A constant temperature electric soldering iron driving power supply circuit

Abstract

The present invention discloses a constant temperature electric soldering iron driving power supply circuit, including a PD protocol charging unit, an MCU control unit, an electric soldering iron heating wire, a direct current power supply unit and an LED digital tube, wherein the input end of the PD protocol charging unit is connected to an external PD charger, and the output end is respectively connected to the MCU control unit and the electric soldering iron heating wire, and the MCU control unit is connected to the electric soldering iron heating wire, the direct current power supply unit and the LED digital tube. The present invention has a compact layout and can be directly installed inside the handle of the electric soldering iron device. The PD charger can directly drive the electric soldering iron heating wire through the PD protocol charging unit. The overall circuit only has power loss in the MCU control unit, and there is no large current conversion loss. Therefore, more than 99.5% of the electric energy output by the PD charger can act on the electric soldering iron heating wire, and the power supply efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of electric soldering irons, and in particular to a constant temperature electric soldering iron driving power supply circuit. Background Art

[0002] At present, there are two common types of electric soldering irons on the market in my country, one is the 230Vac direct plug-in handle type (non-isolated), and the other is the thermostatic control console (isolated). The first type of 230Vac direct plug-in non-isolated electric soldering iron has low cost and simple circuit, but it has the fatal disadvantage of easy leakage after long-term use, which may cause damage to electronic devices during the soldering process, and may affect personal safety in serious cases. The second type of electric soldering iron is equipped with a thermostatic control console (isolated type), which has good safety, accurate temperature control, and good electrostatic protection. It is currently the most used electric soldering iron on the market. However, this type of constant temperature electric soldering iron has a complex circuit and mostly uses old silicon steel sheet transformers for isolation and voltage reduction. It has low efficiency, and the general conversion efficiency is about 60%. It is also costly and large in size, occupies the workbench area, and is not conducive to operation. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a constant temperature electric soldering iron driving power supply circuit which has small size, high efficiency and is easy to operate.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] The present invention provides a constant temperature electric soldering iron driving power supply circuit, comprising a PD protocol charging unit, an MCU control unit, an electric soldering iron heating wire, a direct current power supply unit and an LED digital tube, wherein the input end of the PD protocol charging unit is connected to an external PD charger, and the output end is respectively connected to the MCU control unit and the electric soldering iron heating wire, and the MCU control unit is connected to the electric soldering iron heating wire, the direct current power supply unit and the LED digital tube; wherein the PD protocol charging unit is used to send a power configuration table from the PD charger to the MCU control unit, and receive a power value request issued by the MCU control unit based on the power configuration table, and send the power request to the PD charger; the direct current power supply unit is used to input direct current to the MCU control unit, the LED digital tube is used to display the temperature of the electric soldering iron heating wire, and the MCU control unit is used to control the heating temperature of the electric soldering iron heating wire.

[0006] In the present invention, as an optional embodiment, the PD protocol charging unit includes a power chip, the model of the power chip is IP2716_QFN32, and the power chip is respectively connected to an external PD charger, an MCU control unit and the electric soldering iron heating wire.

[0007] In the present invention, as an optional embodiment, the PD protocol charging unit also includes a charging circuit, the charging circuit includes a fuse, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a resistor RS1, one end of the fuse F1 is connected to the PD charger, and the capacitor C1 One end of the resistor RS1, one end of the resistor R1 and one end of the resistor R5 are all connected to the other end of the fuse F1, the other end of the capacitor C1, one end of the capacitor C3 and one end of the capacitor C6 are all grounded, the other end of the capacitor C3 and one end of the capacitor C2 are all connected to the power chip, the other end of the capacitor C2, one end of the resistor R2 and one end of the capacitor C4 are connected to the power chip, the other end of the resistor RS1 is connected to the other end of the resistor R2, the other end of the capacitor C4 is grounded, one end of the resistor R3 is respectively connected to the other end of the resistor RS1 and the electric soldering iron heating wire, The other end of the resistor R3 is connected to the power chip, the other end of the capacitor C6 and the other end of the resistor R5 are both connected to the power chip, one end of the resistor R6 and one end of the resistor R7 are both connected to the PD charger, the other end of the resistor R6 and the other end of the resistor R7 are respectively connected to the power chip, one end of the resistor R11 and one end of the resistor R12 are connected to direct current, the other end of the resistor R11 and the other end of the resistor R12 are respectively connected to the power chip, the other end of the resistor R11 and the other end of the resistor R12 are also respectively connected to the MCU control unit, one end of the resistor R14, one end of the resistor R10, one end of the resistor R9 and one end of the resistor R8 are respectively connected to the power chip, the other end of the resistor R14, the other end of the resistor R10, and the other end of the resistor R9 are all grounded, the other end of the resistor R8 is connected to one end of the resistor R9, one end of the resistor R13 and one end of the capacitor C8 are respectively connected to the power chip, the other end of the resistor R13 is connected to one end of the capacitor C7, the other end of the capacitor C7, the other end of the capacitor C8 and one end of the capacitor C5 are all grounded, and the other end of the capacitor C5 is connected to the DC power supply unit.

[0008] In the present invention, as an optional embodiment, the electric soldering iron heating wire includes a heating wire RL, one end of the heating wire RL is connected to the DC power supply unit and the PD protocol charging unit, and the other end of the heating wire RL is connected to the MCU control unit.

[0009] In the present invention, as an optional embodiment, the electric soldering iron heating wire further includes a thermistor NTC1, and the other end of the heating wire RL is connected to the MCU control unit through the thermistor NTC1.

[0010] In the present invention, as an optional embodiment, the MCU control unit includes a single chip microcomputer of model CMS8S6990NA.

[0011] In the present invention, as an optional embodiment, the MCU control unit further includes a first control button and a second control button, and the first control button and the second control button are both connected to the single-chip microcomputer.

[0012] In the present invention, as an optional embodiment, the MCU control unit also includes a resistor R15, a resistor R16, a resistor R17, and a resistor R18. The resistor R15 and the resistor R16 are connected to form a series branch, and the resistor R17 and the resistor R18 are connected to form another series branch. The first control button is connected in parallel at both ends of the resistor R16, and the second control button is connected in parallel at both ends of the resistor R18. The connection between the resistor R15 and the resistor R16 and the connection between the resistor R17 and the resistor R18 are connected to the single-chip computer, and the end of the resistor R15 away from the resistor R16 is connected to the DC power supply unit, and the end of the resistor R17 away from the resistor R18 is connected to the DC power supply unit.

[0013] In the present invention, as an optional embodiment, the MCU control unit also includes a resistor R20, a resistor R21, a capacitor C11, a capacitor C12, and a capacitor C13, one end of the resistor R20 is connected to the thermistor NTC1, one end of the capacitor C12, one end of the capacitor C13, and one end of the resistor R21 are all grounded, the other end of the resistor R20, the other end of the capacitor C12, one end of the capacitor C11, and the resistor R21 are all connected to the single-chip computer, and the other end of the capacitor C13 is connected to the other end of the capacitor C11.

[0014] In the present invention, as an optional embodiment, the DC power supply unit includes a three-terminal voltage regulator, the input end of the three-terminal voltage regulator is connected to the PD protocol charging unit, and the output end of the three-terminal voltage regulator is provided to the MCU control unit.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] A constant temperature electric soldering iron driving power supply circuit provided by the present invention has a compact layout and can be directly installed inside the handle of the electric soldering iron device. The PD charger can directly drive the electric soldering iron heating wire through the PD protocol charging unit. Only the MCU control unit has power loss in the overall circuit, and there is no large current conversion loss. Therefore, more than 99.5% of the electric energy output by the PD charger can act on the electric soldering iron heating wire, and the power supply efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1A schematic diagram of the module structure of a constant temperature electric soldering iron driving power supply circuit according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the circuit structure of a PD protocol charging unit according to an embodiment of the present invention;

[0019] Figure 3 The circuit structure diagram of the electric soldering iron heating wire, MCU control unit, LED digital tube and DC power supply unit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Below, in conjunction with the accompanying drawings and specific embodiments, the present invention is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Except for special instructions, the materials and equipment used in this embodiment can be purchased from the market. Examples of embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0021] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "plurality" means two or more, unless otherwise precisely and specifically specified.

[0022] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The embodiment of the present application provides a constant temperature electric soldering iron driving power supply circuit, which has a compact circuit layout and can be directly installed inside the handle of the electric soldering iron device. The PD charger can directly drive the electric soldering iron heating wire through the PD protocol charging unit. Only the MCU control unit has power loss in the overall circuit, and there is no large current conversion loss. Therefore, more than 99.5% of the electric energy output by the PD charger can act on the electric soldering iron heating wire, and the power supply efficiency is high.

[0025] Figure 1 The module structure of a constant temperature electric soldering iron driving power supply circuit of this embodiment is shown. Figure 2 The circuit structure of the PD protocol charging unit according to the embodiment of the present invention is shown; Figure 3 The circuit structure of the electric soldering iron heating wire, the MCU control unit, the LED digital tube and the direct current power supply unit according to the embodiment of the present invention is shown.

[0026] Please refer to Figure 1 As shown, a constant temperature electric soldering iron driving power supply circuit provided in this embodiment includes a PD protocol charging unit, an MCU control unit, an electric soldering iron heating wire, a DC power supply unit and an LED digital tube, wherein the input end of the PD protocol charging unit is connected to an external PD charger, and the output end is respectively connected to the MCU control unit and the electric soldering iron heating wire, and the MCU control unit is connected to the electric soldering iron heating wire, the DC power supply unit and the LED digital tube. Among them, the PD protocol charging unit is used to send the power configuration table from the PD charger to the MCU control unit, and receive the power value request issued by the MCU control unit based on the power configuration table, and send the power request to the PD charger; the DC power supply unit is used to input DC power to the MCU control unit, the LED digital tube is used to display the temperature of the electric soldering iron heating wire, and the MCU control unit is used to control the heating temperature of the electric soldering iron heating wire. In the embodiment, the constant temperature is achieved by the MCU control unit controlling the output current of the PD charger through the PD protocol charging unit. After the temperature monitoring reaches the set time without change, it will automatically cool down to 100 degrees for standby. After a period of standby at 100 degrees, there is still no change, and the PD charger is automatically requested to reduce the voltage and current and enter the standby mode to save electricity.

[0027] Combination Figure 1 , Figure 2 and Figure 3 The PD protocol charging unit of the embodiment includes a power chip, the model of the power chip is IP2716_QFN32, and the power chip is respectively connected to an external PD charger, an MCU control unit and the electric soldering iron heating wire.

[0028] Furthermore, the PD protocol charging unit also includes a charging circuit, which includes a fuse, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a resistor RS1. One end of the fuse F1 is connected to the PD charger, and one end of the capacitor C1, one end of the resistor RS1, one end of the resistor R1, and one end of the resistor R5 are all connected to the other end of the fuse F1. , the other end of capacitor C1, one end of capacitor C3 and one end of capacitor C6 are all grounded, the other end of capacitor C3 and one end of capacitor C2 are all connected to the SENSEN pin of power chip U1, the other end of capacitor C2, one end of resistor R2 and one end of capacitor C4 are connected to the SENSEP pin of power chip U1, the other end of resistor RS1 is connected to the other end of resistor R2, the other end of capacitor C4 is grounded, one end of resistor R3 is respectively connected to the other end of resistor RS1 and the soldering iron heating wire, the other end of resistor R3 is connected to the power chip U1, the other end of capacitor C6 and the other end of resistor R5 are both connected to VBU of power chip U1 S, one end of the resistor R6 and one end of the resistor R7 are connected to the PD charger, the other end of the resistor R6 and the other end of the resistor R7 are respectively connected to the power chip U1, one end of the resistor R11 and one end of the resistor R12 are connected to the DC power VDD, the other end of the resistor R11 and the other end of the resistor R12 are respectively connected to the power chip U1, wherein the resistor R11 is connected to the SCL pin of the power chip U1, the resistor R12 is connected to the R12 pin of the power chip, the other end of the resistor R11 and the other end of the resistor R12 are also respectively connected to the MCU control unit, one end of the resistor R14, one end of the resistor R10, and the resistor R9 One end of the resistor R14 and one end of the resistor R8 are respectively connected to the PLIM pin of the power chip U1, the other ends of the resistor R14, the other ends of the resistor R10, and the other ends of the resistor R9 are all grounded, the other end of the resistor R8 is connected to one end of the resistor R9, one end of the resistor R13 and one end of the capacitor C8 are respectively connected to the power chip U1, the capacitor C8 is connected to the VDD pin of the power chip, the resistor R13 is connected to the ROLE2 pin of the power chip, the other end of the resistor R13 is connected to one end of the capacitor C7, the other ends of the capacitor C7, the other ends of the capacitor C8 and one end of the capacitor C5 are all grounded, and the other end of the capacitor C5 is connected to the DC power supply unit.

[0029] Furthermore, the electric soldering iron heating wire includes a heating wire RL, one end of which is connected to the DC power supply unit and the PD protocol charging unit, and the other end of which is connected to the MCU control unit. The electric soldering iron heating wire also includes a thermistor NTC1, and the other end of the heating wire RL is connected to the MCU control unit through the thermistor NTC1. That is, one end of the resistor R3 is connected to the heating wire RL. Further, in actual implementation, it also includes a capacitor C9 and a capacitor EC1, and the capacitor C9 and the capacitor EC1 form a parallel circuit, one end of which is connected to one end of R3, and the other end is connected to the heating wire RL.

[0030] Preferably, the MCU control unit includes a single chip microcomputer of model CMS8S6990NA. The MCU control unit also includes a first control button SW1 and a second control button SW2, and the first control button SW1 and the second control button SW2 are both connected to the single chip microcomputer U3. The MCU control unit also includes a resistor R15, a resistor R16, a resistor R17, and a resistor R18, wherein the resistor R15 and the resistor R16 are connected to form a series branch, and the resistor R17 and the resistor R18 are connected to form another series branch, the first control button SW1 is connected in parallel to the two ends of the resistor R16, and the second control button SW2 is connected in parallel to the two ends of the resistor R18, and the connection between the resistor R15 and the resistor R16 and the connection between the resistor R17 and the resistor R18 are connected to the single chip microcomputer U3, and the end of the resistor R15 away from the resistor R16 is connected to the DC power supply unit, and the end of the resistor R17 away from the resistor R18 is connected to the DC power supply unit.

[0031] The MCU control unit also includes a resistor R20, a resistor R21, a capacitor C11, a capacitor C12, and a capacitor C13. One end of the resistor R20 is connected to the thermistor NTC1, one end of the capacitor C12, one end of the capacitor C13, and one end of the resistor R21 are all grounded, the other end of the resistor R20, the other end of the capacitor C12, one end of the capacitor C11, and the resistor R21 are all connected to the microcontroller U3, and the other end of the capacitor C13 is connected to the other end of the capacitor C11.

[0032] The DC power supply unit includes a three-terminal voltage regulator U2, an input terminal Vin of the three-terminal voltage regulator U2 is connected to the PD protocol charging unit, and an output terminal Vout of the three-terminal voltage regulator U2 outputs 3.3V DC power to the MCU control unit.

[0033] In the embodiment, after the PD charger is connected, the power chip U1 in the PD protocol charging unit will communicate with the PD charger through CC1, and the PD charger will send an output power configuration table to the power chip U1. For example, the PD charger output is configured with 3.3V-20V, 0A-3.25A. After receiving the power configuration table, the power chip U1 will communicate with the MCU control unit through I2C (that is, the SCL and SDA pins), and send the power configuration table to the single-chip microcomputer U3 in the MCU control unit. The single-chip microcomputer U3 will send a requested power value to the power chip U1 of the PD protocol charging unit according to the feed setting value of the heating wire RL. The power chip U1 will notify the PD charger of the required power value. For example, the maximum power of the heating wire RL is 20V / 3.25A=65W, then the power chip U1 will send the communication code of pps: 20V / 0-3.25A to the PD charger. After receiving it, the PD charger will output a voltage of 20V, and the current will be adjusted between 0-3.25A according to the set temperature.

[0034] In the embodiment, the PD charger will automatically turn on when it is turned on, and the shutdown can be achieved by pressing and holding the SW1 button for more than 3 seconds. In the MCU control unit, the temperature is adjusted up through the first control button SW1, and the temperature is adjusted down through the second control button SW2. Each press is adjusted by 1 degree by default. When it is necessary to carry to 10 degrees, it is necessary to press and hold the second control button SW2 for more than 3 seconds to adjust. The single-chip microcomputer U3 has a memory function. The resistance value of the thermistor NTC1 is detected through the PIN15 pin and the PIN16 pin to determine the temperature. Then, the PIN20 and PIN21 pins in the power chip U1 of the PD protocol charging unit are communicated through the PIN11 and PIN12 of the single-chip microcomputer U3, and the output current of the PD charger is adjusted through the CC1 communication of the power chip U1 to achieve the constant temperature function. In the embodiment, the single-chip microcomputer U3 detects the resistance value of the thermistor NTC1 through PIN15 and PIN16 to determine the temperature parameters. After internal calculation, the corresponding LED digital tube is driven through PIN6-PIN10 to display the temperature value. The LED digital tube is a 3-digit digital tube for displaying temperature.

[0035] Although only certain components and embodiments of the present application have been illustrated and described, many modifications and changes may be conceived by those skilled in the art without actually departing from the scope and spirit of the claims, such as changes in the size, dimensions, structure, shape and proportion of the various elements, mounting arrangements, material usage, color, orientation, etc.

[0036] The above implementation modes are only preferred implementation modes of the embodiments of the present invention and cannot be used to limit the protection scope of the embodiments of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the embodiments of the present invention shall fall within the scope of protection required by the embodiments of the present invention.

Claims

1. A constant temperature electric soldering iron driving power supply circuit, characterized in that: It includes a PD protocol charging unit, an MCU control unit, an electric soldering iron heating wire, a DC power supply unit and an LED digital tube, wherein the input end of the PD protocol charging unit is connected to an external PD charger, and the output end is respectively connected to the MCU control unit and the electric soldering iron heating wire, and the MCU control unit is connected to the electric soldering iron heating wire, the DC power supply unit and the LED digital tube; wherein the PD protocol charging unit is used to send a power configuration table from the PD charger to the MCU control unit, and receive a power value request issued by the MCU control unit based on the power configuration table, and send the power request to the PD charger; the DC power supply unit is used to input DC power to the MCU control unit, the LED digital tube is used to display the temperature of the electric soldering iron heating wire, and the MCU control unit is used to control the heating temperature of the electric soldering iron heating wire; the PD protocol charging unit includes a power chip, the model of the power chip is IP2716_QFN32, and the power chip is respectively connected to an external PD charger, an MCU control unit and the electric soldering iron heating wire;The PD protocol charging unit also includes a charging circuit, which includes a fuse, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, and a resistor RS1. One end of the fuse F1 is connected to the PD charger, and one end of the capacitor C1, one end of the resistor RS1, one end of the resistor R1, and one end of the resistor R5 are all connected. The other end of the fuse F1 is connected, the other end of the capacitor C1, one end of the capacitor C3 and one end of the capacitor C6 are grounded, the other end of the capacitor C3 and one end of the capacitor C2 are connected to the power chip, the other end of the capacitor C2, one end of the resistor R2 and one end of the capacitor C4 are connected to the power chip, the other end of the resistor RS1 is connected to the other end of the resistor R2, the other end of the capacitor C4 is grounded, one end of the resistor R3 is respectively connected to the other end of the resistor RS1 and the electric soldering iron heating wire, the other end of the resistor R3 is connected to the power chip, the other end of the capacitor C6 and the other end of the resistor R5 are connected to the power chip, the One end of the resistor R6 and one end of the resistor R7 are connected to the PD charger, the other end of the resistor R6 and the other end of the resistor R7 are connected to the power chip respectively, one end of the resistor R11 and one end of the resistor R12 are connected to the DC power, the other end of the resistor R11 and the other end of the resistor R12 are connected to the power chip respectively, the other end of the resistor R11 and the other end of the resistor R12 are also connected to the MCU control unit respectively, one end of the resistor R14, one end of the resistor R10, one end of the resistor R9 and one end of the resistor R8 are connected to the power chip respectively, the other end of the resistor R14, the resistor R10, the resistor R9 and the resistor R8 are connected to the power chip respectively, 0 and the other end of resistor R9 are grounded, the other end of resistor R8 is connected to one end of resistor R9, one end of resistor R13 and one end of capacitor C8 are connected to the power chip respectively, the other end of resistor R13 is connected to one end of capacitor C7, the other end of capacitor C7, the other end of capacitor C8 and one end of capacitor C5 are grounded, and the other end of capacitor C5 is connected to the DC power supply unit; the electric soldering iron heating wire includes a heating wire RL, one end of the heating wire RL is connected to the DC power supply unit and the PD protocol charging unit, and the other end of the heating wire RL is connected to the MCU control unit. ; 2. The constant temperature electric soldering iron driving power supply circuit according to claim 1, characterized in that: The electric soldering iron heating wire further includes a thermistor NTC1, and the other end of the heating wire RL is connected to the MCU control unit through the thermistor NTC1.

3. The constant temperature electric soldering iron driving power supply circuit according to claim 2, characterized in that: The MCU control unit includes a single chip microcomputer of model CMS8S6990NA.

4. The constant temperature electric soldering iron driving power supply circuit according to claim 3, characterized in that: The MCU control unit also includes a first control button and a second control button, and the first control button and the second control button are both connected to the single chip computer.

5. The constant temperature electric soldering iron driving power supply circuit according to claim 4, characterized in that: The MCU control unit also includes a resistor R15, a resistor R16, a resistor R17, and a resistor R18. The resistor R15 and the resistor R16 are connected to form a series branch, and the resistor R17 and the resistor R18 are connected to form another series branch. The first control button is connected in parallel at both ends of the resistor R16, and the second control button is connected in parallel at both ends of the resistor R18. The connection between the resistor R15 and the resistor R16 and the connection between the resistor R17 and the resistor R18 are connected to the single-chip computer. The end of the resistor R15 away from the resistor R16 is connected to the DC power supply unit, and the end of the resistor R17 away from the resistor R18 is connected to the DC power supply unit.

6. The constant temperature electric soldering iron driving power supply circuit according to claim 5, characterized in that: The MCU control unit also includes a resistor R20, a resistor R21, a capacitor C11, a capacitor C12, and a capacitor C13. One end of the resistor R20 is connected to the thermistor NTC1, one end of the capacitor C12, one end of the capacitor C13, and one end of the resistor R21 are all grounded, the other end of the resistor R20, the other end of the capacitor C12, one end of the capacitor C11, and the resistor R21 are all connected to the single-chip computer, and the other end of the capacitor C13 is connected to the other end of the capacitor C11.

7. The constant temperature electric soldering iron driving power supply circuit according to claim 1 or 6, characterized in that: The DC power supply unit includes a three-terminal voltage regulator tube, the input end of the three-terminal voltage regulator tube is connected to the PD protocol charging unit, and the output end of the three-terminal voltage regulator tube is provided to the MCU control unit.

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