Inductive control device and electric soldering iron

Abstract

The utility model discloses an inductive control device and an electric soldering iron, and relates to the technical field of electronic control. The electric soldering iron comprises a power supply access end and a soldering iron temperature control circuit; the induction control device comprises a main control circuit; the induction circuit is used for detecting human body movement in a preset range and outputting an induction signal; the power supply circuit is used for converting voltage input by the power supply access end into power supply voltage and outputting the power supply voltage; the switching circuit is used for switching on or switching off a path between the power supply circuit and the soldering iron temperature control circuit according to the switching control signal output by the main control circuit; wherein the main control circuit is used for outputting a corresponding switch control signal according to the induction signal. The utility model aims to reduce the loss rate of the soldering bit on the electric soldering iron.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic control, in particular to an induction control device and an electric soldering iron. Background Art

[0002] A soldering iron is a tool that heats a metal tip (called a "tip") to melt solder, securing electronic components to printed circuit boards or other substrates. However, due to negligence, the tip can become oxidized, leaving it unused for extended periods. This oxidized tip can affect its thermal conductivity and soldering performance, while frequent tip replacement wastes resources and inconvenience for the engineer. Therefore, preventing oxidation caused by unused tips is a pressing technical challenge. Utility Model Content

[0003] The main purpose of the utility model is to provide an induction control device, aiming to reduce the loss rate of the soldering iron tip on the electric soldering iron.

[0004] To achieve the above-mentioned purpose, the induction control device proposed in the present invention is applied to an electric soldering iron, wherein the electric soldering iron includes a power supply input terminal and a soldering iron temperature control circuit, and the induction control device includes:

[0005] Main control circuit;

[0006] a sensing circuit, wherein an output end of the sensing circuit is electrically connected to the main control circuit, and is used to detect human activities within a preset range and output a sensing signal;

[0007] a power supply circuit, wherein the input end of the power supply circuit is electrically connected to the power supply input end, and the output end of the power supply circuit is electrically connected to the power supply end of the main control circuit, the power supply end electrically connected to the sensing circuit, and the soldering iron temperature control circuit, and is used to convert the voltage input from the power supply input end into a supply voltage and output it;

[0008] a switch circuit, wherein an input end of the switch circuit is electrically connected to the power supply circuit, an output end of the switch circuit is electrically connected to the soldering iron temperature control circuit, and a controlled end of the switch circuit is electrically connected to the main control circuit, and is configured to open or close a path between the power supply circuit and the soldering iron temperature control circuit according to a switch control signal output by the main control circuit;

[0009] The main control circuit is used to output a corresponding switch control signal according to the sensing signal.

[0010] In one embodiment, the supply voltage includes a first supply voltage and a second supply voltage, and the power supply circuit includes:

[0011] a rectifier circuit, wherein the input end of the rectifier circuit is electrically connected to the power supply input end, and is used to convert the input AC voltage into a DC voltage and output it;

[0012] a first voltage conversion circuit, wherein an input end of the first voltage conversion circuit is electrically connected to an output end of the rectifier circuit, and an output end of the first voltage conversion circuit is electrically connected to the switch circuit, and is configured to convert a DC voltage output by the rectifier circuit into a first supply voltage and output the first supply voltage;

[0013] A second voltage conversion circuit, wherein the input end of the second voltage conversion circuit is electrically connected to the output end of the rectifier circuit, and the output end of the second voltage conversion circuit is electrically connected to the main control circuit and the induction circuit respectively, and is used to convert the DC voltage output by the rectifier circuit into a second power supply voltage and output it.

[0014] In one embodiment, the rectifier circuit includes a transformer, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a second capacitor, and a voltage-stabilized power supply access terminal;

[0015] In which, the transformer includes a primary coil and a secondary coil, and the primary coil is coupled to the secondary coil; the first end of the primary coil is electrically connected to the live wire access end of the power access end, and the second end of the primary coil is electrically connected to the neutral wire access end of the power access end; the first end of the secondary coil is electrically connected to the anode of the first diode and the cathode of the second diode, and the second end of the secondary coil is electrically connected to the cathode of the third diode and the anode of the fourth diode; the first end of the first capacitor is electrically connected to the cathode of the first diode, the cathode of the fourth diode, the anode of the fifth diode, and the regulated power supply access end, and the second end of the first capacitor is electrically connected to the anode of the second diode, the anode of the third diode, and the second end of the second capacitor; the cathode of the fifth diode is electrically connected to the first end of the second capacitor; the two ends of the second capacitor are electrically connected to the input end of the first voltage conversion circuit and the input end of the second voltage conversion circuit.

[0016] In one embodiment, the first voltage conversion circuit includes a first voltage conversion chip and a third capacitor; the second voltage conversion circuit includes a second voltage conversion chip, a fourth capacitor, and a fifth capacitor;

[0017] Among them, the VIN pin of the first voltage conversion chip is electrically connected to the first end of the second capacitor, the OUT pin of the first voltage conversion chip is electrically connected to the first end of the third capacitor and the switching circuit, and the GND pin of the first voltage conversion chip is electrically connected to the second end of the second capacitor, the second end of the third capacitor, and the ground end; the VIN pin of the second voltage conversion chip is electrically connected to the first end of the second capacitor, the OUT pin of the second voltage conversion chip is electrically connected to the first end of the fourth capacitor, the first end of the fifth capacitor, the main control circuit, and the sensing circuit, and the GND pin of the second voltage conversion chip is electrically connected to the second end of the second capacitor, the second end of the fourth capacitor, the second end of the fifth capacitor, and the ground end.

[0018] In one embodiment, the switch circuit includes a first resistor, a second resistor, a third resistor, a PMOS transistor, and a first NPN transistor;

[0019] Among them, the first end of the first resistor is electrically connected to the output end of the first voltage conversion circuit and the source of the PMOS tube, the second end of the first resistor is electrically connected to the first end of the second resistor and the gate of the PMOS tube; the drain of the PMOS tube is electrically connected to the soldering iron temperature control circuit; the second end of the second resistor is electrically connected to the collector of the first NPN transistor; the base of the first NPN transistor is electrically connected to the second end of the third resistor, and the emitter of the first NPN transistor is electrically connected to the ground end; the second end of the third resistor is electrically connected to the main control circuit.

[0020] The present invention further provides an electric soldering iron, which comprises a power supply input terminal, a soldering iron temperature control circuit and the induction control device as described in any one of the above items.

[0021] In one embodiment, the electric soldering iron includes a soldering iron tip, and the soldering iron temperature control circuit includes:

[0022] a temperature detection circuit, the temperature detection circuit being electrically connected to the switch circuit, the temperature detection circuit being used to detect the operating temperature of the soldering iron tip and output a temperature detection signal;

[0023] a comparison control circuit, the comparison control circuit being electrically connected to the temperature detection circuit, and the comparison control circuit being configured to output a corresponding temperature control switch signal according to the temperature detection signal;

[0024] A temperature control switch circuit is electrically connected to the comparison control circuit, and the temperature control switch circuit is used to heat or stop heating the soldering iron tip according to the temperature control switch signal.

[0025] In one embodiment, the temperature detection circuit includes a fourth resistor and a thermistor;

[0026] Among them, the first end of the fourth resistor is electrically connected to the switching circuit and the comparison control circuit, and the second end of the fourth resistor is electrically connected to the first end of the thermistor; the first end of the thermistor is electrically connected to the comparison control circuit, and the second end of the thermistor is electrically connected to the ground end.

[0027] In one embodiment, the comparison control circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an operational amplifier, a comparator, an adjustable resistor, a sixth diode, a sixth capacitor, and a seventh capacitor;

[0028] Among them, the first end of the sixth capacitor is electrically connected to the first end of the thermistor and the non-inverting input terminal of the operational amplifier, and the second end of the sixth capacitor is electrically connected to the ground terminal; the first end of the fifth resistor is electrically connected to the inverting input terminal of the operational amplifier and the first end of the adjustable resistor, and the second end of the fifth resistor is electrically connected to the ground terminal; the first end of the sixth resistor is electrically connected to the output terminal of the operational amplifier and the inverting input terminal of the comparator, and the second end of the sixth resistor is electrically connected to the second end of the adjustable resistor; the first end of the seventh resistor is electrically connected to the first end of the fourth resistor and the positive power supply terminal of the comparator, and the second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the anode of the sixth diode; the second end of the eighth resistor is electrically connected to the non-inverting input terminal of the comparator and the first end of the seventh capacitor; the second end of the seventh capacitor is electrically connected to the first end of the ninth resistor and the output terminal of the comparator; the negative power supply terminal of the comparator is electrically connected to the ground terminal; and the second end of the ninth resistor is electrically connected to the temperature control switch circuit.

[0029] In one embodiment, the temperature control switch circuit includes a tenth resistor, an eleventh resistor, a light emitting diode, a heating wire, a second NPN transistor, and a third NPN transistor;

[0030] In which, the anode of the light-emitting diode is electrically connected to the power supply circuit and the first end of the heating wire, and the cathode of the light-emitting diode is electrically connected to the first end of the tenth resistor; the second end of the tenth resistor is electrically connected to the second end of the heating wire, the collector of the second NPN transistor, and the collector of the third NPN transistor; the base of the second NPN transistor is electrically connected to the second end of the ninth resistor, and the emitter of the second NPN transistor is electrically connected to the base of the third NPN transistor; the emitter of the third NPN transistor is electrically connected to the ground end.

[0031] This utility model utilizes a sensing circuit to detect human activity within a preset range and outputs a sensing signal to a main control circuit, which then generates a corresponding switch control signal based on the sensing signal. The switch circuit connects or disconnects the path between the power supply circuit and the soldering iron temperature control circuit based on the switch control signal output by the main control circuit. This allows the power supply from the power supply circuit to the soldering iron temperature control circuit to be shut down when no human activity is detected within the preset range, effectively preventing oxidation of the soldering iron tip when the soldering iron is unattended. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0033] Figure 1 This is a schematic diagram of the module of the induction control device of the present utility model;

[0034] Figure 2 This is a circuit diagram of an embodiment of the induction control device of the present utility model;

[0035] Figure 3 This is a circuit diagram of an embodiment of the induction control device of the present utility model;

[0036] Figure 4 This is a circuit diagram of an embodiment of the electric soldering iron of the present invention.

[0037] Description of Figure Numbers:

[0038] 10. Main control circuit; 20. Sensing circuit; 30. Power supply circuit; 40. Switching circuit; 50. Soldering iron temperature control circuit; 60. Power supply input terminal.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0043] A soldering iron is a tool that heats a metal tip (called a "tip") to melt solder, securing electronic components to printed circuit boards or other substrates. However, due to negligence, the tip can become oxidized, leaving it unused for extended periods. This oxidized tip can affect its thermal conductivity and soldering performance, while frequent tip replacement wastes resources and inconvenience for the engineer. Therefore, preventing oxidation caused by unused tips is a pressing technical challenge.

[0044] Therefore, reference Figures 1 to 3 The present invention provides an induction control device for use with an electric soldering iron. The electric soldering iron includes a power supply terminal 60 and a soldering iron temperature control circuit 50. The induction control device includes:

[0045] Main control circuit 10;

[0046] A sensing circuit 20, the output end of which is electrically connected to the main control circuit 10, for detecting human activities within a preset range and outputting a sensing signal;

[0047] a power supply circuit 30, wherein the input end of the power supply circuit 30 is electrically connected to the power supply input end 60, and the output end of the power supply circuit 30 is electrically connected to the power supply end of the main control circuit 10, the power supply end electrically connected to the sensing circuit 20, and the soldering iron temperature control circuit 50, and is used to convert the voltage input from the power supply input end 60 into a supply voltage and output it;

[0048] a switch circuit 40, wherein an input end of the switch circuit 40 is electrically connected to the power circuit 30, an output end of the switch circuit 40 is electrically connected to the soldering iron temperature control circuit 50, and a controlled end of the switch circuit 40 is electrically connected to the main control circuit 10, and is configured to open or close a path between the power circuit 30 and the soldering iron temperature control circuit 50 according to a switch control signal output by the main control circuit 10;

[0049] The main control circuit 10 is configured to output a corresponding switch control signal according to the sensing signal.

[0050] In this embodiment, the main control circuit 10 can be implemented using a main controller, such as a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), an MCU (Microcontroller Unit), or a SOC (System on Chip). The main control circuit 10 obtains and processes different input signals to output corresponding control signals, thereby controlling corresponding circuits to perform corresponding actions.

[0051] In this embodiment, the sensing circuit 20 can be implemented using a sensing radar, a human infrared detection circuit, or the like. For example, the sensing circuit 20 uses an FMCW-based sensing radar circuit. FMCW radar is a continuous wave radar technology that utilizes frequency modulation. It can detect the presence of a human body within a preset range, including both stationary and moving states. The FMCW radar transmits a linearly varying frequency modulated signal (i.e., a swept frequency signal), the frequency of which increases or decreases linearly over time. The radar receives the reflected signal and mixes it with the transmitted signal to generate a difference frequency signal containing target distance information. Using signal processing techniques such as FFT (Fast Fourier Transform), the target's distance and speed information are extracted from the difference frequency signal. In this way, the FMCW radar can effectively determine whether a human body is within the preset range, and whether the human body is stationary or moving. Furthermore, the FMCW radar also outputs the detected sensing signal to the main control circuit 10, so that the main control circuit 10 performs corresponding actions based on the sensing signal. Specifically, when the main control circuit 10 receives that there is no human body within the preset range, it outputs a shutdown control signal to the switch circuit 40, so that the switch circuit 40 quickly disconnects the path between the power circuit 30 and the soldering iron temperature control circuit 50, thereby achieving a quick power-off effect; when the main control circuit 10 receives that the human body within the preset range is in a stationary state, it enters a three-minute delay control state. When the human body has been in a stationary state for three minutes, the main control circuit 10 will output a shutdown control signal to the switch circuit 40, so that the switch circuit 40 delays disconnecting the path between the power circuit 30 and the soldering iron temperature control circuit 50, thereby achieving a delayed power-off effect; when the main control circuit 10 receives that there is human body movement within the preset range, it does not take any action based on the sensing signal.

[0052] In this embodiment, the power supply circuit 30 needs to convert the voltage input from the power supply input terminal 60 into appropriate voltages and respectively power the main control circuit 10, the sensing circuit 20, and the soldering iron temperature control circuit 50. Therefore, the power supply circuit 30 includes multiple voltage conversion circuits, such as an AC / DC voltage conversion circuit and a DC / DC voltage conversion circuit. Specifically, the supply voltage includes a first supply voltage and a second supply voltage. The power supply circuit 30 includes: a rectifier circuit, the input terminal of which is electrically connected to the power supply input terminal 60 and is configured to convert the input AC voltage into a DC voltage for output; a first voltage conversion circuit, the input terminal of which is electrically connected to the output terminal of the rectifier circuit and the output terminal of which is electrically connected to the switching circuit 40 and is configured to convert the DC voltage output by the rectifier circuit into the first supply voltage for output; and a second voltage conversion circuit, the input terminal of which is electrically connected to the output terminal of the rectifier circuit and the output terminal of which is electrically connected to the main control circuit 10 and the sensing circuit 20 respectively and is configured to convert the DC voltage output by the rectifier circuit into the second supply voltage for output.

[0053] Furthermore, the rectifier circuit includes a transformer, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first capacitor C1, a second capacitor C2, and a stabilized power supply access terminal;

[0054] The transformer includes a primary coil and a secondary coil, which are coupled to the secondary coil; a first end of the primary coil is electrically connected to the live wire access terminal of the power access terminal 60, and a second end of the primary coil is electrically connected to the neutral wire access terminal of the power access terminal 60; a first end of the secondary coil is electrically connected to the anode of the first diode D1 and the cathode of the second diode D2, and a second end of the secondary coil is electrically connected to the cathode of the third diode D3 and the anode of the fourth diode D4; a first end of the first capacitor C1 is electrically connected to the cathode of the first diode D1, the cathode of the fourth diode D4, the anode of the fifth diode D5, and the regulated power access terminal, a second end of the first capacitor C1 is electrically connected to the anode of the second diode D2, the anode of the third diode D3, and the second end of the second capacitor C2; a cathode of the fifth diode D5 is electrically connected to the first end of the second capacitor C2; and two ends of the second capacitor C2 are electrically connected to the input end of the first voltage conversion circuit and the input end of the second voltage conversion circuit.

[0055] The first voltage conversion circuit includes a first voltage conversion chip and a third capacitor C3; the second voltage conversion circuit includes a second voltage conversion chip, a fourth capacitor C4, and a fifth capacitor C5;

[0056] Among them, the VIN pin of the first voltage conversion chip is electrically connected to the first end of the second capacitor C2, the OUT pin of the first voltage conversion chip is electrically connected to the first end of the third capacitor C3 and the switching circuit 40, and the GND pin of the first voltage conversion chip is electrically connected to the second end of the second capacitor C2, the second end of the third capacitor C3, and the ground end; the VIN pin of the second voltage conversion chip is electrically connected to the first end of the second capacitor C2, the OUT pin of the second voltage conversion chip is electrically connected to the first end of the fourth capacitor C4, the first end of the fifth capacitor C5, the main control circuit 10, and the sensing circuit 20, and the GND pin of the second voltage conversion chip is electrically connected to the second end of the second capacitor C2, the second end of the fourth capacitor C4, the second end of the fifth capacitor C5, and the ground end.

[0057] In this embodiment, the AC voltage input from the power supply input terminal 60 is converted to a DC voltage by a rectifier circuit and output to the output terminals of the first and second voltage conversion circuits. The output terminal of the rectifier circuit is also provided with a voltage-stabilizing power supply input terminal for stabilizing the output voltage. Furthermore, the first voltage conversion circuit converts the DC voltage output from the rectifier circuit into a 12V DC voltage and outputs it to the switch circuit 40, which controls the power on and off of the soldering iron temperature control circuit 50. The second voltage conversion circuit converts the DC voltage output from the rectifier circuit into a 5V DC voltage and outputs it to the main control circuit 10 and the sensing circuit 20, ensuring stable operation of the main control circuit 10 and the sensing circuit 20.

[0058] Optionally, the primary coil of the transformer in the rectifier circuit may be provided with a switch button, a fuse and other protective circuits.

[0059] In this embodiment, the switch circuit 40 can be implemented using at least one switch transistor, such as a MOS transistor, an IGBT transistor, a thyristor, a transistor, a power transistor, etc., and / or at least one switching device, such as a contactor, a circuit breaker, and a relay. Specifically, the switch circuit 40 includes a first resistor R1, a second resistor R2, a third resistor R3, a PMOS transistor Q1, and a first NPN transistor Q2. The first end of the first resistor R1 is electrically connected to the output end of the first voltage conversion circuit and the source of the PMOS transistor Q1. The second end of the first resistor R1 is electrically connected to the first end of the second resistor R2 and the gate of the PMOS transistor Q1. The drain of the PMOS transistor Q1 is electrically connected to the soldering iron temperature control circuit 50. The second end of the second resistor R2 is electrically connected to the collector of the first NPN transistor Q2. The base of the first NPN transistor Q2 is electrically connected to the second end of the third resistor R3. The emitter of the first NPN transistor Q2 is electrically connected to the ground. The second end of the third resistor R3 is electrically connected to the main control circuit 10. The first NPN transistor Q2 receives high or low level signals output by the main control circuit 10 through its base to connect or disconnect the path between the gate of the PMOS transistor Q1 and the ground terminal. When the first NPN transistor Q2 receives a high level signal output by the main control circuit 10 through its base, the first NPN transistor Q2 is turned on, thereby connecting the path between the gate of the PMOS transistor Q1 and the ground terminal, thereby connecting the path between the power supply circuit 30 and the soldering iron temperature control circuit 50. When the first NPN transistor Q2 receives a low level signal output by the main control circuit 10 through its base, the first NPN transistor Q2 is turned off, thereby disconnecting the path between the gate of the PMOS transistor Q1 and the ground terminal, thereby disconnecting the path between the power supply circuit 30 and the soldering iron temperature control circuit 50.

[0060] In this embodiment, a sensing circuit 20 detects human activity within a preset range and outputs a sensing signal to the main control circuit 10, causing the main control circuit 10 to output a corresponding switch control signal based on the sensing signal. A switch circuit 40 connects or disconnects the path between the power supply circuit 30 and the soldering iron temperature control circuit 50 based on the switch control signal output by the main control circuit 10. This allows the power supply from the power supply circuit 30 to the soldering iron temperature control circuit 50 to be shut off when no human activity is detected within the preset range, thereby stopping the soldering iron from operating. This effectively prevents oxidation of the soldering iron tip when the soldering iron is not being operated.

[0061] The present invention further provides an electric soldering iron comprising a power supply terminal 60, a soldering iron temperature control circuit 50, and any of the aforementioned induction control devices. It is worth noting that, because the present invention utilizes the aforementioned induction control device, the embodiments of the present invention include all technical solutions of all of the aforementioned induction control device embodiments, and the technical effects achieved are identical, and therefore will not be further elaborated upon here.

[0062] refer to Figure 4 In one embodiment of the present invention, the electric soldering iron includes a soldering iron tip, and the soldering iron temperature control circuit 50 includes:

[0063] a temperature detection circuit, the temperature detection circuit being electrically connected to the switch circuit 40 and configured to detect the operating temperature of the soldering iron tip and output a temperature detection signal;

[0064] a comparison control circuit, the comparison control circuit being electrically connected to the temperature detection circuit, and the comparison control circuit being configured to output a corresponding temperature control switch signal according to the temperature detection signal;

[0065] A temperature control switch circuit is electrically connected to the comparison control circuit, and the temperature control switch circuit is used to heat or stop heating the soldering iron tip according to the temperature control switch signal.

[0066] In this embodiment, the temperature detection circuit can be implemented using a detection circuit based on a thermistor, such as a resistor divider circuit based on an NTC resistor or an NTC probe, or a resistor divider circuit based on a PTC resistor or a PTC probe. Specifically, the temperature detection circuit includes a fourth resistor R4 and a thermistor; wherein a first end of the fourth resistor R4 is electrically connected to the switch circuit 40 and the comparison control circuit, and a second end of the fourth resistor R4 is electrically connected to a first end of the thermistor; a first end of the thermistor is electrically connected to the comparison control circuit, and a second end of the thermistor is electrically connected to ground.

[0067] In this embodiment, the comparison control circuit can be implemented by a main controller and a comparison circuit. Specifically, the comparison control circuit includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, an operational amplifier, a comparator, an adjustable resistor, a sixth diode D6, a sixth capacitor C6, and a seventh capacitor C7; wherein the first end of the sixth capacitor C6 is electrically connected to the first end of the thermistor and the non-inverting input end of the operational amplifier, and the second end of the sixth capacitor C6 is electrically connected to the ground end; the first end of the fifth resistor R5 is electrically connected to the inverting input end of the operational amplifier and the first end of the adjustable resistor, and the second end of the fifth resistor R5 is electrically connected to the ground end; the first end of the sixth resistor R6 is electrically connected to the output end of the operational amplifier and the comparator The inverting input terminal of the comparator is electrically connected, the second end of the sixth resistor R6 is electrically connected to the second end of the adjustable resistor; the first end of the seventh resistor R7 is electrically connected to the first end of the fourth resistor R4 and the positive power supply terminal of the comparator, the second end of the seventh resistor R7 is electrically connected to the first end of the eighth resistor R8 and the anode of the sixth diode D6; the second end of the eighth resistor R8 is electrically connected to the non-inverting input terminal of the comparator and the first end of the seventh capacitor C7; the second end of the seventh capacitor C7 is electrically connected to the first end of the ninth resistor R9 and the output terminal of the comparator; the negative power supply terminal of the comparator is electrically connected to the ground terminal; the second end of the ninth resistor R9 is electrically connected to the temperature control switch circuit.

[0068] In this embodiment, the temperature control switch circuit can be implemented using a switch tube circuit and a heating circuit. Specifically, the temperature control switch circuit includes a tenth resistor R10, an eleventh resistor R11, a light-emitting diode (LED), a heating wire, a second NPN transistor Q3, and a third NPN transistor Q4. The anode of the LED is electrically connected to the power supply circuit 30 and the first end of the heating wire, and the cathode of the LED is electrically connected to the first end of the tenth resistor R10. The second end of the tenth resistor R10 is electrically connected to the second end of the heating wire, the collector of the second NPN transistor Q3, and the collector of the third NPN transistor Q4. The base of the second NPN transistor Q3 is electrically connected to the second end of the ninth resistor R9, and the emitter of the second NPN transistor Q3 is electrically connected to the base of the third NPN transistor Q4. The emitter of the third NPN transistor Q4 is electrically connected to ground.

[0069] In summary, the voltage divided by the thermistor and the fourth resistor R4 is input to the non-inverting input of the operational amplifier. After amplification by the operational amplifier, the voltage is output to the inverting input of the comparator, where it is compared with the non-inverting input, thereby controlling the on / off switching of the second NPN transistor Q3. The operational amplifier implements closed-loop temperature control. When the soldering iron is powered on, the voltage at the non-inverting input of the comparator is higher than the voltage at the inverting input, turning on the second and third NPN transistors Q3 and Q4. As the heating wire operates, the resistance of the thermistor increases, and the voltage at the non-inverting input of the operational amplifier increases. This voltage is amplified by the operational amplifier and compared with the voltage at the non-inverting input of the comparator. When the voltage output by the operational amplifier is greater than the voltage at the non-inverting input of the comparator, the comparator outputs a low voltage, turning off the second and third NPN transistors Q3 and Q4. As the temperature of the heating wire decreases, the resistance of the thermistor decreases, and the voltage at the non-inverting input of the operational amplifier decreases. This voltage is amplified by the operational amplifier and compared with the voltage at the non-inverting input of the comparator. When the voltage output by the operational amplifier is less than the voltage at the comparator's non-inverting input, the comparator's output becomes high, turning on the second and third NPN transistors Q3 and Q4. This is controlled by the reciprocating temperature fluctuations. Furthermore, the temperature of the soldering iron tip can be controlled by adjusting the adjustable resistor.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An induction control device, used for an electric soldering iron, characterized in that: The electric soldering iron includes a power supply input terminal and a soldering iron temperature control circuit, and the induction control device includes: Main control circuit; a sensing circuit, wherein an output end of the sensing circuit is electrically connected to the main control circuit, and is used to detect human activities within a preset range and output a sensing signal; a power supply circuit, wherein the input end of the power supply circuit is electrically connected to the power supply input end, and the output end of the power supply circuit is electrically connected to the power supply end of the main control circuit, the power supply end electrically connected to the sensing circuit, and the soldering iron temperature control circuit, and is used to convert the voltage input from the power supply input end into a supply voltage and output it; a switch circuit, wherein an input end of the switch circuit is electrically connected to the power supply circuit, an output end of the switch circuit is electrically connected to the soldering iron temperature control circuit, and a controlled end of the switch circuit is electrically connected to the main control circuit, and is configured to open or close a path between the power supply circuit and the soldering iron temperature control circuit according to a switch control signal output by the main control circuit; The main control circuit is used to output a corresponding switch control signal according to the sensing signal.

2. The induction control device according to claim 1, characterized in that: The power supply voltage includes a first power supply voltage and a second power supply voltage, and the power supply circuit includes: a rectifier circuit, wherein the input end of the rectifier circuit is electrically connected to the power supply input end, and is used to convert the input AC voltage into a DC voltage and output it; a first voltage conversion circuit, wherein an input end of the first voltage conversion circuit is electrically connected to an output end of the rectifier circuit, and an output end of the first voltage conversion circuit is electrically connected to the switch circuit, and is configured to convert a DC voltage output by the rectifier circuit into a first supply voltage and output the first supply voltage; A second voltage conversion circuit, wherein the input end of the second voltage conversion circuit is electrically connected to the output end of the rectifier circuit, and the output end of the second voltage conversion circuit is electrically connected to the main control circuit and the induction circuit respectively, and is used to convert the DC voltage output by the rectifier circuit into a second power supply voltage and output it.

3. The induction control device according to claim 2, characterized in that: The rectifier circuit includes a transformer, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a second capacitor, and a voltage-stabilized power supply access terminal; In which, the transformer includes a primary coil and a secondary coil, and the primary coil is coupled to the secondary coil; the first end of the primary coil is electrically connected to the live wire access end of the power access end, and the second end of the primary coil is electrically connected to the neutral wire access end of the power access end; the first end of the secondary coil is electrically connected to the anode of the first diode and the cathode of the second diode, and the second end of the secondary coil is electrically connected to the cathode of the third diode and the anode of the fourth diode; the first end of the first capacitor is electrically connected to the cathode of the first diode, the cathode of the fourth diode, the anode of the fifth diode, and the regulated power supply access end, and the second end of the first capacitor is electrically connected to the anode of the second diode, the anode of the third diode, and the second end of the second capacitor; the cathode of the fifth diode is electrically connected to the first end of the second capacitor; the two ends of the second capacitor are electrically connected to the input end of the first voltage conversion circuit and the input end of the second voltage conversion circuit.

4. The induction control device according to claim 3, characterized in that: The first voltage conversion circuit includes a first voltage conversion chip and a third capacitor; the second voltage conversion circuit includes a second voltage conversion chip, a fourth capacitor and a fifth capacitor; Among them, the VIN pin of the first voltage conversion chip is electrically connected to the first end of the second capacitor, the OUT pin of the first voltage conversion chip is electrically connected to the first end of the third capacitor and the switching circuit, and the GND pin of the first voltage conversion chip is electrically connected to the second end of the second capacitor, the second end of the third capacitor, and the ground end; the VIN pin of the second voltage conversion chip is electrically connected to the first end of the second capacitor, the OUT pin of the second voltage conversion chip is electrically connected to the first end of the fourth capacitor, the first end of the fifth capacitor, the main control circuit, and the sensing circuit, and the GND pin of the second voltage conversion chip is electrically connected to the second end of the second capacitor, the second end of the fourth capacitor, the second end of the fifth capacitor, and the ground end.

5. The induction control device according to claim 4, characterized in that: The switch circuit includes a first resistor, a second resistor, a third resistor, a PMOS transistor, and a first NPN transistor; Among them, the first end of the first resistor is electrically connected to the output end of the first voltage conversion circuit and the source of the PMOS tube, the second end of the first resistor is electrically connected to the first end of the second resistor and the gate of the PMOS tube; the drain of the PMOS tube is electrically connected to the soldering iron temperature control circuit; the second end of the second resistor is electrically connected to the collector of the first NPN transistor; the base of the first NPN transistor is electrically connected to the second end of the third resistor, and the emitter of the first NPN transistor is electrically connected to the ground end; the second end of the third resistor is electrically connected to the main control circuit.

6. An electric soldering iron, characterized in that: The electric soldering iron comprises a power supply input terminal, a soldering iron temperature control circuit and the induction control device according to any one of claims 1 to 5.

7. The electric soldering iron according to claim 6, wherein: The electric soldering iron includes a soldering iron tip, and the soldering iron temperature control circuit includes: a temperature detection circuit, the temperature detection circuit being electrically connected to the switch circuit, the temperature detection circuit being used to detect the operating temperature of the soldering iron tip and output a temperature detection signal; a comparison control circuit, the comparison control circuit being electrically connected to the temperature detection circuit, and the comparison control circuit being configured to output a corresponding temperature control switch signal according to the temperature detection signal; A temperature control switch circuit is electrically connected to the comparison control circuit, and the temperature control switch circuit is used to heat or stop heating the soldering iron tip according to the temperature control switch signal.

8. The electric soldering iron according to claim 7, wherein: The temperature detection circuit includes a fourth resistor and a thermistor; Among them, the first end of the fourth resistor is electrically connected to the switching circuit and the comparison control circuit, and the second end of the fourth resistor is electrically connected to the first end of the thermistor; the first end of the thermistor is electrically connected to the comparison control circuit, and the second end of the thermistor is electrically connected to the ground end.

9. The electric soldering iron according to claim 8, wherein The comparison control circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an operational amplifier, a comparator, an adjustable resistor, a sixth diode, a sixth capacitor, and a seventh capacitor; Among them, the first end of the sixth capacitor is electrically connected to the first end of the thermistor and the non-inverting input terminal of the operational amplifier, and the second end of the sixth capacitor is electrically connected to the ground terminal; the first end of the fifth resistor is electrically connected to the inverting input terminal of the operational amplifier and the first end of the adjustable resistor, and the second end of the fifth resistor is electrically connected to the ground terminal; the first end of the sixth resistor is electrically connected to the output terminal of the operational amplifier and the inverting input terminal of the comparator, and the second end of the sixth resistor is electrically connected to the second end of the adjustable resistor; the first end of the seventh resistor is electrically connected to the first end of the fourth resistor and the positive power supply terminal of the comparator, and the second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the anode of the sixth diode; the second end of the eighth resistor is electrically connected to the non-inverting input terminal of the comparator and the first end of the seventh capacitor; the second end of the seventh capacitor is electrically connected to the first end of the ninth resistor and the output terminal of the comparator; the negative power supply terminal of the comparator is electrically connected to the ground terminal; and the second end of the ninth resistor is electrically connected to the temperature control switch circuit.

10. The electric soldering iron according to claim 9, wherein The temperature control switch circuit includes a tenth resistor, an eleventh resistor, a light emitting diode, a heating wire, a second NPN transistor, and a third NPN transistor; In which, the anode of the light-emitting diode is electrically connected to the power supply circuit and the first end of the heating wire, and the cathode of the light-emitting diode is electrically connected to the first end of the tenth resistor; the second end of the tenth resistor is electrically connected to the second end of the heating wire, the collector of the second NPN transistor, and the collector of the third NPN transistor; the base of the second NPN transistor is electrically connected to the second end of the ninth resistor, and the emitter of the second NPN transistor is electrically connected to the base of the third NPN transistor; the emitter of the third NPN transistor is electrically connected to the ground end.

Images