Impedance calibration circuit and electronic atomization device

Abstract

The utility model discloses an impedance calibration circuit and an electronic atomization device. The impedance calibration circuit comprises a first switch branch, a second switch branch, a resistor branch, a voltage detection branch, a controller, a first connecting end and a second connecting end. A test resistor is connected between the first connecting end and the second connecting end. The voltage detection branch circuit detects the voltage at the two ends of the test resistor. The controller outputs a first control signal or a second control signal. The first switching branch is turned on in response to a first control signal, and the second switching branch is turned on in response to a second control signal. Determining the impedance of the test resistor when the first switch branch is conducted and the second switch branch is not conducted, and calibrating the impedance when the second switch branch is conducted when the first switch branch is not conducted and the second switch branch is conducted. Through the above mode, the impedance when the second switch branch is conducted can be calibrated, so that the accuracy and reliability of follow-up overcurrent detection are improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to an impedance calibration circuit and an electronic atomization device. Background Technology

[0002] With the increasing demand for e-cigarette devices, safety issues have also arisen. Reports of e-cigarette devices catching fire or exploding, exceeding limits for hazardous substances, and malfunctioning frequently appear online and in newspapers. The safety of e-cigarette devices encompasses the safety of their electrical, heating, battery, and charging systems; meeting safety requirements is a fundamental requirement.

[0003] One safety requirement is to perform overcurrent detection in e-cigarette devices to reduce damage caused by excessive current. Currently, the common overcurrent detection method involves detecting the voltage across a switch (used to control the operation of the heating element in the e-cigarette device) and determining the current flowing through the switch based on this voltage and the switch's typical internal resistance. However, due to manufacturing errors and other factors, the actual internal resistance of different switches may vary, potentially leading to malfunctions in the overcurrent detection function. Utility Model Content

[0004] This application provides an impedance calibration circuit and an electronic atomizing device that can calibrate the impedance of the second switch branch when it is turned on, so as to improve the accuracy and reliability of subsequent overcurrent detection.

[0005] In a first aspect, embodiments of this application provide an impedance calibration circuit, including:

[0006] The circuit consists of a first switch branch, a second switch branch, a resistor branch, a voltage detection branch, a controller, a first connection terminal, and a second connection terminal.

[0007] The first switch branch and the resistor branch are connected in series between the power supply and the first connection terminal. The second switch branch is connected between the power supply and the first connection terminal. The controller is connected to the first connection terminal, the first switch branch and the second switch branch respectively. The voltage detection branch is connected to the first connection terminal. A test resistor is connected between the first connection terminal and the second connection terminal.

[0008] The voltage detection branch is used to detect the voltage across the test resistor;

[0009] The controller is used to output a first control signal to the first switch branch, or to output a second control signal to the second switch branch;

[0010] The first switch branch is turned on in response to the first control signal, and the second switch branch is turned on in response to the second control signal;

[0011] Specifically, when the first switch branch is on and the second switch branch is not on, the impedance of the test resistor is determined based on the fact that the current flowing through the resistor branch is equal to the current flowing through the test resistor. When the first switch branch is not on and the second switch branch is on, the impedance when the second switch branch is on is calibrated based on the fact that the current flowing through the second switch branch is equal to the current flowing through the test resistor.

[0012] In one or more embodiments, the first switching branch includes a first switching transistor and a first resistor;

[0013] The first terminal of the first switching transistor is connected to the controller, the second terminal of the first switching transistor is connected to the power supply, the third terminal of the first switching transistor is connected to the resistor branch, and the first resistor is connected between the first terminal of the first switching transistor and the power supply.

[0014] In one or more embodiments, the first switch is a PMOS transistor;

[0015] The first terminal of the first switch is the gate of the PMOS transistor, the second terminal of the first switch is the source of the PMOS transistor, and the third terminal of the first switch is the drain of the PMOS transistor.

[0016] In one or more embodiments, the resistor branch includes a second resistor;

[0017] The second resistor is connected between the first switch branch and the first connection terminal.

[0018] In one or more embodiments, the second switching branch includes a second switching transistor and a third resistor;

[0019] The first terminal of the second switching transistor is connected to the controller, the second terminal of the second switching transistor is connected to the power supply, the third terminal of the second switching transistor is connected to the first connection terminal, and the third resistor is connected between the first terminal and the second terminal of the second switching transistor.

[0020] Wherein, the impedance of the second switch branch when it is turned on is the internal resistance of the second switch tube when it is turned on.

[0021] In one or more embodiments, the second switch is a PMOS transistor;

[0022] The first terminal of the second switch is the gate of the PMOS transistor, the second terminal of the second switch is the source of the PMOS transistor, and the third terminal of the second switch is the drain of the PMOS transistor.

[0023] In one or more embodiments, the voltage detection branch includes a controller and a fourth resistor;

[0024] The fourth resistor is connected between the ADC pin of the controller and the first connection terminal, and the second connection terminal is grounded.

[0025] Secondly, embodiments of this application provide an electronic atomizing device, including a heating element and an impedance calibration circuit as described above, wherein the heating element is connected between the first connection terminal and the second connection terminal.

[0026] In one or more embodiments, the electronic atomizing device further includes a communication interface;

[0027] The communication interface is used to connect to external devices to receive calibration signals output by the external devices. The communication interface is also connected to the controller to input the calibration signals to the controller and enable the controller to enter the mode of calibrating the impedance when the second switch branch is turned on.

[0028] In one or more embodiments, the electronic atomizing device further includes a fifth resistor and a sixth resistor;

[0029] The fifth resistor and the sixth resistor are connected in series between the communication interface and ground, and the connection point between the fifth resistor and the sixth resistor is connected to the controller;

[0030] The fifth resistor and the sixth resistor divide the voltage of the calibration signal and input it to the controller.

[0031] The beneficial effects of this application are as follows: The impedance calibration circuit of this application includes a first switch branch, a second switch branch, a resistor branch, a voltage detection branch, a controller, a first connection terminal, and a second connection terminal. The first switch branch and the resistor branch are connected in series between the power supply and the first connection terminal. The second switch branch is connected between the power supply and the first connection terminal. The controller is connected to the first connection terminal, the first switch branch, and the second switch branch. The voltage detection branch is connected to the first connection terminal. A test resistor is connected between the first connection terminal and the second connection terminal. First, the controller outputs only a first control signal, so the first switch branch is turned on, and the second switch branch is not turned on. At this time, the current flowing through the resistor branch is determined by the ratio of the voltage of the power supply to the sum of the impedances of the resistor branch and the test resistor. The current flowing through the test resistor is determined by the ratio of the voltage across the test resistor to the impedance of the test resistor. Finally, the impedance of the test resistor is determined by the fact that the current flowing through the resistor branch is equal to the current flowing through the test resistor. Next, the controller outputs only the second control signal, thus turning on the second switch branch and turning off the first switch branch. At this time, the current flowing through the second switch branch is determined by the ratio of the power supply voltage to the sum of the impedances of the second switch branch and the test resistor. The current flowing through the test resistor is determined by the ratio of the voltage across the test resistor to the impedance of the test resistor. Finally, based on the fact that the current flowing through the second switch branch is equal to the current flowing through the test resistor, and combined with the already determined impedance of the test resistor, the impedance of the second switch branch when it is turned on can be determined. Therefore, through the above process, the impedance of the second switch branch when it is turned on can be calibrated, thereby improving the accuracy and reliability of subsequent overcurrent detection. Attached Figure Description

[0032] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0033] Figure 1 This is a schematic diagram of the composition block diagram of the impedance calibration circuit provided in the embodiments of this application;

[0034] Figure 2 Is with Figure 1 The circuit structure corresponding to the block diagram shown;

[0035] Figure 3 This is a schematic diagram of the electronic atomizing device provided in the embodiments of this application. Figure 1 ;

[0036] Figure 4 This is a schematic diagram of the electronic atomizing device provided in the embodiments of this application. Figure 2 ;

[0037] Figure 5This is a schematic diagram of the electronic atomizing device provided in the embodiments of this application. Figure 3 . Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0039] It should be noted that 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 intermediate elements between them.

[0040] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the block diagram of the impedance calibration circuit provided in the embodiments of this application. Figure 1 As shown, the impedance calibration circuit 100 includes a first switch branch 10, a second switch branch 20, a resistor branch 30, a voltage detection branch 40, a controller 50, a first connection terminal LIN1, and a second connection terminal LIN2.

[0042] The first switch branch 10 and the resistor branch 30 are connected in series between the power supply VC1 and the first connection terminal LIN1. The second switch branch 20 is connected between the power supply VC1 and the first connection terminal LIN1. The controller 50 is connected to the first connection terminal LIN1, the first switch branch 10 and the second switch branch 20 respectively. The voltage detection branch 40 is connected to the first connection terminal LIN1. The test resistor Rt is connected between the first connection terminal LIN1 and the second connection terminal LIN2.

[0043] Specifically, the voltage detection branch 40 is used to detect the voltage across the test resistor Rt. The controller 50 is used to output a first control signal to the first switch branch 10, or a second control signal to the second switch branch 20, that is, the controller 50 only outputs one of the first and second control signals. The first switch branch 10 is turned on in response to the first control signal, and the second switch branch 20 is turned on in response to the second control signal. When the first switch branch 10 is on and the second switch branch 20 is not on, the impedance of the test resistor Rt is determined based on the fact that the current flowing through the resistor branch 30 is equal to the current flowing through the test resistor Rt. When the first switch branch 10 is not on and the second switch branch 20 is on, the impedance of the second switch branch 20 when it is on is calibrated based on the fact that the current flowing through the second switch branch 20 is equal to the current flowing through the test resistor Rt.

[0044] In practical applications, firstly, the controller 50 outputs only the first control signal to the first switch branch 10 (i.e., the controller 50 does not output the second control signal at this time), so the first switch branch 10 is turned on and the second switch branch 20 is not turned on. At this time, the power supply VC1, the first switch branch 10, the resistor branch 30 and the test resistor Rt form a loop. On the one hand, the ratio of the voltage of the power supply VC1 to the total impedance of the loop (i.e., the sum of the impedance of the resistor branch 30 (denoted as R30) and the impedance of the test resistor Rt; in this embodiment, the impedance of the first switch branch 10 is zero when it is turned on is taken as an example) determines the current flowing through the resistor branch 30 (denoted as I30), that is, I30 = VC1 / (R30 + Rt); on the other hand, the ratio of the voltage across the test resistor Rt (denoted as VRt) to the impedance of the test resistor Rt can determine the current flowing through the test resistor Rt (denoted as IRt), that is, IRt = VRt / Rt. Since the current flowing through the resistor branch 30 is equal to the current flowing through the test resistor Rt, I30 = VC1 / (R30 + Rt) = IRt = VRt / Rt. Here, the voltage of the power supply VC1 and the impedance R30 of the resistor branch 30 can be known values ​​after the device is determined. The voltage detection branch 40 can also detect the voltage VRt across the test resistor Rt. Therefore, the impedance of the test resistor Rt can be determined based on the above formula I30 = IRt.

[0045] Next, the controller 50 outputs only the second control signal to the second switch branch 20 (i.e., the controller 50 does not output the first control signal at this time), so the first switch branch 10 is turned on and the second switch branch 20 is not turned on. At this time, the power supply VC1, the second switch branch 20 and the test resistor Rt form a loop. On the one hand, the ratio of the voltage of the power supply VC1 to the total impedance of the loop (i.e., the sum of the impedance of the second switch branch 20 (denoted as R20) and the impedance of the test resistor Rt) determines the current flowing through the second switch branch 20 (denoted as I20), that is, I20 = VC1 / (R20 + Rt); on the other hand, the ratio of the voltage VRt across the test resistor Rt to the impedance of the test resistor Rt can determine the current IRt flowing through the test resistor Rt, that is, IRt = VRt / Rt. Since the current flowing through the second switch branch 20 is equal to the current flowing through the test resistor Rt, then I20=VC1 / (R20+Rt)=IRt=VRt / Rt. Here, the voltage of the power supply VC1, the voltage VRt across the test resistor Rt, and the impedance of the test resistor Rt are all known values. Therefore, based on the above formula I20=IRt, the impedance R20 when the second switch branch 20 is turned on can be determined.

[0046] Through the above process, the impedance R20 when the second switch branch 20 is turned on can be calibrated. Therefore, when performing overcurrent detection in the future, the current flowing through the second switch branch 20 can be accurately determined based on the impedance R20 when the second switch branch 20 is turned on, and thus the overcurrent can be accurately determined. It can be seen that the accuracy and reliability of the subsequent overcurrent detection are improved.

[0047] Please refer to Figure 2 , Figure 2 The embodiments provided in this application are related to Figure 1 The block diagram shown corresponds to one type of circuit structure. For example... Figure 2 As shown, the first switch branch 10 includes a first switch transistor Q1 and a first resistor R1.

[0048] In this circuit, the first terminal of the first switch Q1 is connected to the controller 50, the second terminal of the first switch Q1 is connected to the power supply VC1, and the third terminal of the first switch Q1 is connected to the resistor branch 30. A first resistor R1 is connected between the first terminal of the first switch Q1 and the power supply VC1. Thus, the pull-up effect of the first resistor R1 prevents the first terminal of the first switch Q1 from being in a high-impedance state when powered on, ensuring that the first terminal of the first switch Q1 has a defined voltage level for control. Furthermore, the first resistor R1 also provides discharge during the disconnection process of the first switch Q1, ensuring reliable turn-off of the first switch Q1.

[0049] In this embodiment, taking a PMOS transistor as an example, the first terminal of the first switch Q1 is the gate (G) of the PMOS transistor, the second terminal is the source (S) of the PMOS transistor, and the third terminal is the drain (D) of the PMOS transistor. When the controller 50 does not output the first control signal, a high level is input to the gate, and the first switch Q1 is turned off; when the controller 50 outputs the first control signal, a low level is input to the gate, and the first switch Q1 is turned on.

[0050] In addition, the first switching transistor Q1 can be any 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. Furthermore, Figure 2 The first switch Q1 shown can be implemented as multiple switches connected in parallel.

[0051] In this embodiment, the resistor branch 30 includes a second resistor R2.

[0052] The second resistor R2 is connected between the first switch branch 10 and the first connection terminal LIN1, that is, the second resistor R2 is connected between the drain of the first switch Q1 and the first connection terminal LIN1. The impedance of the second resistor R2 is the impedance of the resistor branch 30.

[0053] In this embodiment, the second switch branch 20 includes a second switch Q2 and a third resistor R3.

[0054] In this circuit, the first terminal of the second switch Q2 is connected to the controller 50, the second terminal of the second switch Q2 is connected to the power supply VC1, and the third terminal of the second switch Q2 is connected to the first connection terminal LIN1. A third resistor R3 is connected between the first and second terminals of the second switch Q2. Therefore, the pull-up effect of the third resistor R3 prevents the first terminal of the second switch Q2 from being in a high-impedance state when powered on, ensuring that the first terminal of the second switch Q2 has a defined voltage level for control. Additionally, the third resistor R3 also provides discharge during the turn-off process of the second switch Q2, ensuring reliable turn-off of the second switch Q2.

[0055] In this embodiment, taking the second switch Q2 as a PMOS transistor as an example, the first terminal of the second switch Q2 is the gate (G) of the PMOS transistor, the second terminal of the second switch Q2 is the source (S) of the PMOS transistor, and the third terminal of the second switch Q2 is the drain (D) of the PMOS transistor. When the controller 50 does not output the second control signal, a high level is input to the gate, and the second switch Q2 is turned off; when the controller 50 outputs the second control signal, a low level is input to the gate, and the second switch Q2 is turned on.

[0056] In addition, the second switch Q2 can be any 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. Furthermore, Figure 2 The second switch Q2 shown can be implemented as multiple switches connected in parallel.

[0057] In this embodiment, the impedance of the second switch branch 20 when it is turned on is the internal resistance of the second switch Q2 when it is turned on, that is, the resistance between the source and drain of the second switch Q2 when it is turned on.

[0058] In this embodiment, the voltage detection branch 40 includes a controller 50 and a fourth resistor R4.

[0059] The fourth resistor R4 is connected between the ADC pin of the controller 50 and the first connection terminal LIN1, while the second connection terminal LIN2 is grounded to GND. Since the second connection terminal LIN2 is grounded to GND, the voltage detected by the ADC pin of the controller 50 is the voltage across the test resistor Rt.

[0060] The following are Figure 2 The principle of the circuit structure shown will be explained again.

[0061] Specifically, firstly, the controller 50 outputs only the first control signal to the first switch Q1 (i.e., the controller 50 does not output the second control signal at this time), so the first switch Q1 is turned on and the second switch Q2 is not turned on. At this time, the power supply VC1, the first switch Q1, the second resistor R2 and the test resistor Rt form a loop. On the one hand, the ratio of the voltage of the power supply VC1 to the total impedance of the loop (i.e., the sum of the impedances of the second resistor R2 and the test resistor Rt, which in this embodiment is taken as the impedance being zero when the first switch Q1 is turned on) determines the current flowing through the second resistor R2 (denoted as IR2, which corresponds to I30 in the above embodiment), that is, IR2 = VC1 / (R2 + Rt); on the other hand, the ratio of the voltage VLIN1 at the first connection terminal LIN1 (i.e., the voltage across the test resistor Rt) to the impedance of the test resistor Rt can determine the current IRt flowing through the test resistor Rt, that is, IRt = VLIN1 / Rt. Since the current flowing through the second resistor R2 is equal to the current flowing through the test resistor Rt, then IR2 = VC1 / (R2 + Rt) = IRt = VLIN1 / Rt. Here, the voltage of the power supply VC1 and the impedance of the second resistor R2 can be known values ​​after the device is determined. The controller 50 also determines the voltage VLIN1 of the first connection terminal LIN1 based on the detection signal. Therefore, the impedance of the test resistor Rt can be determined based on the above formula IR2 = IRt.

[0062] Next, the controller 50 outputs only the second control signal to the second switch Q2 (i.e., the controller 50 does not output the first control signal at this time), so the first switch Q1 is not turned on, and the second switch Q2 is turned on. At this time, the power supply VC1, the second switch Q2, and the test resistor Rt form a loop. On the one hand, the ratio of the voltage of the power supply VC1 to the total impedance of the loop (i.e., the sum of the impedance of the second switch Q2 (denoted as RQ2) and the impedance of the test resistor Rt) determines the current flowing through the second switch Q2 (denoted as IQ2, which corresponds to I20 in the above embodiment), that is, IQ2 = VC1 / (RQ2 + Rt); on the other hand, the ratio of the voltage VLIN1 at the first connection terminal LIN1 (i.e., the voltage across the test resistor Rt) to the impedance of the test resistor Rt can determine the current IRt flowing through the test resistor Rt, that is, IRt = VLIN1 / Rt. Since the current flowing through the second switch Q2 is equal to the current flowing through the test resistor Rt, IQ2 = VC1 / (RQ2 + Rt) = IRt = VLIN1 / Rt. Here, the voltage of the power supply VC1, the voltage VLIN1 of the first connection terminal LIN1, and the impedance of the test resistor Rt are all known values. Therefore, based on the above formula IQ2 = IRt, the impedance RQ2 when the second switch Q2 is turned on can be determined.

[0063] Through the above process, the impedance RQ2 when the second switch Q2 is turned on can be calibrated. Therefore, when performing overcurrent detection in the future, the current flowing through the second switch Q2 can be accurately determined based on the impedance RQ2 when the second switch Q2 is turned on, and thus the overcurrent can be accurately determined. It can be seen that the accuracy and reliability of the subsequent overcurrent detection are improved.

[0064] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the composition of the electronic atomizing device provided in the embodiments of this application. Figure 3 As shown, the electronic atomizing device 1000 includes a heating element 200 and an impedance calibration circuit 100 in any embodiment of this application, wherein the heating element 200 is connected between a first connection terminal LIN1 and a second connection terminal LIN2.

[0065] In practical applications, the second switch Q2 can be kept on. Since Q2 is connected in series with the heating element 200, the current flowing through Q2 is the same as the current flowing through the heating element 200. Therefore, after calibrating the internal resistance of Q2 using the impedance calibration circuit 100, the current flowing through Q2 can be determined by obtaining the voltage between its source (S) and drain (D) terminals, thus determining the current flowing through the heating element 200. This facilitates accurate determination of whether overcurrent has occurred in the heating element 200, resulting in high accuracy and reliability of overcurrent detection.

[0066] In some embodiments, such as Figure 4 As shown, the electronic atomizing device 1000 also includes a communication interface 300.

[0067] The communication interface 300 is used to connect with the external device 2000 to receive the calibration signal output by the external device 2000. The communication interface 300 is also connected to the controller 50 to input the calibration signal to the controller 50 and to put the controller 50 into a mode that calibrates the impedance when the second switch branch 20 is turned on (i.e., the internal resistance when the second switch Q2 is turned on).

[0068] For example, in some implementations, the communication interface 300 is a USB interface (such as a TYPE-C interface). The external device 2000 is connected to the communication interface 300. When it is necessary to calibrate the internal resistance of the second switch Q2 when it is turned on, the external device 2000 outputs a calibration signal, which is input to the controller 50 through the communication interface 300. Then the controller 50 enters the mode of calibrating the internal resistance of the second switch Q2 when it is turned on.

[0069] In some embodiments, such as Figure 5 As shown, the electronic atomizing device 1000 also includes a fifth resistor R5 and a sixth resistor R6.

[0070] The fifth resistor R5 and the sixth resistor R6 are connected in series between the communication interface 300 and ground (GND). The connection point between the fifth resistor R5 and the sixth resistor R6 is connected to the controller 50. The fifth resistor R5 and the sixth resistor R6 divide the voltage of the calibration signal before inputting it to the controller 50. By setting the fifth resistor R5 and the sixth resistor R6 to divide the calibration signal, the voltage input to the controller 50 can be reduced, thereby reducing the risk of damage to the controller 50 due to excessive input voltage.

[0071] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0072] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An impedance calibration circuit, characterized in that, include: The circuit consists of a first switch branch, a second switch branch, a resistor branch, a voltage detection branch, a controller, a first connection terminal, and a second connection terminal. The first switch branch and the resistor branch are connected in series between the power supply and the first connection terminal. The second switch branch is connected between the power supply and the first connection terminal. The controller is connected to the first connection terminal, the first switch branch and the second switch branch respectively. The voltage detection branch is connected to the first connection terminal. A test resistor is connected between the first connection terminal and the second connection terminal. The voltage detection branch is used to detect the voltage across the test resistor; The controller is used to output a first control signal to the first switch branch, or to output a second control signal to the second switch branch; The first switch branch is turned on in response to the first control signal, and the second switch branch is turned on in response to the second control signal; Specifically, when the first switch branch is on and the second switch branch is not on, the impedance of the test resistor is determined based on the fact that the current flowing through the resistor branch is equal to the current flowing through the test resistor. When the first switch branch is not on and the second switch branch is on, the impedance when the second switch branch is on is calibrated based on the fact that the current flowing through the second switch branch is equal to the current flowing through the test resistor.

2. The impedance calibration circuit according to claim 1, characterized in that, The first switching branch includes a first switching transistor and a first resistor; The first terminal of the first switching transistor is connected to the controller, the second terminal of the first switching transistor is connected to the power supply, the third terminal of the first switching transistor is connected to the resistor branch, and the first resistor is connected between the first terminal of the first switching transistor and the power supply.

3. The impedance calibration circuit according to claim 2, characterized in that, The first switching transistor is a PMOS transistor; The first terminal of the first switch is the gate of the PMOS transistor, the second terminal of the first switch is the source of the PMOS transistor, and the third terminal of the first switch is the drain of the PMOS transistor.

4. The impedance calibration circuit according to claim 1, characterized in that, The resistor branch includes a second resistor; The second resistor is connected between the first switch branch and the first connection terminal.

5. The impedance calibration circuit according to claim 1, characterized in that, The second switching branch includes a second switching transistor and a third resistor; The first terminal of the second switching transistor is connected to the controller, the second terminal of the second switching transistor is connected to the power supply, the third terminal of the second switching transistor is connected to the first connection terminal, and the third resistor is connected between the first terminal and the second terminal of the second switching transistor. Wherein, the impedance of the second switch branch when it is turned on is the internal resistance of the second switch tube when it is turned on.

6. The impedance calibration circuit according to claim 5, characterized in that, The second switch is a PMOS transistor; The first terminal of the second switch is the gate of the PMOS transistor, the second terminal of the second switch is the source of the PMOS transistor, and the third terminal of the second switch is the drain of the PMOS transistor.

7. The impedance calibration circuit according to any one of claims 1-6, characterized in that, The voltage detection branch includes the controller and the fourth resistor; The fourth resistor is connected between the ADC pin of the controller and the first connection terminal, and the second connection terminal is grounded.

8. An electronic atomizing device, characterized in that, It includes a heating element and an impedance calibration circuit as described in any one of claims 1-7, wherein the heating element is connected between the first connection terminal and the second connection terminal.

9. The electronic atomizing device according to claim 8, characterized in that, The electronic atomizing device also includes a communication interface; The communication interface is used to connect to external devices to receive calibration signals output by the external devices. The communication interface is also connected to the controller to input the calibration signals to the controller and enable the controller to enter the mode of calibrating the impedance when the second switch branch is turned on.

10. The electronic atomizing device according to claim 9, characterized in that, The electronic atomizing device also includes a fifth resistor and a sixth resistor; The fifth resistor and the sixth resistor are connected in series between the communication interface and ground, and the connection point between the fifth resistor and the sixth resistor is connected to the controller; The fifth resistor and the sixth resistor divide the voltage of the calibration signal and input it to the controller.

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