Over-current protection circuit, battery module, and aerosol generating device

Abstract

The utility model discloses an overcurrent protection circuit, a battery module and an aerosol generating device. The overcurrent protection circuit comprises: an interface circuit; the charging management circuit is connected between the battery to be charged and the interface circuit; the first switch is electrically connected to a charging loop of the battery to be charged, comprises a first input end connected with the interface circuit, and is configured to conduct the charging loop based on the voltage of the first input end; and the second switch is electrically connected between the grounding end and the first input end, comprises a second input end connected with the charging loop, and is configured to be switched on or switched off in response to the current change flowing through the charging loop through the second input end, and can pull down the voltage of the first input end in the switched-on state, so that the first switch is switched off. Therefore, the charging loop of the battery to be charged is conducted through the first switch, and the working states of the second switch and the first switch are controlled according to the current of the charging loop, so that overcurrent protection is realized.

Description

Technical Field

[0001] The present application relates to the field of electronic atomization technology, and in particular to an overcurrent protection circuit, a battery module and an aerosol generating device. Background Art

[0002] Aerosol generating devices are generally powered by rechargeable batteries, and the charging current of the rechargeable batteries is managed by a charging management circuit. However, when the charging management circuit fails due to a short circuit, the charging current increases, which may cause damage to the circuit or equipment. Therefore, it is particularly important to provide an overcurrent protection circuit in the aerosol generating device. Utility Model Content

[0003] The present application provides an overcurrent protection circuit, a battery module and an aerosol generating device, aiming to achieve overcurrent protection.

[0004] In a first aspect, an embodiment of the present application provides an overcurrent protection circuit, comprising:

[0005] An interface circuit, used for connecting an external power source to provide a power supply voltage;

[0006] A charging management circuit, connected between the battery to be charged and the interface circuit, configured to receive a power supply voltage and provide a charging voltage to the battery to be charged;

[0007] a first switch, electrically connected to a charging circuit of the battery to be charged, the first switch comprising a first input terminal connected to the interface circuit, the first switch being configured to conduct the charging circuit based on a voltage at the first input terminal;

[0008] A second switch is electrically connected between a ground terminal and the first input terminal, the second switch includes a second input terminal connected to the charging circuit, the second switch is configured to be turned on or off in response to a change in current flowing through the charging circuit through the second input terminal, and can pull down the voltage of the first input terminal in a turned-on state, thereby turning off the first switch.

[0009] Optionally, the interface circuit includes:

[0010] A charging interface, used to connect an external power source to provide a power supply voltage;

[0011] A voltage divider circuit is electrically connected between the charging port and the ground terminal. The voltage divider circuit is also electrically connected to the first input terminal. The voltage divider circuit is configured to divide the power supply voltage to provide a voltage for the first input terminal.

[0012] Optionally, the overcurrent protection circuit also includes a current acquisition circuit, which is electrically connected between the first switch and the ground terminal and is also connected to the second input terminal, and the current acquisition circuit is configured to provide a voltage to the second input terminal in response to changes in current flowing through the charging circuit.

[0013] Optionally, the overcurrent protection circuit further includes a current limiting circuit electrically connected between the second input terminal and the charging circuit, and the current limiting circuit is configured to limit the current flowing into the second switch.

[0014] Optionally, the first switch includes an NMOS tube, the gate of the NMOS tube serves as the first input end, the source of the NMOS tube is electrically connected to the current acquisition circuit and the negative electrode of the battery to be charged, and the drain of the NMOS tube is electrically connected between the charging management circuit and the positive electrode of the battery to be charged.

[0015] Optionally, the current acquisition circuit includes a first resistor electrically connected between the source of the NMOS tube and a ground terminal, and the first resistor is also connected to the second input terminal.

[0016] Optionally, the second switch includes an NPN transistor, the base of the NPN transistor serves as the second input terminal, the collector of the NPN transistor is electrically connected to the first input terminal, and the emitter of the NPN transistor is grounded.

[0017] Optionally, the current limiting circuit includes a second resistor, and the second resistor is electrically connected between the base of the NPN transistor and the charging circuit.

[0018] Optionally, the voltage divider circuit includes a third resistor and a fourth resistor, the third resistor and the fourth resistor are connected in series and electrically connected between the charging interface and the ground terminal, and a connection node is set between the third resistor and the fourth resistor and is electrically connected to the first input terminal.

[0019] In a second aspect, an embodiment of the present application provides a battery module, comprising an overcurrent protection circuit as described in any of the above embodiments and a battery to be charged electrically connected to the overcurrent protection circuit, wherein the overcurrent protection circuit is used to provide a charging voltage for the battery to be charged.

[0020] In a third aspect, an embodiment of the present application provides an aerosol generating device, comprising the battery module as described in the above embodiment.

[0021] The above-mentioned embodiments have at least the following beneficial effects: the overcurrent protection circuit, battery module and aerosol generating device provided in the embodiments of the present application connect the charging circuit of the battery to be charged through the first switch, and control the working states of the second switch and the first switch according to the current of the charging circuit, thereby achieving overcurrent protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0023] Figure 1 A schematic diagram of the structure of an overcurrent protection circuit provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of an overcurrent protection circuit provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of an overcurrent protection circuit provided in an embodiment of the present application;

[0026] Figure 4 A circuit connection diagram of an overcurrent protection circuit provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of the structure of a battery module provided in an embodiment of the present application.

[0028] Figure 6 A schematic structural diagram of an aerosol generating device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] See also Figures 1 to 4 The overcurrent protection circuit 10 includes an interface circuit 11, a charging management circuit 12, a first switch 13 and a second switch 14.

[0031] The interface circuit 11 is used to connect to an external power source to provide a power supply voltage.

[0032] Among them, the external power supply includes a charger, a mobile power supply, a smart terminal, etc. that are compatible with the interface circuit 11. For example, the external power supply is plugged into the interface circuit 11 to provide a standard 5V input voltage for the overcurrent protection circuit 10.

[0033] like Figure 2 and Figure 3 As shown, the interface circuit 11 includes a charging interface 111 and a voltage divider circuit 112 .

[0034] The charging interface 111 is used to connect to an external power source to provide a power supply voltage.

[0035] Preferably, the charging interface 111 includes a USB interface or a Type-C interface. As common interface types, the USB interface or the Type-C interface can be adapted for use with most external power sources. Figure 4 Take the charging interface 111 including the charging interface USB1 as an example.

[0036] It can be understood that the charging interface 111 is not limited to the interface type provided in the embodiment of the present application, and it can also be designed as other interface types according to product requirements, such as a Lightning interface.

[0037] The voltage divider circuit 112 is electrically connected between the charging interface 111 and the ground terminal. The voltage divider circuit 112 is also electrically connected to the first input terminal 130 . The voltage divider circuit 112 is configured to divide the power supply voltage to provide voltage for the first input terminal 130 .

[0038] like Figure 4 As shown, the voltage divider circuit 112 includes a third resistor R3 and a fourth resistor R4, which are connected in series and electrically connected between the charging interface 111 and the ground terminal, and a connection node is set between the third resistor R3 and the fourth resistor R4 and is electrically connected to the first input terminal 130.

[0039] The first input terminal 130 is connected to a series connection circuit of the third resistor R3 and the fourth resistor R4, that is, a connection node is set on the series connection circuit of the third resistor R3 and the fourth resistor R4, and the first input terminal 130 is connected to the connection node. The third resistor R3 and the fourth resistor R4 divide the power supply voltage input by the charging interface 111, and the output voltage from the connection node acts on the first input terminal 130.

[0040] The charging management circuit 12 is connected between the battery 20 to be charged and the interface circuit 11 , and is configured to receive a power supply voltage and provide a charging voltage to the battery 20 to be charged.

[0041] like Figure 4 As shown, the charging management circuit 12 includes a charging management chip U1 . The charging management chip U1 is connected between the positive charging interface 111 of the battery 20 to be charged.

[0042] When the charging management chip U1 is working normally, the power supply voltage input by the interface circuit 11 charges the battery 20 to be charged through the charging management chip U1. When the charging management chip U1 fails due to a short circuit, the power supply voltage input by the interface circuit 11 directly enters the battery 20 to be charged, causing the current in the charging circuit to increase sharply, which may cause damage to the circuit or equipment.

[0043] The first switch 13 is electrically connected to the charging circuit of the battery 20 to be charged. The first switch 13 includes a first input terminal 130 connected to the interface circuit 11 . The first switch 13 is configured to turn on the charging circuit based on the voltage of the first input terminal 130 .

[0044] When the charging management circuit 12 works normally, the external power supply is connected to the interface circuit 11, and the power supply voltage provided by the external power supply passes through the interface circuit 11 and the charging management circuit 12 to the positive electrode of the battery to be charged 20. At the same time, the power supply voltage provided by the external power supply passes through the interface circuit 11 to the first switch 13, so that the first switch 13 works in the on state, so that the positive electrode of the battery to be charged 20 passes through the first switch 13 to the negative electrode of the battery to be charged 20. At this time, the charging circuit of the battery to be charged 20 is a circuit formed by the interface circuit 11, the charging management circuit 12, the positive electrode of the battery to be charged 20, the first switch 13 and the negative electrode of the battery to be charged 20.

[0045] When the charging management circuit 12 works normally, the first switch 13 includes a first input terminal 130 connected to the interface circuit 11, and the voltage divider circuit 112 is configured to divide the power supply voltage to provide voltage to the first input terminal 130. The voltage divider circuit 112 is configured to divide the power supply voltage to control the first switch 13 to operate in a conductive state, thereby turning on the charging circuit, and the rechargeable battery 20 starts to charge.

[0046] In one example, the voltage of the first input terminal 130 meets certain conditions, and the first switch 13 works in a partially cut-off state to reduce the current of the charging circuit.

[0047] In one example, the voltage of the first input terminal 130 meets certain conditions, the first switch 13 works in a completely cut-off state to shut off the charging circuit, and the charging battery 20 stops charging.

[0048] Please refer again Figure 2 The overcurrent protection circuit 10 also includes a current acquisition circuit 15, which is electrically connected between the first switch 13 and the ground terminal. The current acquisition circuit 15 is also connected to the second input terminal 140. The current acquisition circuit 15 is configured to provide a voltage to the second input terminal 140 in response to a change in current flowing through the charging circuit.

[0049] like Figure 4As shown, the first switch 13 includes an NMOS transistor Q1, the gate of the NMOS transistor Q1 serves as the first input terminal 130, the source of the NMOS transistor Q1 is electrically connected to the current acquisition circuit 15 and the negative electrode of the battery to be charged 20, and the drain of the NMOS transistor Q1 is electrically connected between the charging management circuit 12 and the positive electrode of the battery to be charged 20. The current acquisition circuit 15 includes a first resistor R1, the first resistor R1 is electrically connected between the source of the NMOS transistor Q1 and the ground terminal, and the first resistor R1 is also connected to the second input terminal 140.

[0050] The current of the charging circuit flows through the first resistor R1 to form a voltage drop at both ends of the first resistor R1. Since the base of the NPN transistor Q2 serves as the second input terminal 140, the first resistor R1 is also connected to the second input terminal 140. The first resistor R1 responds to the change of the current flowing through the charging circuit to provide a voltage to the second input terminal 140, thereby controlling the working state of the second switch 14.

[0051] The second switch 14 is electrically connected between the ground terminal and the first input terminal 130. The second switch 14 includes a second input terminal 140 connected to the charging circuit. The second switch 14 is configured to be able to turn on or off in response to the change of the current flowing through the charging circuit through the second input terminal 140, and can pull down the voltage of the first input terminal 130 in the on state, so that the first switch 13 is turned off. When the charging management chip U1 is working normally, the voltage divider circuit 112 is configured to divide the power supply voltage to control the first switch 13 to work in the on state, thereby turning on the charging circuit, and the rechargeable battery 20 starts to charge. At this time, the voltage drop across the first resistor R1 does not meet the on condition of the second switch 14, and the second switch 14 works in the off state, that is, the first resistor R1 responds to the change of the current flowing through the charging circuit to provide a voltage to the second input terminal 140 to control the second switch 14 to work in the off state.

[0052] When the charging management chip U1 fails due to a short circuit, the power supply voltage input by the interface circuit 11 directly enters the battery to be charged 20, causing the current in the charging circuit to increase sharply, and the voltage drop across the first resistor R1 increases, satisfying the conduction condition of the second switch 14. The second switch 14 operates in the on state, that is, the first resistor R1 responds to the change in the current flowing through the charging circuit to provide a voltage to the second input terminal 140 to control the second switch 14 to operate in the on state. Since the second switch 14 is electrically connected between the ground terminal and the first input terminal 130, the second switch 14 operates in the on state, resulting in a decrease in the voltage of the first input terminal 130, thereby turning off the first switch 13.

[0053] It should be noted that the first switch 13 being turned off here means that the first switch 13 is in the cut-off region but the first switch 13 is not completely turned off. At this time, the charging circuit is still turned on, but the internal resistance of the first switch 13 increases, so that the current flowing through the charging circuit of the first switch 13 is reduced, and the current of the charging circuit is prevented from exceeding the preset current threshold, thereby achieving the purpose of overcurrent protection. Figure 4 As shown, the second switch 14 includes an NPN transistor Q2, the base of the NPN transistor Q2 serves as the second input terminal 140, the collector of the NPN transistor Q2 is electrically connected to the first input terminal 130, and the emitter of the NPN transistor Q2 is grounded.

[0054] Please refer again Figure 3 The overcurrent protection circuit 10 further includes a current limiting circuit 16 electrically connected between the second input terminal 140 and the charging circuit, and the current limiting circuit 16 is configured to limit the current flowing into the second switch 14. Figure 4 As shown, the current limiting circuit 16 includes a second resistor R2, and the second resistor R2 is electrically connected between the base of the NPN transistor Q2 and the second input terminal 140. By setting the current limiting circuit 16, it is prevented that the large current damages the second switch 14. Figure 4 Taking an example for illustration, the working principle of the overcurrent protection circuit 10 is as follows:

[0055] When the charging circuit chip U1 is working normally, the external power supply is connected to the charging interface USB1, and the external power supply provides a power supply voltage to the voltage divider circuit 112 and the charging circuit chip U1 through the charging interface USB1. The third resistor R3 and the fourth resistor R4 divide the power supply voltage in series and input it to the gate of the NMOS tube Q1, satisfying the conduction condition of the NMOS tube Q1. The NMOS tube Q1 works in the conduction state, thereby turning on the charging circuit, and the battery 20 to be charged starts to charge.

[0056] When the charging circuit chip U1 fails due to a short circuit, the power supply voltage provided by the external power supply through the charging interface USB1 directly enters the battery to be charged 20, so that the current in the charging circuit increases sharply, and the voltage drop across the first resistor R1 increases, satisfying the conduction condition of the NPN transistor Q2. The NPN transistor Q2 works in the on state, and the internal resistance of the NPN transistor Q2, the third resistor R3 and the fourth resistor R4 are connected in series to divide the power supply voltage and input it to the gate of the NMOS tube Q1, which does not meet the conduction condition of the NMOS tube Q1. The NMOS tube Q1 works in the off state but the NMOS tube Q1 is not completely cut off. The internal resistance of the NMOS tube Q1 increases, so that the current flowing through the charging circuit of the NMOS tube Q1 is reduced, thereby preventing the current of the charging circuit from exceeding the preset current threshold, thereby achieving the purpose of overcurrent protection.

[0057] The overcurrent protection circuit provided in the embodiment of the present application turns on the charging circuit of the battery to be charged through the first switch, and controls the working states of the second switch and the first switch according to the current of the charging circuit, thereby achieving overcurrent protection.

[0058] See also Figure 5 , is a schematic diagram of the structure of a battery module provided in an embodiment of the present application. Figure 5 As shown, the battery module 100 includes the overcurrent protection circuit 10 as described in any of the above embodiments and a battery 20 to be charged electrically connected to the overcurrent protection circuit 10 , and the overcurrent protection circuit 10 is used to provide a charging voltage for the battery 20 to be charged.

[0059] The battery to be charged 20 may include one battery, or a battery assembly consisting of multiple batteries connected in series, in parallel, or in series and parallel, and having only one pair of positive and negative output terminals. In one example, the battery to be charged 20 also includes a housing for protection.

[0060] In one example, the battery 20 to be charged is a lithium-ion battery.

[0061] See also Figure 6 , is a schematic diagram of the structure of an aerosol generating device provided in an embodiment of the present application. Figure 6 As shown, the aerosol generating device 200 includes the battery module 100 as described in the above embodiment.

[0062] A typical aerosol generating device 200 includes an electronic atomizer, and the battery module 100 serves as a power source for the electronic atomizer, and is used to provide power to the electronic atomizer so that the electronic atomizer heats an atomized aerosol generating substrate to generate an aerosol.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An overcurrent protection circuit, characterized in that: include: An interface circuit, used for connecting an external power source to provide a power supply voltage; A charging management circuit, connected between the battery to be charged and the interface circuit, configured to receive a power supply voltage and provide a charging voltage to the battery to be charged; a first switch, electrically connected to a charging circuit of the battery to be charged, the first switch comprising a first input terminal connected to the interface circuit, the first switch being configured to conduct the charging circuit based on a voltage at the first input terminal; A second switch is electrically connected between a ground terminal and the first input terminal, the second switch includes a second input terminal connected to the charging circuit, the second switch is configured to be turned on or off in response to a change in current flowing through the charging circuit through the second input terminal, and can pull down the voltage of the first input terminal in a turned-on state, thereby turning off the first switch.

2. The overcurrent protection circuit according to claim 1, characterized in that: The interface circuit comprises: A charging interface, used to connect an external power source to provide a power supply voltage; A voltage divider circuit is electrically connected between the charging port and the ground terminal. The voltage divider circuit is also electrically connected to the first input terminal. The voltage divider circuit is configured to divide the power supply voltage to provide a voltage for the first input terminal.

3. The overcurrent protection circuit according to claim 1 or 2, characterized in that: The overcurrent protection circuit also includes a current acquisition circuit, which is electrically connected between the first switch and the ground terminal and is also connected to the second input terminal. The current acquisition circuit is configured to provide a voltage to the second input terminal in response to changes in current flowing through the charging circuit.

4. The overcurrent protection circuit according to claim 3, characterized in that: The overcurrent protection circuit further includes a current limiting circuit electrically connected between the second input terminal and the charging circuit, and the current limiting circuit is configured to limit a current flowing into the second switch.

5. The overcurrent protection circuit according to claim 3, characterized in that: The first switch includes an NMOS tube, the gate of the NMOS tube serves as the first input end, the source of the NMOS tube is electrically connected to the current acquisition circuit and the negative electrode of the battery to be charged, and the drain of the NMOS tube is electrically connected between the charging management circuit and the positive electrode of the battery to be charged.

6. The overcurrent protection circuit according to claim 5, characterized in that: The current collection circuit includes a first resistor electrically connected between the source of the NMOS tube and a ground terminal, and the first resistor is also connected to the second input terminal.

7. The overcurrent protection circuit according to claim 4, characterized in that: The second switch includes an NPN transistor, the base of the NPN transistor serves as the second input terminal, the collector of the NPN transistor is electrically connected to the first input terminal, and the emitter of the NPN transistor is grounded.

8. The overcurrent protection circuit according to claim 7, characterized in that: The current limiting circuit includes a second resistor, and the second resistor is electrically connected between the base of the NPN transistor and the charging loop.

9. The overcurrent protection circuit according to claim 2, characterized in that: The voltage divider circuit includes a third resistor and a fourth resistor, the third resistor and the fourth resistor are connected in series and electrically connected between the charging interface and the ground terminal, and a connection node is set between the third resistor and the fourth resistor and is electrically connected to the first input terminal.

10. A battery module, characterized in that: It comprises the overcurrent protection circuit as described in any one of claims 1 to 9 and a battery to be charged electrically connected to the overcurrent protection circuit, wherein the overcurrent protection circuit is used to provide a charging voltage for the battery to be charged.

11. An aerosol generating device, characterized in that: Comprising the battery module as claimed in claim 10.

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