CN219394447U

CN219394447U - Driving circuit suitable for lithium battery protection board and lithium battery

Info

Publication number: CN219394447U
Application number: CN202223504908.5U
Authority: CN
Inventors: 吴建良; 顾南昌; 吴洁
Original assignee: Wuxi Hengxin Micro Technology Co ltd
Current assignee: Wuxi Hengxin Micro Technology Co ltd
Priority date: 2022-12-27
Filing date: 2022-12-27
Publication date: 2023-07-21
Anticipated expiration: 2032-12-27

Abstract

The application discloses a driving circuit suitable for a lithium battery protection board and a lithium battery, wherein the driving circuit comprises an input end, a first output end and/or a second output end; further comprises: the voltage conversion unit is connected with the input end and is used for converting the level of the input signal of the input end; the first switch unit is respectively connected with the voltage conversion unit and the first output end and is used for switching on and off the transmission from the input signal to the first output end; the first protection unit is respectively connected with the first output end and the second output end and is used for protecting equipment connected with the first output end; and the second protection unit is respectively connected with the voltage conversion unit, the first protection unit and the second output end and is used for protecting equipment connected with the second output end. The utility model realizes the control of the on-off of the external switch through the level conversion unit, the switch unit and the protection unit.

Description

Driving circuit suitable for lithium battery protection board and lithium battery

Technical Field

The application relates to the technical field of lithium batteries, in particular to a driving circuit suitable for a lithium battery protection board and a lithium battery.

Background

Due to the safety problem of the lithium battery, when the lithium battery is used, a lithium battery protection Board (BMS) must be used to control and protect the charge and discharge of the lithium battery. Most applications of lithium batteries have high current usage requirements, which makes a charge-discharge control circuit require multiple power MOSFETs to be used in parallel to increase the operating current capability of the BMS.

At present, the internal part of the lithium battery protection board is provided with a discharging MOSFET and a charging MOSFET which are respectively driven, and driving circuits for driving the two MOSFETs are different, wherein the circuit for driving the discharging MOSFET is simple, but negative pressure and high pressure can occur due to the connection of the charging MOFSET and a charger, the driving is complex, the conventional driving mode adopts an open-drain driving mode, and meanwhile, the discharging is carried out by driving a large resistor between the grid electrode and the source electrode of the MOSFET. When the charge overcurrent protection and the overcharge protection occur, the charge MOSFET is turned off by means of large-resistance discharge between the grid electrode and the source electrode of the MOSFET, the turn-off time of the charge MOSFET is quite different from a set value, the speed of turning off the charge MOSFET is slow, the circuit performance is affected, and even safety accidents are caused.

Disclosure of Invention

In view of the above technical problems, it is an object of embodiments of the present application to provide a driving circuit suitable for a lithium battery protection board. The driving circuit includes an input terminal, a first output terminal, and or a second output terminal.

Further comprises: the voltage conversion unit is connected with the input end and is used for converting the level of the input signal of the input end;

the first switch unit is respectively connected with the voltage conversion unit and the first output end and is used for switching on and off the transmission from the input signal to the first output end;

the first protection unit is respectively connected with the first output end and the second output end and is used for protecting equipment connected with the first output end;

the second protection unit is respectively connected with the voltage conversion unit, the first protection unit and the second output end and is used for protecting equipment connected with the second output end;

and the second switch unit is respectively connected with the input end, the first protection unit and the second protection unit and is used for controlling the opening and closing of the first protection unit and the second protection unit.

As an alternative embodiment, the voltage conversion unit includes a low-voltage to high-voltage circuit and a first high-voltage inverter, one end of the low-voltage to high-voltage circuit is connected to the input terminal, and the other end is connected to the first high-voltage inverter.

As an optional embodiment, the first switch unit includes a first field effect transistor, a gate of the first field effect transistor is connected to the first high voltage inverter, and a drain of the first field effect transistor is connected to the first output terminal.

As an optional embodiment, the first protection unit includes a first resistor, a third field effect transistor, a fourth field effect transistor, and an eighth field effect transistor, where one end of the first resistor is connected to the first output end, and a source electrode of the eighth field effect transistor is connected to the second output end.

As an optional embodiment, the second protection unit includes a second high-voltage inverter, a third resistor, a fifth field effect transistor, a sixth field effect transistor, and a seventh field effect transistor, where one end of the second high-voltage inverter is connected to the first high-voltage inverter, the other end of the second high-voltage inverter is connected to the third resistor, the third resistor is connected to a drain of the seventh field effect transistor, and a source of the fifth field effect transistor is connected to the second output end.

As an optional embodiment, the second switch unit includes a second field effect tube, a ninth field effect tube and a tenth field effect tube, where a gate of the second field effect tube is connected to the input end, a source of the second field effect tube is grounded, a drain of the second field effect tube is connected to gates of the ninth field effect tube and the tenth field effect tube respectively, a source of the tenth field effect tube is connected to a source of the first field effect tube, a drain of the tenth field effect tube is connected to the first protection unit and the second protection unit respectively, and is also connected to the second output end through a second resistor and a fourth resistor.

As an alternative embodiment, one end of the fourth resistor is connected to a control circuit inside the protection board.

As an optional embodiment, the ninth field effect transistor, the tenth field effect transistor and the first field effect transistor are P-type field effect transistors, and the second field effect transistor, the third field effect transistor, the fourth field effect transistor, the eighth field effect transistor, the fifth field effect transistor, the sixth field effect transistor and the seventh field effect transistor are N-type field effect transistors.

An object of the embodiment of the present application is to provide a lithium battery, which includes a protection board, a battery, a device connection end, and the driving circuit suitable for the protection board of the lithium battery.

As an alternative embodiment, the protection board includes a DO pin, a CO pin, and a CS pin, where the DO pin is connected to the external switch one; the first output end is connected with the CO pin, and the CO pin is connected with the external switch II; the second output end is connected with the CS pin.

The beneficial effects of this application embodiment lie in:

the utility model realizes the control of the on-off of the external switch through the level conversion unit, the switch unit and the protection unit, reduces the turn-off time through simple circuit design and turns off the charging MOSFET in time, thereby protecting the safety of the battery and ensuring more reliable use. Moreover, by using an appropriate resistor, the effect of low power consumption of the present device can be ensured.

Drawings

FIG. 1 is a schematic diagram of a prior art structure;

FIG. 2 is a circuit diagram of a driving circuit according to an embodiment of the present application;

fig. 3 is a schematic view of a part of the structure of a lithium battery according to an embodiment of the present application;

fig. 4 is a schematic diagram of forming a back gate after field effect transistors in the embodiments of the present application are connected in series.

Reference numerals:

10. an input end; 20. a voltage conversion unit; 21. a low-voltage to high-voltage circuit; A. a first high voltage inverter; 30. a first switching unit; p3, a first field effect transistor; 40. a first protection unit; r1, a first resistor; n2, a third field effect transistor; n3, a fourth field effect transistor; n4, eighth field effect transistor; 50. a second protection unit; r3, a third resistor; B. a second high voltage inverter; n5, a fifth field effect transistor; n6, a sixth field effect transistor; n7, a seventh field effect transistor; 60. a second switching unit; n1, a second field effect transistor; p1, a ninth field effect transistor; p2, a tenth field effect transistor; 71. a first output terminal; 72. a second output terminal; 80. an internal control circuit; r2, a second resistor; r4, a fourth resistor; m1, an external switch I; m2, an external switch II.

Detailed Description

Various aspects and features of the present application are described herein with reference to the accompanying drawings.

It should be understood that various modifications may be made to the embodiments of the application herein. Therefore, the above description should not be taken as limiting, but merely as exemplification of the embodiments. Other modifications within the scope and spirit of this application will occur to those skilled in the art.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with a general description of the application given above and the detailed description of the embodiments given below, serve to explain the principles of the application.

These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment, given as a non-limiting example, with reference to the accompanying drawings.

It is also to be understood that, although the present application has been described with reference to some specific examples, those skilled in the art can certainly realize many other equivalent forms of the present application.

The foregoing and other aspects, features, and advantages of the present application will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings.

Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the application, which can be embodied in various forms. Well-known and/or repeated functions and constructions are not described in detail to avoid obscuring the application with unnecessary or excessive detail. Therefore, specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present application in virtually any appropriately detailed structure.

The specification may use the word "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may each refer to one or more of the same or different embodiments as per the application.

Fig. 1 is a schematic diagram of a CO port driving mode currently in common use in the market, and, with reference to fig. 3, the main principle is as follows: when the system is in a normal working state, the PMOS tube (P3) is driven to be opened, the external MOSFET (M2) is driven to be opened, and the system is in a normal charging and discharging state.

When the system is in overcharge protection, an input signal is overturned, and is converted into a high-voltage signal through a low-voltage conversion high-voltage circuit to drive a PMOS tube (P3) to close the PMOS tube (P3), at the moment, the external MOSFET (M2) discharges through a resistor RCO_CS connected with a grid electrode and a source electrode, and generally, in order to achieve the purpose of low power consumption after overdischarge, the resistance value of the resistor RCO_CS is about 4M-6M, so that the capacitance between the grid electrode and the source electrode of the MOSFET (M2) discharges through the RCO_CS resistor, and the discharge time is T=4xRC.

The discharging time is determined according to the parasitic capacitance between the gate and the source of the external MOSFET (M2), and in high-current applications, the parasitic capacitance of the external MOSFET (M2) is often large, resulting in a discharging time as long as several tens of milliseconds, especially in case of charging overcurrent, the MOSFET (M2) is damaged due to too long time.

One of the objects of the embodiments of the present application is to provide a driving circuit suitable for a lithium battery protection board. As shown in fig. 2, the driving circuit comprises an input 10, a first output 71 and or a second output 72. The first output terminal 71 is a CO port, and the second output terminal 72 is a CS port.

Further comprises: a voltage conversion unit 20 connected to the input terminal 10 for converting a level of an input signal of the input terminal 10;

the first switch unit 30 is connected with the voltage conversion unit 20 and the first output end 71 respectively, and is used for switching on and off the transmission of the input signal to the first output end 71;

a first protection unit 40 connected to the first output terminal 71 and the second output terminal 72, respectively, for protecting a device to which the first output terminal 71 is connected;

a second protection unit 50 connected to the voltage conversion unit 20, the first protection unit 40, and the second output terminal 72, respectively, for protecting devices to which the second output terminal 72 is connected;

and a second switch unit 60, which is connected to the input terminal 10, the first protection unit 40, and the second protection unit 50, respectively, and is used for controlling the opening and closing of the first protection unit 40 and the second protection unit 50.

As an alternative embodiment, the voltage conversion unit 20 includes a low-voltage to high-voltage circuit 21 and a first high-voltage inverter a, where one end of the low-voltage to high-voltage circuit 21 is connected to the input terminal 10, and the other end is connected to the first high-voltage inverter a.

As an alternative embodiment, the first switching unit 30 includes a first fet P3, where a gate of the first fet P3 is connected to the first high-voltage inverter a, and a drain thereof is connected to the first output terminal 71.

As an alternative embodiment, the first protection unit 40 includes a first resistor R1, a third fet N2, a fourth fet N3, and an eighth fet N4, where one end of the first resistor R1 is connected to the first output terminal 71, and a source of the eighth fet N4 is connected to the second output terminal 72.

As an alternative embodiment, the second protection unit 50 includes a second high-voltage inverter B, a third resistor R3, a fifth fet N5, a sixth fet N6, and a seventh fet N7, wherein one end of the second high-voltage inverter B is connected to the first high-voltage inverter a, the other end thereof is connected to the third resistor R3, the third resistor R3 is connected to the drain of the seventh fet N7, and the source of the fifth fet N5 is connected to the second output terminal 72.

As an alternative embodiment, the second switching unit 60 includes a second fet N1, a ninth fet P1, and a tenth fet P2, where a gate of the second fet N1 is connected to the input terminal 10, a source of the second fet N1 is grounded, drains of the second fet N1 are respectively connected to gates of the ninth fet P1 and the tenth fet P2, a source of the tenth fet P2 is connected to a source of the first fet P3, and a drain of the tenth fet P2 is respectively connected to the first protection unit 40 and the second protection unit 50, and is further connected to the second output terminal 72 through a second resistor R2 and a fourth resistor R4.

As an alternative embodiment, one end of the fourth resistor R4 is connected to the protection board internal control circuit 80.

As an alternative embodiment, the ninth fet P1, the tenth fet P2, and the first fet P3 are P-type fets, and the second fet N1, the third fet N2, the fourth fet N3, the eighth fet N4, the fifth fet N5, the sixth fet N6, and the seventh fet N7 are N-type fets.

Under normal conditions, the input signal of the input end 10 is converted into a high-voltage signal through the low-voltage to high-voltage circuit 21, then the first high-voltage inverter A is driven, the first field effect transistor P3 is opened, so that the CO port outputs a high potential, and the external switch M1 is driven to start.

Meanwhile, the eighth fet N4 is turned off by the input signal of the input terminal 10, and the currents on the ninth fet P1 and the tenth fet P2 are 0, and the voltage drop of the second resistor R2 is 0, so that the second fet N1, the third fet N2, the fourth fet N3, the eighth fet N4, the fifth fet N5, the sixth fet N6, and the seventh fet N7 are all turned off. No leakage current exists between the CO port and the CS port, so that the requirement of low power consumption is ensured.

When the system is in overdischarge protection, the input signal of the input terminal 10 jumps, and the first field effect transistor P3 is driven to be turned off by the low-voltage to high-voltage circuit 21 and the first high-voltage inverter a in the same manner.

Meanwhile, the input signal of the input terminal 10 turns on the second fet N1, and the current I1 is transferred to the ninth fet P1 and transferred to the tenth fet P2 through the mirror ratio.

Assume that the aspect ratio of the ninth fet P1 isThe width-to-length ratio of the tenth FET P2 is +.>The current ratio is: />Then the current of the tenth FET P2 is M.times.I ₁ The current of the tenth fet P2 flows through the second resistor R2, so that a voltage drop is formed on the second resistor R2, and the voltage drop is set to about 3.5V-5V, and at this time, the third fet N2, the fourth fet N3, and the eighth fet N4 can be turned on, so that the CO port and the CS port discharge the capacitance between the gate and the source of the external switch two M2 through the third fet N2, the fourth fet N3, and the eighth fet N4.

The discharge time can be controlled by controlling the resistance value of the first resistor R1, and the first resistor R1 is generally set at about 5K, and then the discharge time can be less than 100us. Compared with the prior tens of milliseconds, the method improves the operation, particularly under the condition of charging overcurrent protection, the external switch M2 can be rapidly turned off, and the damage of the external switch M2 caused by overlong delay is prevented.

Meanwhile, the fifth fet N5, the sixth fet N6, and the seventh fet N7 are also turned on due to the second resistor R2. The third resistor R3 is set to about 600K, and the second high-voltage inverter B grounds the third resistor R3 and is connected to the CS port through the fifth fet N5, the sixth fet N6, and the seventh fet N7.

After overcharge or overdischarge occurs, the MOSFET corresponding to the charge is turned off, so that negative pressure occurs at the CS port, and at this time, current flows out from the second high-voltage inverter B and flows through the third resistor R3, the fifth fet N5, the sixth fet N6, and the seventh fet N7 to the CS port.

The CS port negative voltage is usually guaranteed to be-20V, and the circuit is not damaged. Then the second fet N1-eighth fet N4 are required to be fully isolated devices, which cannot be provided by the normal high voltage process, but are provided by BCD only process. In addition, because of a lot of plates and high cost, in a general high-voltage process, 3N-type field effect transistors of a low-voltage device are connected in series, and gate oxide is changed into a thick gate to form a new device, as shown in fig. 4. Thus, the PSUB has no parasitic diode to the source electrode and the drain electrode of the device, and no leakage phenomenon occurs.

It is also an object of an embodiment of the present application to provide a lithium battery, as shown in fig. 3, including a protection plate, a battery, and a device connection terminal. The batteries are arranged in two and correspondingly connected with the VCC pin, the VC pin and the GND pin of the protection plate. The driving circuit suitable for the lithium battery protection board is further included.

As an alternative embodiment, the protection board includes a DO pin, a CO pin, and a CS pin, where the DO pin is connected to an external switch M1; the first output end 71 is connected with the CO pin, and the CO pin is connected with the external switch II M2; the second output terminal 72 is connected to the CS pin, and one end of the CS pin is connected to the resistor RCS.

The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, the scope of which is defined by the claims. Various modifications and equivalent arrangements may be made to the present application by those skilled in the art, which modifications and equivalents are also considered to be within the scope of the present application.

Claims

1. A drive circuit suitable for a lithium battery protection plate, characterized by comprising an input terminal (10), a first output terminal (71) and/or a second output terminal (72), and further comprising:

a voltage conversion unit (20) connected to the input terminal (10) for converting the level of the input signal of the input terminal (10);

the first switch unit (30) is respectively connected with the voltage conversion unit (20) and the first output end (71) and is used for switching on and off the transmission of the input signal to the first output end (71);

a first protection unit (40) connected to the first output terminal (71) and the second output terminal (72) respectively, for protecting a device to which the first output terminal (71) is connected;

a second protection unit (50) connected to the voltage conversion unit (20), the first protection unit (40) and the second output terminal (72), respectively, for protecting a device to which the second output terminal (72) is connected;

and the second switch unit (60) is respectively connected with the input end (10), the first protection unit (40) and the second protection unit (50) and is used for controlling the opening and closing of the first protection unit (40) and the second protection unit (50).

2. The driving circuit for a lithium battery protection plate according to claim 1, wherein the voltage converting unit (20) comprises a low-voltage to high-voltage circuit (21) and a first high-voltage inverter (a), one end of the low-voltage to high-voltage circuit (21) is connected to the input terminal (10), and the other end is connected to the first high-voltage inverter (a).

3. The driving circuit for a lithium battery protection plate according to claim 2, wherein the first switching unit (30) comprises a first field effect transistor (P3), the gate of the first field effect transistor (P3) is connected to the first high voltage inverter (a), and the drain thereof is connected to the first output terminal (71).

4. A driving circuit suitable for a lithium battery protection plate according to claim 3, wherein the first protection unit (40) comprises a first resistor (R1), a third field effect transistor (N2), a fourth field effect transistor (N3) and an eighth field effect transistor (N4), one end of the first resistor (R1) is connected to the first output end (71), and a source electrode of the eighth field effect transistor (N4) is connected to the second output end (72).

5. The driving circuit for a lithium battery protection board according to claim 4, wherein the second protection unit (50) comprises a second high-voltage inverter (B), a third resistor (R3), a fifth field-effect transistor (N5), a sixth field-effect transistor (N6) and a seventh field-effect transistor (N7), one end of the second high-voltage inverter (B) is connected to the first high-voltage inverter (a), the other end thereof is connected to the third resistor (R3), the third resistor (R3) is connected to the drain of the seventh field-effect transistor (N7), and the source of the fifth field-effect transistor (N5) is connected to the second output terminal (72).

6. The driving circuit suitable for a lithium battery protection board according to claim 5, wherein the second switching unit (60) comprises a second field effect transistor (N1), a ninth field effect transistor (P1) and a tenth field effect transistor (P2), wherein a gate of the second field effect transistor (N1) is connected to the input terminal (10), a source of the second field effect transistor (N1) is grounded, a drain of the second field effect transistor (N1) is respectively connected to gates of the ninth field effect transistor (P1) and the tenth field effect transistor (P2), a source of the tenth field effect transistor (P2) is connected to a source of the first field effect transistor (P3), and a drain of the tenth field effect transistor (P2) is respectively connected to the first protection unit (40) and the second protection unit (50), and is further connected to the second output terminal (72) through a second resistor (R2) and a fourth resistor (R4).

7. The driving circuit for a lithium battery protection plate according to claim 6, wherein one end of the fourth resistor (R4) is connected to a protection plate internal control circuit (80).

8. The driving circuit for a lithium battery protection plate according to claim 7, wherein the ninth field effect transistor (P1), the tenth field effect transistor (P2), and the first field effect transistor (P3) are P-type field effect transistors, and the second field effect transistor (N1), the third field effect transistor (N2), the fourth field effect transistor (N3), the eighth field effect transistor (N4), the fifth field effect transistor (N5), the sixth field effect transistor (N6), and the seventh field effect transistor (N7) are N-type field effect transistors.

9. A lithium battery comprising a protection plate, a battery and a device connection terminal, characterized by further comprising a driving circuit according to any one of claims 1-8 adapted for use in a lithium battery protection plate.

10. The lithium battery of claim 9, wherein the protection plate comprises a DO pin, a CO pin, and a CS pin, the DO pin being connected to an external switch one (M1); the first output end (71) is connected with the CO pin, and the CO pin is connected with the external switch II (M2); the second output (72) is connected to the CS pin.