Heating device

Abstract

The utility model discloses heating equipment, and belongs to the technical field of heating. The heating equipment comprises a first switch control circuit, and when the first switch control circuit receives a control signal through the control end of the first switch control circuit, the first end and the second end of the first switch control circuit are switched on; when the first end and the second end of the first switch control circuit are switched on, the control electrode of the first switch circuit obtains a switch-on voltage, so that the first electrode and the second electrode of the first switch circuit are switched on, and alternating current is transmitted to the second electrode of the first switch circuit; the control electrode of the second switching circuit can also obtain the conduction voltage, so that the second electrode and the first electrode of the second switching circuit are conducted to supply power to a load; the rectifying circuit is used for rectifying the alternating current to generate direct current; and the holding circuit obtains and stores the electric energy from the output end of the rectifying circuit through the first end of the holding circuit, so that the voltage of the control power supply end is held. The heating equipment has the advantages of being small in heating amount, high in response speed, capable of reducing alternating current loss and the like.

Description

Technical Field

[0001] The present application relates to the field of heating technology, and in particular to a heating device. Background Art

[0002] Soldering irons are basic tools commonly used in the electronics industry. Currently, more and more soldering irons are controlled by controlling alternating current to control heating. With the miniaturization of electronic devices and the modularization and high integration of circuit boards, higher and higher requirements are placed on the size and heat dissipation of heating equipment such as soldering irons.

[0003] In the related art, there are two main ways to control the heating of a soldering iron: rectifying and filtering the AC power to DC and then controlling it with a MOS (Metal Oxide Semiconductor Field Effect Transistor) or controlling it with a thyristor. The method of using a MOS tube to control the heating requires a rectifier bridge to rectify and filter the AC power, which will cause voltage loss and high heat generation. When using a thyristor to control the AC power, there is a problem that the AC power cannot be shut off in real time, resulting in a slow response speed of the device. Utility Model Content

[0004] This application provides a heating device that can directly control alternating current, with advantages such as reduced heat generation and shortened response time. The technical solution is as follows:

[0005] In one aspect, a heating device is provided, comprising:

[0006] a first switch control circuit, the first switch control circuit comprising a control terminal, a first terminal, and a second terminal; the control terminal of the first switch control circuit is used to receive a control signal, and the first terminal of the first switch control circuit is connected to a control power supply terminal; when the first switch control circuit receives the control signal through the control terminal, the first terminal and the second terminal are connected; otherwise, the first terminal and the second terminal are disconnected;

[0007] a first switch circuit, the first switch circuit comprising a control electrode, a first electrode, and a second electrode; the control electrode of the first switch circuit being connected to the second end of the first switch control circuit, the first electrode of the first switch circuit being used to connect to the positive terminal of the AC power source, and the second electrode of the first switch circuit being connected to the working ground; when the first end and the second end of the first switch control circuit are conductive, the control electrode of the first switch circuit can obtain a conductive voltage from the second end of the first switch control circuit, thereby conductively connecting the first electrode and the second electrode thereof, thereby transmitting the AC power corresponding to the AC power source connected to the first electrode to the second electrode thereof; conversely, the first switch circuit disconnects the first electrode and the second electrode thereof;

[0008] a second switch circuit, the second switch circuit comprising a control electrode, a first electrode, and a second electrode; the control electrode of the second switch circuit being connected to the second end of the first switch control circuit; a load being connected between the first electrode of the second switch circuit and the negative end of the AC power supply; and a second electrode of the second switch circuit being connected to the second electrode of the first switch circuit; the second electrode of the second switch circuit being further connected to a working ground; the control electrode of the second switch circuit being capable of obtaining a conduction voltage from the second end of the first switch control circuit, thereby conducting conduction between the second electrode and the first electrode, thereby transmitting AC power from the second electrode of the second switch circuit to the load, thereby powering the load; conversely, the second switch circuit being capable of disconnecting the first electrode and the second electrode, thereby not powering the load;

[0009] a rectifier circuit, the rectifier circuit comprising a first end, a second end, and an output end; the first end of the rectifier circuit being connected to the negative end of the AC power source, and the second end of the rectifier circuit being connected to a working ground; the rectifier circuit being configured to rectify the AC power of the AC power source to generate DC power and output the DC power through the output end;

[0010] A holding circuit, the holding circuit comprising a first end and a second end, the first end of the holding circuit being respectively connected to the output end of the rectifier circuit and the control power supply end, and the second end of the holding circuit being connected to a working ground; the holding circuit obtains and stores electrical energy from the output end of the rectifier circuit through its first end, so that the voltage of the control power supply end connected to its first end is maintained.

[0011] Optionally, the first switch circuit includes a MOS transistor Q1, and the MOS transistor Q1 further has a body diode V1;

[0012] The MOS transistor Q1 has a gate, a drain, and a source. The gate of the MOS transistor Q1 is connected to the second end of the first switch control circuit. The drain of the MOS transistor Q1 is used to connect to the positive end of the AC power supply. The source of the MOS transistor Q1 is connected to the working ground.

[0013] The gate of the MOS transistor Q1 serves as the control electrode of the first switch circuit, the drain of the MOS transistor Q1 serves as the first electrode of the first switch circuit, and the source of the MOS transistor Q1 serves as the second electrode of the first switch circuit;

[0014] The anode of the body diode V1 is connected to the source of the MOS transistor Q1, and the cathode of the body diode V1 is connected to the drain of the MOS transistor Q1. The body diode V1 is used to provide a path for the AC power to flow from the negative end of the AC power supply to the positive end of the AC power supply when the AC power supply is in the negative half cycle.

[0015] Optionally, the second switch circuit includes a MOS transistor Q2, and the MOS transistor Q2 further has a body diode V2;

[0016] The MOS transistor Q2 has a gate, a drain, and a source. The gate of the MOS transistor Q2 is connected to the second end of the first switch control circuit. The drain of the MOS transistor Q2 and the negative end of the AC power supply are used to connect a load. The source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1 and is also connected to the working ground.

[0017] The gate of the MOS transistor Q2 serves as the control electrode of the second switch circuit, the drain of the MOS transistor Q2 serves as the first electrode of the second switch circuit, and the source of the MOS transistor Q2 serves as the second electrode of the second switch circuit;

[0018] The anode of the body diode V2 is connected to the source of the MOS transistor Q2, and the cathode of the body diode V2 is connected to the drain of the MOS transistor Q2. The body diode V2 is used to provide a path for the AC power to flow from the positive end of the AC power supply to the negative end of the AC power supply when the AC power supply is in the positive half cycle.

[0019] Optionally, the first switch control circuit includes an optocoupler U1;

[0020] The optocoupler U1 has a power supply end, a control end, a first end, and a second end. The power supply end of the optocoupler U1 is used to connect to a power supply; the control end of the optocoupler U1 is used to receive a control signal. The first end of the optocoupler U1 is connected to the control power supply end, and the second end of the optocoupler U1 is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 respectively. When the optocoupler U1 receives the control signal through its control end, the first end and the second end are connected, otherwise, the first end and the second end are disconnected.

[0021] The control end of the optocoupler U1 serves as the control end of the first switch control circuit, the first end of the optocoupler U1 serves as the first end of the first switch control circuit, and the second end of the optocoupler U1 serves as the second end of the first switch control circuit.

[0022] Optionally, the first switch control circuit further includes a voltage divider subcircuit;

[0023] The voltage divider sub-circuit is connected between the second end of the optocoupler U1 and the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, and is used to distribute the voltage of the control power supply to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2.

[0024] Optionally, the holding circuit includes a capacitor C1;

[0025] One end of the capacitor C1 is connected to the output end of the rectifier circuit and the control power supply end respectively, and the other end of the capacitor C1 is connected to the working ground;

[0026] One end of the capacitor C1 serves as the first end of the holding circuit; the other end of the capacitor C1 serves as the second end of the holding circuit.

[0027] Optionally, the rectifier circuit includes a diode V3, a resistor R1 and a voltage stabilizing diode ZD1;

[0028] The anode of the diode V3 is connected to the negative terminal of the AC power supply, and the cathode of the diode V3 is connected to the first end of the resistor R1; the second end of the resistor R1 is connected to the cathode of the voltage-stabilizing diode ZD1 and one end of the capacitor C1, respectively. The resistor R1 is used to limit the current amplitude to prevent damage to the components in the heating device; the anode of the voltage-stabilizing diode ZD1 is connected to the working ground;

[0029] The anode of the diode V3 serves as the first end of the rectifier circuit, the anode of the voltage-stabilizing diode ZD1 serves as the second end of the rectifier circuit, and the second end of the resistor R1 serves as the output end of the rectifier circuit.

[0030] Optionally, the heating device further comprises:

[0031] a second switch control circuit, the second switch control circuit comprising a control terminal, a first terminal, a second terminal, and a third terminal;

[0032] The control end is used to receive a control signal. The first end is connected to a working ground. The second end is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, respectively. The third end is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, respectively. When the second switch control circuit receives the control signal through its control end, the second end and the third end are disconnected. Otherwise, the second end and the third end are connected. When the MOS transistor Q1 and the MOS transistor Q2 are disconnected, discharge control between the gate and the source is achieved, thereby improving the anti-interference capability of the heating device.

[0033] Optionally, the second switch control circuit includes an optocoupler U2;

[0034] The optocoupler U2 has a control end, a first end, a second end, and a third end. The control end of the optocoupler U2 is used to receive the control signal. The first end of the optocoupler U2 is connected to the working ground. The second end of the optocoupler U2 is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, respectively. The third end of the optocoupler U2 is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, respectively. When the optocoupler U2 receives the control signal through its control end, its second end and third end are disconnected. Otherwise, its second end and third end are disconnected.

[0035] The control end of the optocoupler U2 serves as the control end of the second switch control circuit, the first end of the optocoupler U2 serves as the first end of the second switch control circuit, the second end of the optocoupler U2 serves as the second end of the second switch control circuit, and the third end of the optocoupler U2 serves as the third end of the second switch control circuit.

[0036] Optionally, the second switch control circuit further includes a current control subcircuit;

[0037] The current control subcircuit includes a first end, a second end, and a third end; the first end of the current control subcircuit is connected to the second end of the optocoupler U2, the second end of the current control subcircuit is connected to the third end of the optocoupler U2, and the third end of the current control subcircuit is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 respectively; the current control subcircuit is used to control the flow direction of the discharge current of the gate and source of the MOS transistor Q1 and the gate and source of the MOS transistor Q2 when the second switch control circuit is turned on, so as to avoid interference with other parts of the heating device.

[0038] The technical solution provided by this application can at least bring the following beneficial effects:

[0039] By connecting the second pole of the first switching circuit to the second pole of the second switching circuit, an electronic switch can be formed. By controlling the conduction or disconnection of the first switching circuit and the second switching circuit, the conduction or disconnection of the alternating current can be directly controlled, eliminating the need to rectify the alternating current to direct current for control. This can reduce AC power loss and heat generation. Furthermore, the heating device includes a first switch control circuit capable of switching the first and second switching circuits on and off in real time, improving response speed. The rectifier circuit can be directly connected to the negative terminal of the AC power supply to obtain AC power, eliminating the need for an external AC power source, thereby reducing the size of the heating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic structural diagram of a heating device provided in an embodiment of the present application;

[0041] Figure 2 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0042] Figure 3 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0043] Figure 4 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0044] Figure 5 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0045] Figure 6 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0046] Figure 7 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0047] Figure 8 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0048] Figure 9 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0049] Figure 10 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0050] Figure 11 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0051] Figure 12 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0052] Figure 13 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0053] Figure 14 A schematic structural diagram of another heating device provided in an embodiment of the present application;

[0054] Figure 15 A schematic structural diagram of another heating device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The present application is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0056] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various implementations, and the operational steps involved in each embodiment may be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for the purpose of clearly describing a particular embodiment and do not imply a required composition and / or sequence.

[0057] The serial numbers assigned to components herein, such as "first," "second," etc., are used solely to distinguish the objects being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0058] Figure 1 This is a schematic diagram of the structure of a heating device provided in an embodiment of the present application. Figure 1The terminal device includes a first switch control circuit 1, a first switch circuit 2, a second switch circuit 3, a rectifier circuit 4, and a holding circuit 5. The first switch control circuit 1 includes a control terminal k1, a first terminal k2, and a second terminal k3. The control terminal k1 of the first switch control circuit 1 is used to receive a control signal. The first terminal k2 of the first switch control circuit 1 is connected to the control power supply terminal. When the first switch control circuit 1 receives a control signal through its control terminal k1, its first terminal k2 and second terminal k3 are turned on. Otherwise, its first terminal k2 and second terminal k3 are turned off. The first switch circuit 2 has a control electrode y1, a first electrode y2, and a second electrode y3. The control electrode y1 of the first switch circuit 2 is connected to the second terminal k3 of the first switch control circuit 1. The first electrode y2 of the first switch circuit 2 is used to connect to the positive terminal A of the AC power supply. C+, the second pole y3 of the first switch circuit 2 is connected to the working ground. When the first terminal k2 and the second terminal k3 of the first switch control circuit 1 are turned on, the control pole y1 of the first switch circuit 2 can obtain the conduction voltage from the second terminal k3 of the first switch control circuit 1, thereby turning on its first pole y2 and the second pole y3, so as to transmit the AC power corresponding to the AC power supply connected to its first pole y2 to its second pole y3. On the contrary, the first switch circuit 2 disconnects its first pole y2 and the second pole y3; the second switch circuit 3 has a control pole e1, a first pole e2 and a second pole e3. The control pole e1 of the second switch circuit 3 is connected to the second terminal k3 of the first switch control circuit 1, and the second pole e3 is connected to the control pole e1 of the second switch circuit 3. A load RL is connected between the first electrode e2 of the switch circuit 3 and the negative terminal AC- of the AC power supply. The second electrode e3 of the second switch circuit 3 is connected to the second electrode y3 of the first switch circuit 1. The second electrode e3 of the second switch circuit 3 is also connected to the working ground. The control electrode e1 of the second switch circuit 3 can obtain a conduction voltage from the second terminal k3 of the first switch control circuit 1, thereby conducting the second electrode e3 and the first electrode e2 of the second switch circuit 3 to transmit the AC power of the second electrode e3 of the second switch circuit 3 to the load, thereby supplying power to the load. Conversely, the second switch circuit 3 disconnects the first electrode e2 and the second electrode e3, thereby not supplying power to the load. The rectifier circuit 4 includes a first terminal z1, the second end z2 and the output end z3, the first end z1 of the rectifier circuit 4 is used to connect to the negative end AC- of the AC power supply, the second end z2 of the rectifier circuit 4 is connected to the working ground, the rectifier circuit 4 is used to rectify the AC power of the AC power supply to generate DC power, and output it through its output end z3; the holding circuit 5 includes a first end b1 and a second end b2, the first end b1 of the holding circuit 5 is respectively connected to the output end z3 and the control power supply end of the rectifier circuit 4, the second end b2 of the holding circuit 5 is connected to the working ground, the holding circuit 5 obtains and stores electrical energy from the output end z3 of the rectifier circuit through its first end b1, so that the voltage of the control power supply end connected to its first end b1 is maintained.

[0059] Since the control terminal of the first switch control circuit is used to receive a control signal, when the control signal is received, the first switch control circuit will connect its first terminal and second terminal, and if the control signal is not received, the first terminal and second terminal will be disconnected. In other words, if the control terminal of the first switch control circuit continues to receive a control signal, the first terminal and second terminal will continue to connect; if the control terminal of the first switch control circuit does not receive a control signal, the first terminal and second terminal will remain disconnected until a control signal is received, at which time the first terminal and second terminal will be connected.

[0060] For example, assuming the heating device is a soldering iron, the soldering iron has an external toggle switch that is used to control the transmission of a signal. That is, a user can toggle the toggle switch to enable or disable the control terminal of the first switch control circuit to receive a control signal. For example, if the toggle switch is toggled, the control terminal of the first switch control circuit can receive the control signal, and in this case, the first switch control circuit will conduct between its first terminal and its second terminal. If the toggle switch is not toggled, the control terminal of the first switch control circuit cannot receive the control signal, and in this case, the first switch control circuit will disconnect between its first terminal and its second terminal.

[0061] It should be noted that the above description is based on the assumption that the control end of the first switch control circuit connects the first and second ends when receiving a control signal, and disconnects the first and second ends when not receiving a control signal. Alternatively, in application, the first and second ends may be connected or disconnected based on information carried in the control signal. For example, if the control signal carries information to connect the first and second ends of the first switch control circuit, the first switch control circuit connects the first and second ends; if the control signal carries information to disconnect the first and second ends of the first switch control circuit, the first switch control circuit disconnects the first and second ends. In other words, the embodiments of the present application do not limit the control signal that controls the first switch control circuit to be connected or disconnected.

[0062] Continuing with the above description, since the first terminal of the first switch control circuit is also connected to the control power terminal, when the first and second terminals of the first switch control circuit are conductive, a transmission path is provided for the voltage corresponding to the control power terminal. In other words, when the first and second terminals of the first switch control circuit are conductive, the voltage corresponding to the control power terminal can be transmitted from the first terminal to the second terminal and then output from the second terminal. When the first and second terminals of the first switch control circuit are not conductive, the voltage corresponding to the control power terminal cannot be transmitted from the first terminal to the second terminal and thus cannot be output from the second terminal.

[0063] Based on the above description, it can be seen that since the control electrode of the first switching circuit is connected to the second end of the first switching control circuit, when the first end and the second end of the first switching control circuit are turned on, the voltage corresponding to the control power supply end can be transmitted to the control electrode of the first switching circuit through the path formed by the first end and the second end. At this time, the control electrode of the first switching circuit can obtain the turn-on voltage from the second end of the first switching circuit, thereby turning on its first electrode and second electrode.

[0064] Since the first pole of the first switching circuit is used to connect to the positive end of the AC power supply and the second pole is connected to the working ground, when the first pole and the second pole of the first switching circuit are turned on, the AC power corresponding to the AC power supply connected to the first pole can be transmitted to the second pole, that is, the AC power is turned on at this time.

[0065] When the first end and the second end of the first switch control circuit are not conductive, the voltage corresponding to the control power supply end cannot be transmitted to the control electrode of the first switch circuit. At this time, the control electrode of the first switch circuit cannot obtain the conduction voltage from the second end of the first switch control circuit, and cannot conduct its own first and second electrodes. Furthermore, the AC power corresponding to the AC power supply connected to the first electrode cannot be transmitted to the second electrode. In other words, the AC power is disconnected at this time.

[0066] Similar to the first switching circuit, the second switching circuit also has a control electrode, and the control electrode of the second switching control circuit is also connected to the second end of the first switching control circuit. Therefore, when the first end and the second end of the first switching control circuit are turned on, the second switching circuit can also obtain the turn-on voltage from the second end of the first switching control circuit, thereby turning on its own first electrode and second electrode.

[0067] Because the second pole of the second switching circuit is connected to the second pole of the first switching circuit, when the first pole and the second pole of the first switching circuit are conductive, AC power can flow from the second pole of the first switching circuit to the second pole of the second switching circuit. Furthermore, a load is connected between the first pole of the second switching circuit and the negative terminal of the AC power source, and thus, when the first pole and the second pole of the second switching circuit are conductive, AC power can be supplied to the load.

[0068] Based on the above description, it can be seen that when the first end and the second end of the first switch control circuit are not conductive, the control electrode of the second switch circuit cannot obtain the conduction voltage from the second end of the first switch control circuit, and cannot conduct its own first electrode and second electrode. At this time, the first switch circuit cannot conduct its own first electrode and first electrode, and cannot provide AC power to the load.

[0069] Since the first end of the rectifier circuit can be directly connected to the negative end of the AC power supply, when the AC power is in the negative half cycle of the AC power, the AC power can enter the rectifier circuit from the first end of the rectifier circuit. The rectifier circuit will rectify the AC power to generate DC power and output it through its own output end. In other words, the current output by the rectifier circuit is DC power. Compared with the method that still requires an external AC power supply, the above method of directly connecting to the negative end of the internal AC power supply can reduce the volume of the heating device.

[0070] Since the first end of the holding circuit is connected to the output end of the rectifier circuit, the holding circuit can obtain direct current from the output end of the rectifier circuit and store the obtained direct current as electrical energy; the first end of the holding circuit is also connected to the control power supply end, so the control power supply end can obtain voltage from the holding circuit to maintain its own voltage, thereby ensuring that the turn-on voltage obtained by the first switching circuit and the second switching circuit from the second end of the first switching control circuit can turn on the first pole and the first pole of the first switching circuit, and turn on the first pole and the second pole of the second switching circuit.

[0071] In some embodiments, please refer to Figure 2 The first switch circuit 2 includes a MOS transistor Q1, which also has a body diode V1. The MOS transistor Q1 has a gate G, a drain D, and a source S. The gate G of the MOS transistor Q1 is connected to the second terminal k3 of the first switch control circuit 1. The drain D of the MOS transistor Q1 is used to connect to the positive terminal of the AC power supply. The source S of the MOS transistor Q1 is connected to the working ground. The gate G of the MOS transistor Q1 serves as the control electrode y1 of the first switch circuit 2. The drain D of the MOS transistor Q1 serves as the first electrode y2 of the first switch circuit 2. The source S of the MOS transistor Q1 serves as the second electrode y1 of the first switch circuit 2. The anode of the body diode V1 is connected to the source S of the MOS transistor Q1, and the cathode of the body diode V1 is connected to the drain D of the MOS transistor Q1. The body diode V1 is used to provide a path for AC power to flow from the negative terminal of the AC power supply to the positive terminal of the AC power supply when the AC power supply is in the negative half cycle.

[0072] That is, the gate of the MOS transistor Q1 is connected to the second terminal of the first switch control circuit. Thus, when the first and second terminals of the first switch control circuit are conductive, the gate of the MOS transistor Q1 can obtain a conductive voltage from the second terminal of the first switch control circuit, thereby conductively connecting its drain and source. Furthermore, the drain of the MOS transistor Q1 is also connected to the positive terminal of the AC power supply. Thus, when its drain and source are conductive, the AC power corresponding to the AC power supply connected to its drain can be transmitted to its drain.

[0073] For example, assuming that the MOS transistor Q1 is an N-MOS transistor (N-Metal Oxide Semiconductor Field Effect Transistor), a turn-on condition for the N-MOS transistor is that the voltage between the gate and the source is greater than or equal to a threshold voltage. Since the gate of the MOS transistor Q1 can obtain the turn-on voltage from the second terminal of the first switch control circuit, and the source of the MOS transistor Q1 is connected to the working ground, it can be seen that the voltage between the gate and the source of the MOS transistor Q1 is equal to the turn-on voltage. In other words, the turn-on voltage is greater than the threshold voltage. Therefore, when the gate of the MOS transistor Q1 obtains the turn-on voltage from the second terminal of the first switch control circuit, the MOS transistor Q1 is turned on and transmits the AC power corresponding to the AC power source connected to its drain to the drain. If the gate of the MOS transistor Q1 does not obtain the turn-on voltage, the MOS transistor Q1 is turned off.

[0074] It should be noted that the above description is based on the MOS transistor Q1 being an N-MOS transistor. Alternatively, in an application, the MOS transistor Q1 may also be a P-MOS transistor (P-Metal Oxide Semiconductor Field Effect Transistor) or other MOS transistors, and the embodiments of the present application are not limited to this.

[0075] Continuing with the above description, MOS transistor Q1 may also have a body diode V1. Since the anode of body diode V1 is connected to the source of MOS transistor Q1, and the cathode is connected to the drain of MOS transistor Q1, when the AC power supply is in the negative half cycle, the body diode V1 can ensure that the AC power flows from the negative end of the AC power supply to the positive end of the AC power supply.

[0076] In some embodiments, please refer to Figure 3The second switch circuit 3 includes a MOS transistor Q2, which also has a body diode V2. The MOS transistor Q2 has a gate G, a drain D, and a source S. The gate G of the MOS transistor Q2 is connected to the second terminal k3 of the first switch control circuit 1. The drain D of the MOS transistor Q2 is connected to the negative terminal of the AC power supply for connecting a load. The source S of the MOS transistor Q2 is connected to the source S of the MOS transistor Q1 and is also connected to the working ground. The gate G of the MOS transistor Q2 serves as the control electrode e1 of the second switch circuit 3. The drain D of the MOS transistor Q2 serves as the first electrode e2 of the second switch circuit 3. The source S of the MOS transistor Q2 serves as the second electrode e3 of the second switch circuit 3. The anode of the body diode V2 is connected to the source S of the MOS transistor Q2, and the cathode of the body diode V2 is connected to the drain D of the MOS transistor Q2. The body diode V2 is used to provide a path for AC power to flow from the positive terminal of the AC power supply to the negative terminal of the AC power supply when the AC power supply is in the positive half cycle.

[0077] That is, the gate of MOS transistor Q2 is connected to the second end of the first switch control circuit. Thus, when the first and second ends of the first switch control circuit are conductive, the gate of MOS transistor Q2 receives the conductive voltage from the second end of the first switch control circuit, thereby conductively connecting its drain and source. Furthermore, the source of MOS transistor Q2 is also connected to the source of MOS transistor Q1. Thus, when both MOS transistor Q1 and MOS transistor Q2 are conductive, the source of MOS transistor Q2 can receive AC power corresponding to the AC power supply from the source of MOS transistor Q1 and transmit the AC power from its own source to its drain.

[0078] When AC power is transmitted from the source to the drain of the MOS transistor Q2, since the load is also connected between the MOS transistor Q2 and the negative electrode of the AC power source, the AC power can be transmitted to the load through the drain output of the MOS transistor Q2, thereby powering the load.

[0079] Similar to the above-mentioned MOS transistor Q1 , the MOS transistor Q2 may be an N-MOS transistor or a P-MOS transistor, which is not limited in the embodiment of the present application.

[0080] Continuing with the above description, the MOS transistor Q2 may further include a body diode V2. Since the anode of the body diode V2 is connected to the source of the MOS transistor Q2, and the cathode is connected to the drain of the MOS transistor Q2, when the AC power supply is in the positive half cycle, the body diode V2 can ensure that the AC power flows from the positive end of the AC power supply to the negative end of the AC power supply.

[0081] Based on the above description, it can be seen that the embodiment of the present application can directly control the conduction or disconnection of the alternating current by controlling the conduction or disconnection of the MOS tube Q1 and the MOS tube Q2, which has the advantage of fast response time and does not require the use of a rectifier bridge to rectify the alternating current into direct current for control. In this way, the current conversion efficiency can be high, the heat generated by the heating device during operation is small, and the safe operation of the heating device is ensured.

[0082] In some embodiments, please refer to Figure 4 The first switch control circuit 1 includes an optocoupler U1, which has a power supply terminal g1, a control terminal g2, a first terminal g3, and a second terminal g4. The power supply terminal g1 of the optocoupler U1 is used to connect to a power supply, and the control terminal g2 of the optocoupler U1 is used to receive a control signal. The first terminal g3 of the optocoupler U1 is connected to the control power supply terminal, and the second terminal g4 of the optocoupler U1 is respectively connected to the gate G of the MOS transistor Q1 and the gate G of the MOS transistor Q2. When the optocoupler U1 receives a control signal through its control terminal g2, the first terminal g3 and the second terminal g4 are turned on, and otherwise, the first terminal g3 and the second terminal g4 are turned off; the control terminal g2 of the optocoupler U1 serves as the control terminal k1 of the first switch control circuit 1, the first terminal g3 of the optocoupler U1 serves as the first terminal k2 of the first switch control circuit 1, and the second terminal g4 of the optocoupler U1 serves as the second terminal k3 of the first switch control circuit 1.

[0083] Since optocoupler U1 is a photoelectric device, it requires a power source to operate. Therefore, the power supply terminal of optocoupler U1 is used to connect to a power supply, thereby powering optocoupler U1. Furthermore, the control terminal of optocoupler U1 is used to receive a control signal. The first terminal of optocoupler U1 is connected to the control power terminal, and the second terminal is connected to the gate of MOS transistor Q1 and the gate of MOS transistor Q2, respectively. Therefore, when the control terminal of optocoupler U1 receives a control signal, optocoupler U1 will conduct its first and second terminals. In this way, the voltage corresponding to the control power source will be transmitted from the second terminal of optocoupler U1 to the gate of MOS transistor Q1 and the gate of MOS transistor Q2, so that both gates can obtain the conduction voltage.

[0084] Since the first switch control circuit includes the optocoupler U1 , the heating device has the advantage of isolating the first switch control circuit from other circuits, thereby playing a protective role.

[0085] In some embodiments, please refer to Figure 5 The first switch control circuit 1 further includes a voltage divider sub-circuit 11, which is connected between the second terminal g4 of the optocoupler U1 and the gate G of the MOS transistor Q1 and the gate G of the MOS transistor Q2. The voltage divider sub-circuit 11 is used to distribute the voltage of the control power supply to the gate G of the MOS transistor Q1 and the gate G of the MOS transistor Q2.

[0086] In order to ensure that the turn-on voltages obtained by the gates of the MOS transistor Q1 and the MOS transistor Q2 can both meet their respective turn-on conditions, the first switch control circuit may further include a voltage divider circuit.

[0087] In some embodiments, please refer to Figure 6 The voltage divider subcircuit can include resistors R2 and R3. One end of resistor R2 is connected to the second end of the optocoupler U1, and the other end of resistor R2 is connected to one end of resistor R3, the gate of MOS transistor Q1, and the gate of MOS transistor Q2, respectively. The other end of resistor R3 is grounded. In this way, resistors R2 and R3 can perform a voltage divider, thereby ensuring that the turn-on voltages obtained by the gates of MOS transistors Q1 and Q2 meet the turn-on conditions.

[0088] In some embodiments, please refer to Figure 7 The first switch control circuit may further include a current limiting resistor R4, which is connected between the power supply and the optocoupler U1 and can limit the current, thereby preventing the optocoupler U1 from being burned out due to excessive current.

[0089] In some embodiments, please refer to Figure 8 Holding circuit 5 includes capacitor C1. One end of capacitor C1 is connected to output terminal z3 of rectifier circuit 4 and the control power supply terminal, respectively. The other end of capacitor C1 is connected to the operating ground. One end of capacitor C1 serves as first end b1 of holding circuit 5, and the other end of capacitor C1 serves as second end b2 of holding circuit 5. In other words, capacitor C1 can obtain and store electrical energy from the output of the rectifier circuit, thereby maintaining the voltage of the control power supply terminal connected to it.

[0090] In addition, in some embodiments, since the capacitor maintains the voltage of the control power supply terminal by discharging the capacitor to the control power supply terminal, and the control power supply terminal can enable the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 to obtain their corresponding voltages through the optocoupler U1, the magnitude of the voltage obtained by the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 can be changed by changing the magnitude of the discharge of the capacitor C1 to the control power supply terminal, thereby controlling the switching on or off of the MOS transistor Q1 and the MOS transistor Q2.

[0091] It should be noted that the above description is based on the holding circuit including the capacitor C1. In application, the holding circuit may also include other components capable of storing energy, which is not limited in the embodiments of the present application.

[0092] In some embodiments, please refer to Figure 9The rectifier circuit 4 includes a diode V3, a resistor R1 and a Zener diode ZD1. The positive electrode of the diode V3 is used to connect to the negative terminal AC- of the AC power supply, the negative electrode of the diode V3 is connected to the first end of the resistor R1, and the second end of the resistor R1 is respectively connected to the negative electrode of the Zener diode ZD1 and one end of the capacitor C1. The resistor R1 is used to limit the current amplitude to prevent damage to the components in the heating equipment. The positive electrode of the Zener diode ZD1 is connected to the working ground. The positive electrode of the diode V3 serves as the first end z1 of the rectifier circuit 4, the positive electrode of the Zener diode ZD1 serves as the second end z2 of the rectifier circuit 4, and the second end of the resistor R1 serves as the output end z3 of the rectifier circuit 4.

[0093] Since the diode V3 has unidirectional conductivity, that is, it only allows current to pass in one direction, the rectifier circuit can include the diode V3 to rectify the AC power; in addition, in order to maintain voltage stability, the rectifier circuit can also include a voltage regulator diode ZD1.

[0094] It should be noted that the above description is based on the rectifier circuit including the diode V3, the resistor R1 and the Zener diode ZD1. In application, other components may also be included. The embodiment of the present application does not limit the composition of the rectifier resistor.

[0095] In some embodiments, please refer to Figure 10 The heating device also includes a second switch control circuit 6, which includes a control terminal d1, a first terminal d2, a second terminal d3, and a third terminal d4. The control terminal d1 is used to receive a control signal, the first terminal d2 is connected to the working ground, the second terminal d3 is connected to the gate G of the MOS transistor Q1 and the gate G of the MOS transistor Q2, respectively, and the third terminal d4 is connected to the source S of the MOS transistor Q1 and the source S of the MOS transistor Q2, respectively. When the second switch control circuit 6 receives a control signal through its control terminal d1, the second terminal d2 and the third terminal d3 are disconnected. Otherwise, the second terminal d2 and the third terminal d3 are connected. When the MOS transistor Q1 and the MOS transistor Q2 are disconnected, discharge control between the gate and the source is achieved, thereby improving the anti-interference capability of the heating device.

[0096] Because the control terminal of the second switch control circuit is used to receive a control signal, the second switch control circuit disconnects its second and third terminals when it receives a control signal, and connects its second and third terminals when it does not receive a control signal. In other words, if the control terminal of the second switch control circuit continues to receive a control signal, the second and third terminals remain disconnected; if the control terminal of the second switch control circuit does not receive a control signal, the second and third terminals remain connected until a control signal is received, at which point the second and third terminals are disconnected.

[0097] For example, assuming the heating device is a soldering iron, the soldering iron has an external toggle switch that is used to control the transmission of a signal. That is, a user can toggle the toggle switch to enable the control terminal of the second switch control circuit to receive a control signal or to disable the control signal. For example, if the toggle switch is not toggled, the control terminal of the second switch control circuit can receive the control signal, and in this case, the second switch control circuit will conduct between its second and third terminals. If the toggle switch is toggled, the control terminal of the second switch control circuit cannot receive the control signal, and in this case, the second switch control circuit will disconnect between its second and third terminals.

[0098] It should be noted that the above description is based on the assumption that the second switch control circuit disconnects its second and third terminals when the control terminal receives a control signal, and connects its second and third terminals when it does not receive a control signal. Alternatively, in application, the second and third terminals can also be connected or disconnected based on information carried in the control signal. For example, if the control signal carries information to connect the second and third terminals of the second switch control circuit, the second switch control circuit connects its second and third terminals; if the control signal carries information to disconnect the second and third terminals of the second switch control circuit, the second switch control circuit disconnects its second and third terminals. In other words, the embodiments of the present application do not limit the control signal that controls the second switch control circuit to be connected or disconnected.

[0099] Continuing with the above description, since the second end of the second switch control circuit is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, respectively, and the third end of the second switch control circuit is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, respectively, and the first end of the second switch control circuit is also connected to the working ground, when the second and third ends are conductive, discharge can be achieved between the gate and source of the MOS transistor Q1 and between the gate and source of the MOS transistor Q2 when the MOS transistor Q1 and the MOS transistor Q2 are disconnected, thereby enhancing the anti-interference capability of the heating device.

[0100] Based on the above description, it can be seen that when the first and second terminals of the first switch control circuit are conductive, the gates of MOS transistors Q1 and Q2 can obtain the conduction voltage from the second terminal of the first switch control circuit, thereby turning on MOS transistors Q1 and Q2. When the second and third terminals of the second switch control circuit are conductive, discharge control between the gate and source can be achieved when MOS transistors Q1 and Q2 are disconnected. When MOS transistors Q1 and Q2 are disconnected, it means that the gates of MOS transistors Q1 and Q2 do not obtain the conduction voltage from the second terminal of the first switch control circuit, that is, the first and second terminals of the first switch control circuit are disconnected. Therefore, when the first and second terminals of the first switch control circuit are conductive, the second and third terminals of the second switch control circuit are disconnected; when the first and second terminals of the first switch control circuit are disconnected, the second and third terminals of the second switch control circuit are conductive.

[0101] In some embodiments, please refer to Figure 11 The second switch control circuit 6 includes an optocoupler U2, which has a control end u1, a first end u2, a second end u3 and a third end u4. The control end u1 of the optocoupler U2 is used to receive a control signal. The first end u2 of the optocoupler U2 is connected to the working ground. The second end u3 of the optocoupler U2 is respectively connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2. The third end of the optocoupler U2 is respectively connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2. When the optocoupler U2 receives a control signal through its control end u1, the second end u3 and the third end u4 are disconnected. Conversely, the second end u3 and the third end u4 are disconnected. The control end u1 of the optocoupler U2 serves as the control end z1 of the second switch control circuit 6, the first end u2 of the optocoupler U2 serves as the first end z2 of the second switch control circuit 6, the second end u3 of the optocoupler U2 serves as the second end z3 of the second switch control circuit 6, and the third end u4 of the optocoupler U2 serves as the third end z4 of the second switch control circuit 6.

[0102] Since the control end of optocoupler U2 is used to receive control signals, its second end is connected to the gate of MOS transistor Q1 and the gate of MOS transistor Q2, respectively, and its third end is connected to the source of MOS transistor Q1 and the source of MOS transistor Q2, respectively. The first end is also connected to the operating ground. Therefore, when the control end of optocoupler U2 does not receive a control signal, optocoupler U2 will conduct its second and third ends, thereby discharging the gate and source of MOS transistor Q1 and the gate and source of MOS transistor Q2. When the control end of optocoupler U2 receives a control signal, optocoupler U2 will disconnect its second and third ends, thereby preventing discharge of the gate and source of MOS transistor Q1 and the gate and source of MOS transistor Q2. Thus, by controlling the conduction or disconnection of the second and third ends of optocoupler U2, discharge between the gate and source can be controlled when MOS transistors Q1 and Q2 are disconnected, thereby enhancing the anti-interference capability of the heating device.

[0103] Based on the above description, it can be seen that the gates of MOS transistors Q1 and Q2 can obtain a turn-on voltage from the second terminal of optocoupler U1 when optocoupler U1 is turned on. Thus, when the first switch control circuit further includes a voltage divider subcircuit, and the voltage divider subcircuit includes resistors R2 and R3, the magnitude of the turn-on voltage obtained by the gates of MOS transistors Q1 and Q2 is related to the value of resistor R3. For example, the larger the resistance of resistor R3, the greater the turn-on voltage obtained by the gates of MOS transistors Q1 and Q2; and the smaller the resistance of resistor R3, the smaller the turn-on voltage obtained by the gates of MOS transistors Q1 and Q2. Therefore, the smaller the resistance of resistor R3, the shorter the discharge time between the gate and source of MOS transistor Q1 and the gate and source of MOS transistor Q2.

[0104] In some embodiments, please refer to Figure 12 The second switch control circuit 6 also includes a current control subcircuit 61. The current control subcircuit 61 includes a first terminal kz1, a second terminal kz2, and a third terminal kz3. The first terminal kz1 of the current control subcircuit 61 is connected to the second terminal u3 of the optocoupler U2, the second terminal kz2 of the current control subcircuit 61 is connected to the third terminal u4 of the optocoupler U2, and the third terminal kz3 of the current control subcircuit 61 is connected to the gate G of the MOS transistor Q1 and the gate G of the MOS transistor Q2, respectively. The current control subcircuit 61 is used to control the flow direction of the discharge current of the gate G and source S of the MOS transistor Q1 and the gate G and source S of the MOS transistor Q2 when the second switch control circuit 6 is turned on, so as to avoid interference with other parts of the heating device.

[0105] In addition, in some embodiments, please refer to Figure 13The current control subcircuit 61 includes a diode V4 and a diode V5. The anode of diode V4 is connected to the second terminal u3 of the optocoupler U2, and the cathode of diode V4 is connected to the cathode of diode V5, the gate G of MOS transistor Q1, and the gate G of MOS transistor Q2, respectively. The anode of diode V5 is connected to the third terminal of optocoupler U2. The anode of diode V4 serves as the first terminal kz1 of the current control subcircuit 61, the anode of diode V5 serves as the second terminal kz2 of the current control subcircuit 61, and the terminal where diodes V4 and V5 are connected serves as the third terminal kz3 of the current control subcircuit 61.

[0106] Since the diode has unidirectional conductivity, and the cathode of the diode V4 is respectively connected to the cathode of the diode V5, the gate G of the MOS transistor Q1, and the gate G of the MOS transistor Q2, the third end of the optocoupler U2 is respectively connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, and the anode of the diode V5 is connected to the third end of the optocoupler U2, therefore, when the gate and source of the MOS transistor Q1 are discharging, the current flow direction can be controlled to avoid interference with other parts of the heating device. Similarly, when the gate and source of the MOS transistor Q2 are discharging, the current flow direction can also be controlled.

[0107] In some embodiments, please refer to Figure 14 The current control subcircuit 61 further includes a resistor R5, which is connected between one end for sending the control signal and the control end u1 of the optocoupler U2, and can limit the current, thereby preventing the optocoupler U2 from being burned out by excessive current.

[0108] In addition, in some embodiments, please refer to Figure 15 The current control subcircuit also includes a resistor R6, one end of which is connected to the third terminal u4 of the optocoupler U2, and the other end is connected to the negative electrode of the diode V4. The resistor R6 plays a role in voltage division to prevent the diode or optocoupler U2 from being damaged due to excessive voltage.

[0109] In an embodiment of the present application, the second pole of the first switching circuit is connected to the second pole of the second switching circuit to form an electronic switch. By controlling the conduction or disconnection of the first switching circuit and the second switching circuit, the conduction or disconnection of the alternating current can be directly controlled, eliminating the need to rectify the alternating current into direct current and then control the conduction or disconnection. This can reduce the loss of the alternating current and lower the heat generation. In addition, the heating device also includes a first switch control circuit that can conduct or disconnect the first switching circuit and the second switching circuit in real time, thereby improving the response speed. The rectifier circuit can be directly connected to the negative terminal of the alternating current power supply to obtain alternating current, eliminating the need for an external alternating current source, thereby reducing the size of the heating device. Furthermore, the first switch control circuit can include an optocoupler. In this way, the optocoupler can achieve the advantage of isolating the first switch control circuit from other circuits, thereby providing a protective effect. The heating device can also include a second switch control circuit that can control the discharge between the gate and source of the MOS transistor Q1 and the gate and source of the MOS transistor Q2, thereby increasing the anti-interference capability of the heating device.

[0110] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art of the present invention can make some simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A heating device, characterized in that: include: a first switch control circuit, the first switch control circuit comprising a control terminal, a first terminal, and a second terminal; the control terminal of the first switch control circuit is used to receive a control signal, and the first terminal of the first switch control circuit is connected to a control power supply terminal; when the first switch control circuit receives the control signal through the control terminal, the first terminal and the second terminal are connected; otherwise, the first terminal and the second terminal are disconnected; a first switch circuit, the first switch circuit comprising a control electrode, a first electrode, and a second electrode; the control electrode of the first switch circuit being connected to the second end of the first switch control circuit, the first electrode of the first switch circuit being used to connect to the positive terminal of the AC power source, and the second electrode of the first switch circuit being connected to the working ground; when the first end and the second end of the first switch control circuit are conductive, the control electrode of the first switch circuit can obtain a conductive voltage from the second end of the first switch control circuit, thereby conductively connecting the first electrode and the second electrode thereof, thereby transmitting the AC power corresponding to the AC power source connected to the first electrode to the second electrode thereof; conversely, the first switch circuit disconnects the first electrode and the second electrode thereof; a second switch circuit, the second switch circuit comprising a control electrode, a first electrode, and a second electrode; the control electrode of the second switch circuit being connected to the second end of the first switch control circuit; a load being connected between the first electrode of the second switch circuit and the negative end of the AC power supply; and a second electrode of the second switch circuit being connected to the second electrode of the first switch circuit; the second electrode of the second switch circuit being further connected to a working ground; the control electrode of the second switch circuit being capable of obtaining a conduction voltage from the second end of the first switch control circuit, thereby conducting conduction between the second electrode and the first electrode, thereby transmitting AC power from the second electrode of the second switch circuit to the load, thereby powering the load; conversely, the second switch circuit being capable of disconnecting the first electrode and the second electrode, thereby not powering the load; a rectifier circuit, the rectifier circuit comprising a first end, a second end, and an output end; the first end of the rectifier circuit being connected to the negative end of the AC power source, and the second end of the rectifier circuit being connected to a working ground; the rectifier circuit being configured to rectify the AC power of the AC power source to generate DC power and output the DC power through the output end; A holding circuit, the holding circuit comprising a first end and a second end, the first end of the holding circuit being respectively connected to the output end of the rectifier circuit and the control power supply end, and the second end of the holding circuit being connected to a working ground; the holding circuit obtains and stores electrical energy from the output end of the rectifier circuit through its first end, so that the voltage of the control power supply end connected to its first end is maintained.

2. The heating device according to claim 1, characterized in that The first switch circuit includes a MOS transistor Q1, and the MOS transistor Q1 also has a body diode V1; The MOS transistor Q1 has a gate, a drain, and a source. The gate of the MOS transistor Q1 is connected to the second end of the first switch control circuit. The drain of the MOS transistor Q1 is used to connect to the positive end of the AC power supply. The source of the MOS transistor Q1 is connected to the working ground. The gate of the MOS transistor Q1 serves as the control electrode of the first switch circuit, the drain of the MOS transistor Q1 serves as the first electrode of the first switch circuit, and the source of the MOS transistor Q1 serves as the second electrode of the first switch circuit; The anode of the body diode V1 is connected to the source of the MOS transistor Q1, and the cathode of the body diode V1 is connected to the drain of the MOS transistor Q1. The body diode V1 is used to provide a path for the AC power to flow from the negative end of the AC power supply to the positive end of the AC power supply when the AC power supply is in the negative half cycle.

3. The heating device according to claim 2, characterized in that The second switch circuit includes a MOS transistor Q2, and the MOS transistor Q2 also has a body diode V2; The MOS transistor Q2 has a gate, a drain, and a source. The gate of the MOS transistor Q2 is connected to the second end of the first switch control circuit. The drain of the MOS transistor Q2 and the negative end of the AC power supply are used to connect a load. The source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1 and is also connected to the working ground. The gate of the MOS transistor Q2 serves as the control electrode of the second switch circuit, the drain of the MOS transistor Q2 serves as the first electrode of the second switch circuit, and the source of the MOS transistor Q2 serves as the second electrode of the second switch circuit; The anode of the body diode V2 is connected to the source of the MOS transistor Q2, and the cathode of the body diode V2 is connected to the drain of the MOS transistor Q2. The body diode V2 is used to provide a path for the AC power to flow from the positive end of the AC power supply to the negative end of the AC power supply when the AC power supply is in the positive half cycle.

4. The heating device according to claim 3, characterized in that The first switch control circuit includes an optocoupler U1; The optocoupler U1 has a power supply end, a control end, a first end, and a second end. The power supply end of the optocoupler U1 is used to connect to a power supply; the control end of the optocoupler U1 is used to receive a control signal. The first end of the optocoupler U1 is connected to the control power supply end, and the second end of the optocoupler U1 is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 respectively. When the optocoupler U1 receives the control signal through its control end, the first end and the second end are connected, otherwise, the first end and the second end are disconnected. The control end of the optocoupler U1 serves as the control end of the first switch control circuit, the first end of the optocoupler U1 serves as the first end of the first switch control circuit, and the second end of the optocoupler U1 serves as the second end of the first switch control circuit.

5. The heating device according to claim 4, characterized in that The first switch control circuit further includes a voltage divider circuit; The voltage divider sub-circuit is connected between the second end of the optocoupler U1 and the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, and is used to distribute the voltage of the control power supply to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2.

6. The heating device according to claim 1, wherein The holding circuit includes a capacitor C1; One end of the capacitor C1 is connected to the output end of the rectifier circuit and the control power supply end respectively, and the other end of the capacitor C1 is connected to the working ground; One end of the capacitor C1 serves as the first end of the holding circuit; the other end of the capacitor C1 serves as the second end of the holding circuit.

7. The heating device according to claim 6, characterized in that The rectifier circuit includes a diode V3, a resistor R1 and a voltage stabilizing diode ZD1; The anode of the diode V3 is connected to the negative terminal of the AC power supply, and the cathode of the diode V3 is connected to the first end of the resistor R1; the second end of the resistor R1 is connected to the cathode of the voltage-stabilizing diode ZD1 and one end of the capacitor C1, respectively. The resistor R1 is used to limit the current amplitude to prevent damage to the components in the heating device; the anode of the voltage-stabilizing diode ZD1 is connected to the working ground; The anode of the diode V3 serves as the first end of the rectifier circuit, the anode of the voltage-stabilizing diode ZD1 serves as the second end of the rectifier circuit, and the second end of the resistor R1 serves as the output end of the rectifier circuit.

8. The heating device according to any one of claims 1 to 7, characterized in that: The heating device also includes: a second switch control circuit, the second switch control circuit comprising a control terminal, a first terminal, a second terminal, and a third terminal; The control end is used to receive a control signal. The first end is connected to a working ground. The second end is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, respectively. The third end is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, respectively. When the second switch control circuit receives the control signal through its control end, the second end and the third end are disconnected. Otherwise, the second end and the third end are connected. When the MOS transistor Q1 and the MOS transistor Q2 are disconnected, discharge control between the gate and the source is achieved, thereby improving the anti-interference capability of the heating device.

9. The heating device according to claim 8, characterized in that The second switch control circuit includes an optocoupler U2; The optocoupler U2 has a control end, a first end, a second end, and a third end. The control end of the optocoupler U2 is used to receive the control signal. The first end of the optocoupler U2 is connected to the working ground. The second end of the optocoupler U2 is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2, respectively. The third end of the optocoupler U2 is connected to the source of the MOS transistor Q1 and the source of the MOS transistor Q2, respectively. When the optocoupler U2 receives the control signal through its control end, its second end and third end are disconnected. Otherwise, its second end and third end are disconnected. The control end of the optocoupler U2 serves as the control end of the second switch control circuit, the first end of the optocoupler U2 serves as the first end of the second switch control circuit, the second end of the optocoupler U2 serves as the second end of the second switch control circuit, and the third end of the optocoupler U2 serves as the third end of the second switch control circuit.

10. The heating device according to claim 9, characterized in that The second switch control circuit further includes a current control subcircuit; The current control subcircuit includes a first end, a second end, and a third end; the first end of the current control subcircuit is connected to the second end of the optocoupler U2, the second end of the current control subcircuit is connected to the third end of the optocoupler U2, and the third end of the current control subcircuit is connected to the gate of the MOS transistor Q1 and the gate of the MOS transistor Q2 respectively; the current control subcircuit is used to control the flow direction of the discharge current of the gate and source of the MOS transistor Q1 and the gate and source of the MOS transistor Q2 when the second switch control circuit is turned on, so as to avoid interference with other parts of the heating device.

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