Over-current protection circuit and aerosol generating device

Abstract

The embodiment of the utility model discloses an overcurrent protection circuit and an aerosol generating device, and the overcurrent protection circuit comprises a load circuit which comprises a load and a switch branch; the load circuit is provided with a first output end for outputting a first voltage; the voltage comparator is provided with a first input end for receiving the first voltage, a second input end for receiving the reference voltage and a second output end electrically connected with the control end of the switch branch; the voltage comparator is configured to output an enable signal based on the comparison of the reference voltage and the first voltage when the load is over-current, so that the switch branch disconnects the connection between the load and the power supply; the reference voltage source is used for providing reference voltage for the first input end when the load is in an off state; wherein the voltage comparator is further configured to output an enable signal based on the comparison of the reference voltage and the reference voltage, so that the switch branch is maintained in an off state. By means of the mode, overcurrent protection of the load circuit is achieved, and the overcurrent protection is locked.

Description

[Technical field]

[0001] The embodiments of the present application relate to the field of hardware circuit technology, and in particular, to an overcurrent protection circuit and an aerosol generating device having the overcurrent protection circuit. [Background technology]

[0002] Currently, load overcurrent protection on the market mainly includes dedicated overcurrent protection chips or protection through software algorithms. However, dedicated integrated overcurrent protection chips are expensive and have a small overcurrent configuration range. Protection through software algorithms has a high degree of freedom, but the response is not timely enough, and once a program abnormality occurs, protection cannot be performed in time, and the reliability is poor. [Contents of the utility model]

[0003] The embodiments of the present application provide an overcurrent protection circuit and an aerosol generating device having the overcurrent protection circuit to solve the technical problems that the current overcurrent protection using dedicated integrated chips is costly or the overcurrent protection using software is less reliable.

[0004] An overcurrent protection circuit, comprising:

[0005] A load circuit, comprising a load and a switch branch, wherein the switch branch is used to conduct or disconnect the electrical connection between the load and a power source; the load circuit has a first output terminal, wherein the first output terminal is used to output a first voltage that varies in association with a voltage of the load;

[0006] a voltage comparator having a first input terminal, a second input terminal and a second output terminal, wherein the first input terminal is electrically connected to the first output terminal to receive the first voltage, the second input terminal is used to provide a reference voltage to the voltage comparator, and the second output terminal is electrically connected to the control terminal of the switch branch; the voltage comparator is configured to output an enable signal based on a comparison between the reference voltage and the first voltage when the load is overcurrent, so that the switch branch disconnects the load from a power source; and

[0007] a reference voltage source, configured to provide a reference voltage to the first input terminal when the load is in a disconnected state;

[0008] The voltage comparator is further configured to output an enable signal based on a comparison between the base voltage and the reference voltage, so that the switch branch maintains an open state.

[0009] In one embodiment, the reference voltage includes a first reference voltage and a second reference voltage. When the switch branch is turned on, the first reference voltage is input to the second input terminal; when the switch branch is turned off, the second reference voltage is input to the second input terminal; wherein the second reference voltage is less than the first reference voltage.

[0010] In one embodiment, the overcurrent protection circuit includes a feedback branch connected between the second output terminal and the second input terminal, the feedback circuit is used to provide a reference voltage to the second input terminal, and the feedback branch is configured to provide a first reference voltage when the switch branch is turned on, and to provide a second reference voltage when the switch branch is turned off.

[0011] In one embodiment, the load circuit further includes a current-sensing resistor connected in series with the load, and an amplifying branch for amplifying the voltage across the current-sensing resistor, and the amplifying branch is used to output the first voltage.

[0012] In one embodiment, the amplifying branch further has the reference voltage source, the first voltage is equal to the reference voltage plus a second voltage, and the second voltage is the voltage after the voltage across the current sensing resistor is amplified.

[0013] In one embodiment, the amplification branch includes a differential operational amplifier, a first input terminal of the differential operational amplifier is electrically connected to a first end of the current sensing resistor, a second input terminal of the differential operational amplifier is electrically connected to a second end of the current sensing resistor, and an output terminal of the differential operational amplifier is electrically connected to the first input terminal.

[0014] In one embodiment, the overcurrent protection circuit also includes an AND gate, wherein the first input terminal of the AND gate is electrically connected to the second output terminal, the second input terminal of the AND gate is electrically connected to the controller to receive a control signal sent by the controller, and the output terminal of the AND gate is electrically connected to the control terminal of the switch branch.

[0015] In one embodiment, the feedback branch includes a first resistor, a second resistor, a third resistor and a fourth resistor, wherein a first end of the first resistor is electrically connected to a power supply of the voltage comparator, and a second end is electrically connected to the second input terminal; a first end of the second resistor is electrically connected to a reference ground, and a second end is electrically connected to the second input terminal; a first end of the third resistor is electrically connected to the second input terminal, and a second end is electrically connected to the second output terminal of the voltage comparator; a first end of the fourth resistor is electrically connected to the power supply of the voltage comparator, and a second end is electrically connected to the second output terminal of the voltage comparator.

[0016] In one embodiment, the overcurrent protection circuit also includes a sixth resistor, a first end of the sixth resistor is electrically connected to the first output end, a second end is electrically connected to the first input end, and a resistance value of the sixth resistor is greater than a resistance value of the first resistor, the second resistor and the third resistor connected in parallel.

[0017] In one embodiment, the switch branch includes a first switch element and a second switch element, the control end of the first switch element is electrically connected to the second output end, the output end of the first switch element is electrically connected to the control end of the second switch element, the input end of the second switch element is electrically connected to the power supply of the load circuit, and the output end of the second switch element is electrically connected to the load in the load circuit, so that the second switch element responds synchronously to the switching state of the first switch element.

[0018] In one embodiment, the first switch element includes an NMOS tube, the second switch element includes a PMOS tube, the gate of the NMOS tube is electrically connected to the second output end, the drain of the NMOS tube is electrically connected to the gate of the PMOS tube, and the source of the NMOS tube is electrically connected to a reference ground; the source of the PMOS tube is electrically connected to a power supply of the load circuit, the drain of the PMOS tube is electrically connected to the load, and a pull-up resistor is connected between the gate of the PMOS tube and the power supply.

[0019] In one embodiment, the overcurrent protection circuit also includes a reset circuit for re-opening the load circuit, the reset circuit includes a third switch element, the control end of the third switch element is electrically connected to the controller to receive a control signal sent by the controller, the input end of the third switch element is electrically connected to the power supply of the overcurrent protection circuit, and the output end of the third switch element is electrically connected to the power supply of the AND gate.

[0020] In one embodiment, the load circuit further includes a fifth resistor, a first end of the fifth resistor being electrically connected to a control end of the switch branch and an output end of the AND gate, respectively, a second end of the fifth resistor being electrically connected to a reference ground, and the fifth resistor being configured to cause the switch branch to be synchronously turned off when the third switch element is turned off.

[0021] The present application also provides an aerosol generating device, including:

[0022] A heating element for heating the aerosol product to generate an aerosol;

[0023] The overcurrent protection circuit described in the above embodiment;

[0024] Wherein, the heating element serves as a load in the overcurrent protection circuit.

[0025] The overcurrent protection circuit provided in the above embodiment, by setting a voltage comparator and a switch branch, when the load circuit is overcurrent, the first voltage of the first input terminal of the input voltage comparator is greater than the reference voltage of the second input terminal, and the voltage comparator outputs an enable signal to disconnect the switch branch, thereby disconnecting the electrical connection between the load and the power supply, thereby achieving overcurrent protection. In addition, by setting a reference voltage, after overcurrent protection, the voltage comparator continues to output the enable signal based on the reference voltage and the reference voltage, so that the switch branch is maintained in a disconnected state, thereby achieving the locking of the overcurrent protection. In the above manner, there is no need to use a dedicated integrated chip for overcurrent protection, which can reduce costs. In addition, the overcurrent protection is implemented by a pure hardware circuit, which is more reliable than the method of implementing overcurrent protection by software.

Brief Description of the Drawings

[0026] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0027] Figure 1 A schematic diagram of the structure of an overcurrent protection circuit provided in one embodiment of the present application;

[0028] Figure 2 A schematic diagram of the structure of an overcurrent protection circuit provided in another embodiment of the present application;

[0029] Figure 3 A schematic diagram of the structure of an overcurrent protection circuit provided in another embodiment of the present application;

[0030] Figure 4 A schematic diagram of the structure of an overcurrent protection circuit provided in another embodiment of the present application;

[0031] Figure 5 A schematic diagram of the structure of an overcurrent protection circuit provided in another embodiment of the present application;

[0032] Figure 6 A schematic diagram of the structure of an overcurrent protection circuit provided in another embodiment of the present application;

[0033] Figure 7 A schematic diagram of the structure of a reset circuit in an overcurrent protection circuit provided in an embodiment of the present application. [Specific implementation method]

[0034] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" / "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "left", "right", "inside", "outside" and similar expressions used in this specification are for illustrative purposes only.

[0035] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0036] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0037] In the embodiments of the present application, the "installation" includes fixing or restricting a component or device to a specific position or place by welding, screwing, clamping, bonding, etc. The component or device can remain stationary at the specific position or place or move within a limited range. After the component or device is fixed or restricted to a specific position or place, it may or may not be disassembled, and there is no limitation in the embodiments of the present application.

[0038] In addition, the terms "first" and "second" 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] An embodiment of the present application provides an overcurrent protection circuit 100, such as Figure 1As shown, the overcurrent protection circuit 100 includes a load circuit 10 and a voltage comparator 20. The load circuit 10 includes a switch branch 11 and a load 12. The switch branch 11 has a control terminal 111, an input terminal 112, and an output terminal 113. The input terminal 112 is electrically connected to the power supply Vout of the load circuit 10, and the output terminal 113 is electrically connected to the load 12. Therefore, when the switch branch 11 is turned on, the power supply Vout can provide electric energy to the load 12 through the switch branch 11, so that the load 12 starts to work; when the switch branch 11 is turned off or disconnected, the load circuit 10 is disconnected, the power supply Vout cannot provide electric energy to the load 12, and the load 12 stops working.

[0040] The load circuit 10 also includes a first output terminal 114, which is used to output a first voltage that varies in association with the voltage of the load 12. For example, when the load 12 operates normally, the first voltage output by the first output terminal 114 is relatively small; and when the load 12 is in an overcurrent state, the first voltage output by the first output terminal 114 is relatively large.

[0041] The voltage comparator 20 has a first input terminal 21, a second input terminal 22 and a second output terminal 23. The first input terminal 21 is electrically connected to the first output terminal 114 to receive the first voltage from the load circuit 10. The second output terminal 23 is electrically connected to the control terminal 111 of the switch branch 11 to control the switch branch 11 to be turned on or off. The second input terminal 22 is used to receive a reference voltage. The overcurrent protection circuit also includes a reference voltage source 50. The reference voltage source 50 is used to provide a reference voltage to the first input terminal 21 when the switch branch 11 is in an off state, and when the switch branch 11 is in an on state, the overcurrent protection circuit 100 provides the first voltage to the first input terminal 21.

[0042] Furthermore, when the load 12 is in an overcurrent state, the first voltage output to the first input terminal 21 increases, the voltage comparator 20 compares the first voltage of the first input terminal 21 with the reference voltage of the second input terminal 22, and outputs an enable signal according to the comparison result. The enable signal is applied to the control terminal 111 of the switch branch 11 and causes the switch branch 11 to change from an on state to an off state, so as to disconnect the electrical connection between the power supply Vout and the load 12, thereby realizing overcurrent protection of the load 12.

[0043] Since the load 12 is in a disconnected state after the overcurrent protection, the voltage input to the first input terminal 21 becomes zero at this time, and the enable signal output by the voltage comparator 20 will change so that the switch branch 11 will be immediately turned back on. In order to prevent the switch branch 11 from being immediately turned back on after the overcurrent protection, after the overcurrent protection, that is, after the switch branch 11 is disconnected, a reference voltage is input to the first input terminal 21 of the voltage comparator 20 through the reference voltage source 50. Under the action of the reference voltage, the voltage comparator 20, based on the reference voltage and the reference voltage of the second input terminal 22, causes the second output terminal 23 to continue to output the original enable signal, so that the switch branch 11 continues to be maintained in the disconnected state, thereby locking the overcurrent protection state.

[0044] The overcurrent protection circuit 100 provided in this embodiment realizes overcurrent protection through discrete electronic components, and does not need to use a dedicated integrated chip for overcurrent protection, which can reduce costs. In addition, since the overcurrent protection circuit 100 provided in this embodiment realizes overcurrent protection through a pure hardware circuit, it is more reliable than the method of realizing overcurrent protection by software. In addition, the overcurrent protection circuit 100 provided in this embodiment can also lock the overcurrent protection state to prevent the load circuit 10 from being immediately turned on again after the overcurrent protection.

[0045] As a specific implementation method, Figure 1 As shown, the first input terminal 21 of the voltage comparator 20 is an inverting input terminal, and the second input terminal 22 is a non-inverting input terminal. When the load circuit 10 works normally, the first voltage input to the first input terminal 21 is small, and the first voltage is less than the reference voltage at this time. The voltage comparator 20 controls the second output terminal 23 to output a high-level enable signal according to the comparison result of the first voltage and the reference voltage, and the high-level signal acts on the control terminal 111 of the switch branch 11 to turn on the switch branch 11.

[0046] When the load circuit 10 is overcurrent, the first voltage input to the first input unit 21 increases. When the first voltage is greater than the reference voltage, the voltage comparator 20 controls the second output terminal 23 to output a low-level enable signal according to the comparison result of the first voltage and the reference voltage. The low level acts on the control terminal 111 of the switch branch 11 to disconnect the switch branch 11, thereby disconnecting the load 12 and the power supply Vout. In some other embodiments, the first voltage can be received at the non-inverting input terminal of the voltage comparator 20, and the reference voltage can be received at the inverting input terminal.

[0047] In some embodiments, in order to facilitate timely locking of the overcurrent protection state after the overcurrent protection, the reference voltage includes a first reference voltage and a second reference voltage, the second reference voltage is less than the first reference voltage, and when the switch branch 11 is turned on, the first reference voltage is input to the first input terminal 21, and when the switch branch 11 is turned off, the second reference voltage is input to the first input terminal 21.

[0048] Thus, when the load circuit 10 generates an overcurrent, the first voltage of the first input terminal 21 will be greater than the first reference voltage of the second input terminal 22, and the voltage comparator 20 outputs a low-level enable signal to disconnect the switch branch 11, thereby achieving overcurrent protection. After the switch branch 11 is disconnected, the reference voltage input to the second input terminal 22 changes from the first reference voltage to the second reference voltage. At the same time, the reference voltage input to the first input terminal 21 is the above-mentioned reference voltage, and the reference voltage is greater than the second reference voltage, thereby causing the second output terminal 23 of the voltage comparator 20 to continue to output a low level, and the overcurrent protection state can be locked in time.

[0049] Further in some implementations, such as Figure 2 As shown, the voltage comparator 20 also includes a feedback branch 24 connected between the second output terminal 23 and the second input terminal 22. The feedback branch 24 is configured to provide a first reference voltage when the switch branch 11 is turned on, and to provide a second reference voltage when the switch branch 12 is turned off. The feedback branch 24 can adjust the reference voltage output to the second input terminal 22 according to the enable signal of the second output terminal 23.

[0050] For example, when the switch branch 11 is in the on state, the voltage comparator 20 outputs a high-level enable signal, which acts on the feedback branch 24, so that the feedback branch 24 provides the first reference voltage to the first input terminal 21. When the load circuit 10 generates an overcurrent so that the first voltage increases and is greater than the first reference voltage, the voltage comparator 20 outputs a low-level enable signal, which acts on the feedback branch 24, so that the feedback branch 24 provides the second reference voltage to the first input terminal 21.

[0051] Specifically, Figure 5 or Figure 6As shown, the feedback branch 24 includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4. The first end of the first resistor R1 is electrically connected to the power supply VDD of the voltage comparator 20, and the second end is electrically connected to the second input terminal 22 of the voltage comparator 20; the first end of the second resistor R2 is electrically connected to the reference ground, and the second end is electrically connected to the second input terminal 22 of the voltage comparator 20; the first end of the third resistor R3 is electrically connected to the second input terminal 22 of the voltage comparator 20, and the second end is electrically connected to the second output terminal 23 of the voltage comparator 20; the first end of the fourth resistor R4 is electrically connected to the second output terminal 23 of the voltage comparator 20, and the second end is electrically connected to the power supply VDD of the voltage comparator 20.

[0052] When the load 12 is operating normally, the first voltage applied by the load circuit 10 to the first input terminal 21 of the voltage comparator 20 is less than the first reference voltage received by the second input terminal 22 of the voltage comparator 20, and the output terminal of the voltage comparator 20 outputs a high impedance state. The voltage comparator 20 outputs a high level through the pull-up effect of the fourth resistor R4. At this time, the reference voltage input to the second input terminal 22 is equal to VDD*R2 / [(R3+R4)||R1+R2], and the reference voltage is the first reference voltage; wherein, (R3+R4)||R1 indicates that the third resistor R3 and the fourth resistor R4 are connected in series and then in parallel with the first resistor R1.

[0053] When the load 12 generates an overcurrent, the first voltage applied by the load circuit 10 to the first input terminal 21 of the voltage comparator 20 is greater than the first reference voltage received by the second input terminal 22 of the voltage comparator 20, and the output terminal of the voltage comparator 20 outputs a low level. One end of the fourth resistor R4 is pulled down to ground. At this time, the reference voltage input to the second input terminal 22 becomes VDD*R2||R3 / (R1+R2||R3), and the reference voltage is the second reference voltage; wherein, R2||R3 indicates that the second resistor R2 and the third resistor R3 are connected in parallel, and then the second reference voltage can be made smaller than the first reference voltage by configuring the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4.

[0054] And, in some embodiments, the first reference voltage and the second reference voltage are input to the first input terminal 21 through the controller, and do not need to be provided through the feedback branch 24. When the load 12 works normally, that is, when the switch branch 11 is in the on state, the controller controls the first reference voltage to be provided to the first input terminal 21. When the load 12 is in an overcurrent state, so that the switch branch 11 is in the off state, the controller controls the second reference voltage to be provided to the first input terminal 21.

[0055] In some embodiments, Figure 3As shown, the load circuit 10 includes a current sensing resistor 13 and an amplifying branch 14 for outputting a first voltage. The current sensing resistor 13 and the load 12 are connected in series, so that the currents flowing through the current sensing resistor 13 and the load 12 are equal. The amplifying circuit 14 is used to amplify the voltage across the current sensing resistor 13 so as to amplify the current signal flowing through the current sensing resistor 13 and convert it into a voltage signal. At the same time, the amplifying branch 14 has a reference voltage, which is used to provide a stable operating point for the amplifying branch 14 to avoid signal distortion.

[0056] When the load 12 works normally, the first voltage output by the amplifier branch 14 is the sum of the voltage across the current-sensing resistor 13 after being amplified and the reference voltage. When an overcurrent is generated on the load 12, the overcurrent protection disconnects the electrical connection between the load 12 and the power supply Vout, and the current flowing through the current-sensing resistor 13 is zero. At this time, the voltage across the current-sensing resistor 13 is also zero. The voltage output by the amplifier branch 14 to the first input terminal 21 is the above-mentioned reference voltage, which is configured to be greater than the second reference voltage. The voltage comparator 20 will continue to output a low level to lock the load circuit 10 in the overcurrent protection state.

[0057] Further in some embodiments, Figure 5 or Figure 6 As shown, the amplification branch 14 is implemented by a differential operational amplifier. The first input terminal 141 of the differential operational amplifier 14 is electrically connected to the first end of the current sensing resistor 13, the second input terminal 142 is electrically connected to the second end of the current sensing resistor 13, and the output terminal 143 is electrically connected to the first input terminal 21 of the voltage comparator 20. The differential operational amplifier 14 also has a REF pin, and a reference voltage Vref is input to the REF pin. The differential operational amplifier 14 is configured to amplify the voltage across the current sensing resistor 13, and output the amplified value superimposed on the reference voltage Vref from the output terminal 143 to the first input terminal 21 of the voltage comparator 20.

[0058] It should be noted that, in some embodiments, the reference voltage may also be provided separately, and does not need to be provided by the reference voltage in the amplifying branch 14. For example, it may be provided by a separate voltage zener diode or a resistor voltage divider circuit. In this case, the amplifying branch 14 only needs to amplify the voltage across the current sensing resistor 13 and provide it as the first voltage to the first input terminal 21 of the voltage comparator 20.

[0059] In some embodiments, to facilitate control of the load 12, such as Figure 4As shown, the switch branch 11 includes a first switch element 11a and a second switch element 11b, the control end 111a of the first switch element 11a is electrically connected to the second output end 23 of the voltage comparator 20, the output end 112a of the first switch element 11a is electrically connected to the control end 111b of the second switch 11b, the input end 112b of the second switch element 11b is electrically connected to the power supply Vout of the load circuit 10, and the output end 113b of the second switch element 11b is electrically connected to the load 12.

[0060] The first switch element 11a and the second switch element 11b are configured such that, when the first switch element 11a is turned on, the first switch element 11a outputs a first level applied to the control end 111b of the second switch element 11b to control the second switch element 11b to be turned on synchronously, so that the power supply Vout of the load circuit 10 can provide electrical energy to the load 12 through the second switch element 11b; when the first switch element 11a is turned off, the first switch element 11a outputs a second level applied to the control end 111b of the second switch element 11b to control the second switch element 11b to be turned off synchronously, so that the load circuit 10 is disconnected, and the power supply Vout of the load circuit 10 cannot provide electrical energy to the load 12.

[0061] Specifically, Figure 5 As shown, the first switch element 11a includes an NMOS tube, and the second switch element 11b includes a PMOS tube. The G pole (gate) of the NMOS tube 11a is electrically connected to the second output terminal 23 of the voltage comparator 20, the S pole (source) of the NMOS tube 11a is electrically connected to the reference ground, and the D pole (drain) of the NMOS tube 11a is electrically connected to the G pole of the PMOS tube; the S pole of the PMOS tube 11b is electrically connected to the power supply Vout of the load circuit 10, the D pole of the PMOS tube 11b is electrically connected to the current detection resistor 13 and the load 12, and the G pole of the PMOS tube 11b is electrically connected to the power supply Vout of the load circuit 10 through the pull-up resistor R8.

[0062] When the load 12 works normally, the first voltage applied by the load circuit 10 to the first input terminal 21 of the voltage comparator 20 is less than the first reference voltage received by the second input terminal 22 of the voltage comparator 20, and the second output terminal 23 of the voltage comparator 20 outputs a high level, which is applied to the G pole of the NMOS tube 11a, so that the NMOS tube 11a is turned on. Since the S pole of the NMOS tube 11a is grounded, the D pole of the NMOS tube outputs a low level, which is applied to the G pole of the PMOS tube 11b, thereby causing the PMOS tube 11b to be turned on synchronously, and the power supply Vout of the load circuit 10 can provide electrical energy to the load 12 through the PMOS tube.

[0063] When the load 12 generates an overcurrent, the first voltage applied by the load circuit 10 to the first input terminal 21 of the voltage comparator 20 is greater than the first reference voltage received by the second input terminal 22 of the voltage comparator 20, and the second output terminal 23 of the voltage comparator 20 outputs a low level, which is applied to the G pole of the NMOS tube 11a, so that the NMOS tube 11a is cut off, so that the G pole of the PMOS tube 11b is at a high level under the action of the pull-up resistor R8, and then the PMOS tube 11b is synchronously cut off, the load circuit 10 is disconnected, and the power supply Vout of the load circuit 10 cannot provide power to the load 12, thereby achieving overcurrent protection for the load 12.

[0064] In some embodiments, the overcurrent protection circuit 100 further includes an AND gate, such as Figure 6 As shown, the AND gate has a first input terminal 31, a second input terminal 32, and an output terminal 33. The first input terminal 31 is electrically connected to the second output terminal 23 of the voltage comparator 20, and the second input terminal 32 is electrically connected to the controller of the electronic device having the overcurrent protection circuit 100, and is used to receive a control signal sent by the controller. The control signal can be a PWM signal, etc., and the output terminal 33 is electrically connected to the G pole of the NMOS tube 11a.

[0065] According to the characteristics of the AND gate, when any one of the first input terminal 31 and the second input terminal 32 of the AND gate is at a low level, the output terminal of the AND gate outputs a low level. Only when the first input terminal 31 and the second input terminal 32 are both at a high level, the output terminal 33 of the AND gate outputs a high level.

[0066] Furthermore, when the load 12 is normal, according to the above content, the voltage comparator 20 outputs a high level, which is applied to the first input terminal 31 of the AND gate, so that the output of the AND gate is determined by the level of the second input terminal 32, that is, determined by the control signal output by the controller. When the control signal is a high level, the level output by the output terminal of the AND gate is also a high level, which is applied to the G pole of the NMOS tube 11a to turn on the NMOS tube 11a, thereby turning on the PMOS tube 11b synchronously, and then turning on the load circuit 10, and the power supply Vout of the load circuit 10 can provide power to the load 12.

[0067] When the control signal is at a low level, the level output by the AND gate output terminal 33 is also at a low level. The low level is applied to the G pole of the NMOS tube 11a to turn off the NMOS tube 11a, thereby turning off the PMOS tube 11b synchronously, and then disconnecting the load circuit 10. The power supply Vout of the load circuit 10 cannot provide electrical energy to the load 12.

[0068] By setting an AND gate, when the load 12 is normal, the control signal output by the controller can be used to control the on or off of the load circuit 10, so as to control the load 12 to start or stop working according to a preset software program.

[0069] For example, the overcurrent protection circuit 100 can be used in an aerosol generating device, in which case the load 12 is a heating element in the aerosol generating device, and the heating element is used to heat the aerosol generating product of the aerosol generating device to generate an aerosol that can be inhaled by the user, so as to replace the traditional tobacco product that burns tobacco to generate smoke. The aerosol generating product can be an atomizable liquid or a solid tobacco product. When the aerosol generating product is an atomizable liquid, the liquid can flow along the internal liquid channel of the aerosol generating device to the heating element, and the heating element heats and atomizes the liquid to generate an aerosol, and the user can inhale the aerosol through the air outlet of the aerosol generating device.

[0070] When the aerosol generating product is a solid tobacco product, the aerosol generating device is usually provided with a chamber for accommodating the tobacco product. The heating element can heat the tobacco product contained in the chamber, and the solid matrix such as tobacco or non-tobacco in the tobacco product volatilizes due to the heat to generate aerosol, and the user can inhale the aerosol on the tobacco product.

[0071] Regardless of whether it is a liquid aerosol generating product or a solid aerosol generating product, the heating element needs to work according to a preset heating curve during the heating process in order to produce an aerosol with a better taste. Therefore, the second input terminal 32 of the AND gate can be electrically connected to the controller of the aerosol generating device, and the controller can input a control signal such as PWM to the second input terminal 32, and then turn on or off the load circuit 10 according to the level of the PWM signal, so that the heating element can be heated according to the preset heating curve.

[0072] In some embodiments, Figure 7 As shown, the overcurrent protection circuit 100 also includes a reset circuit, which is used to release the locked state of the overcurrent protection circuit 100 so that the overcurrent protection circuit 100 is no longer in the overcurrent protection state, that is, to make the load circuit 10 turn on again. The reset circuit includes a third switch element 41, the control end of the third switch element is electrically connected to the controller, and is used to receive a control signal sent by the controller; the input end of the third switch element 41 is electrically connected to the power supply VCC of the overcurrent protection circuit 100, and the output end of the third switch element 41 is electrically connected to the power supply end of the voltage comparator 20 and the AND gate respectively, so as to serve as the input power supply of the voltage comparator 20 and the AND gate.

[0073] When it is necessary to release the locked state of the overcurrent protection circuit 100, the control signal first controls the third switch element 41 to be in the off state, and then controls the third switch element 41 to be in the on state, so that the overcurrent protection circuit 100 can be restored to the initial state, thereby releasing the locked state of the overcurrent protection circuit 100.

[0074] Specifically, Figure 7 As shown, the third switch element 41 is a PMOS tube, the G pole of the PMOS tube 41 is electrically connected to the control signal of the controller, the S pole of the PMOS tube 41 is electrically connected to the power supply VCC of the overcurrent protection circuit 100, and the D pole of the PMOS tube 41 is electrically connected to the power supply VDD, which is the input power supply of the voltage comparator 20 and the AND gate. In addition, in order to prevent the controller pin that sends the control signal from being suspended, the reset circuit 40 also includes a pull-up resistor R9, one end of the pull-up resistor R9 is electrically connected to VCC, and the other end is electrically connected to the G pole of the PMOS tube 41.

[0075] When the locking state of the overcurrent protection circuit 100 needs to be released, the controller controls the output high level to be applied to the G pole of the PMOS tube 41, so that the PMOS tube is turned off, and then the controller controls the output low level to be applied to the G pole of the PMOS tube 41, so that the PMOS tube is turned on again, thereby restoring the overcurrent protection circuit 100 to the initial state. At the same time, by setting the pull-up resistor R9, when the controller pin outputting the control signal is suspended, the G pole voltage on the PMOS tube is pulled up to a high level under the action of the pull-up resistor R9, so that the PMOS tube 41 is turned off.

[0076] Further in some embodiments, Figure 6 As shown, the load circuit 10 further includes a fifth resistor R5, a first end of which is electrically connected to the G pole of the NMOS tube 11a and the output end 33 of the AND gate, respectively, and a second end of which is electrically connected to the reference ground. Further, when the controller fails, that is, the software runs abnormally, the third switch element 41 is always turned off, and the output VDD of the third switch element 41 is zero, which further causes the input power supply of the AND gate to be zero, and the AND gate stops working, and the NMOS tube 11a cannot be turned on or off according to the output end level of the AND gate, and the overcurrent protection of the load 12 cannot be achieved.

[0077] By setting the fifth resistor R5, when the input power supply of the AND gate is zero, the output end of the AND gate is in a high impedance state, and the G pole of the NMOS tube 11a generates a low level under the pull-down effect of the fifth resistor R5, thereby turning off the NMOS tube 11a, and then the PMOS tube 11b is turned off synchronously, and the load circuit 10 is disconnected.

[0078] In this way, when an abnormality occurs in the software program in the controller, the NMOS tube 11 a can also be turned off under the pull-down effect of the fifth resistor R5 , thereby disconnecting the load circuit 10 and realizing overcurrent protection for the load 12 .

[0079] In some embodiments, Figure 5 or Figure 6 As shown, the overcurrent protection circuit 100 also includes a sixth resistor R6, one end of the sixth resistor R6 is electrically connected to the output end of the load circuit 10 to receive the first voltage output by the load circuit 10, the second end of the sixth resistor R6 is electrically connected to the first input end 21 of the voltage comparator 20, and the resistance of the sixth resistor R6 is greater than the resistance of the first resistor R1, the second resistor R2 and the third resistor R3 after being connected in parallel.

[0080] There are parasitic capacitors in both the first input terminal 21 and the second input terminal 22 of the voltage comparator 20. Therefore, when the overcurrent protection circuit 100 is reset, since the resistance of the sixth resistor R6 is greater than the resistance of the first resistor R1, the second resistor R2 and the third resistor R3 in parallel, the charging speed of the first input terminal 21 is slower than the charging speed of the second input terminal 22, that is, the voltage on the first input terminal 21 is lower than the voltage on the second input terminal 22, so that the output terminal of the voltage comparator 20 can output a high level, ensuring that the overcurrent protection circuit 100 can successfully release the locked state of the overcurrent protection.

[0081] It should be noted that, in some embodiments, each switch element can be configured as at least one of a relay, a triode or a metal oxide semi-conductor field effect transistor. Of course, in other embodiments, each switch can also be configured as any other controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0082] 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 described 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: A load circuit, comprising a load and a switch branch, wherein the switch branch is used to switch on or off the electrical connection between the load and a power source; The load circuit has a first output terminal, and the first output terminal is used to output a first voltage that varies in association with the voltage of the load; a voltage comparator having a first input terminal, a second input terminal and a second output terminal, wherein the first input terminal is electrically connected to the first output terminal to receive the first voltage, the second input terminal is used to provide a reference voltage to the voltage comparator, and the second output terminal is electrically connected to the control terminal of the switch branch; The voltage comparator is configured to output an enable signal based on a comparison between the reference voltage and the first voltage when the load is overcurrented, so that the switch branch disconnects the load from the power supply; as well as a reference voltage source, configured to provide a reference voltage to the first input terminal when the load is in a disconnected state; The voltage comparator is further configured to output an enable signal based on a comparison between the base voltage and the reference voltage, so that the switch branch maintains an open state.

2. The overcurrent protection circuit according to claim 1, characterized in that: The reference voltage includes a first reference voltage and a second reference voltage. When the switch branch is turned on, the first reference voltage is input to the second input terminal; when the switch branch is turned off, the second reference voltage is input to the second input terminal; wherein the second reference voltage is less than the first reference voltage.

3. The overcurrent protection circuit according to claim 2, characterized in that: The overcurrent protection circuit includes a feedback branch connected between the second output terminal and the second input terminal, the feedback branch is used to provide a reference voltage to the second input terminal, and the feedback branch is configured to provide a first reference voltage when the switch branch is turned on, and to provide a second reference voltage when the switch branch is turned off.

4. The overcurrent protection circuit according to claim 1, characterized in that: The load circuit also includes a current-sensing resistor connected in series with the load, and an amplifying branch for amplifying the voltage across the current-sensing resistor, wherein the amplifying branch is used to output the first voltage.

5. The overcurrent protection circuit according to claim 4, characterized in that: The amplifying branch also has the reference voltage source, and the first voltage is equal to the reference voltage plus the second voltage; wherein the second voltage is the voltage after the voltage across the current sensing resistor is amplified.

6. The overcurrent protection circuit according to claim 4, characterized in that: The amplification branch includes a differential operational amplifier, a first input terminal of the differential operational amplifier is electrically connected to a first end of the current sensing resistor, a second input terminal of the differential operational amplifier is electrically connected to a second end of the current sensing resistor, and an output terminal of the differential operational amplifier is electrically connected to the first input terminal.

7. The overcurrent protection circuit according to claim 1, characterized in that: The overcurrent protection circuit also includes an AND gate, a first input end of the AND gate is electrically connected to the second output end, a second input end of the AND gate is electrically connected to a controller to receive a control signal sent by the controller, and an output end of the AND gate is electrically connected to the control end of the switch branch.

8. The overcurrent protection circuit according to claim 3, characterized in that: The feedback branch includes a first resistor, a second resistor, a third resistor and a fourth resistor, wherein a first end of the first resistor is electrically connected to a power supply of the voltage comparator, and a second end is electrically connected to the second input terminal; a first end of the second resistor is electrically connected to a reference ground, and a second end is electrically connected to the second input terminal; a first end of the third resistor is electrically connected to the second input terminal, and a second end is electrically connected to the second output terminal of the voltage comparator; a first end of the fourth resistor is electrically connected to the power supply of the voltage comparator, and a second end is electrically connected to the second output terminal of the voltage comparator.

9. The overcurrent protection circuit according to claim 8, characterized in that: The overcurrent protection circuit also includes a sixth resistor, a first end of the sixth resistor is electrically connected to the first output end, a second end is electrically connected to the first input end, and a resistance value of the sixth resistor is greater than a resistance value of the first resistor, the second resistor and the third resistor connected in parallel.

10. The overcurrent protection circuit according to claim 1, characterized in that: The switch branch includes a first switch element and a second switch element, the control end of the first switch element is electrically connected to the second output end, the output end of the first switch element is electrically connected to the control end of the second switch element, the input end of the second switch element is electrically connected to the power supply of the load circuit, and the output end of the second switch element is electrically connected to the load in the load circuit, so that the second switch element responds synchronously to the switching state of the first switch element.

11. The overcurrent protection circuit according to claim 10, characterized in that: The first switch element includes an NMOS tube, and the second switch element includes a PMOS tube. The gate of the NMOS tube is electrically connected to the second output end, the drain of the NMOS tube is electrically connected to the gate of the PMOS tube, and the source of the NMOS tube is electrically connected to a reference ground; the source of the PMOS tube is electrically connected to a power supply of the load circuit, the drain of the PMOS tube is electrically connected to the load, and a pull-up resistor is connected between the gate of the PMOS tube and the power supply.

12. The overcurrent protection circuit according to claim 7, characterized in that: The overcurrent protection circuit also includes a reset circuit for re-opening the load circuit, the reset circuit includes a third switch element, the control end of the third switch element is electrically connected to the controller to receive a control signal sent by the controller, the input end of the third switch element is electrically connected to the power supply of the overcurrent protection circuit, and the output end of the third switch element is electrically connected to the power supply of the AND gate.

13. The overcurrent protection circuit according to claim 12, characterized in that: The load circuit also includes a fifth resistor, a first end of the fifth resistor is electrically connected to the control end of the switch branch and the output end of the AND gate respectively, a second end of the fifth resistor is electrically connected to the reference ground, and the fifth resistor is configured to cause the switch branch to be synchronously turned off when the third switch element is turned off.

14. An aerosol generating device, characterized in that: include: A heating element for heating the aerosol product to generate an aerosol; The overcurrent protection circuit according to any one of claims 1 to 13; Wherein, the heating element serves as a load in the overcurrent protection circuit.

Images