Battery protection circuit and battery charging and discharging system

Abstract

The battery protection circuit and battery charging and discharging system provided by the embodiments of the present application are provided with an isolation field effect transistor in the battery protection circuit, the substrate of the isolation field effect transistor is connected to the anode of the first Schottky diode and the anode of the second Schottky diode, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode, and the drain of the isolation field effect transistor is connected to the cathode of the second Schottky diode, and this connection mode makes it possible for the parasitic diode of the isolation field effect transistor not to be turned on at any time; and the battery protection circuit is also equipped with a control module, and the control module outputs a control signal to the fourth terminal according to the information collected from the first terminal, the second terminal and the third terminal, so as to control the conduction and cutoff of the isolation field effect transistor, so that the battery can be effectively protected when overcharge, overdischarge, overcurrent and the like occur.

Description

Technical Field

[0001] The present application relates to the field of charging and discharging, and specifically to a battery protection circuit and a battery charging and discharging system. Background Art

[0002] In recent years, batteries have been used more and more widely. In order to extend the service life of batteries, special circuits are needed to manage them in various ways, such as providing effective protection when the batteries are overcharged, over-discharged, or over-current. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a battery protection circuit and a battery charging and discharging system, which can solve the technical problem of how to effectively protect the battery when it is overcharged, over-discharged, over-current, etc.

[0004] The embodiment of the present application provides a battery protection circuit, comprising: a battery positive connection terminal, a battery negative connection terminal, a first wiring terminal, a second wiring terminal, an isolation field effect transistor, a first Schottky diode, a second Schottky diode and a control module, wherein the control module has a first terminal, a second terminal, a third terminal and a fourth terminal;

[0005] The gate of the isolation field effect transistor is connected to the fourth end, the substrate of the isolation field effect transistor is connected to the anode of the first Schottky diode and the anode of the second Schottky diode, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode, the negative connection end of the battery and the second end, the drain of the isolation field effect transistor is connected to the cathode of the second Schottky diode, the second terminal and the third end; the positive connection end of the battery is connected to the first terminal and the first end;

[0006] The control module outputs a control signal to the fourth end according to the information collected from the first end, the second end and the third end, so as to control the conduction and cutoff of the isolation field effect transistor.

[0007] In the battery protection circuit described in the present application, the control module includes: a first switch, a second switch, a first resistor, a second resistor, a first detection submodule, a second detection submodule and a driving submodule;

[0008] The input end of the first detection submodule is connected to the first end, the input end of the second detection submodule is connected to the third end, the first output end of the first detection submodule is connected to the first input end of the driving submodule, the second output end of the first detection submodule is connected to the second input end of the driving submodule, the first output end of the second detection submodule is connected to the third input end of the driving submodule, the second output end of the second detection submodule is connected to the fourth input end of the driving submodule, and the output end of the driving submodule is connected to the fourth end;

[0009] One end of the first switch is connected to the first end, the other end of the first switch is connected to one end of the first resistor, the other end of the first resistor is connected to the third end and one end of the second resistor, the other end of the second resistor is connected to one end of the second switch, and the other end of the second switch is connected to the second end;

[0010] The first detection submodule is used to output a signal to the first input terminal of the driving submodule and the second input terminal of the driving submodule according to the voltage information collected from the first terminal, so that the driving submodule outputs the control signal to the fourth terminal;

[0011] The second detection submodule is used to output a signal to the third input terminal of the driving submodule and the fourth input terminal of the driving submodule according to the voltage information collected from the third terminal, so that the driving submodule outputs the control signal to the fourth terminal.

[0012] In the battery protection circuit described in the present application, the first detection submodule includes: a first comparator and a second comparator;

[0013] The first positive terminal of the first comparator and the first negative terminal of the second comparator are both connected to the first terminal, the first negative terminal of the first comparator is connected to the first threshold voltage, the second positive terminal of the second comparator is connected to the second threshold voltage, the output terminal of the first comparator is connected to the first input terminal of the driving submodule, and the output terminal of the second comparator is connected to the second input terminal of the driving submodule.

[0014] In the battery protection circuit described in the present application, the second detection submodule includes: a third comparator and a fourth comparator;

[0015] The third negative terminal of the third comparator and the fourth positive terminal of the fourth comparator are both connected to the third terminal, the third positive terminal of the third comparator and the fourth negative terminal of the fourth comparator are both grounded, the output terminal of the third comparator is connected to the third input terminal of the driving submodule, and the output terminal of the fourth comparator is connected to the fourth input terminal of the driving submodule.

[0016] In the battery protection circuit described in the present application, the driving submodule includes: a first AND gate, a second AND gate, an OR gate, a NOT gate, and a first level converter;

[0017] The first input end of the first AND gate is connected to the first output end of the first detection submodule, the second input end of the first AND gate is connected to the first output end of the second detection submodule, the first input end of the second AND gate is connected to the second output end of the first detection submodule, the second input end of the second AND gate is connected to the second output end of the second detection submodule, the output end of the first AND gate is connected to the first input end of the OR gate, the output end of the second AND gate is connected to the second input end of the OR gate, the output end of the OR gate is connected to the input end of the NOT gate, the output end of the NOT gate is connected to the input end of the first level converter, and the output end of the first level converter is connected to the fourth end.

[0018] In the battery protection circuit described in the present application, the control module further includes a third detection submodule, an input end of the third detection submodule is connected to the third end, a first output end of the third detection submodule is connected to the fifth input end of the driving submodule, a second output end of the third detection submodule is connected to the sixth input end of the driving submodule, and a third output end of the third detection submodule is connected to the seventh input end of the driving submodule;

[0019] The third detection submodule is used to output a signal to the fifth input terminal, the sixth input terminal and the seventh input terminal of the driving submodule according to the current information collected from the third terminal, so that the driving submodule outputs the control signal to the fourth terminal.

[0020] In the battery protection circuit described in the present application, the third detection submodule includes: a fifth comparator, a sixth comparator and a seventh comparator;

[0021] The fifth negative terminal of the fifth comparator, the sixth positive terminal of the sixth comparator and the seventh positive terminal of the seventh comparator are all connected to the third terminal, the fifth positive terminal of the fifth comparator is connected to the third threshold voltage, the sixth negative terminal of the sixth comparator is connected to the fourth threshold voltage, the seventh negative terminal of the seventh comparator is connected to the fifth threshold voltage, the output terminal of the fifth comparator is connected to the fifth input terminal of the driving submodule, the output terminal of the sixth comparator is connected to the sixth input terminal of the driving submodule, and the output terminal of the seventh comparator is connected to the seventh input terminal of the driving submodule.

[0022] In the battery protection circuit described in the present application, the control module includes: a first enhanced field effect transistor, a second enhanced field effect transistor, a second level converter, a third level converter, a fourth level converter, a third AND gate and a fourth detection submodule;

[0023] The fourth detection submodule has a first sub-terminal, a second sub-terminal, a third sub-terminal, a fourth sub-terminal and a fifth sub-terminal; the first sub-terminal is connected to the first end, the second sub-terminal is connected to the third end, the third sub-terminal is connected to the gate of the first enhancement type field effect transistor and one end of the second level converter, the fourth sub-terminal is connected to the gate of the second enhancement type field effect transistor and one end of the second level converter, the other end of the second level converter is connected to the first input end of the third AND gate, the other end of the second level converter is connected to the second input end of the third AND gate, the output end of the third AND gate is connected to one end of the fourth level converter, the other end of the fourth level converter is connected to the fourth end, the fifth sub-terminal is connected to the source, substrate and second end of the first enhancement type field effect transistor, the drain of the first enhancement type field effect transistor is connected to the drain of the second enhancement type field effect transistor, and the source and substrate of the second enhancement type field effect transistor are both connected to the third end;

[0024] The fourth detection submodule is used to output a signal to the third subterminal and to output a signal to the fourth subterminal according to information collected from the first subterminal and the second subterminal, so that the control module outputs the control signal.

[0025] In the battery protection circuit described in the present application, the fourth detection submodule is a traditional series dual-switch circuit.

[0026] An embodiment of the present application also provides a battery charging and discharging system, comprising the battery protection circuit, battery and charger / load described above; wherein the positive connection terminal of the battery is connected to one end of the battery, the negative connection terminal of the battery is connected to the other end of the battery, the first connection terminal is connected to one end of the charger / load, and the second connection terminal is connected to the other end of the charger / load.

[0027] The battery protection circuit and battery charging and discharging system provided by the embodiments of the present application are provided with an isolation field effect transistor in the battery protection circuit, the substrate of the isolation field effect transistor is connected to the anode of the first Schottky diode and the anode of the second Schottky diode, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode, and the drain of the isolation field effect transistor is connected to the cathode of the second Schottky diode, and this connection mode makes it possible for the parasitic diode of the isolation field effect transistor not to be turned on at any time; and the battery protection circuit is equipped with a control module, and the control module outputs a control signal to the fourth terminal according to the information collected from the first terminal, the second terminal and the third terminal, so as to control the conduction and cutoff of the isolation field effect transistor, so that the battery can be effectively protected when overcharge, overdischarge, overcurrent and the like occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic diagram of the structure of a battery protection circuit provided in an embodiment of the present application;

[0030] Figure 1a-1b A schematic diagram of the principle of an isolated field effect transistor in a battery protection circuit provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a first specific structure of a battery protection circuit provided in an embodiment of the present application;

[0032] Figure 3 for Figure 2 A structural schematic diagram of a first detection submodule in a battery protection circuit shown;

[0033] Figure 4 for Figure 2 A structural schematic diagram of a second detection submodule in a battery protection circuit shown;

[0034] Figure 5 for Figure 2A schematic diagram of the structure of a driving submodule in a battery protection circuit shown;

[0035] Figure 6 for Figure 2 The flowchart of the battery protection circuit shown in FIG.

[0036] Figure 7 A second specific structural diagram of a battery protection circuit provided in an embodiment of the present application;

[0037] Figure 8 for Figure 7 A structural schematic diagram of a third detection submodule in the battery protection circuit shown;

[0038] Fig. 9 for Figure 7 A schematic diagram of the structure of a driving submodule in a battery protection circuit shown;

[0039] Fig.10 for Figure 7 A flow chart of a battery protection circuit is shown; and

[0040] Fig.11 A third specific structural diagram of the battery protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0042] In the description of the present application, it should be understood that the terms "first", "second", "third", "fourth", "fifth", "sixth", and "seventh" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first", "second", "third", "fourth", "fifth", "sixth", and "seventh" may explicitly or implicitly include one or more of the said features.

[0043] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of the battery protection circuit provided in the embodiment of the present application. Figure 1As shown, the battery protection circuit provided in the embodiment of the present application includes: a battery positive connection terminal e1, a battery negative connection terminal e2, a first wiring terminal e3, a second wiring terminal e4, an isolation field effect transistor 102, a first Schottky diode D1, a second Schottky diode D2 and a control module 101, and the control module 101 has a first terminal c1, a second terminal c2, a third terminal c3 and a fourth terminal c4. It can be understood that those skilled in the art can connect a corresponding battery between the battery positive terminal e1 and the battery negative terminal e2, and connect a corresponding charger / load between the first wiring terminal e3 and the second wiring terminal e4 as needed.

[0044] Among them, the gate a of the isolation field effect transistor 102 is connected to the fourth terminal c4, the substrate b of the isolation field effect transistor 102 is connected to the anode of the first Schottky diode D1 and the anode of the second Schottky diode D2, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode D1, the negative connection terminal e2 of the battery and the second terminal c2, the drain of the isolation field effect transistor 102 is connected to the cathode of the second Schottky diode D2, the second terminal e4 and the third terminal c3, and the positive connection terminal e1 of the battery is connected to the first terminal e3 and the first terminal c1; the control module 101 outputs a control signal to the fourth terminal c4 according to the information collected from the first terminal c1, the second terminal c2 and the third terminal c3 to control the conduction and cutoff of the isolation field effect transistor 102.

[0045] In the battery protection circuit provided in the embodiment of the present application, an isolation field effect transistor 102 is arranged in the battery protection circuit, a substrate b of the isolation field effect transistor 102 is connected to the anode of the first Schottky diode D1 and the anode of the second Schottky diode D2, a source d of the isolation field effect transistor 102 is connected to the cathode of the first Schottky diode D1, and a drain s of the isolation field effect transistor 102 is connected to the cathode of the second Schottky diode D2. This connection method ensures that the parasitic diode of the isolation field effect transistor 102 will not be turned on at any time.

[0046] For details, please refer to Figure 1a-1b , Figure 1a-1b This is a schematic diagram of the principle of an isolated field effect transistor in a battery protection circuit provided in an embodiment of the present application. Figure 1a , 1bAs shown, the isolated field effect transistor 102 has a source d, a drain S, a gate a and a substrate b. A parasitic diode is provided between the source d of the isolated field effect transistor 102 and the substrate b, and between the drain s of the isolated field effect transistor 102 and the substrate b. In the embodiment of the present application, a first Schottky diode D1 is provided between the source s of the isolated field effect transistor 102 and the substrate b, and a second Schottky diode D2 is provided between the drain d of the isolated field effect transistor 102 and the substrate b, so that the isolated field effect transistor 102 can be automatically biased.

[0047] It can be understood that when substrate b has a reverse bias to drain s, there will be a slight leakage current from drain s to substrate b. This leakage current flows forward through the first Schottky diode D1 to the source, making the voltage of substrate b biased at 0.4V higher than source d. Similarly, when substrate b has a reverse bias to source d, there will be a slight leakage current from source d to substrate b. This leakage current flows forward through the second Schottky diode D2 to the drain, making the voltage source bias of substrate b 0.4V higher than drain s. By the above mechanism, the voltage of substrate b is automatically biased through the first Schottky diode D1 and the second Schottky diode D2. Due to the rectifying characteristics of the diode, the connection direction of the two parasitic diodes of the isolation field effect transistor 102, and the connection configuration of the external first Schottky diode D1 and the second Schottky diode D2, the normal current cannot be conducted between the source and the drain through the diode. That is, the current between the source and drain of the isolation field effect transistor 102 can be conducted only through the conductive channel of the isolation field effect transistor 102 .

[0048] See also Figure 2 , Figure 2 The first specific structural diagram of the battery protection circuit provided in the embodiment of the present application. Figure 1 , Figure 2 As shown, the control module 101 includes: a first switch S1, a second switch S2, a first resistor R1, a second resistor R2, a first detection submodule 1011, a second detection submodule 1012 and a driving submodule 1013a.

[0049] Among them, the input terminal f1 of the first detection submodule 1011 is connected to the first terminal c1, the input terminal f2 of the second detection submodule 1012 is connected to the third terminal c3, the first output terminal g1 of the first detection submodule 1011 is connected to the first input terminal f3 of the driving submodule 1013a, the second output terminal g2 of the first detection submodule 1011 is connected to the second input terminal f4 of the driving submodule 1013a, the first output terminal g3 of the second detection submodule 1012 is connected to the third input terminal f5 of the driving submodule 1013a, the second output terminal g4 of the second detection submodule 1012 is connected to the fourth input terminal f6 of the driving submodule 1013a, and the output terminal g5 of the driving submodule 1013a is connected to the fourth terminal c4. One end of the first switch S1 is connected to the first end c1, the other end of the first switch S1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the third end c3 and one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the second switch S2, and the other end of the second switch S2 is connected to the second end c2.

[0050] The first detection submodule 1011 is used to output a signal to the first input terminal f3 of the driving submodule 1013a and the second input terminal f4 of the driving submodule 1013a according to the voltage information collected from the first terminal c1, so that the driving submodule 1013a outputs a control signal to the fourth terminal c4. The second detection submodule 1012 is used to output a signal to the third input terminal f5 of the driving submodule 1013a and the fourth input terminal f6 of the driving submodule 1013a according to the voltage information collected from the third terminal c3, so that the driving submodule 1013a outputs a control signal to the fourth terminal c4.

[0051] See also Figure 3 , Figure 3 for Figure 2 The structural diagram of the first detection submodule in the battery protection circuit is shown. Figure 2 , Figure 3 As shown, the first detection submodule 1011 includes: a first comparator H1 and a second comparator H2. The first positive terminal of the first comparator H1 and the first negative terminal of the second comparator H2 are both connected to the first terminal c1, the first negative terminal of the first comparator H1 is connected to the first threshold voltage Vth1, the second positive terminal of the second comparator H2 is connected to the second threshold voltage Vth2, the output terminal of the first comparator H1 is connected to the first input terminal f3 of the driving submodule 1013a, and the output terminal of the second comparator H2 is connected to the second input terminal f4 of the driving submodule 1013a.

[0052] The first threshold voltage Vth1 is used to determine whether the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is in an overcharge voltage state, and the second threshold voltage Vth2 is used to determine whether the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is in an overdischarge voltage state.

[0053] When the voltage of the first terminal c1 is greater than the first threshold voltage Vth1, the first comparator H1 outputs a high level, and the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is in an overcharge voltage state; when the voltage of the first terminal c1 is less than the first threshold voltage Vth1, the first comparator H1 outputs a low level, and the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is not in an overcharge voltage state. When the voltage of the first terminal c1 is less than the second threshold voltage Vth2, the second comparator H2 outputs a high level, and the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is in an over-discharge voltage state; when the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, the second comparator H2 outputs a low level, and the battery between the positive battery connection terminal e1 and the negative battery connection terminal e2 is not in an over-discharge voltage state.

[0054] The first threshold voltage Vth1 is greater than the second threshold voltage Vth2. In one embodiment, the first threshold voltage Vth1 is between 4.2V and 4.6V, and the second threshold voltage Vth2 is between 1.9V and 3.4V.

[0055] See also Figure 4 , Figure 4 for Figure 2 The structural diagram of the second detection submodule in the battery protection circuit is shown in FIG. Figure 2 , Figure 4 As shown, the second detection submodule 1012 includes: a third comparator H3 and a fourth comparator H4. The third negative terminal of the third comparator H3 and the fourth positive terminal of the fourth comparator H4 are both connected to the third terminal c3, the third positive terminal of the third comparator H3 and the fourth negative terminal of the fourth comparator H4 are both grounded, the output terminal of the third comparator H3 is connected to the third input terminal f5 of the driving submodule 1013a, and the output terminal of the fourth comparator H4 is connected to the fourth input terminal f6 of the driving submodule 1013a.

[0056] Among them, when the voltage of the third terminal c3 is less than the ground voltage, the third comparator H3 outputs a high level, and a charger is connected between the first terminal e3 and the second terminal e4; when the voltage of the third terminal c3 is greater than the ground voltage, the third comparator H3 outputs a low level, and no charger is connected between the first terminal e3 and the second terminal e4. When the voltage of the third terminal c3 is greater than the ground voltage, the fourth comparator H4 outputs a high level, and a load is connected between the first terminal e3 and the second terminal e4; when the voltage of the third terminal c3 is less than the ground voltage, the fourth comparator H4 outputs a low level, and no load is connected between the first terminal e3 and the second terminal e4.

[0057] See also Figure 5 , Figure 5 for Figure 2 The schematic diagram of the structure of the driving submodule in the battery protection circuit is shown in FIG. Figure 2 , Figure 5 As shown, the driving submodule 1013a includes: a first AND gate M1, a second AND gate M2, an OR gate M3, a NOT gate M4, and a first level converter 10131. The first input end of the first AND gate M1 is connected to the first output end g1 of the first detection submodule 1011, the second input end of the first AND gate M1 is connected to the first output end g3 of the second detection submodule 1012, the first input end of the second AND gate M2 is connected to the second output end g2 of the first detection submodule 1011, the second input end of the second AND gate M2 is connected to the second output end g4 of the second detection submodule 1012, the output end of the first AND gate M1 is connected to the first input end of the OR gate M3, the output end of the second AND gate M2 is connected to the second input end of the OR gate M3, the output end of the OR gate M3 is connected to the input end of the NOT gate M4, the output end of the NOT gate M4 is connected to the input end of the first level converter 10131, and the output end of the first level converter 10131 is connected to the fourth end c4.

[0058] Combine the following Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The working principle of the battery protection circuit in the embodiment of the present application is described. Figure 6 for Figure 2 When the battery protection circuit is working, a battery is connected between the positive connection terminal e1 and the negative connection terminal e2, and a charger / load is connected between the first connection terminal e3 and the second connection terminal e4.

[0059] The embodiment of the present application continuously detects the voltage of the first terminal c1 and the voltage of the second terminal c2, so as to effectively protect the battery when it is overcharged or over-discharged. The battery protection circuit includes the following situations:

[0060] In the first case, when the voltage of the first terminal c1 is greater than the first threshold voltage Vth1, and the voltage of the third terminal c3 is less than or equal to the ground voltage, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in an overcharge voltage state, and a charger is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned off, the first switch S1 is controlled to be turned on, the second switch S2 is controlled to be turned off, and the voltage of the first terminal c1 and the voltage of the second terminal c2 are continuously detected.

[0061] Specifically, when the voltage of the first terminal c1 is greater than the first threshold voltage Vth1 and the voltage of the third terminal c3 is less than the ground voltage, the output terminal of the first comparator H1 and the output terminal of the third comparator H3 both output a high level, the output terminal of the first AND gate M1 outputs a high level, the output terminal of the OR gate M3 outputs a high level, and the output terminal of the NOT gate M4 outputs a low level. The first level converter 10131 converts the low level into a voltage that turns off the isolation field effect transistor 102, and the isolation field effect transistor 102 is turned off.

[0062] In the second case, when the voltage of the first terminal c1 is greater than the first threshold voltage Vth1, and the voltage of the third terminal c3 is greater than the ground voltage, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in an overcharge voltage state, and a load is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned on, and the first switch S1 and the second switch S2 are controlled to be turned off.

[0063] Specifically, when the voltage of the first terminal c1 is greater than the first threshold voltage Vth1, and the voltage of the third terminal c3 is greater than the ground voltage, the output terminal of the first comparator H1 and the output terminal of the fourth comparator H4 both output a high level, the output terminal of the second comparator H2 and the output terminal of the third comparator H3 both output a low level, the output terminal of the first AND gate M1 and the output terminal of the second AND gate M2 both output a low level, the output terminal of the OR gate M3 outputs a low level, and the output terminal of the NOT gate M4 outputs a high level, and the first level converter 10131 converts the high level into a voltage that turns on the isolation field effect transistor 102, and the isolation field effect transistor 102 turns on.

[0064] In the third case, when the voltage of the first terminal c1 is less than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than or equal to the ground voltage, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in an over-discharge voltage state, and a load is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned off, the first switch S1 is controlled to be turned on, and the second switch S2 is controlled to be turned off.

[0065] Specifically, when the voltage of the first terminal c1 is less than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than the ground voltage, the output terminal of the second comparator H2 and the output terminal of the fourth comparator H4 both output a high level, the output terminal of the second AND gate M2 outputs a high level, the output terminal of the OR gate M3 outputs a high level, and the output terminal of the NOT gate M4 outputs a low level, and the first level converter 10131 converts the low level into a voltage that turns off the isolation field effect transistor 102, and the isolation field effect transistor 102 is turned off.

[0066] In the fourth case, when the voltage of the first terminal c1 is less than the second threshold voltage Vth2, and the voltage of the third terminal c3 is less than the ground voltage, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in an over-discharge voltage state, and a charger is connected between the first terminal e1 and the second terminal e2. At this time, the isolation field effect transistor 102 is turned on, controlling the first switch S1 and the second switch S2 to be turned off.

[0067] Specifically, when the voltage of the first terminal c1 is less than the second threshold voltage Vth2, and the voltage of the third terminal c3 is less than the ground voltage, the output terminal of the second comparator H2 and the output terminal of the third comparator both output a high level, the output terminal of the first comparator H1 and the output terminal of the fourth comparator H4 both output a low level, the output terminal of the first AND gate M1 and the output terminal of the second AND gate M2 both output a low level, the output terminal of the OR gate M3 outputs a low level, and the output terminal of the NOT gate M4 outputs a high level, and the first level converter 10131 converts the high level into a voltage that turns on the isolation field effect transistor 102, and the isolation field effect transistor 102 turns on.

[0068] In the fifth case, when the voltage of the first terminal c1 is less than the first threshold voltage Vth1 and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in a normal state. At this time, the isolation field effect transistor 102 is turned on, and the first switch S1 and the second switch S2 are controlled to be turned off.

[0069] Specifically, when it is detected that the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, the output terminal of the first comparator H1 and the output terminal of the second comparator H2 both output a low level, the output terminal of the first AND gate M1 and the output terminal of the second AND gate M2 both output a low level, the output terminal of the OR gate M3 outputs a low level, and the output terminal of the NOT gate M4 outputs a high level, and the first level converter 10131 converts the high level into a voltage that turns on the isolation field effect transistor 102, and the isolation field effect transistor 102 turns on.

[0070] See also Figure 7 , Figure 7A second specific structural diagram of a battery protection circuit provided in an embodiment of the present application. Figure 7 The battery protection circuit shown is Figure 2 The differences in the battery protection circuits shown are: Figure 7 The control module 101 in the battery protection circuit shown also includes a third detection submodule 1014, an input end of the third detection submodule 1014 is connected to the third end c3, a first output end g5 of the third detection submodule 1014 is connected to the fifth input end f7 of the driving submodule 1013a, a second output end g6 of the third detection submodule is connected to the sixth input end f8 of the driving submodule 1013a, and a third output end g7 of the third detection submodule is connected to the seventh input end f9 of the driving submodule 1013a.

[0071] The third detection submodule 1014 is used to output signals to the fifth input terminal f7, the sixth input terminal f8 and the seventh input terminal f9 of the driving submodule 1013a according to the current information collected from the third terminal c3, so that the driving submodule 1013a outputs a control signal to the fourth terminal c4.

[0072] See also Figure 8 , Fig. 9 , Figure 8 for Figure 7 A structural schematic diagram of a third detection submodule in a battery protection circuit is shown. Fig. 9 for Figure 7 The schematic diagram of the structure of the driving submodule in the battery protection circuit is shown in FIG. Figure 8 , Fig. 9 As shown, the third detection submodule 1013b includes: a fifth comparator H5, a sixth comparator H6 and a seventh comparator H7; the fifth negative terminal of the fifth comparator H5, the sixth positive terminal of the sixth comparator H6 and the seventh positive terminal of the seventh comparator H7 are all connected to the third terminal c3, the fifth positive terminal of the fifth comparator H5 is connected to the third threshold voltage Vth3, the sixth negative terminal of the sixth comparator H6 is connected to the fourth threshold voltage Vth4, the seventh negative terminal of the seventh comparator H7 is connected to the fifth threshold voltage Vth5, the output terminal of the fifth comparator H5 is connected to the fifth input terminal f7 of the driving submodule 1013b, the output terminal of the sixth comparator H6 is connected to the sixth input terminal f8 of the driving submodule 1013b, and the output terminal of the seventh comparator H7 is connected to the seventh input terminal f9 of the driving submodule 1013b.

[0073] The third threshold voltage Vth3, the fourth threshold voltage Vth4 and the fifth threshold voltage Vth5 are all used to determine whether the current of the battery protection circuit is normal.

[0074] When the voltage c3 of the third terminal is less than the third threshold voltage Vth3, the fifth comparator H5 outputs a high level, and the current of the battery protection circuit exceeds the overcharge current threshold; when the voltage of the third terminal c3 is greater than the third threshold voltage, the fifth comparator H5 outputs a low level, and the current of the battery protection circuit does not exceed the overcharge current threshold. When the voltage of the third terminal c3 is greater than the fourth threshold voltage Vth4, the sixth comparator H6 outputs a high level, and the current of the battery protection circuit exceeds the over-discharge current threshold; when the voltage of the third terminal c3 is less than the fourth threshold voltage Vth4, the sixth comparator H6 outputs a low level, and the current of the battery protection circuit does not exceed the over-discharge current threshold. When the voltage of the third terminal c3 is greater than the fifth threshold voltage Vth5, the seventh comparator H7 outputs a high level, and the battery protection circuit is in a short-circuit state; when the voltage of the third terminal c3 is less than the fifth threshold voltage Vth5, the sixth comparator H6 outputs a low level, and the battery protection circuit is not in a short-circuit state.

[0075] In one implementation, the third threshold voltage Vth3 is between -0.05V and -0.2V, the fourth threshold voltage Vth4 is between 0.05V and 0.2V, and the fifth threshold voltage Vth5 is between 0.5V and 3V.

[0076] Combine the following Figure 1 , Figure 3 , Figure 4 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 The working principle of the battery protection circuit in the embodiment of the present application is described. Fig.10 for Figure 7 When the battery protection circuit is working, a battery is connected between the positive connection terminal e1 and the negative connection terminal e2, and a charger / load is connected between the first connection terminal e3 and the second connection terminal e4.

[0077] in, Fig.10 The process diagram shown is Figure 6 The difference from the flow chart shown is that the battery protection circuit also includes the following cases:

[0078] In the sixth case, when the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal C3 is less than the third threshold voltage Vth3, the voltage between the battery positive connection terminal e1 and the battery negative connection terminal e2 is in a normal state, the current of the battery protection circuit exceeds the overcharge current threshold, and a charger is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned off, the first switch S1 is controlled to be turned off, and the second switch S2 is controlled to be turned on.

[0079] Specifically, when it is detected that the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal c3 is less than the third threshold voltage Vth3, the output terminal of the first comparator H1 and the output terminal of the second comparator H2 both output a low level, the output terminal of the fifth comparator H5 outputs a high level, the output terminal of the first AND gate M1 and the output terminal of the second AND gate M2 both output a low level, the output terminal of the OR gate M3 outputs a high level, and the output terminal of the NOT gate M4 outputs a low level, and the first level converter 10131 converts the low level into a voltage that turns off the isolation field effect transistor 102, and the isolation field effect transistor 102 is turned off.

[0080] In the seventh case, when the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than the fourth threshold voltage Vth4, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in a normal state, the current of the battery protection circuit exceeds the over-discharge current threshold, and a load is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned off, the first switch S1 is controlled to be turned off, and the second switch S2 is controlled to be turned on.

[0081] Specifically, when it is detected that the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than the fourth threshold voltage Vth4, the output end of the first comparator H1 and the output end of the second comparator H2 both output a low level, the output end of the sixth comparator H6 outputs a high level, the output end of the first AND gate M1 and the output end of the second AND gate M2 both output a low level, the output end of the OR gate M3 outputs a high level, and the output end of the NOT gate M4 outputs a low level, and the first level converter 10131 converts the low level into a voltage that turns off the isolation field effect transistor 102, and the isolation field effect transistor 102 is turned off.

[0082] In the eighth case, when the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than the fifth threshold voltage Vth5, the battery between the positive connection terminal e1 and the negative connection terminal e2 is in a normal state, the battery protection circuit is short-circuited, and a load is connected between the first terminal e3 and the second terminal e4. At this time, the isolation field effect transistor 102 is turned off, the first switch S1 is controlled to be turned off, and the second switch S2 is controlled to be turned on.

[0083] Specifically, when it is detected that the voltage of the first terminal c1 is less than the first threshold voltage Vth1, and the voltage of the first terminal c1 is greater than the second threshold voltage Vth2, and the voltage of the third terminal c3 is greater than the fifth threshold voltage Vth5, the output end of the first comparator H1 and the output end of the second comparator H2 both output a low level, the output end of the sixth comparator H6 outputs a high level, the output end of the first AND gate M1 and the output end of the second AND gate M2 both output a low level, the output end of the OR gate M3 outputs a high level, and the output end of the NOT gate M4 outputs a low level, and the first level converter 10131 converts the low level into a voltage that turns off the isolation field effect transistor 102, and the isolation field effect transistor 102 is turned off.

[0084] See also Fig.11 , Fig.11 This is a third specific structural diagram of the battery protection circuit provided in the embodiment of the present application. Fig.11 The battery protection circuit shown is Figure 2 The differences in the battery protection circuits shown are: Fig.11 The control module 101 in the battery protection circuit shown includes: a first enhanced field effect transistor N1, a second enhanced field effect transistor N2, a second level converter 10, a third level converter 20, a fourth level converter 30, a third AND gate 40 and a fourth detection submodule 50;

[0085] The fourth detection submodule 50 has a first sub-terminal k1, a second sub-terminal k2, a third sub-terminal k3, a fourth sub-terminal k4 and a fifth sub-terminal k5; the first sub-terminal k1 is connected to the first terminal c1, the second sub-terminal k2 is connected to the third terminal c3, the third sub-terminal k3 is connected to the gate of the first enhanced field effect transistor N1 and one end of the second level converter, the fourth sub-terminal k4 is connected to the gate of the second enhanced field effect transistor N2 and one end of the second level converter 20, the other end of the second level converter 20 is connected to the third AND gate M5. The first and second terminals of the first and second enhancement mode field effect transistors N1 and N2 are connected to a first input terminal, the other end of the second level converter 20 is connected to a second input terminal of the third AND gate M5, the output terminal of the third AND gate M5 is connected to one end of the fourth level converter 40, the other end of the fourth level converter is connected to the fourth terminal c4, the fifth sub-terminal k5 is connected to the source, substrate and second terminal c2 of the first enhancement mode field effect transistor N1, the drain of the first enhancement mode field effect transistor N1 is connected to the drain of the second enhancement mode field effect transistor N2, and the source and substrate of the second enhancement mode field effect transistor N2 are both connected to the third terminal c3.

[0086] The fourth detection submodule 50 is used to output a signal to the third subterminal k3 and the fourth subterminal k4 according to the information collected from the first subterminal k1 and the second subterminal k2, so that the control module 101 outputs a control signal. The fourth detection submodule 50 is a traditional series double switch circuit, which will not be described in detail here.

[0087] Fig.11 The principle of the battery protection circuit shown still adopts the existing dual-switch series architecture and the existing dual-switch control method, and in addition, a logic circuit and a level converter are added. When the first enhanced field effect transistor N1 and the second enhanced field effect transistor N2 are both turned on at the same time, the isolation field effect transistor (main switch) 102 is turned on. At this time, the first enhanced field effect transistor N1 and the second enhanced field effect transistor N2 do not play the role of the main switch, but provide a temporary transition current path when the main switch has entered the shutdown protection, so the switch resistance of the first enhanced field effect transistor N1 and the second enhanced field effect transistor N2 itself can be much larger than that of the main switch without consuming too much chip area cost.

[0088] The present application also provides a battery charging and discharging system, which includes the battery protection circuit, battery and charger / load described above; wherein the battery positive connection terminal is connected to one end of the battery, the battery negative connection terminal is connected to the other end of the battery, the first connection terminal is connected to one end of the charger / load, and the second connection terminal is connected to the other end of the charger / load.

[0089] The battery protection circuit and battery charging and discharging system provided by the embodiments of the present application are provided with an isolation field effect transistor in the battery protection circuit, the substrate of the isolation field effect transistor is connected to the anode of the first Schottky diode and the anode of the second Schottky diode, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode, and the drain of the isolation field effect transistor is connected to the cathode of the second Schottky diode, and this connection mode makes it possible for the parasitic diode of the isolation field effect transistor not to be turned on at any time; and the battery protection circuit is equipped with a control module, and the control module outputs a control signal to the fourth terminal according to the information collected from the first terminal, the second terminal and the third terminal, so as to control the conduction and cutoff of the isolation field effect transistor, so that the battery can be effectively protected when overcharge, overdischarge, overcurrent and the like occur.

Claims

1. A battery protection circuit, characterized in that: include: A battery positive connection terminal, a battery negative connection terminal, a first terminal, a second terminal, an isolation field effect transistor, a first Schottky diode, a second Schottky diode and a control module, wherein the control module has a first terminal, a second terminal, a third terminal and a fourth terminal; The gate of the isolation field effect transistor is connected to the fourth end, the substrate of the isolation field effect transistor is connected to the anode of the first Schottky diode and the anode of the second Schottky diode, the source of the isolation field effect transistor is connected to the cathode of the first Schottky diode, the negative connection end of the battery and the second end, the drain of the isolation field effect transistor is connected to the cathode of the second Schottky diode, the second terminal and the third end; the positive connection end of the battery is connected to the first terminal and the first end; The control module outputs a control signal to the fourth terminal according to the information collected from the first terminal, the second terminal and the third terminal, so as to control the conduction and cutoff of the isolation field effect transistor; Wherein, the control module includes: a first switch, a second switch, a first resistor, a second resistor, a first detection submodule, a second detection submodule and a driving submodule; The input end of the first detection submodule is connected to the first end, the input end of the second detection submodule is connected to the third end, the first output end of the first detection submodule is connected to the first input end of the driving submodule, the second output end of the first detection submodule is connected to the second input end of the driving submodule, the first output end of the second detection submodule is connected to the third input end of the driving submodule, the second output end of the second detection submodule is connected to the fourth input end of the driving submodule, and the output end of the driving submodule is connected to the fourth end; One end of the first switch is connected to the first end, the other end of the first switch is connected to one end of the first resistor, the other end of the first resistor is connected to the third end and one end of the second resistor, the other end of the second resistor is connected to one end of the second switch, and the other end of the second switch is connected to the second end; The first detection submodule is used to output a signal to the first input terminal of the driving submodule and the second input terminal of the driving submodule according to the voltage information collected from the first terminal, so that the driving submodule outputs the control signal to the fourth terminal; The second detection submodule is used to output a signal to the third input terminal of the driving submodule and the fourth input terminal of the driving submodule according to the voltage information collected from the third terminal, so that the driving submodule outputs the control signal to the fourth terminal.

2. The battery protection circuit according to claim 1, characterized in that: The first detection submodule includes: a first comparator and a second comparator; The first positive terminal of the first comparator and the first negative terminal of the second comparator are both connected to the first terminal, the first negative terminal of the first comparator is connected to the first threshold voltage, the second positive terminal of the second comparator is connected to the second threshold voltage, the output terminal of the first comparator is connected to the first input terminal of the driving submodule, and the output terminal of the second comparator is connected to the second input terminal of the driving submodule.

3. The battery protection circuit according to claim 1, characterized in that: The second detection submodule includes: a third comparator and a fourth comparator; The third negative terminal of the third comparator and the fourth positive terminal of the fourth comparator are both connected to the third terminal, the third positive terminal of the third comparator and the fourth negative terminal of the fourth comparator are both grounded, the output terminal of the third comparator is connected to the third input terminal of the driving submodule, and the output terminal of the fourth comparator is connected to the fourth input terminal of the driving submodule.

4. The battery protection circuit according to claim 1, characterized in that: The driving submodule includes: a first AND gate, a second AND gate, an OR gate, a NOT gate and a first level converter; The first input end of the first AND gate is connected to the first output end of the first detection submodule, the second input end of the first AND gate is connected to the first output end of the second detection submodule, the first input end of the second AND gate is connected to the second output end of the first detection submodule, the second input end of the second AND gate is connected to the second output end of the second detection submodule, the output end of the first AND gate is connected to the first input end of the OR gate, the output end of the second AND gate is connected to the second input end of the OR gate, the output end of the OR gate is connected to the input end of the NOT gate, the output end of the NOT gate is connected to the input end of the first level converter, and the output end of the first level converter is connected to the fourth end.

5. The battery protection circuit according to claim 1, characterized in that: The control module further includes a third detection submodule, an input end of the third detection submodule is connected to the third end, a first output end of the third detection submodule is connected to the fifth input end of the driving submodule, a second output end of the third detection submodule is connected to the sixth input end of the driving submodule, and a third output end of the third detection submodule is connected to the seventh input end of the driving submodule; The third detection submodule is used to output a signal to the fifth input terminal, the sixth input terminal and the seventh input terminal of the driving submodule according to the current information collected from the third terminal, so that the driving submodule outputs the control signal to the fourth terminal.

6. The battery protection circuit according to claim 5, characterized in that: The third detection submodule includes: a fifth comparator, a sixth comparator and a seventh comparator; The fifth negative terminal of the fifth comparator, the sixth positive terminal of the sixth comparator and the seventh positive terminal of the seventh comparator are all connected to the third terminal, the fifth positive terminal of the fifth comparator is connected to the third threshold voltage, the sixth negative terminal of the sixth comparator is connected to the fourth threshold voltage, the seventh negative terminal of the seventh comparator is connected to the fifth threshold voltage, the output terminal of the fifth comparator is connected to the fifth input terminal of the driving submodule, the output terminal of the sixth comparator is connected to the sixth input terminal of the driving submodule, and the output terminal of the seventh comparator is connected to the seventh input terminal of the driving submodule.

7. The battery protection circuit according to claim 1, characterized in that: The control module includes: a first enhanced field effect transistor, a second enhanced field effect transistor, a second level converter, a third level converter, a fourth level converter, a third AND gate and a fourth detection submodule; The fourth detection submodule has a first sub-terminal, a second sub-terminal, a third sub-terminal, a fourth sub-terminal and a fifth sub-terminal; the first sub-terminal is connected to the first end, the second sub-terminal is connected to the third end, the third sub-terminal is connected to the gate of the first enhancement type field effect transistor and one end of the second level converter, the fourth sub-terminal is connected to the gate of the second enhancement type field effect transistor and one end of the second level converter, the other end of the second level converter is connected to the first input end of the third AND gate, the other end of the second level converter is connected to the second input end of the third AND gate, the output end of the third AND gate is connected to one end of the fourth level converter, the other end of the fourth level converter is connected to the fourth end, the fifth sub-terminal is connected to the source, substrate and second end of the first enhancement type field effect transistor, the drain of the first enhancement type field effect transistor is connected to the drain of the second enhancement type field effect transistor, and the source and substrate of the second enhancement type field effect transistor are both connected to the third end; The fourth detection submodule is used to output a signal to the third subterminal and to output a signal to the fourth subterminal according to information collected from the first subterminal and the second subterminal, so that the control module outputs the control signal.

8. The battery protection circuit according to claim 7, characterized in that: The fourth detection submodule is a traditional series dual-switch circuit.

9. A battery charging and discharging system, characterized in that: The invention comprises a battery protection circuit, a battery and a charger / load according to any one of claims 1 to 8; wherein the positive connection terminal of the battery is connected to one end of the battery, the negative connection terminal of the battery is connected to the other end of the battery, the first terminal is connected to one end of the charger / load, and the second terminal is connected to the other end of the charger / load.

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