Charging control circuit for electronic cigarette and electronic cigarette

Abstract

The utility model discloses a charging control circuit for an electronic cigarette and the electronic cigarette, and the charging control circuit comprises an airflow induction module which is used for outputting a first electric signal when a user smokes; the charging module is used for charging a battery in the electronic cigarette, and is also used for receiving the first electric signal and stopping charging the battery in the electronic cigarette when receiving the first electric signal, and the charging module is connected with the airflow sensing module. According to the technical scheme, when a user smokes, the airflow sensing module can output the first electric signal, the charging module receives the first electric signal and stops charging the battery after receiving the first electric signal, the battery is protected, and therefore pins of the control chip do not need to be occupied when the battery is protected by smoking, and the user experience is improved. Therefore, the control chip can adopt a chip with a small number of pins, so that the cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of electronic cigarette technology, and in particular to a charging control circuit for electronic cigarettes and an electronic cigarette. Background Technology

[0002] To protect the battery in e-cigarettes, the charging module in e-cigarettes on the market needs to be turned off when smoking, so as to stop charging the battery and protect it during smoking.

[0003] Currently, the common solution for controlling the charging module to shut down during smoking involves connecting the control chip in the e-cigarette to the airflow sensor module and the charging module. When the user smokes, the airflow sensor module outputs a sensing signal to the control chip. Upon receiving the sensing signal, the control chip outputs a control signal to the charging module, causing it to shut down, thus protecting the battery during smoking. While this method effectively protects the battery during smoking, both the charging module and the airflow sensor module require one pin on the control chip. Therefore, when the control chip's pins are insufficient, it needs to be replaced with a control chip that has more pins, increasing costs.

[0004] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a charging control circuit for electronic cigarettes and an electronic cigarette, so as to solve the problem in the prior art that when protecting the battery during smoking, if the control chip has not enough pins, it is necessary to replace it with a control chip with more pins, which leads to increased costs.

[0006] This utility model provides a charging control circuit for electronic cigarettes, the charging control circuit comprising:

[0007] An airflow sensing module is used to output a first electrical signal when a user smokes;

[0008] The charging module is used to charge the battery in the electronic cigarette and to receive the first electrical signal and stop charging the battery in the electronic cigarette when the first electrical signal is received. The charging module is connected to the airflow sensing module.

[0009] In a further embodiment of this invention, the first electrical signal is either a high-level signal or a low-level signal.

[0010] In a further embodiment of this invention, the airflow sensing module includes: a three-needle microphone, a first resistor, and a second resistor;

[0011] The first pin of the three-pin microphone is connected to one end of the first resistor, the other end of the first resistor is connected to the power supply, the second pin of the three-pin microphone is grounded, the third pin of the three-pin microphone is connected to the charging module, one end of the second resistor is connected to the third pin of the three-pin microphone, and the other end of the second resistor is grounded.

[0012] In a further embodiment of this invention, the charging module includes: a first interface unit, a first filter unit, a second filter unit, a first chip, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor for connecting to the charging source;

[0013] The first interface unit and the first filter unit are connected to pin 4 of the first chip;

[0014] The first chip has its first pin grounded, its second pin connected to one end of the third resistor, the other end of the third resistor grounded, its third pin grounded, its fifth pin connected to the positive terminal of the battery and the second filter unit, its sixth pin connected to one end of the fourth resistor, the other end of the fourth resistor connected to one end of the fifth resistor, the other end of the fifth resistor connected to the battery, its seventh pin connected to one end of the sixth resistor, the other end of the sixth resistor connected to the other end of the fourth resistor, and its eighth pin connected to the airflow sensing module.

[0015] In a further embodiment of this invention, the first interface unit includes: a first interface, a seventh resistor, and an eighth resistor;

[0016] Pins A1, A12, B1, and B12 of the first interface are all grounded. Pins A4, A9, B4, and B9 of the first interface are connected. Pin A4 of the first interface is also connected to pin 4 of the first chip. Pin A5 of the first interface is connected to one end of the seventh resistor, and the other end of the seventh resistor is grounded. Pin B5 of the first interface is connected to one end of the eighth resistor, and the other end of the eighth resistor is grounded.

[0017] In a further embodiment of this invention, the first filtering unit includes a ninth resistor and a first capacitor. One end of the ninth resistor is connected to pin A4 of the first interface, and the other end of the ninth resistor is connected to one end of the first capacitor. The other end of the first capacitor is grounded.

[0018] In a further embodiment of this invention, the second filtering unit includes a second capacitor, one end of which is connected to pin 5 of the first chip, and the other end of which is grounded.

[0019] In a further embodiment of this invention, the battery is a lithium battery.

[0020] This utility model also provides an electronic cigarette that uses the charging control circuit for electronic cigarettes as described above, the electronic cigarette comprising:

[0021] Atomizer module;

[0022] A control module is connected to the atomizer module and the airflow sensing module. The control module is used to receive the first electrical signal and start the atomizer module according to the first electrical signal.

[0023] In a further embodiment of this invention, the atomizer module includes: a first switching tube, a second switching tube, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first heating wire, and a second heating wire;

[0024] The source of the first switching transistor is connected to the battery; one end of the ninth resistor is connected to the source of the first switching transistor, and the other end of the ninth resistor is connected to the gate of the first switching transistor; one end of the tenth resistor is connected to the gate of the first switching transistor, and the other end of the tenth resistor is connected to the control module; the drain of the first switching transistor is connected to one end of the first heating wire, and the other end of the first heating wire is grounded; one end of the eleventh resistor is connected to the drain of the first switching transistor, and the other end of the eleventh resistor is connected to the control module.

[0025] The source of the second switching transistor is connected to the battery. One end of the twelfth resistor is connected to the source of the second switching transistor, and the other end of the twelfth resistor is connected to the gate of the second switching transistor. One end of the thirteenth resistor is connected to the gate of the second switching transistor, and the other end of the thirteenth resistor is connected to the control module. The drain of the second switching transistor is connected to one end of the second heating wire, and the other end of the second heating wire is grounded together with the other end of the first heating wire. One end of the fourteenth resistor is connected to the drain of the second switching transistor, and the other end of the fourteenth resistor is connected to the control module.

[0026] This invention provides a charging control circuit for electronic cigarettes and an electronic cigarette. The charging control circuit includes: an airflow sensing module for outputting a first electrical signal when a user smokes; and a charging module for charging the battery in the electronic cigarette and stopping charging the electronic cigarette upon receiving the first electrical signal. The charging module is connected to the airflow sensing module. When a user smokes, the airflow sensing module outputs the first electrical signal to the charging module. In this invention, when a user smokes, the airflow sensing module outputs the first electrical signal, the charging module receives the first electrical signal, and stops charging the battery upon receiving the first electrical signal to protect the battery. Therefore, protecting the battery during smoking does not require occupying pins of the control chip, allowing the control chip to have fewer pins, thus reducing costs. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the charging control circuit for electronic cigarettes in this utility model.

[0029] Figure 2 This is a circuit diagram of the airflow sensing module in one embodiment of the present invention.

[0030] Figure 3 This is a circuit diagram of the charging module in one embodiment of this utility model.

[0031] Figure 4 This is a schematic diagram of the principle of the electronic cigarette in this utility model.

[0032] Figure 5 This is a circuit diagram of the control module in one embodiment of the present invention.

[0033] Figure 6 This is a circuit diagram of the atomizer module in one embodiment of the present invention.

[0034] The labels in the attached diagram are as follows: 10, airflow sensing module; 101, three-needle microphone; 11, charging module; 111, first interface unit; 112, first filter unit; 113, second filter unit; 12, control module; 13, atomizer module; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor; R12, twelfth resistor; U1, first chip; U2, second chip; Q1, first switching transistor; Q2, second switching transistor; J1, first interface; C1, first capacitor; C2, second capacitor. Detailed Implementation

[0035] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0036] like Figure 1 As shown, this utility model provides a charging control circuit for electronic cigarettes. The charging control circuit may include an airflow sensing module 10 and a charging module 11. The airflow sensing module 10 is used to output a first electrical signal when the user smokes. The charging module 11 is used to charge the battery in the electronic cigarette and stop charging the electronic cigarette when it receives the first electrical signal. The charging module 11 is connected to the airflow sensing module 10. When the user smokes, the airflow sensing module 10 outputs the first electrical signal to the charging module 11.

[0037] In this embodiment, when a user smokes, the airflow sensing module 10 outputs a first electrical signal, and the charging module 11 receives the first electrical signal and stops charging the battery after receiving the first electrical signal to protect the battery. It can be seen that when protecting the battery by smoking, there is no need to occupy the pins of the control chip. Therefore, the control chip can be a chip with fewer pins, which reduces the cost.

[0038] It should be noted that when setting up the charging module 11, it is necessary to consider whether the electrical signal output by the airflow sensing module 10 when the user smokes and the electrical signal required by the charging module 11 when it is turned off (stops charging the battery) match. That is, when the electrical signal output by the airflow sensing module 10 is sent to the charging module 11, the charging module 11 should be able to stop charging the battery. For example, if the electrical signal output by the airflow sensing module 10 when the user smokes is a high-level signal, the charging module 11 will turn off (stop charging the battery) when it receives the high-level signal. As another example, if the electrical signal output by the airflow sensing module 10 when the user smokes is a low-level signal, the charging module 11 will turn off when it receives the low-level signal.

[0039] In some embodiments, the first electrical signal can be a high-level signal or a low-level signal. When the first electrical signal is a high-level signal, the charging module 11 needs to be configured to turn off when a high-level signal is received. When the first electrical signal is a low-level signal, the charging module 11 needs to be configured to turn off when a low-level signal is received.

[0040] In some embodiments, such as Figure 2 As shown, the airflow sensing module 10 may include a three-pin microphone 101, a first resistor R1, and a second resistor R2; pin 1 of the three-pin microphone 101 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the power supply, pin 2 of the three-pin microphone 101 is grounded, pin 3 of the three-pin microphone 101 is connected to the charging module 11, one end of the second resistor R2 is connected to pin 3 of the three-pin microphone 101, and the other end of the second resistor R2 is grounded.

[0041] In a practical application, when a user is smoking, pin 3 of the three-pin microphone 101 will output a high-level signal (at this time, the first electrical signal is a high-level signal) to the charging module 11 (at this time, the charging module 11 needs to be set to turn off when it receives a high-level signal). After receiving the high-level signal output by pin 3 of the three-pin microphone 101, the charging module 11 turns off, that is, stops charging the battery.

[0042] In this embodiment, the three-pin microphone 101 can be a MIC (Microphone) microphone, for example, a silicon-labeled MIC microphone.

[0043] In this embodiment, the first resistor R1 is a voltage divider resistor, the second resistor R2 is a pull-down resistor, and the power supply can be a DC positive 5V power supply.

[0044] In some embodiments, such as Figure 3As shown, the charging module 11 may include a first interface unit 111, a first filter unit 112, a second filter unit 113, a first chip U1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The first interface unit 111 is used to connect to a charging source. The first interface unit 111 and the first filter unit 112 are connected to pin 4 of the first chip U1. Pin 1 of the first chip U1 is grounded. Pin 2 of the first chip U1 is connected to one end of the third resistor R3, and the other end of the third resistor is grounded. Pin 3 of the first chip U1 is grounded. Pin 5 of the first chip U1 is connected to the positive terminal of the battery and the second filter unit 113. Pin 6 of the first chip U1 is connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the battery. Pin 7 of the first chip U1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the other end of the fourth resistor R4. Pin 8 of the first chip U1 is connected to the airflow sensing module 10.

[0045] Specifically, during charging, a charging power source is connected through the first interface unit 111, and the current output by the charging power source flows to pin 4 of the first chip U1. Pin 5 of the first chip U1 outputs charging current to charge the battery. When the user smokes, pin 3 of the three-pin microphone 101 outputs a high-level signal to pin 8 of the first chip U1. At this time, pin 5 of the first chip U1 stops outputting charging current, and the battery stops charging. The first filtering unit 112 filters out interference signals in the current connected to the first interface unit 111, and the second filtering unit 113 filters out interference signals in the charging current output by the first chip U1 to the battery.

[0046] In this embodiment, the first chip U1 may be, but is not limited to, a chip with the model number WSCH6057T.

[0047] In this embodiment, the third resistor R3 is a pull-down resistor, and the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are voltage divider resistors.

[0048] In some embodiments, such as Figure 3 As shown, the first interface unit 111 may include a first interface J1, a seventh resistor R7, and an eighth resistor R8; pins A1, A12, B1, and B12 of the first interface J1 are grounded together, pins A4, A9, B4, and B9 of the first interface J1 are connected, pin A4 of the first interface J1 is also connected to pin 4 of the first chip U1, pin A5 of the first interface J1 is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is grounded, pin B5 of the first interface J1 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is grounded.

[0049] Specifically, the first interface J1 is a Tape-C interface. The seventh resistor R7 and the eighth resistor R8 are pull-down resistors.

[0050] In some embodiments, such as Figure 3 As shown, the first filter unit 112 may include a ninth resistor R9 and a first capacitor C1. One end of the ninth resistor R9 is connected to pin A4 of the first interface J1, and the other end of the ninth resistor R9 is connected to one end of the first capacitor C1. The other end of the first capacitor C1 is grounded.

[0051] It should be noted that the first filter unit 112 can also be any other circuit capable of performing the above functions. Those skilled in the art can also select other filter circuits as the first filter unit 112 according to the actual situation.

[0052] In some embodiments, such as Figure 3 As shown, the second filter unit 113 may include a second capacitor C2, one end of which is connected to pin 5 of the first chip U1, and the other end of which is grounded.

[0053] It should be noted that the second filter unit 113 can also be any other circuit capable of performing the above functions. Those skilled in the art can also select other filter circuits as the second filter unit 113 according to the actual situation.

[0054] In some embodiments, the battery in the electronic cigarette may be a rechargeable lithium battery.

[0055] In some embodiments, such as Figure 4 As shown, this utility model also provides an electronic cigarette that uses the charging control circuit for electronic cigarettes as described above. The electronic cigarette may include an atomizer module 13 and a control module 12. The control module 12 is connected to the atomizer module 13 and the airflow sensing module 10. The control module 12 is used to receive a first electrical signal and start the atomizer module 13 according to the first electrical signal.

[0056] In this embodiment, when a user smokes, the first electrical signal output by the airflow sensing module 10 can be transmitted to the control module 12. When the control module 12 receives the first electrical signal, it starts the atomizer module 13 to smoke according to the first electrical signal. When the user smokes, the charging module 11 also receives the first electrical signal, and after receiving the first electrical signal, the charging module 11 stops charging the battery to protect the battery.

[0057] Therefore, it can be seen that the electronic cigarette does not need to occupy the pins of the control chip when protecting the battery during smoking. As a result, the control chip can be a chip with fewer pins, which reduces the cost.

[0058] In one specific embodiment, the control module 12 is connected to pin 3 of the three-pin microphone 101. When the user smokes, the high-level signal output from pin 3 of the three-pin microphone 101 is divided into two paths, one of which is output to pin 8 of the first chip U1, and the other is output to the control module 12.

[0059] In some embodiments, such as Figure 6 As shown, the atomizer module 13 may include a first switch Q1, a second switch Q2, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor, a fourteenth resistor, a first heating wire, and a second heating wire.

[0060] In this configuration, the source of the first switching transistor Q1 is connected to the battery; one end of the ninth resistor R9 is connected to the source of the first switching transistor Q1, and the other end of the ninth resistor R9 is connected to the gate of the first switching transistor Q1; one end of the tenth resistor R10 is connected to the gate of the first switching transistor Q1, and the other end of the tenth resistor R10 is connected to the control module 12; the drain of the first switching transistor Q1 is connected to one end of the first heating wire, and the other end of the first heating wire is grounded; one end of the eleventh resistor R11 is connected to the drain of the first switching transistor Q1, and the other end of the eleventh resistor R11 is connected to the control module 12.

[0061] The source of the second switch Q2 is connected to the battery. One end of the twelfth resistor R12 is connected to the source of the second switch Q2, and the other end of the twelfth resistor R12 is connected to the gate of the second switch Q2. One end of the thirteenth resistor is connected to the gate of the second switch Q2, and the other end of the thirteenth resistor is connected to the control module 12. The drain of the second switch is connected to one end of the second heating wire, and the other end of the second heating wire is grounded together with the other end of the first heating wire. One end of the fourteenth resistor is connected to the drain of the second switch Q2, and the other end of the fourteenth resistor is connected to the control module 12.

[0062] Both the first switch Q1 and the second switch Q2 can be, but are not limited to, a P-MOS transistor (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor).

[0063] When the user smokes, the control module 12 receives the first electrical signal output by the airflow sensing module 10. After receiving the first electrical signal output by the airflow sensing module 10, the control module 12 outputs a control signal to the first switch Q1 and the second switch Q2, so that the first switch Q1 and the second switch Q2 are turned on. At this time, the battery supplies power to the first heating wire and the second heating wire, and the user smokes.

[0064] In this embodiment, the first heating wire and the second heating wire are grounded together, which reduces one solder pad and further reduces costs.

[0065] In some embodiments, such as Figure 5 As shown, the control module 12 can be the second chip U2, and the model of the second chip U2 can be, but is not limited to, the MC9959QEN-20 chip.

[0066] In summary, the charging control circuit and electronic cigarette provided by this utility model have the following beneficial effects:

[0067] When a user smokes, the airflow sensing module 10 outputs a first electrical signal. The charging module 11 receives the first electrical signal and stops charging the battery after receiving the first electrical signal to protect the battery. It can be seen that when the battery is protected by smoking, there is no need to occupy the pins of the control chip. Therefore, the control chip can be a chip with fewer pins, which reduces the cost.

[0068] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A charging control circuit for an electronic cigarette, characterized in that, The charging control circuit comprises: An airflow sensing module for outputting a first electrical signal when a user is smoking; A charging module for charging a battery in the electronic cigarette, and for receiving the first electrical signal and stopping charging the battery in the electronic cigarette when the first electrical signal is received, the charging module being connected to the airflow sensing module.

2. The charging control circuit for an electronic cigarette according to claim 1, characterized in that, The first electrical signal is a high-level signal or a low-level signal.

3. The charging control circuit for an electronic cigarette according to claim 1, wherein The airflow sensing module comprises a three-pin microphone, a first resistor and a second resistor; A first pin of the three-pin microphone is connected to one end of the first resistor, the other end of the first resistor is connected to a power supply, a second pin of the three-pin microphone is grounded, a third pin of the three-pin microphone is connected to the charging module, one end of the second resistor is connected to the third pin of the three-pin microphone, and the other end of the second resistor is grounded.

4. The charging control circuit for an electronic cigarette according to claim 1, wherein The charging module comprises a first interface unit for connecting to a charging power supply, a first filter unit, a second filter unit, a first chip, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; The first interface unit and the first filter unit are connected to a fourth pin of the first chip; A first pin of the first chip is grounded, a second pin of the first chip is connected to one end of the third resistor, the other end of the third resistor is grounded, a third pin of the first chip is grounded, a fifth pin of the first chip is connected to a positive electrode of the battery and the second filter unit, a sixth pin of the first chip is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fifth resistor is connected to the battery, a seventh pin of the first chip is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the other end of the fourth resistor, and an eighth pin of the first chip is connected to the airflow sensing module.

5. A charging control circuit for an electronic cigarette according to claim 4, characterised in that, The first interface unit comprises a first interface, a seventh resistor and an eighth resistor; A1 pin, A12 pin, B1 pin and B12 pin of the first interface are grounded, A4 pin, A9 pin, B4 pin and B9 pin of the first interface are connected, A4 pin of the first interface is also connected to the fourth pin of the first chip, A5 pin of the first interface is connected to one end of the seventh resistor, the other end of the seventh resistor is grounded, and B5 pin of the first interface is connected to one end of the eighth resistor, the other end of the eighth resistor is grounded.

6. A charging control circuit for an electronic cigarette according to claim 5, wherein The first filter unit comprises a ninth resistor and a first capacitor, one end of the ninth resistor is connected to A4 pin of the first interface, the other end of the ninth resistor is connected to one end of the first capacitor, and the other end of the first capacitor is grounded.

7. A charging control circuit for an electronic cigarette according to claim 6, wherein The second filter unit comprises a second capacitor, one end of the second capacitor is connected to the fifth pin of the first chip, and the other end of the second capacitor is grounded.

8. The charging control circuit for an electronic cigarette of claim 1, wherein, The battery is a lithium battery.

9. Electronic cigarette applying the charging control circuit for electronic cigarette according to any one of claims 1-8, characterized in that, The electronic cigarette comprises: An atomizer module; A control module connected to the atomizer module and the airflow sensing module, the control module being configured to receive the first electrical signal and start the atomizer module according to the first electrical signal.

10. The electronic cigarette of claim 9, wherein, The atomizer module comprises a first switch tube, a second switch tube, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first heating wire and a second heating wire; The source of the first switch tube is connected with the battery, one end of the ninth resistor is connected with the source of the first switch tube, the other end of the ninth resistor is connected with the gate of the first switch tube, one end of the tenth resistor is connected with the gate of the first switch tube, the other end of the tenth resistor is connected with the control module, the drain of the first switch tube is connected with one end of the first heating wire, the other end of the first heating wire is grounded, one end of the eleventh resistor is connected with the drain of the first switch tube, the other end of the eleventh resistor is connected with the control module; The source of the second switch tube is connected with the battery, one end of the twelfth resistor is connected with the source of the second switch tube, the other end of the twelfth resistor is connected with the gate of the second switch tube, one end of the thirteenth resistor is connected with the gate of the second switch tube, the other end of the thirteenth resistor is connected with the control module, the drain of the second switch tube is connected with one end of the second heating wire, the other end of the second heating wire is grounded with the other end of the first heating wire, one end of the fourteenth resistor is connected with the drain of the second switch tube, the other end of the fourteenth resistor is connected with the control module.

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