CN219498976U - Switch tube protection circuit with load switch, battery management system and power supply equipment - Google Patents

Abstract

The utility model discloses a switch tube protection circuit with a load switch, a battery management system and power supply equipment, comprising: the energy storage device access end is used for accessing the energy storage device; the charging and discharging access terminal is used for accessing a load/charger; the current limiting circuits are arranged between the energy storage device access end and the charge and discharge access end in parallel, and are used for limiting the current flowing through; the switch circuits are arranged between the charge and discharge access end and one current limiting circuit in series; and/or, each switch circuit is arranged in series between the energy storage device access end and one current limiting circuit; the switching circuit is used for controlling the energy storage device access terminal to be electrically connected with the charge and discharge access terminal when being closed; the utility model aims to solve the problem that a switching tube with heavy load is easy to burn out when the switching tube is opened and closed.

Description

Switch tube protection circuit with load switch, battery management system and power supply equipment

Technical Field

The utility model relates to the field of on-load switches, in particular to a switching tube protection circuit of an on-load switch, a battery management system and power supply equipment.

Background

There are many energy storage products, low-speed electric vehicles, electric bicycles, electric motorcycles, electric special vehicles and the like in the market, and lithium batteries are used, and basically, the energy storage products are tens to twenty strings. The battery management system is limited by space, and most of the battery management system adopts a switch tube to switch, and a relay is not used, so that the cost of the relay is much higher than that of the switch tube, and the battery management system is large in size.

The existing switch tube protection circuit of the on-load switch is easy to burn out the switch tube when being opened and closed, so that the switch tube is used as a switch and has a certain limitation.

Disclosure of Invention

The utility model mainly aims to provide a switching tube protection circuit with a load switch, a battery management system and power supply equipment, and aims to solve the problem that the switching tube is easy to burn out when the switching tube with a heavy load is opened and closed.

In order to achieve the above object, the switch tube protection circuit with load switch according to the present utility model includes:

the energy storage device access end is used for accessing the energy storage device;

the charging and discharging access terminal is used for accessing a load/charger;

the current limiting circuits are arranged between the energy storage device access end and the charge and discharge access end in parallel, and are used for limiting the current flowing through;

the switch circuits are arranged between the charge and discharge access end and one current limiting circuit in series;

and/or, each switch circuit is arranged in series between the energy storage device access end and one current limiting circuit; wherein, the liquid crystal display device comprises a liquid crystal display device,

and the switching circuit is used for controlling the energy storage device access terminal to be electrically connected with the charge and discharge access terminal when being closed.

Optionally, the current limiting capability of the current limiting circuit increases as the current flowing therethrough increases.

Optionally, the current limiting circuit includes:

the positive temperature coefficient thermosensitive device, the first end of positive temperature coefficient thermosensitive device is connected with the input of one way charging switch circuit, the second end of positive temperature coefficient thermosensitive device is connected with the output of one way discharging switch circuit.

Optionally, when each switching circuit is serially arranged between the energy storage device access end and one of the current limiting circuits and serially arranged between the charge and discharge access end and one of the current limiting circuits, the switching circuit comprises a first switching tube and a second switching tube;

the grid electrode of the first switching tube is used for being connected with an external charging control signal, the source electrode of the first switching tube is electrically connected with the access end of the energy storage device, and the drain electrode of the first switching tube is electrically connected with one path of current limiting circuit.

Optionally, the first switching tube is a power tube;

and/or the second switching tube is a power tube.

Optionally, the power tube is a MOS tube and/or an IGBT.

The utility model also provides a battery management system, which comprises a controller and the switch tube protection circuit of the on-load switch, wherein the output end of the controller is electrically connected with the controlled end of the switch tube protection circuit of the on-load switch.

Optionally, the battery management system further comprises:

the power detection circuit is respectively and electrically connected with the switching tube protection circuit of the on-load switch and the controller, and is used for detecting the output current of the switching tube protection circuit of the on-load switch and outputting a corresponding current detection signal to the controller;

the controller is also used for controlling the switching tube protection circuit of the on-load switch to be disconnected when the overcurrent of the switching tube protection circuit of the on-load switch is detected according to the received current detection signal.

Optionally, the current detection circuit includes:

and one end of the sampling resistor is electrically connected with the access end of the energy storage device, and the other end of the sampling resistor is connected with the output end of the switching tube protection circuit of the on-load switch.

The utility model also provides power supply equipment, which comprises a power supply, a controller, a current detection circuit and the switch tube protection circuit of the on-load switch, or comprises the power supply and the battery management system.

According to the technical scheme, the current limiting circuit and the switching circuit connected with the current limiting circuit are arranged in each channel, so that when a first closed or last opened switching circuit receives a large load current, the current limiting circuit increases the current limiting capacity of the channel where the first closed or last opened switching circuit is positioned due to the fact that the large load current is received, and the load current in a loop is reduced, and therefore overload burning of a switching element on the channel is prevented due to the fact that current is fully applied to one channel when the first closed or last opened switching circuit is arranged, and further the circuit is prevented from firing.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic block diagram of an embodiment of a switch tube protection circuit with a load switch according to the present utility model;

FIG. 2 is a schematic block diagram of another embodiment of a switch tube protection circuit of the on-load switch of the present utility model;

FIG. 3 is a schematic block diagram of a switch tube protection circuit of an on-load switch according to another embodiment of the present utility model;

FIG. 4 is a circuit diagram of an embodiment of a switch tube protection circuit with a load switch according to the present utility model;

FIG. 5 is a circuit diagram illustrating an embodiment of a battery management system according to the present utility model;

FIG. 6 is a schematic diagram of an embodiment of the prior art;

FIG. 7 is a schematic diagram of another embodiment of the prior art;

fig. 8 is a schematic diagram of an internal structure of an embodiment of a switching tube.

Reference numerals illustrate:

the achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The utility model provides a switching tube protection circuit with a load switch.

At present, in a method for connecting switch tubes in a battery management system in parallel in the market, as shown in fig. 6, B1-Bk are batteries, rs are power sampling resistors, RL are loads, qd1-Qdn are second switch tubes, qc1-Qcn are first switch tubes, B-are total negative interfaces on a battery management system board, and are connected with the negative terminals of the battery B1 through a wire harness. P-is the interface of the negative load terminal on the battery management system board and is connected with the negative load terminal through a wire harness. The charge switch or the discharge switch is in parallel connection, and the capacitance between the GS inside the switch is also in parallel connection. When a plurality of charging switches or discharging switches are connected in parallel, the capacity value after the parallel connection is not negligible.

Fig. 7 is an equivalent connection circuit of the parallel connection of the GS and the parasitic capacitance at both ends of the switching tube GS when the multiple first switching tube and the multiple second switching tube are connected in parallel.

Because the circuit needs too much current to connect the multiple switching tubes in parallel, a single switching tube can also select a switching tube with very large overcurrent capacity, but the larger the overcurrent capacity is, the larger the capacitance value of the internal parasitic capacitance is, and many of the parasitic capacitance is in tens of nano-meters. The capacitance values of the capacitors connected in parallel are accumulated, the total capacitance value Cd of the second switching tube in fig. 7 is calculated as formula 1, and the total capacitance value Cc of the first switching tube is calculated as formula 2.

Cd=cd1+cd2+cdn … … … … … … … … formula 1.

Cc=cc1+cc2+ Ccn … … … … … … … … equation 2.

The essence of driving the switching tube is to charge and discharge parasitic capacitance between the GS of the switching tube. At small currents, the driving circuit is well designed, but at relatively large currents, such as one hundred amperes, two hundred amperes or more, the driving circuit of the switching tube is not required to be high. In addition, no matter how the driving circuit is designed, when the driving circuit works under high current, the switching tubes cannot be accurately disconnected at the same moment, the front and back disconnection always occurs, one switching tube is always disconnected at last, the load originally distributed on each switching tube is fully added on the last disconnected switching tube, and therefore the switching tubes are easy to burn.

Referring to fig. 1 to 4, in an embodiment, the switching tube protection circuit of the on-load switch includes:

an energy storage device access terminal 100 for accessing an energy storage device;

a charge-discharge access terminal 200 for accessing a load/charger;

the current limiting circuits 300 are all arranged in parallel between the energy storage device access terminal 100 and the charge-discharge access terminal 200, and the current limiting circuits 300 are used for limiting the current flowing through;

a plurality of switch circuits 400, each of the switch circuits 400 is serially connected between the charge/discharge access terminal 200 and one of the current limiting circuits 300;

and/or, each of the switch circuits 400 is serially connected between the energy storage device access terminal 100 and one of the current limiting circuits 300; wherein, the liquid crystal display device comprises a liquid crystal display device,

the switch circuit 400 is configured to control the energy storage device access terminal 100 to be electrically connected to the charge/discharge access terminal 200 when closed.

In this embodiment, the switching circuit 400 may include a MOS transistor, an IGBT, or the like, the current limiting circuit 300 may include a thermistor, and the current limiting capability of the current limiting circuit 300 increases as the current flowing therethrough increases.

It should be noted that, a plurality of current channels are provided between the energy storage device access terminal 100 and the charge/discharge access terminal 200, each channel includes a current limiting circuit 300 and a switching circuit 400 connected to the current limiting circuit 300, the number of the switching circuits 400 in each channel may be one or two, and when the number of the switching circuits 400 is one, the switching circuits 400 are switched on and switched off under the control of an external control signal; when the number of the switch circuits 400 is two, the two switch circuits 400 are simultaneously switched on and switched off under the control of an external control signal.

Specifically, the utility model is described by taking the heavy load of the power supply as an example, and the same is true when the power supply is charged:

when the power supply is in heavy load, the switch circuits 400 are closed when receiving an external on control signal, and the first switch circuit 400 is firstly closed, namely the first channel is conducted, other channels are not conducted, at the moment, the load current is all pressed on the first channel, and the switch circuits 400 in the channels cannot bear such large current under normal conditions, however, the current limiting circuit 300 is provided, and the current limiting capacity of the current limiting circuit 300 is increased along with the increase of the current flowing through the first channel, so that the load current flowing through the first channel is limited. When the rest of the switch circuits 400 are sequentially closed, the current limiting circuit 300 is used for limiting the current, so that when each channel is connected with a large load current, the current limiting circuit 300 can be used for limiting each channel of the switch circuits 400 under the action of the large current until the last switch circuit 400 is closed, the large load current is split by a plurality of channels, the load current flowing through the current limiting circuit 300 is reduced, the current limiting capacity of the current limiting circuit 300 on each channel is reduced, and the currents flowing through all channels are equal at the moment, so that the MOS tube with heavy load output is realized.

When the circuit with the heavy load of the power supply is disconnected, the plurality of switch circuits 400 receive the external disconnection control signal to disconnect, and it is assumed that the first discharge switch circuit 400 is disconnected first, that is, the first channel is disconnected first, and other channels are not disconnected yet. At this time, the current flowing before the first channel is disconnected is uniformly distributed to other channels, the load current flowing in other channels does not reach the action current of the current limiting circuit 300, and the current limiting circuit 300 does not limit the load current flowing. When the rest of the switching circuits 400 are turned off in turn, the load current flowing through each channel before the switching circuit 400 is turned off is uniformly distributed to the rest of the channels, so that the load current flowing through the current limiting circuit 300 reaches the action current thereof, the current limiting circuit 300 starts to limit the load current flowing through the current limiting circuit, the current limiting capability of the last turned-off channel is continuously increased due to the continuous increase of the load current, the load current flowing through the last channel is reduced until the last switching circuit 400 is turned off, the load current in the channel is zero, and the current limiting circuit 300 stops working at the moment. Thus, the switch circuit 400 is not burnt out due to overload of a large load current, and the circuit disconnection of the power supply when the power supply is in heavy load is realized.

According to the utility model, the current limiting circuit 300 and the switching circuit 400 connected with the current limiting circuit 300 are arranged in each channel, so that when a first closed or last opened switching circuit 400 receives a large load current, the current limiting circuit 300 increases the current limiting capacity of the channel where the first closed or last opened switching circuit 400 is positioned due to the large current, and the load current in a loop is reduced, thereby preventing overload burning of a switching element on the channel due to the fact that the current is fully applied to one channel when the first closed or last opened switching circuit 400 is positioned, and further preventing the circuit from igniting.

Optionally, when each of the switching circuits 400 is disposed in series between the energy storage device access terminal 100 and one of the current limiting circuits 300, and in series between the charge/discharge access terminal 200 and one of the current limiting circuits 300, the switching circuit 400 includes first switching transistors Qc1-Qcn and second switching transistors Qd 1-Qdn;

the grid electrodes of the first switching tubes Qc1-Qcn are used for accessing external control signals, the source electrodes of the first switching tubes Qc1-Qcn are electrically connected with the charge-discharge access terminal 200, and the drain electrodes of the first switching tubes Qc1-Qcn are electrically connected with one path of the current limiting circuit 300;

the gates of the second switching tubes Qd1-Qdn are used for accessing external control signals, the drains of the second switching tubes Qd1-Qdn are electrically connected with the energy storage device access terminal 100, and the sources of the second switching tubes Qd1-Qdn are electrically connected with one path of the current limiting circuit 300.

In this embodiment, the first switching transistors Qc1 to Qcn are power transistors; and/or the second switching transistors Qd1 to Qdn are power transistors. The power tube is a MOS tube and/or an IGBT.

It should be noted that, since the diode is actually integrated inside the switching tube, as shown in fig. 8, even when no voltage drop is formed at the GS end of the switching tube, the diode is turned on unidirectionally, so that the switching tube cannot be completely turned off, and a tailing current exists, the first switching tubes Qc1 to Qcn and the second switching tubes Qd1 to Qdn are respectively provided in each switching circuit 400, so that the current is completely turned off when no voltage drop is formed at the GS end of the switching tube due to the unidirectional conduction directions of the diodes inside the two switching tubes.

Taking the case when the power supply supplies power for a large load as an example, the same applies to the case when the power supply is charged:

when the source supplies power to a large load, the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn receive an external on control signal to be closed, so that the GS ends of the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn form voltage drops, that is, parasitic capacitances of the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn are charged, and the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn in the same channel are conducted; when the power source is disconnected to supply power to a large load, the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn receive external turn-off control signals to disconnect, parasitic capacitances of the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn are discharged until no voltage drop exists at the GS ends of the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn, and due to the existence of diodes in the switching tubes, trailing top current still flows through the first switching tubes Qc1-Qcn, at the moment, the connection directions of the diodes in the second switching tubes Qd1-Qdn are opposite to the flow direction of the trailing current, and a current loop of the micro current is disconnected.

Optionally, the current limiting circuit 300 includes:

positive temperature coefficient thermosensitive devices PT 1-PTn, which are serially connected between the charge-discharge access terminal 200 and the switch circuit 400;

and/or, the switch circuit 400 is disposed in series between the energy storage device access terminal 100 and the switch circuit.

In this embodiment, the internal resistances of the ptc devices PT1 to PTn are in direct proportion to the self temperature, and the large current flowing through the ptc devices PT1 to PTn make the ptc devices PT1 to PTn work and generate heat, so that when the load current is fully pressed on the first closed or last opened switch circuit 400, the ptc devices PT1 to PTn receive the large current and generate heat, and increase the internal resistance of the switch circuit 400 where the ptc devices PT1 to PTn are located, and limit the load current flowing through the switch circuit 400, thereby preventing overload damage to elements on the circuit due to the fact that the current is fully applied on one branch when a certain switch circuit 400 is first closed or last opened, and further preventing the circuit from firing.

In order to better illustrate the inventive concept, the following description is made in connection with the above embodiments:

when the switch tube is closed with heavy load, the types of the switch tubes are the same, but parasitic capacitances inside the switch tubes are different, so that the switch tubes are in sequence in the closing process. It is assumed that the switching tube of the first channel is first closed, that is, the positive temperature coefficient thermosensitive device PT1, the second switching tube Qd1, and the current loop of the first switching tube Qc1 are first turned on, and the other channels are not turned on yet. The load current goes to the first channel, and under normal conditions, the first switching tube Qc1 and the second switching tube Qd1 cannot bear such large current, however, when the load current is far beyond the holding current of the ptc thermistor PT1, and also far beyond the action current of the ptc thermistor PT1, the ptc thermistor PT1 rapidly heats, and the internal resistance also rapidly rises, so that the impedance of the first switching circuit 400 becomes large, and further, the current of the first switching circuit 400 is reduced. The first switching tube Qc1 and the second switching tube Qd1 in the first channel can not be burnt out due to the heating caused by the large load current. Further, the load current flowing through the first switching circuit 400 is reduced due to the current limitation of the ptc thermistor PT1, and the temperature of the ptc thermistor PT1 is also gradually reduced.

Assuming that the switching tube of the second channel is closed, that is, the positive temperature coefficient thermosensitive device PT2, the second switching tube Qd2 and the current loop of the first switching tube Qc2 begin to be conducted after the first channel is conducted, at this time, the first channel is already conducted, only the current is smaller, most of the load current flows to the second switching circuit 400, and similarly, the positive temperature coefficient thermosensitive device PT2 in the second channel rapidly heats due to the large load current, and the internal resistance also rapidly increases, so that the impedance in the second channel becomes larger, and further, the load current flowing through the second channel decreases. Therefore, the first switching tube Qc2 and the second switching tube Qd2 in the second channel will not burn out due to the heat generated by the large load current. Also, as the load current flowing through the second switching circuit 400 decreases, the temperature of the ptc thermosensitive device PT2 also slowly decreases.

Thus, when the switching tubes of all channels are closed, the impedance of all channels is equal and the current flowing through all switching circuits 400 is equal because the switching tubes of the last channel are turned on, and the positive temperature coefficient thermosensitive devices PT 1-PTn in the other channels are also gradually reduced to the internal resistance value at normal temperature. Thus, the heavy load output of the switch tube is realized.

When the switching tube is disconnected with heavy load, the switching tubes in the first channel are supposed to be disconnected firstly, namely, the current loops of the positive temperature coefficient thermosensitive device PT1, the second switching tube Qd1 and the first switching tube Qc1 are disconnected firstly, and the switching tubes in other channels are not disconnected yet. At this time, the current flowing before the first channel is disconnected is uniformly distributed to other channels, and the load current in other channels does not reach the action current of the positive temperature coefficient thermosensitive devices PT2 to PTn, and the positive temperature coefficient thermosensitive devices PT2 to PTn do not generate heat yet.

It is assumed that the switching tube in the second channel is turned off secondly, i.e. the current loop of the ptc thermistor PT2, the second switching tube Qd2, the first switching tube Qc2 is turned off secondly, at which time the first channel has been turned off. Because two channels are disconnected, the current flowing before the two channels are disconnected is uniformly distributed on the other channels, and the load current flowing through the other channels can reach the action current of the positive temperature coefficient thermosensitive devices PT 3-PTn, so that the positive temperature coefficient thermosensitive devices PT 3-PTn start to generate heat, and the internal resistance is increased.

As the switching tubes in the channels are turned off in sequence, the heat productivity of the ptc thermosensitive devices PTn in the remaining channels increases, and the internal resistance of the remaining channels increases.

Before the switching tube in the last channel is disconnected, the channels continuously distribute current, so that the heating value of the positive temperature coefficient thermosensitive device PTn in the last channel is continuously increased, the internal resistance of the last channel is continuously increased, and the load current flowing through the last channel is not increased but is reduced. When the switching tube in the last channel is turned off, the load current is zero. Therefore, when the first switching tubes Qc1-Qcn and the second switching tubes Qd1-Qdn are disconnected, the switching tubes cannot be heated and burnt out due to the fact that large load current flows, and load disconnection output is achieved.

Referring to fig. 5, in an embodiment, the present utility model further provides a battery management system, including a controller 500 and the above-mentioned switching tube protection circuit with a load switch, where an output end of the controller 500 is electrically connected to a controlled end of the switching tube protection circuit with a load switch; the specific structure of the switch tube protection circuit of the on-load switch refers to the above embodiments, and because the battery management system adopts all the technical schemes of all the embodiments, the battery management system at least has all the beneficial effects brought by the technical schemes of the embodiments, and the detailed description is omitted.

In this embodiment, when the battery management system supplies power to the load component through the power supply, the power supply is connected with the load component, and the direct current power supply output by the power supply is gradually increased through the battery management system, so that the power supply can output a large current to supply power to a large power load, and the problem of overload damage of the switch circuit 400 of the battery management system caused by overlarge load is reduced.

Referring to fig. 4 and 5, in an embodiment, the battery management system further includes:

the current detection circuit 600 is electrically connected to the switching tube protection circuit of the on-load switch and the controller 500, and the current detection circuit 600 is configured to detect an output current of the switching tube protection circuit of the on-load switch and output a corresponding current detection signal to the controller 500;

the controller 500 is further configured to control the switching tube protection circuit of the on-load switch to be turned off when detecting that the switching tube protection circuit of the on-load switch is over-current according to the received current detection signal.

In this embodiment, the overcurrent detection circuit 00 may include a current detection resistor and an amplifier, and a preset overcurrent voltage is preset in the controller 500, where the preset overcurrent voltage represents a peak current critical value of normal operation of the switching tube protection circuit of the on-load switch.

Optionally, the current detection circuit 600 includes:

and one end of the sampling resistor Rs is electrically connected with the access end 100 of the energy storage device, and the other end of the sampling resistor Rs is connected with the output end of the switch tube protection circuit of the load switch.

In this embodiment, the sampling resistor Rs is a power sampling resistor Rs.

When the switch tube protection circuit of the on-load switch is connected with the power supply and the load component, the loop current flowing through the switch tube protection circuit of the on-load switch is output to the current detection resistor Rt, the controller 500 collects the voltage values at two ends of the current detection resistor Rt through the current detection end, and according to ohm law, the current value flowing through the current detection resistor Rt, namely, the current value of the loop current flowing through the switch tube protection circuit of the on-load switch, can be obtained according to the received voltage values at two ends of the current detection resistor Rt and the resistance value known by the current detection resistor Rt, and when the current value represented by the current detection signal is larger than the preset overcurrent voltage, the controller 500 compares the current value represented by the current detection signal with the preset overcurrent voltage, and outputs a control signal to the switch tube protection circuit of the on-load switch, so that the switch tube protection circuit of the on-load switch disconnects the loop between the power supply and the load component.

The utility model also provides a power supply device, which comprises a power supply, a controller 500, a current detection circuit 600 and the switch tube protection circuit of the on-load switch, or comprises the power supply and the battery management system; the specific structure of the switch tube protection circuit of the on-load switch refers to the above embodiments, and because the power supply equipment adopts all the technical schemes of all the embodiments, the on-load switch tube protection circuit at least has all the beneficial effects brought by the technical schemes of the embodiments, and the detailed description is omitted.

The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims (10)

1. A switching tube protection circuit for a load switch, comprising:

the energy storage device access end is used for accessing the energy storage device;

the charging and discharging access terminal is used for accessing a load/charger;

the current limiting circuits are arranged between the energy storage device access end and the charge and discharge access end in parallel, and are used for limiting the current flowing through;

the switch circuits are arranged between the charge and discharge access end and one current limiting circuit in series;

and/or, each switch circuit is arranged in series between the energy storage device access end and one current limiting circuit; wherein, the liquid crystal display device comprises a liquid crystal display device,

and the switching circuit is used for controlling the energy storage device access terminal to be electrically connected with the charge and discharge access terminal when being closed.

2. The switch tube protection circuit of the on-load switch of claim 1, wherein the current limiting capability of the current limiting circuit increases as the current flowing therethrough increases.

3. The switch tube protection circuit of the on-load switch of claim 2, wherein the current limiting circuit comprises:

the positive temperature coefficient thermosensitive device is arranged in series between the charge-discharge access terminal and one of the switch circuits;

and/or, the energy storage device is arranged between the energy storage device access end and the switching circuit in series.

4. The switch tube protection circuit of the on-load switch of claim 1, wherein when each of the switch circuits is arranged in series between the energy storage device access terminal and one of the current limiting circuits, and in series between the charge and discharge access terminal and one of the current limiting circuits, the switch circuit comprises a first switch tube and a second switch tube;

the grid electrode of the first switching tube is used for accessing an external control signal, the source electrode of the first switching tube is electrically connected with the charge-discharge access end, and the drain electrode of the first switching tube is electrically connected with one current limiting circuit;

the grid electrode of the second switching tube is used for being connected with an external control signal, the drain electrode of the second switching tube is electrically connected with the access end of the energy storage device, and the source electrode of the second switching tube is electrically connected with one current limiting circuit.

5. The switch tube protection circuit of the on-load switch of claim 4, wherein the first switch tube is a power tube;

and/or the second switching tube is a power tube.

6. The switch tube protection circuit of the on-load switch according to claim 5, wherein the power tube is a MOS tube and/or an IGBT.

7. A battery management system, comprising a controller and a switching tube protection circuit of the on-load switch according to any one of claims 1-6, wherein an output end of the controller is electrically connected to a controlled end of the switching tube protection circuit of the on-load switch.

8. The battery management system of claim 7, wherein the battery management system further comprises:

the current detection circuit is respectively and electrically connected with the switching tube protection circuit of the on-load switch and the controller, and is used for detecting the output current of the switching tube protection circuit of the on-load switch and outputting a corresponding current detection signal to the controller;

the controller is also used for controlling the switching tube protection circuit of the on-load switch to be disconnected when the overcurrent of the switching tube protection circuit of the on-load switch is detected according to the received current detection signal.

9. The battery management system of claim 8 wherein the current detection circuit comprises:

and one end of the sampling resistor is electrically connected with the access end of the energy storage device, and the other end of the sampling resistor is connected with the output end of the switching tube protection circuit of the on-load switch.

10. A power supply device comprising a power supply, a controller, a current detection circuit and a switching tube protection circuit with a load switch according to any one of claims 1-6, or comprising a power supply and a battery management system according to claims 7-9.