage signal.

One aspect of the present application provides a battery pack, including: the battery cell module and the battery management system provided by the application are provided. The battery cell module comprises at least one battery cell, the battery cell module is electrically connected with the battery management system, and the battery cell module is used for supplying power to the battery management system.

One aspect of the present application provides a powered device, comprising: the battery pack comprises a load and a battery pack, wherein the battery pack is electrically connected with the load and is used for supplying power to the load.

An aspect of the present application provides a switching circuit control method for controlling the switching circuit provided in the present application, the control method including: when the first pin outputs a first voltage signal, the second switch tube is controlled to be conducted, and charges between the first end of the first switch tube and the second end of the first switch tube are discharged through the primary discharge loop.

In some embodiments of the present application, when a voltage between the third terminal of the first switch tube and the second terminal of the first switch tube is greater than or equal to a first threshold voltage, the third switch tube and the fourth switch tube are controlled to be turned on, and charges between the first terminal of the first switch tube and the second terminal of the first switch tube are further discharged through the secondary discharge loop.

In some embodiments of the present application, when the third switching tube is turned on, the charging module is in a charging state, and when the charge between the first end of the first switching tube and the second end of the first switching tube is released, the charging module stops charging.

According to the switch circuit, the battery management system, the battery pack, the electric equipment and the switch circuit control method, the first switch tube, the control module and the discharging module are arranged, the control module comprises the first pin, the control module is configured to output a voltage signal through the first pin, and the voltage signal is used for indicating the first switch tube to be connected or disconnected; the voltage signal comprises a first voltage signal, the first voltage signal is used for indicating the first switch tube to be turned off, and when the first pin outputs the first voltage signal, the first switch tube discharges through the discharging module. When the first switch tube is turned off, the first switch tube is discharged through the discharging module, so that the electric charge stored in the first switch tube is quickly released, and the turn-off speed of the first switch tube can be increased.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present application.

Fig. 1 is a schematic structural diagram of a switching circuit provided in an embodiment of the present application;

fig. 2 is a schematic circuit structure diagram of a switching circuit provided in an embodiment of the present application under a first scenario;

fig. 3 is a schematic circuit structure diagram of a switching circuit provided in the embodiment of the present application in a second scenario;

fig. 4 is a schematic circuit structure diagram of a switching circuit provided in an embodiment of the present application under a third scenario;

fig. 5 is a schematic circuit structure diagram of a switching circuit in a fourth scenario according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a battery management system provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a battery pack provided in an embodiment of the present application;

fig. 8 is a schematic structural diagram of an electric device provided in an embodiment of the present application;

fig. 9 is a schematic flowchart of a control method of a switch circuit according to an embodiment of the present application;

fig. 10 is a schematic flowchart of another method for controlling a switch circuit according to an embodiment of the present disclosure.

Detailed Description

The battery management system is a system for managing charging and discharging of a battery. In the battery management system, the MCU can control the on-off of a switching tube such as an MOS tube and the like, so that the connection and disconnection of the battery and external equipment (including electric equipment and charging equipment) are realized, and the discharge or the charge of the battery is managed. When the switch tube is turned off, the switch tube needs to be turned off as fast as possible, and the switch tube is prevented from working in an over-power state for a long time to cause damage to the switch tube.

In the related art, when the switching tube is turned off by using the driving circuit, if the switching tube is to be turned off quickly, the performance requirement on the driving circuit is high, the cost is correspondingly increased, and the driving circuit with common performance cannot achieve the purpose of turning off the switching tube quickly. Therefore, it is difficult to rapidly turn off the switching tube in the related art.

In order to solve the above technical problem, an embodiment of the present application provides a switching circuit, when a switching tube is turned off, the switching tube is discharged through a discharging module, so that a charge in the switching tube is quickly discharged, and the turn-off speed of the switching tube is increased. Thus, the switching tube can be quickly turned off.

The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The following embodiments and their technical features may be combined with each other without conflict.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a switch circuit according to an embodiment of the present disclosure. In fig. 1, the switching circuit includes a first switching tube Q1, a control module 101, and a discharging module 102, where the first switching tube Q1 is disposed in a main circuit loop, and the main circuit loop is a loop formed by a positive electrode B +, a P + port of a battery, a load 103, a P-port, and a negative electrode B-of the battery, that is, the main circuit loop is: b + → P + port → load 103 → P-port → B-. It should be noted that the P + port and the P-port may be two ports of the external device connected to the battery. In the embodiment of the present application, the load 103 may be an analog load, and in some embodiments, the load may also be a digital load according to specific requirements.

In the embodiment of the present application, the first switching tube Q1 may be used to output the battery voltage as a positive switch of the battery, and the battery voltage may be controlled to supply power by turning on or off the first switching tube Q1. When the first switch Q1 is turned on, the battery voltage can be outputted to supply power to the electric equipment (load 103), and when the first switch Q1 is turned off, the battery voltage cannot be outputted, and at this time, the power is not supplied.

The first switching tube Q1 is electrically connected to the control module 101 and the discharge module 102, respectively. Wherein the control module 101 may be an AFE, the control module 101 includes a first pin DSG, and the control module 101 may be configured to output a voltage signal through the first pin DSG, the voltage signal being used to instruct the first switch tube Q1 to turn on or off. That is, the first switch Q1 can be instructed to turn on or off by outputting different voltage signals through the first pin DSG. For example, the voltage signal greater than or equal to the first threshold voltage is output through the first pin DSG, which may be considered as outputting a high voltage signal, for indicating that the first switch Q1 is turned on; the output of the voltage signal through the first pin DSG is less than or equal to a second threshold voltage, which is less than the first threshold voltage, which can be considered to be an output low voltage signal, and is used to instruct the first switch Q1 to turn off. For example, a voltage signal of about 12V is output through the first pin DSG to close the first switch transistor Q1, and a voltage signal of about 0V is output through the first pin DSG to turn off the first switch transistor Q1.

It should be noted that the voltage signals may include a first voltage signal, and the first voltage signal is used to instruct the first switch Q1 to turn off. That is, when the first pin DSG outputs the first voltage signal, the first voltage signal may be a low voltage signal, such as a voltage signal of about 0V, for instructing the first switch Q1 to turn off. In addition, when the first pin DSG outputs the first voltage signal, which indicates that the first switch tube Q1 is turned off, when the first switch tube Q1 is switched from the on state to the off state, the first switch tube Q1 cannot be turned off completely at once, at this time, the first switch tube Q1 needs to discharge the charges stored in the parasitic capacitor, and after the charges are completely discharged, the first switch tube Q1 is turned off completely. The first switch Q1 should not be turned off for too long, otherwise the first switch Q1 would be damaged due to the long-time over-power state of the first switch Q1.

By providing the discharge module 102, when the first switching tube Q1 is to be turned off, the first switching tube Q1 may be discharged by the discharge module 102, so as to accelerate the discharge of the charges stored in the parasitic capacitor of the first switching tube Q1. For example, during normal operation, the first pin DSG outputs a high voltage signal, the first switch Q1 is turned on, and is in a conducting state, the main circuit loop operates normally, and when there is a need to turn off the first switch Q1, for example, when a user turns off the first switch Q1 normally, or when overcurrent, large current, or large voltage protection occurs, the first switch Q1 needs to be turned off, so as to avoid burning out the battery.

The first pin DSG of the control module 101 outputs a low voltage signal, where the low voltage signal is from a controller in the battery management system, the controller sends a digital signal to the control module 101, and after receiving the digital signal, the control module 101 outputs an analog low voltage signal, such as a low voltage signal of about 0V, through the first pin DSG, and the low voltage signal is used to instruct the first switch tube Q1 to turn off. During the turn-off of the first switch tube Q1, the charges between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 are discharged through the discharging module 102, and after the charges between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 are discharged, the first switch tube Q1 is completely turned off. Therefore, the discharging module 102 discharges to increase the turn-off speed of the first switching tube Q1.

It is understood that, in the embodiment of the present application, by providing the first switch Q1, the control module 101 and the discharging module 102, the control module 101 is configured to output a voltage signal through the first pin DSG, where the voltage signal is used to instruct the first switch Q1 to turn on or off. The voltage signal includes a first voltage signal indicating that the first switch Q1 is turned off, and the first switch Q1 may discharge through the discharge module 102 when the first pin DSG outputs the first voltage signal. When the first switch tube Q1 is turned off, the discharge module 102 discharges the first switch tube Q1, so that the rapid discharge of charges can be realized, specifically, the rapid discharge of charges between the first end and the second end of the first switch tube Q1 is realized, and the turn-off speed of the first switch tube Q1 can be increased.

Referring to fig. 2, fig. 2 is a schematic circuit structure diagram of a switch circuit according to a first scenario provided in the present application. In fig. 2, the discharge module 102 includes a primary discharge circuit 201, two ends of the primary discharge circuit 201 are electrically connected to a first end of a first switch Q1 and a second end of a first switch Q1, respectively, a first end of the first switch Q1 is further electrically connected to a first pin DSG for receiving a voltage signal, and a third end of the first switch Q1 is electrically connected to a first end of a battery, for example, the first end of the battery may be a positive electrode B + of the battery, the second end of the battery may be a negative electrode B + of the battery, and the third end of the first switch Q1 may be used for being connected to the positive electrode B + of the battery to output a battery voltage as a positive switch of the battery.

Alternatively, the first switch Q1 may be a MOS transistor, the first terminal of the first switch Q1 may be a gate of the MOS transistor, the second terminal of the first switch Q1 may be a source of the MOS transistor, and the third terminal of the first switch Q1 may be a drain of the MOS transistor. In some embodiments, the first switch tube may also be another type of electronic switch dedicated tube, such as a triode, and may also be another type of power switch tube, and so on.

The first-stage discharge loop 201 is configured to accelerate the discharge of charges between the first end and the second end of the first switch transistor Q1, and when the first switch transistor Q1 is an MOS transistor, the first-stage discharge loop 201 may accelerate the discharge of charges between the gate and the source of the MOS transistor.

The primary discharge circuit 201 includes a second switch tube Q2, the second switch tube Q2 is electrically connected to the first pin DSG, and is configured to receive a voltage signal output by the first pin DSG, when the second switch tube Q2 is turned on, the first switch tube Q1 may discharge through the primary discharge circuit 201, that is, the charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 is discharged through the primary discharge circuit 201. During the turn-off of the first switch transistor Q1, the first switch transistor Q1 is discharged through the primary discharge circuit 201, so that the turn-off speed of the first switch transistor Q1 can be increased.

Optionally, the primary discharge circuit 102 may further include a first resistor R1 and a second resistor R2, wherein the first resistor R1, the second resistor R2 and the second switch transistor Q2 are connected in series between the first end of the first switch transistor Q1 and the second end of the first switch transistor Q1. Specifically, a first end of the first resistor R1 is electrically connected to a first end of the first switch Q1, a second end of the first resistor R1 is electrically connected to a second end of the second switch Q2, a third end of the second switch Q2 is electrically connected to a first end of the second resistor R2, a first end of the second switch Q2 is electrically connected to the first pin DSG, and a second end of the second resistor R2 is electrically connected to a second end of the first switch Q1.

Alternatively, the second switch Q2 may be a MOS transistor, the first terminal of the second switch Q2 may be a gate of the MOS transistor, the second terminal of the second switch Q2 may be a source of the MOS transistor, and the third terminal of the second switch Q2 may be a drain of the MOS transistor. In some embodiments, the second switch tube may also be another type of electronic switch dedicated tube, such as a triode, and may also be another type of power switch tube, and so on.

It should be noted that, in the embodiment of the present application, the first resistor R1 is used to reduce the speed of turning on and off the first switch Q1, so as to avoid generating oscillation. The second resistor R2 is a bleeding resistor of the first switch transistor Q1, and is used for bleeding charges between the first end of the first switch transistor Q1 and the second end of the second switch transistor Q2, so as to increase the turn-off speed of the first switch transistor Q1.

For example, when the first pin DSG outputs a first voltage signal, such as a low voltage signal of about 0V, the voltage of the first end of the second switching tube Q2 is a low voltage, such as 0V, because the first switching tube Q1 cannot be turned off instantaneously when turned off, the voltage of the second end of the second switching tube Q2 does not change suddenly, at this time, the voltage of the second end of the second switching tube Q2 is a high voltage, such as 12V, a voltage difference exists between the first end of the second switching tube Q2 and the second end of the second switching tube Q2, the second switching tube Q2 is turned on, and charges between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 are discharged through the first resistor R1, the second switching tube Q2 and the second resistor R2, so as to increase the turn-off speed of the first switching tube Q1.

Referring to fig. 3, fig. 3 is a schematic circuit structure diagram of a switch circuit in a second scenario according to an embodiment of the present disclosure. In fig. 3, the discharge module 102 may further include a secondary discharge circuit 202, two ends of the secondary discharge circuit 202 are electrically connected to the first end of the first switch Q1 and the second end of the first switch Q1, respectively, and the secondary discharge circuit 202 is configured to discharge the first switch Q1, so as to accelerate the discharge of the charges between the first end of the first switch Q1 and the second end of the first switch Q1.

The secondary discharge circuit 202 may include a third switch Q3, wherein a first terminal of the third switch Q3 is electrically connected to a third terminal of the first switch Q1, and a second terminal of the third switch Q3 is electrically connected to a second terminal of the first switch Q1. When the third switch Q3 is turned on, the first switch Q1 may be discharged through the secondary discharge circuit 202, i.e., the charge between the first terminal of the first switch Q1 and the second terminal of the first switch Q1 is discharged through the secondary discharge circuit 202. During the turn-off of the first switch Q1, the second-stage discharge circuit 202 discharges the first switch Q1, which further increases the turn-off speed of the first switch Q1.

Optionally, the two-stage discharge circuit 202 may further include a first resistor R1 and a third resistor R3, and the first resistor R1, the third resistor R3 and the third switch tube Q3 are connected in series between the first end of the first switch tube Q1 and the second end of the first switch tube Q2. Specifically, a first end of the first resistor R1 is electrically connected to a first end of the first switching tube Q1, a second end of the first resistor R1 is electrically connected to a first end of the third resistor R3, and a second end of the third resistor R3 is electrically connected to a third end of the third switching tube Q3.

Alternatively, the third switching tube Q3 may be a triode, the first terminal of the third switching tube Q3 may be a base of the triode, the second terminal of the third switching tube Q3 may be an emitter of the triode, and the third terminal of the third switching tube Q3 may be a collector of the triode. In some embodiments, the third switch tube may also be another type of electronic switch dedicated tube, such as another type of triode, another type of power switch tube, and so on.

It should be noted that, in the embodiment of the present application, the third resistor R3 is a bleeding resistor of the first switch tube Q1, and is used for bleeding charges between the first end of the first switch tube Q1 and the second end of the second switch tube Q2, so as to increase the turn-off speed of the first switch tube Q1.

When the third switching tube Q3 is turned on, the electric charge between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 is discharged through the first resistor R1, the third resistor R3 and the third switching tube Q3, so as to further increase the turn-off speed of the first switching tube Q1.

Optionally, the switching circuit may further include a fourth switching tube Q4 and a fourth resistor R4, and the fourth switching tube Q4 and the fourth resistor R4 are connected in series between the third terminal of the first switching tube Q1 and the first terminal of the third switching tube Q3. Specifically, a first end of the fourth switching tube Q4 is electrically connected to a second end of the third switching tube Q3, a second end of the fourth switching tube Q4 is electrically connected to a third end of the first switching tube Q1, a third end of the fourth switching tube Q4 is electrically connected to a first end of a fourth resistor R4, and a second end of the fourth resistor R4 is electrically connected to a first end of the third switching tube Q3.

The fourth resistor R4 is used to provide a driving current for the first terminal of the third switching transistor Q3. For example, when the third transistor Q3 is a triode, the fourth resistor R4 may be a base resistor of the third transistor Q3 for injecting a current, i.e., a bias current, into the base of the third transistor Q3.

When the fourth switching tube Q4 is turned on, the driving current passes through the fourth resistor R4 to the first end of the third switching tube Q3, when the voltage between the first end of the third switching tube Q3 and the second end of the third switching tube Q3 reaches the turn-on voltage Vbe1 (typically 0.7V), the third switching tube Q3 is turned on, and the charge between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 is further discharged through the first resistor R1, the third resistor R3 and the third switching tube Q3, so as to further increase the turn-off speed of the first switching tube Q1.

Alternatively, the fourth switching tube Q4 may be a triode, the first terminal of the fourth switching tube Q4 may be a base of the triode, the second terminal of the fourth switching tube Q4 may be an emitter of the triode, and the third terminal of the fourth switching tube Q4 may be a collector of the triode. In some embodiments, the fourth switching tube may also be another type of electronic switching dedicated tube, such as another type of triode, another type of power switching tube, and so on.

Referring to fig. 4, fig. 4 is a schematic circuit structure diagram of a switch circuit in a third scenario according to an embodiment of the present disclosure. In fig. 4, the switching circuit may further include a charging module 104, and the charging module 104 may include a fifth resistor R5 and a capacitor unit 401, wherein the fifth resistor R5 and the capacitor unit 401 are connected in series between the first terminal of the fourth switching transistor Q4 and the second terminal of the third switching transistor Q3.

It should be noted that the fifth resistor R5 is used for providing a driving current for the first terminal of the fourth switch transistor Q4. For example, when the fourth switching transistor Q4 is a triode, the fifth resistor R5 may serve as a base resistor of the fourth switching transistor Q4 for injecting a current, i.e., a bias current, into the base of the fourth switching transistor Q4.

Taking the example that the first switch Q1 is a MOS transistor, the third switch Q3 is a triode, and the fourth switch Q4 is a triode, as the first switch Q1 discharges, the voltage Vgs between the first end of the first switch Q1 and the second end of the first switch Q1 gradually decreases, which results in an increase in the impedance Rds between the third end of the first switch Q1 and the second end of the first switch Q1, and accordingly, the voltage Vds between the third end of the first switch Q1 and the second end of the first switch Q1 gradually increases. It should be noted that Vgs of the MOS transistor is generally about 3V, and impedance Rds rapidly increases in the process of gradually decreasing Vgs, and generally increases from m Ω level to Ω level.

The fourth switching tube Q4 includes a body diode, and when the voltage Vds between the third terminal of the first switching tube Q1 and the second terminal of the first switching tube Q1 is gradually increased to the conduction voltage Vbe2 (generally 0.7V) of the body diode of the fourth switching tube Q4, the first terminal of the fourth switching tube Q4 is conducted to the second terminal of the fourth switching tube Q4, and the battery charges the capacitor unit 401, thereby forming a driving current.

The driving current drives the fourth switching tube Q4 to conduct, the driving current further flows to the first end of the third switching tube Q3 through the fourth resistor R4, when the voltage between the first end of the third switching tube Q3 and the second end of the third switching tube Q3 reaches the conducting voltage Vbe1 of the third switching tube Q3, the third switching tube Q3 conducts, and at the moment, the electric charge between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 is further discharged or discharged through the first resistor R1, the third resistor R3 and the third switching tube Q3, so that the turn-off speed of the first switching tube Q1 is further improved.

In addition, when the electric charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 is discharged or discharged through the first resistor R1, the third resistor R3 and the third switch tube Q3, the Vds of the first switch tube Q1 is increased (the on-resistance Ron is increased), so that the driving current of the third switch tube Q3 is increased, the third switch tube Q3 is kept in saturated conduction until the Vds of the first switch tube Q1 is not increased any more, and the voltage of the Vds of the first switch tube Q1 is reduced to 0V, so as to ensure that the first switch tube Q1 is completely turned off and the safety of the circuit is ensured.

Optionally, the capacitor unit 401 may include a first capacitor C1 and a second capacitor C2, where the first capacitor C1 and the second capacitor C2 are used to provide a driving current to the fourth switching tube Q4 to turn on the fourth switching tube Q4, and meanwhile, when the first switching tube Q1 is completely turned off, the first capacitor C1 and the second capacitor C2 are fully charged, which is equivalent to turning off a loop where the fourth switching tube Q4, the fifth resistor R5, the first capacitor C1 and the second capacitor C2 are located, so as to reduce power consumption and ensure that the P + port has no leakage.

It can be understood that, after the second switch tube Q2 is turned on, as Vgs of the first switch tube Q1 is decreased, Vds of the first switch tube Q1 is gradually increased, when Vds of the first switch tube Q1 is greater than a turn-on voltage Vbe2 of the fourth switch tube Q4, the first capacitor C1 and the second capacitor C2 are charged through the fourth switch tube Q4 and the fifth resistor R5, an emitter current at the moment of the fourth switch tube Q4 is greater, the fourth switch tube Q4 is in saturated conduction, a total positive electrode B + voltage of the battery directly drives the third switch tube Q3 to be turned on, and charges between the first end and the second end of the first switch tube Q1 are rapidly discharged through the first resistor R1, the third resistor R3 and the third switch tube Q3, so that the first switch tube Q1 is rapidly turned off.

Optionally, the switch circuit may further include a first diode D1, an anode of the first diode D1 is electrically connected to the first terminal of the fourth switch tube Q4, and a cathode of the first diode D1 is electrically connected to the third terminal of the first switch tube Q1 and the second terminal of the fourth switch tube Q4, respectively. The first diode D1 is used to provide a bleeder circuit for the first capacitor C1 and the second capacitor C2, and to ensure that the fourth switch Q4 is not broken down reversely when the first capacitor C1 and the second capacitor C2 are discharged.

Referring to fig. 5, fig. 5 is a schematic circuit structure diagram of a switch circuit in a fourth scenario according to an embodiment of the present disclosure. In fig. 5, the discharging module 102 may further include a three-stage discharging circuit 203, and the first switching tube Q1 may be discharged through the three-stage discharging circuit 203, that is, the charge between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 may be discharged through the three-stage discharging circuit 203.

The three-stage discharging circuit 203 may include a first resistor R1 and a sixth resistor R6, wherein the first resistor R1 and the sixth resistor R6 are connected in series between the first end of the first switch tube Q1 and the second end of the first switch tube Q2. Specifically, a first end of the first resistor R1 is electrically connected to a first end of the first switch Q1, a first end of the sixth resistor R6 is electrically connected to a second end of the first switch Q1, and a second end of the first resistor R1 is electrically connected to a second end of the sixth resistor R6.

It should be noted that the sixth resistor R6 is a bleeder resistor of the first switch tube Q1, and may be specifically a pull-down resistor, and when the first pin DSG outputs the first voltage signal indicating to turn off the first switch tube Q1, the voltage between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 may be fixed at a low level, so that the level is more stable, and the circuit instability caused by the suspension of the voltage may be avoided.

It can be understood that, when the first switch tube Q1 is turned off, the first resistor R1 and the sixth resistor R6 can discharge electric charges, that is, electric charges between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 can be discharged through the first resistor R1 and the sixth resistor R6, so as to further increase the turn-off speed of the first switch tube Q1.

Optionally, the switch circuit further includes a second diode D2, an anode of the second diode D2 is electrically connected to the first pin DSG, and a cathode of the second diode D2 is electrically connected to the first end of the first switch Q1. The second diode D2 is an anti-reverse diode, which has an anti-reverse function, and can prevent the high voltage pulse of P + from directly impacting the first pin DSG when coming in, so that the first pin DSG has sufficient high voltage pulse protection capability. The switching circuit not only has the function of quickly switching off the first switching tube Q1, but also has the function of high-voltage pulse protection. Since no special requirement is imposed on the control module 101 itself, the embodiment of the present application can improve the safety and reliability of the switching circuit at low cost, and can ensure safe and reliable operation of the battery management system and safe and efficient operation of the battery system.

Optionally, the switch circuit may further include a seventh resistor R7 and an eighth resistor R8, a first end of the seventh resistor R7 is electrically connected to the first pin DSG, a second end of the seventh resistor R7 is electrically connected to an anode of the second diode D2, a first end of the second switch tube Q2, and a first end of the eighth resistor R8, respectively, and a second end of the eighth resistor R8 is electrically connected to a second end of the first switch tube Q1.

The seventh resistor R7 and the eighth resistor R8 are used as a bleeder resistor of the second switching tube Q2, and the seventh resistor R7 may also be used as a current limiting resistor to limit the magnitude of the current of the branch, so as to prevent the first pin DSG from outputting an excessive transient current, which results in the first pin DSG outputting an excessive rated current.

The first switch Q1 in the embodiment of the present application may be a power MOS transistor of the positive electrode B + (total positive terminal of the battery), typically the parasitic capacitance Cgs of the gate and source of a single MOS transistor is about 7nF, in order to increase the overcurrent capacity and reduce the temperature rise of the power MOS transistor, a plurality of power MOS transistors are usually connected in parallel, where Cgs has a large capacitance, when the power MOS transistor is turned on, the magnitude of the seventh resistor R7 will affect the turn-on time of the power MOS transistor, therefore, the resistances of the first resistor R1 and the seventh resistor R7 cannot be too large, for example, the sum of the resistances of R1 and R7 may be limited to be less than or equal to a preset resistance threshold, such as 1K Ω for R1+ R7 ≦ 1K Ω for R1+ R7, and so on, the resistance values of the first resistor R1 and the seventh resistor R7 may be adjusted according to a specific application scenario or a specific requirement, and the embodiment of the present application is not particularly limited thereto.

Taking the example that the second switching tube Q2 is a MOS transistor, when the first pin DSG outputs the first voltage signal, the first switching tube Q1 starts to turn off, and the voltage of the gate of the second switching tube Q2 is discharged through the seventh resistor R7 and the eighth resistor R8, the voltage drop between the source and the gate of the second switching tube Q2 is greater than or equal to the threshold voltage vgs (th) between the gate and the source when the second switching tube Q2 starts to turn on, the second switching tube Q2 is in saturated conduction, and the voltage between the first end of the first switching tube Q1 and the second end of the first switching tube Q1 is rapidly dropped, so as to further increase the turn-off speed of the first switching tube Q1.

It should be noted that the eighth resistor R8 may be a resistor with a larger resistance, for example, a resistor of K Ω or M Ω class is selected. The eighth resistor R8 may also be used as a pull-down resistor at the first end of the second switch Q2, and when the first pin DSG outputs the first voltage signal for turning off the first switch Q1, the voltage level at the first end of the second switch Q2 is pulled down to the voltage level at the P + port, so as to prevent the second switch Q2 from being turned on by mistake.

Optionally, the switch circuit further includes a voltage regulator ZD1, where ZD1 is a Vgs protection voltage regulator of the first switch transistor Q1, and is used to prevent Vgs of the first switch transistor Q1 from exceeding a rated voltage, so as to damage the first switch transistor Q1.

An embodiment of the present application further provides a battery management system, please refer to fig. 6, and fig. 6 is a schematic structural diagram of the battery management system provided in the embodiment of the present application. The battery management system 500 includes a controller 501 and a switch circuit 502 provided in this embodiment of the present application, where the switch circuit 502 includes a control module 503, where the controller 501 is electrically connected to the control module 503, and the control module 503 obtains a first signal of the controller 501, where the first signal is configured to instruct the control module 503 to output a first voltage signal, such as a low voltage signal, where the low voltage signal instructs a first switch in the switch circuit 502 to turn off.

An embodiment of the present application further provides a battery pack, please refer to fig. 7, and fig. 7 is a schematic structural diagram of the battery pack provided in the embodiment of the present application. This battery package 600 includes electric core module 601 and the battery management system 602 that this application embodiment provided, wherein, electric core module 601 includes at least one electric core, and electric core module 601 can include one or more electric cores promptly, and electric core module 601 is connected with battery management system 602 electricity, and electric core module 601 is used for the power supply of battery management system 602 to make battery management system 602 normally work.

An electrical device is further provided in the embodiment of the present application, please refer to fig. 8, and fig. 8 is a schematic structural diagram of the electrical device provided in the embodiment of the present application. The electric device 700 includes a load 701 and a battery pack 702 provided in this embodiment, where the battery pack 702 is electrically connected to the load 701, and the battery pack 702 is used to supply power to the load 701, so that the load 701 operates normally.

On the basis of the switching circuits described in fig. 2 to 5, a switching circuit control method according to an embodiment of the present application will be described below by taking fig. 9 and 10 as an example. The switch circuit control method is used for controlling the switch circuit provided by the embodiment of the application.

Referring to fig. 9, fig. 9 is a schematic flowchart of a switch circuit control method according to an embodiment of the present disclosure. The switching circuit control method may include:

and S11, when the first pin outputs the first voltage signal, the second switch tube is controlled to be conducted, and the electric charge between the first end of the first switch tube and the second end of the first switch tube is discharged through the primary discharging loop.

When a first pin of the control module outputs a first voltage signal, if a low-voltage signal of about 0V is output, the second switching tube is controlled to be switched on, and charges between the first end of the first switching tube and the second end of the first switching tube are discharged through the primary discharge circuit, if the charges are discharged through the second switching tube, so that the switching-off speed of the first switching tube is increased. It can be understood that, when the first switch tube is turned off, the first switch tube is discharged through the primary discharge loop, so that the rapid discharge of the charges is realized, and the turn-off speed of the first switch tube can be increased. Therefore, the switch tube can be quickly turned off.

Referring to fig. 10, fig. 10 is another schematic flow chart of a switch circuit control method according to an embodiment of the present disclosure. The switching circuit control method may include:

and S21, when the first pin outputs the first voltage signal, the second switch tube is controlled to be conducted, and the electric charge between the first end of the first switch tube and the second end of the first switch tube is discharged through the primary discharging loop.

The specific embodiment of S21 can be seen in the embodiment of S11, which is not described herein again.

And S22, when the voltage between the third end of the first switch tube and the second end of the first switch tube is greater than or equal to the first threshold voltage, controlling the third switch tube and the fourth switch tube to be conducted, and discharging the charges between the first end of the first switch tube and the second end of the first switch tube through the secondary discharging loop.

When the voltage between the third end of the first switch tube and the second end of the first switch tube is greater than or equal to the first threshold voltage, the fourth switch tube is controlled to be conducted, so that the third switch tube is further controlled to be conducted, the electric charges between the first end of the first switch tube and the second end of the first switch tube are discharged through the secondary discharge loop, the discharge of the electric charges is further accelerated, and the turn-off speed of the first switch tube is further improved. It should be noted that the first threshold voltage may be a conduction voltage of the fourth switching tube, and when the fourth switching tube is a triode, the conduction voltage of the fourth switching tube is a conduction voltage between a base and an emitter of the triode, and is generally 0.7V.

And S23, when the third switching tube is conducted, the charging module is in a charging state, and when the charge between the first end of the first switching tube and the second end of the first switching tube is released, the charging module stops charging.

When the third switch tube is switched on, the charging module is in a charging state, and when the charge between the first end of the first switch tube and the second end of the first switch tube is released completely, the charging module stops charging when the first switch tube is completely switched off. By completely switching off the first switching tube, the safety of the circuit can be enhanced.

Although the application has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. This application is intended to embrace all such modifications and variations and is limited only by the scope of the appended claims. In particular regard to the various functions performed by the above described components, the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the specification.

That is, the above description is only an embodiment of the present application, and not intended to limit the scope of the present application, and all equivalent structures or equivalent flow transformations made by using the contents of the specification and the drawings, such as mutual combination of technical features between various embodiments, or direct or indirect application to other related technical fields, are included in the scope of the present application.

In addition, in the description of the present application, it is to be understood that the terms "in" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present application. In addition, structural elements having the same or similar characteristics may be identified by the same or different reference numerals. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, the word "exemplary" is used to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The previous description is provided to enable any person skilled in the art to make and use the present application. In the foregoing description, various details have been set forth for the purpose of explanation. It will be apparent to one of ordinary skill in the art that the present application may be practiced without these specific details. In other instances, well-known structures and processes are not shown in detail to avoid obscuring the description of the present application with unnecessary detail. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

1. A switching circuit comprises a first switching tube, a control module and a discharge module,

the first switch tube is arranged in a main circuit loop and is respectively and electrically connected with the control module and the discharge module;

the control module comprises a first pin, and the control module is configured to output a voltage signal through the first pin, wherein the voltage signal is used for indicating the first switch tube to be switched on or switched off;

the voltage signal comprises a first voltage signal, the first voltage signal is used for indicating the first switch tube to be turned off, and when the first pin outputs the first voltage signal, the first switch tube discharges through the discharging module.

2. The switch circuit according to claim 1, wherein the discharge module comprises a primary discharge loop, two ends of the primary discharge loop are electrically connected to the first end of the first switch tube and the second end of the first switch tube, respectively, the first end of the first switch tube is further electrically connected to the first pin for receiving the voltage signal, and the third end of the first switch tube is electrically connected to the first end of the battery;

the primary discharge circuit comprises a second switch tube, the second switch tube is electrically connected with the first pin and used for receiving the voltage signal, and when the second switch tube is conducted, the first switch tube discharges through the primary discharge circuit.

3. The switching circuit of claim 2, wherein the primary discharge circuit further comprises a first resistor and a second resistor, and the first resistor, the second resistor and the second switching tube are connected in series between the first end of the first switching tube and the second end of the first switching tube.

4. The switch circuit according to claim 2, wherein the discharge module further comprises a secondary discharge loop, and two ends of the secondary discharge loop are electrically connected to the first end of the first switch tube and the second end of the first switch tube, respectively;

the second-stage discharge circuit comprises a third switching tube, a first end of the third switching tube is electrically connected with a third end of the first switching tube, a second end of the third switching tube is electrically connected with a second end of the first switching tube, and when the third switching tube is conducted, the first switching tube discharges through the second-stage discharge circuit.

5. The switch circuit of claim 4, wherein the secondary discharge circuit further comprises a first resistor and a third resistor, and the first resistor, the third resistor and the third switch tube are connected in series between the first end of the first switch tube and the second end of the first switch tube.

6. The switch circuit of claim 4, further comprising a fourth switching tube and a fourth resistor, wherein the fourth switching tube and the fourth resistor are connected in series between the third terminal of the first switching tube and the first terminal of the third switching tube.

7. The switching circuit of claim 6, further comprising a charging module comprising a fifth resistor and capacitor unit;

the fifth resistor and the capacitor unit are connected in series between the first end of the fourth switching tube and the second end of the third switching tube.

8. The switch circuit of claim 7, further comprising a first diode, wherein an anode of the first diode is electrically connected to the first terminal of the fourth switch tube, and a cathode of the first diode is electrically connected to the third terminal of the first switch tube and the second terminal of the fourth switch tube, respectively.

9. The switching circuit of claim 2, wherein the discharge module further comprises a three-stage discharge loop comprising a first resistor and a sixth resistor;

the first resistor and the sixth resistor are connected in series between the first end of the first switch tube and the second end of the first switch tube, and the first switch tube discharges through the three-stage discharge loop.

10. The switching circuit according to any one of claims 2 to 9, further comprising a second diode, wherein an anode of the second diode is electrically connected to the first pin, and a cathode of the second diode is electrically connected to the first terminal of the first switching tube.

11. The switch circuit of claim 10, further comprising a seventh resistor and an eighth resistor, wherein a first end of the seventh resistor is electrically connected to the first pin, a second end of the seventh resistor is electrically connected to an anode of the second diode, a first end of the second switch tube, and a first end of the eighth resistor, respectively, and a second end of the eighth resistor is electrically connected to a second end of the first switch tube.

12. A battery management system, characterized in that the battery management system comprises: a controller, and the switching circuit of any one of claims 1 to 11;

the controller is electrically connected with the control module, the control module acquires a first signal of the controller, and the first signal is configured to instruct the control module to output a first voltage signal.

13. A battery pack, comprising: a cell module, and the battery management system of claim 12;

the battery cell module comprises at least one battery cell, the battery cell module is electrically connected with the battery management system, and the battery cell module is used for supplying power to the battery management system.

14. An electrical device, comprising: a load, and the battery pack of claim 13, the battery pack electrically connected to the load, the battery pack for powering the load.

15. A switching circuit control method for controlling a switching circuit according to any one of claims 7 to 11, the control method comprising:

when the first pin outputs a first voltage signal, the second switch tube is controlled to be conducted, and charges between the first end of the first switch tube and the second end of the first switch tube are discharged through the primary discharge loop.

16. The method according to claim 15, wherein when a voltage between the third terminal of the first switch tube and the second terminal of the first switch tube is greater than or equal to a first threshold voltage, the third switch tube and the fourth switch tube are controlled to be turned on, and the charge between the first terminal of the first switch tube and the second terminal of the first switch tube is further discharged through the secondary discharge loop.

17. The method according to claim 16, wherein the charging module is in a charging state when the third switch tube is turned on, and the charging module stops charging when the charge between the first end of the first switch tube and the second end of the first switch tube is discharged.