Control circuit for soldering apparatus
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN ASCHIP TECH CO LTD
- Filing Date
- 2025-07-21
- Publication Date
- 2026-06-12
Smart Images
Figure CN224347092U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of welding instrument technology, and in particular to a control circuit and soldering iron device. Background Technology
[0002] In fields such as electronic research and development, circuit board debugging, and repair of small electronic devices, the soldering iron is one of the most basic and commonly used soldering tools. Traditional soldering irons require the tip to be maintained at a relatively high operating temperature (typically between 300°C and 450°C) to ensure rapid melting of the solder during soldering. However, prolonged exposure to high temperatures during use can lead to tip corrosion, decreased soldering quality, damage to sensitive components, and increased safety risks, such as causing a fire. Utility Model Content
[0003] The main purpose of this invention is to propose a control circuit and soldering iron device, which aims to solve the problems of existing soldering irons being in a high-temperature state for a long time, resulting in corrosion of the soldering iron tip, reduced soldering quality, and increased safety risks.
[0004] To achieve the above objectives, this application proposes a control circuit for use in a soldering iron device, the soldering iron device including a soldering tip, comprising:
[0005] A power supply circuit is used to process the input power and output it.
[0006] The transistor detection circuit is used to detect whether the soldering iron tip is in use and generate a first detection signal.
[0007] The personnel detection circuit is used to detect whether the operator is within a preset range and generate a second detection signal.
[0008] The soldering iron control circuit is connected to the output terminals of the tube detection circuit and the personnel detection circuit. The power supply input terminal of the soldering iron control circuit is connected to the output terminal of the power supply circuit. The soldering iron control circuit is used to receive and control the soldering iron tip to enter the corresponding mode according to the first detection signal and the second detection signal.
[0009] The soldering iron control circuit is further configured to continuously receive a detection signal indicating that the soldering iron tip is not in use within a preset time, and control the soldering iron tip to enter a low-temperature standby mode; the soldering iron control circuit is also configured to continuously receive a detection signal indicating that the operator is not within a preset range within a preset time while the soldering iron tip is in the low-temperature standby mode, and control the soldering iron tip to enter a power-off mode.
[0010] In one embodiment, the soldering iron control circuit is further configured to receive a detection signal indicating that the soldering iron tip is in use within a preset time, and control the soldering iron tip to enter the working mode; the soldering iron control circuit is further configured to receive a detection signal from the operator within a preset range when the soldering iron tip is in the power-off mode, and control the soldering iron tip to enter the low-temperature standby mode.
[0011] In one embodiment, in the working mode, the soldering tip operates and maintains a first preset temperature;
[0012] In low-temperature standby mode, the soldering tip maintains a second preset temperature and remains in standby mode;
[0013] In power-off mode, the soldering tip is inactive.
[0014] In one embodiment, the soldering iron control circuit includes:
[0015] Temperature detection circuit is used to detect the temperature of the soldering iron tip and output a temperature detection signal;
[0016] The soldering iron output circuit has its input terminal electrically connected to an external power supply and is used to adjust the temperature of the soldering iron tip.
[0017] The main control circuit has its input terminal electrically connected to the output terminal of the temperature detection circuit, and its control terminal electrically connected to the controlled terminal of the soldering iron output circuit. It is used to output corresponding control signals to the soldering iron output circuit according to the received first detection signal, second detection signal and temperature detection signal, so as to dynamically adjust the temperature of the soldering iron tip.
[0018] In one embodiment, the temperature detection circuit includes a thermistor, one end of which is electrically connected to the input terminal of the main control circuit and the output terminal of the power supply circuit, and the other end is grounded. A capacitor is connected in parallel across the two ends of the thermistor.
[0019] In one embodiment, the soldering iron tip is provided with a heating element, and the soldering iron output circuit includes:
[0020] A bidirectional thyristor, with its input terminal electrically connected to an external power supply, and its output terminal connected to one end of a heating element via an inductor, while the other end of the heating element is electrically connected to an external power supply;
[0021] The first switching transistor has its input terminal electrically connected to the controlled terminal of the bidirectional thyristor, the controlled terminal electrically connected to the main control circuit, and its output terminal grounded.
[0022] In one embodiment, the transistor detection circuit includes:
[0023] Light-emitting diode;
[0024] The second switching transistor has its input terminal electrically connected to the output terminal of the power supply circuit via the light-emitting diode, its controlled terminal electrically connected to the control terminal of the main control circuit, and its output terminal grounded.
[0025] The phototransistor's input terminal is electrically connected to the output terminal of the power supply circuit, and its output terminal is grounded.
[0026] The third switching transistor has its input terminal electrically connected to the output terminal of the power supply circuit and the input terminal of the main control circuit, its controlled terminal electrically connected to the output terminal of the power supply circuit, and its output terminal grounded.
[0027] In one embodiment, the power supply circuit includes:
[0028] The power conversion circuit has its input terminal electrically connected to an external power source, and is used to convert and output the external power source.
[0029] The zero-crossing detection circuit has its input terminal electrically connected to an external power supply and its output terminal electrically connected to the main control circuit. It is used to detect the zero-crossing signal of the external power supply and output it to the main control circuit to synchronize the control signal of the main control circuit with the phase of the external power supply.
[0030] In one embodiment, it further includes:
[0031] The temperature input circuit has its output terminal electrically connected to the input terminal of the main control circuit. It is used to respond to the operator's input of a preset temperature and output it to the main control circuit.
[0032] In addition, to achieve the above objectives, this application also proposes a soldering iron device, including a soldering iron tip and a control circuit as described above.
[0033] This application monitors the usage status of the soldering iron tip through a tube detection circuit and a personnel detection circuit that detects in real time whether the operator is within a preset range. Based on this, the soldering iron control circuit continuously detects that the soldering iron tip is not in use within a preset time and controls the soldering iron tip to enter a low-temperature standby mode; in the low-temperature standby mode, if it continuously detects that the operator is not within a preset range within a preset time, it controls the soldering iron tip to enter a power-off mode. By automatically entering the low-temperature standby and complete power-off modes, the equipment significantly reduces power consumption when idle or unattended, effectively saving energy and reducing operating costs, and preventing the soldering iron tip from oxidizing due to prolonged dry burning at high temperatures, effectively extending the service life of the soldering iron tip and reducing replacement frequency and maintenance costs. At the same time, the low-temperature standby state itself significantly reduces the temperature of the soldering iron tip, combined with the complete power-off guarantee after personnel leave, the dual effect makes the equipment extremely difficult to ignite surrounding flammable materials, improving the safety of the operating environment. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0035] Figure 1 This is a structural diagram of a control circuit according to the present invention.
[0036] Figure 2 This is a structural diagram of an embodiment of the control circuit of this utility model;
[0037] Figure 3 This is a circuit diagram of one embodiment of the control circuit of this utility model.
[0038] Reference numerals: Power supply circuit 01, Power conversion circuit 11, Zero crossing detection circuit 12, Transistor detection circuit 02, Personnel detection circuit 03, Soldering iron control circuit 04, Temperature detection circuit 41, Soldering iron output circuit 42, Main control circuit 43.
[0039] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0041] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.
[0042] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0043] This application proposes a control circuit for use in a soldering iron device, the soldering iron device including a soldering tip, such as... Figure 1 As shown, it includes: a power supply circuit 01, used to process and output the input power; a pin detection circuit 02, used to detect whether the soldering iron tip is in use and generate a first detection signal output; a personnel detection circuit 03, used to detect whether the operator is within a preset range and generate a second detection signal output; and a soldering iron control circuit 04, connected to the output terminals of the pin detection circuit 02 and the personnel detection circuit 03. The power supply input terminal of the soldering iron control circuit 04 is connected to the output terminal of the power supply circuit 01. The soldering iron control circuit 04 is used to receive and control the soldering iron tip to enter the corresponding mode according to the first detection signal and the second detection signal.
[0044] The soldering iron control circuit 04 is further configured to continuously receive a detection signal indicating that the soldering iron tip is not in use within a preset time, and control the soldering iron tip to enter a low-temperature standby mode; the soldering iron control circuit 04 is also configured to continuously receive a detection signal indicating that the operator is not within a preset range within a preset time while the soldering iron tip is in the low-temperature standby mode, and control the soldering iron tip to enter a power-off mode.
[0045] More specifically, in the field of electronic research and development, soldering irons are indispensable basic tools used for soldering, debugging, and repairing components. However, their conventional usage mode, which involves maintaining the soldering iron tip at a high temperature for extended periods, leads to a series of significant problems. The primary issue is accelerated corrosion and wear of the soldering iron tip. The core of the soldering iron tip is typically made of a copper-based alloy and plated with iron or other protective layers. When continuously exposed to high-temperature air, a process known as "dry burning," the protective plating on its surface undergoes a violent oxidation reaction with oxygen, resulting in a blackened, pitted surface and the formation of an oxide layer that is difficult to solder. This not only directly shortens the lifespan of the soldering iron tip, but more importantly, the severely oxidized tip experiences a sharp decline in thermal conductivity, resulting in poor temperature uniformity and difficulty in effectively melting solder and forming good wetting. As a result, the solder joint may exhibit defects such as incomplete soldering, cold soldering, or rough, spiked solder joints, severely impairing the reliability and electrical performance of the soldered connection, leading to a significant decrease in soldering quality.
[0046] Secondly, the continuously high temperature of a soldering iron tip itself poses a significant heat hazard. In meticulous R&D operations, especially when handling microcontrollers, precision sensors, small surface-mount components, or thermistors, operators must be extremely careful to control heat input and duration. If a soldering iron tip, in a high-temperature standby state, accidentally touches or gets too close to these sensitive components, the intense heat radiation emitted or the heat transferred through direct contact can instantly exceed the component's heat resistance limit, causing internal structural damage, parameter drift, or even permanent failure. Such unintended thermal damage is particularly difficult to detect during the debugging phase, increasing the complexity and risk of R&D.
[0047] Finally, and most seriously, is the safety risk posed by the sustained high temperatures. Research and development workbenches are complex environments, often containing numerous flammable or combustible materials such as paper documents, plastic casings, wires, flux, cleaning solvents, and even wooden tools. An unattended soldering iron tip at operating temperature can easily cause smoke, fire, or even a major fire if it accidentally tipps over, falls, or if its hot parts come into prolonged contact with or are near these flammable materials. This risk is particularly pronounced when operators briefly leave the workbench or focus on other tasks.
[0048] To address these issues, common mitigation methods include manually lowering the temperature or turning off the power, or using a soldering iron with an automatic sleep function. However, manual operation relies heavily on human awareness and memory, and is easily overlooked or forgotten during busy or complex R&D processes. Automatic sleep functions based on fixed time intervals are difficult to adapt flexibly to the varying lengths of actual soldering tasks, potentially leading to untimely temperature drops during use or failure to enter energy-saving and safe mode during short breaks, resulting in less than satisfactory performance.
[0049] Currently, an ideal solution should be able to sense the actual usage status of the soldering iron tip and the presence of the operator in real time, and intelligently and dynamically adjust the working mode of the soldering iron accordingly: providing sufficient temperature when soldering is necessary, automatically entering a safe low-temperature standby mode during short pauses to protect the soldering iron tip and avoid overheating risks, and completely cutting off the main power supply to eliminate fire hazards after the operator has been away for an extended period. This state-aware automated power management is considered a good starting point for effectively solving the aforementioned pain points. Therefore, this application proposes a control circuit for a soldering iron device, which includes a soldering iron tip, a power supply circuit 01, a transistor detection circuit 02, a personnel detection circuit 03, and a soldering iron control circuit 04. The power supply circuit 01 is used to process and output the input power. It performs necessary processing and conversion on the raw power supply from the external source. This typically includes voltage conversion and other steps, providing reliable and safe power support for subsequent soldering iron tip heating, signal detection, and logic control.
[0050] The diode detection circuit 02 is used to detect whether the soldering iron tip is in use and generate a first detection signal output. It typically utilizes one or more optical devices, such as an infrared emitting diode and a receiving diode. Its working principle is based on detecting the light in a specific area near the soldering iron tip, usually whether the infrared light is blocked. When the operator holds the soldering iron for soldering, the solder, components, or the operator's hand naturally block the light path from the emitting diode to the receiving diode, causing a significant change in the light signal received by the receiving diode. The circuit detects this change and determines that the soldering iron tip is in use. Conversely, if the light path is unobstructed, it indicates that the soldering iron tip is not in use and is in an idle or "dry burning" state. This circuit continuously converts this state judgment into a first detection signal and outputs it to the soldering iron control circuit 04 in real time, providing a crucial basis for determining whether energy saving or protection is needed.
[0051] Personnel detection circuit 03 is used to detect whether the operator is within a preset range and generate a second detection signal output. It employs technologies such as an infrared pyroelectric sensor to sense specific infrared radiation emitted by the human body, ultrasonic ranging to measure the distance to the operator, microwave radar to detect subtle human movements, or a camera combined with simple image recognition. These sensors can detect the distance between the operator and the soldering iron. When the sensors detect a person moving or present within the preset effective range, the circuit outputs a signal indicating "personnel present"; once the person leaves the range and remains undetected for a period of time, the circuit outputs a signal indicating "personnel absent." This crucial information about the operator's location is converted into a second detection signal and output to the soldering iron control circuit 04, primarily used to assess whether the equipment needs to enter a higher level of safety protection. In this embodiment, personnel detection circuit 03 detects whether there is a person nearby at the power source; therefore, the preset range is the area near the power source.
[0052] The soldering iron control circuit 04 is connected to the output terminals of the tube detection circuit 02 and the personnel detection circuit 03. The power input terminal of the soldering iron control circuit 04 is connected to the output terminal of the power supply circuit 01. The soldering iron control circuit 04 receives and, based on the first and second detection signals, actively issues commands to control the heating element inside the soldering iron tip, thereby controlling the soldering iron tip to enter the corresponding mode. Specifically, if the soldering iron control circuit 04 continuously receives a signal from the tube detection circuit 02 indicating that the soldering iron tip is "not in use" (i.e., the optical path is continuously detected to be unobstructed) for a preset time period, it determines that the soldering iron tip is idle and unheated. At this time, to save energy and prevent high-temperature oxidation of the soldering iron tip, the control circuit actively issues commands to control the heating element, switching the soldering iron tip from the high-temperature working mode to a significantly lower-temperature "low-temperature standby mode." If, under the premise that the soldering iron tip is already in the aforementioned low-temperature standby mode, the soldering iron control circuit 04 continuously receives a signal from the personnel detection circuit 03 indicating that the operator is "not within the preset range" for another preset time period, it determines that the equipment is in an unattended state. To completely eliminate potential safety risks (such as fire) that may arise from unattended equipment, the control circuit will issue a final instruction to control the heating element and related main circuits, causing the soldering iron tip to enter a "power-off mode," almost completely cutting off its power supply, and retaining only a very low-power wake-up capability.
[0053] This application monitors the usage status of the soldering iron tip through a tube detection circuit 02 and a personnel detection circuit 03 to detect in real time whether the operator is within a preset range. Based on this, the soldering iron control circuit 04 continuously detects that the soldering iron tip is not in use within a preset time and controls the soldering iron tip to enter a low-temperature standby mode; in the low-temperature standby mode, if it continuously detects that the operator is not within a preset range within a preset time, it controls the soldering iron tip to enter a power-off mode. By automatically entering the low-temperature standby and complete power-off modes, the equipment significantly reduces power consumption when idle or unattended, effectively saving energy and reducing operating costs, and preventing the soldering iron tip from oxidizing due to prolonged dry burning at high temperatures, effectively extending the service life of the soldering iron tip and reducing replacement frequency and maintenance costs. At the same time, the low-temperature standby state itself significantly reduces the temperature of the soldering iron tip, combined with the complete power-off guarantee after personnel leave, the dual effect makes the equipment extremely difficult to ignite surrounding flammable materials, improving the safety of the operating environment.
[0054] In one embodiment, the soldering iron control circuit 04 is further configured to receive a detection signal indicating that the soldering iron tip is in use within a preset time, and control the soldering iron tip to enter the working mode; the soldering iron control circuit 04 is further configured to receive a detection signal from the operator within a preset range when the soldering iron tip is in the power-off mode, and control the soldering iron tip to enter the low-temperature standby mode.
[0055] This can be understood as follows: when the operator needs to begin soldering, their actions, such as picking up the soldering iron or blocking the optical path of the diode detection circuit, are captured in real time by the diode detection circuit 02. This circuit immediately generates and outputs a detection signal indicating that the soldering iron tip is in use. The soldering iron control circuit 04 continuously receives this signal. If this "in use" signal is continuously confirmed within a preset, very short time window, thus avoiding misjudgments caused by brief obstruction or interference, the control circuit will accurately determine that the user has a clear soldering need at this moment. At this time, to ensure the immediacy and high quality of the soldering operation, the soldering iron tip needs to quickly reach and maintain a sufficiently high molten solder temperature. The control circuit will immediately issue a control command to drive the heating element into full-power operation mode, so that the soldering iron tip quickly heats up or maintains at the set high-temperature operating mode. This is the device's proactive switching from energy-saving or standby mode to high-efficiency operation mode, directly responding to the user's operating intentions and ensuring soldering performance.
[0056] Even after the equipment has entered the highest safety level power-off mode due to lack of supervision, the system still needs to be able to quickly restore availability when personnel return. Personnel detection circuit 03 continuously monitors a preset range. When an operator re-enters this range and is consistently detected, personnel detection circuit 03 generates and outputs a detection signal indicating "operator is within the preset range." Upon receiving this signal, soldering iron control circuit 04 determines that the operator has returned to the working position, and the equipment needs to be ready to be activated at any time. However, considering that soldering may not be immediately required upon personnel's return, and that heating directly from a cold state to working temperature is time-consuming and energy-intensive, the control circuit adopts a compromise strategy between safety and efficiency. It controls the soldering iron tip to switch from a completely power-off state to a low-temperature standby mode. In this mode, the soldering iron tip is heated and maintained at a safe temperature significantly lower than the working temperature but higher than room temperature. This significantly shortens the waiting time to heat up to the working temperature when soldering is needed later, improving response speed and user experience; furthermore, maintaining the low temperature itself consumes very little power and is far below the ignition point of common flammable materials, so its safety risks are completely controllable under the supervision of personnel. This enables a smooth and secure transition from a deep secure hibernation state to a ready-to-use state.
[0057] In one embodiment, in the working mode, the soldering tip works and is maintained at a first preset temperature; in the low-temperature standby mode, the soldering tip is maintained at a second preset temperature and is in standby mode; in the power-off mode, the soldering tip is in a non-working state.
[0058] In essence, when the soldering iron control circuit 04 determines that it needs to enter the working mode, it controls the heating element to apply full power or adjust the power as needed. The soldering iron control circuit 04 monitors the actual temperature of the soldering iron tip in real time through its temperature feedback system. It compares the monitored temperature value with a preset, higher first preset temperature, i.e., the ideal working temperature required for soldering. If the actual temperature is lower than the target temperature, the control circuit increases the heating power; if it approaches or reaches the target temperature, it dynamically adjusts the power to precisely maintain the soldering iron tip at this high temperature level. This closed-loop temperature control ensures that the soldering iron tip is always at the optimal soldering temperature, ready for efficient and high-quality soldering operations.
[0059] When the soldering iron control circuit 04 determines that it needs to enter low-temperature standby mode, it instructs the heating system to reduce its power output to maintain a level far below the soldering temperature. The control circuit also continuously monitors the soldering tip temperature via a temperature sensor, but the goal at this time is to maintain it at a lower second preset temperature, which is low temperature. This temperature is far below the first preset temperature, but still significantly higher than the ambient room temperature. The control circuit dynamically compensates for the heat loss of the soldering tip through intermittent heating with extremely low power or continuous heating with extremely low power, precisely stabilizing its temperature at this safe, energy-efficient, and rapidly recoverable low-temperature platform. At this time, the soldering tip is in a "standby" state, ready to quickly heat up to the operating temperature at any time based on the usage signal. This mode is an energy-saving and protective state activated when the soldering tip is not used for a short period. Its main functions are threefold: first, it significantly reduces the temperature of the soldering tip, slowing down the high-temperature oxidation rate on its surface, thereby greatly extending the lifespan of the expensive soldering tip; second, it significantly reduces energy consumption, saving a large amount of electricity compared to the operating mode; and third, it maintains a basic preheating state, shortening the heating waiting time for soldering operations that may be needed at any time, and improving response speed. At the same time, the maintained low temperature needs to be far below the ignition point of common combustibles, and it is safe under the supervision of personnel on site.
[0060] When the soldering iron control circuit 04 determines that it needs to enter power-off mode, it issues a command to completely or almost completely cut off the main power supply to the heating element. At this time, the heating system stops working and no longer generates any heat. The soldering iron tip loses external heat input, and its temperature begins to drop continuously through natural heat dissipation, eventually reaching equilibrium with the ambient temperature and entering a non-working state. At this time, the device only maintains extremely low-power monitoring circuit operation, and the main heating circuit is completely de-energized. Only when a personnel detection signal confirms the operator's return will the control circuit reconnect the necessary power, restoring the device from a cold state to a low-temperature standby state. This mode is the highest level of safety protection and is activated when it is confirmed that the operator has been away for an extended period and the device is unattended. Its sole and most important function is to completely eliminate the fire hazard caused by the high temperature of the soldering iron. By almost completely cutting off the heating energy supply, it ensures that the temperature of the soldering iron tip and its heating components can naturally cool to or near room temperature, fundamentally eliminating the possibility of the high-temperature heat source igniting surrounding combustibles. This is the ultimate guarantee for the safety of the working environment.
[0061] In one embodiment, such as Figure 2 As shown, the soldering iron control circuit 04 includes:
[0062] Temperature detection circuit 41 is used to detect the temperature of the soldering iron tip and output a temperature detection signal; soldering iron output circuit 42 has its input terminal electrically connected to an external power supply and is used to adjust the temperature of the soldering iron tip; main control circuit 43 has its input terminal electrically connected to the output terminal of the temperature detection circuit 41 and its control terminal electrically connected to the controlled terminal of the soldering iron output circuit 42, and is used to output corresponding control signals to the soldering iron output circuit 42 according to the received first detection signal, second detection signal and temperature detection signal, so as to dynamically adjust the temperature of the soldering iron tip.
[0063] This can be understood as follows: the temperature detection circuit 41 typically utilizes a temperature-sensitive element to maintain a tight thermal coupling with the soldering iron tip. When the temperature of the soldering iron tip changes, the electrical characteristics of the sensitive element will change predictably, linearly, or non-linearly. The detection circuit is responsible for providing suitable operating conditions for the sensitive element and accurately measuring the change in its output. Subsequently, the circuit performs necessary signal conditioning on this raw change and finally outputs a stable and reliable temperature detection signal that corresponds to the actual temperature of the soldering iron tip, which is then transmitted to the main control circuit 43.
[0064] The core of the soldering iron output circuit 42 is a power regulating device and its driving circuit. This power device is equivalent to a controlled switch or variable resistor, connected in series in the power supply circuit of the heating element. The control signal output by the main control circuit 43 determines the conduction level of this power device. When the control signal requires an increase in power, the output circuit makes the power device conduct more fully or for a longer time, allowing more current to flow through the heating element and increasing its heat generation; when the control signal requires a decrease in power, the output circuit limits the current and reduces the heat generation. Therefore, the soldering iron output circuit 42 dynamically adjusts the heating power by responding to the main control command in real time, and is the execution link that directly affects the temperature change of the soldering iron tip.
[0065] The main control circuit 43 receives a temperature detection signal from the temperature detection circuit 41, representing the current actual temperature of the soldering iron tip, as well as the first and second detection signals. The main control circuit 43 continuously monitors the detected actual temperature. If the actual temperature is lower than the target, it sends a command signal to the controlled terminal of the soldering iron output circuit 42 to increase the heating power; conversely, if the actual temperature is close to or exceeds the target, it sends a command signal to decrease or maintain the power. Through this continuous signal monitoring, the main control circuit 43 dynamically and in a closed-loop manner drives the soldering iron output circuit 42 to adjust the heating power, ultimately ensuring that the actual temperature of the soldering iron tip can quickly reach and stabilize at the user-set target temperature, achieving precise and stable temperature control.
[0066] In one embodiment, such as Figure 3 As shown, the temperature detection circuit 41 includes a thermistor. One end of the thermistor is electrically connected to the input terminal of the main control circuit 43 and the output terminal of the power supply circuit 01, and the other end is grounded. A capacitor is connected in parallel across the two ends of the thermistor.
[0067] Thermistors are typically mounted close to or inside the soldering iron tip to quickly and accurately sense changes in the tip's temperature. A key characteristic of thermistors is that their resistance changes significantly and predictably with temperature. When the soldering tip temperature changes, the thermistor's resistance also changes. This changing resistance is the basis for converting physical temperature into an electrical quantity.
[0068] The thermistor, along with the output terminal and ground terminal of power supply circuit 01, forms a simple resistor voltage divider network. The voltage output from power supply circuit 01 is applied across this variable resistor formed by the thermistor. Since one end of the thermistor is connected to the positive terminal of the power supply and the other end is grounded, the voltage across the thermistor depends entirely on its current resistance. According to Ohm's law, when the thermistor's resistance decreases due to increased temperature, the voltage across it also decreases accordingly; conversely, when the temperature decreases causing the thermistor's resistance to increase, the voltage across it increases. This changing voltage signal is the "temperature detection signal," which directly and continuously reflects the temperature of the thermistor.
[0069] The capacitor connected in parallel across the thermistor primarily serves to filter and stabilize the signal. Various high-frequency noise interferences are unavoidable in the circuit environment. These interference signals are superimposed on the voltage signal generated by the thermistor, which reflects the actual temperature change, causing the signal read by the main control circuit 43 to be unstable or inaccurate. The capacitor has the characteristic of "passing AC and blocking DC," acting like a miniature energy pool. When high-frequency noise occurs, the capacitor quickly eliminates rapidly changing interference energy, effectively "short-circuiting" it to ground or significantly attenuating it, allowing only the relatively slow-moving DC or low-frequency voltage signal reflecting temperature changes to pass through. This capacitor smoothly outputs the voltage signal to the main control circuit 43, filtering out noise spikes, improving the stability and anti-interference capability of temperature detection, and enabling the main control circuit 43 to obtain cleaner and more reliable actual temperature information.
[0070] In one embodiment, the soldering iron tip is provided with a heating element, and the soldering iron output circuit 42 includes: a bidirectional thyristor, the input terminal of which is electrically connected to an external power supply, the output terminal of which is connected to one end of the heating element through an inductor, and the other end of the heating element is electrically connected to an external power supply; a first switching transistor, the input terminal of which is electrically connected to the controlled terminal of the bidirectional thyristor, the controlled terminal of which is electrically connected to the main control circuit 43, and the output terminal of which is grounded.
[0071] A bidirectional thyristor is connected in series in the power supply circuit between the AC power source and the heating element. Its unique structure allows current to conduct in both directions, perfectly suited for AC power supply scenarios. When the bidirectional thyristor is in the off state, it blocks the current path from the external power source to the heating element, stopping heating; while when it is controlled to conduct, it establishes a complete power supply circuit, allowing AC current to flow through the heating element to generate heat. The core value of this device lies in its ability to control high-power loads with a small trigger current, and to automatically maintain conduction until the current crosses zero, making it key to achieving efficient AC power regulation.
[0072] The first switching transistor serves as a relay and amplification signal for the trigger signal. Its input is connected to the trigger electrode of the bidirectional thyristor, its output is grounded to form a loop, and its controlled end is directly connected to the low-voltage control signal of the main control circuit 43. When the main control circuit 43 needs to start heating, it sends a high-level drive signal to the controlled end of the first switching transistor, causing the first switching transistor to saturate and conduct instantaneously. At this time, the trigger electrode of the bidirectional thyristor forms a low-impedance path to ground through the first switching transistor, allowing the trigger current to flow and thus activating the main circuit of the bidirectional thyristor. Conversely, when the main control output is low, the first switching transistor is turned off, the trigger circuit is broken, and the bidirectional thyristor naturally turns off after the AC zero crossing.
[0073] The inductor connected in series between the bidirectional thyristor and the heating element impedes sudden current changes through its self-inductance effect at the moment the bidirectional thyristor is turned on, thus avoiding the generation of destructive surge current; it smooths the current ripple generated by the thyristor chopper, reducing pulse impacts on the heating element, and at the same time reducing high-frequency interference conducted to the power supply; it forms an inductive load with the heating element, utilizing the current phase lag characteristic to reduce the stress on the thyristor and extend the device life.
[0074] During the heating start-up phase, the main control circuit 43 outputs a high level according to the temperature requirement → the first switching transistor turns on → the trigger electrode of the bidirectional thyristor forms a grounding path → the bidirectional thyristor conducts bidirectionally → the AC current drives the heating element to heat up after being filtered by the inductor. During the power adjustment phase, the main control circuit 43 precisely controls the turn-on timing of the first switching transistor through phase-shift triggering or zero-crossing triggering technology, delaying the trigger time within the AC half-cycle. The smaller the conduction angle, the lower the output power. It controls the number of full-wave / half-wave transistors turned on each cycle, and adjusts the average power by changing the on / off ratio. During the heating stop phase, the main control circuit 43 outputs a continuous low level → the first switching transistor remains off → the bidirectional thyristor loses its trigger current → it naturally turns off at the end of the current half-cycle → the heating circuit is completely cut off.
[0075] In one embodiment, the transistor detection circuit 02 includes:
[0076] Light-emitting diode; second switching transistor, the input terminal is electrically connected to the output terminal of the power supply circuit 01 via the light-emitting diode, the controlled terminal is electrically connected to the control terminal of the main control circuit 43, and the output terminal is grounded; phototransistor, the input terminal is electrically connected to the output terminal of the power supply circuit 01, and the output terminal is grounded; third switching transistor, the input terminal is electrically connected to the output terminal of the power supply circuit 01 and the input terminal of the main control circuit 43, the controlled terminal is electrically connected to the output terminal of the power supply circuit 01, and the output terminal is grounded.
[0077] The light-emitting diode (LED) emits infrared or visible light of a specific wavelength driven by a constant current. Its beam path is precisely calibrated and directed directly to the phototransistor receiver. When the soldering iron tip is not placed on the stand, the light reaches the receiver unobstructed; when the soldering iron tip is returned to the stand, the metal structure completely blocks the beam transmission, creating an optical blockage. This device creates the physical conditions for non-contact detection and eliminates mechanical wear issues. The second switch acts as the power enable switch for the LED and is connected in series in the LED's power supply circuit. Its controlled terminal is connected to the control pin of the main control circuit 43. When the main control circuit 43 needs to perform detection, it sends a high-level signal to the second switch to turn it on. At this time, current flows from the power supply circuit 01 through the LED, the second switch, and ground to form a complete loop, activating the LED to emit light. When illuminated by the LED, the photon energy of the phototransistor excites electron-hole pairs inside the semiconductor, causing a sharp increase in reverse leakage current; when the light is blocked by the soldering iron tip, only a very weak dark current is maintained. This change in photocurrent directly reflects the on / off state of the light beam, converting optical information into electrical signals and providing raw detection data for subsequent circuits.
[0078] The third switching transistor constitutes a current-to-voltage conversion and logic shaping circuit. Its controlled terminal is connected to the output terminal of the phototransistor, and its input terminal is connected to a pull-up resistor to the power supply. When the phototransistor is illuminated and conducts, the generated photocurrent flows into the controlled terminal of the third switching transistor, causing it to saturate and conduct, resulting in the output voltage being pulled down to near ground level. When there is no illumination, the phototransistor is cut off, and the third switching transistor turns off due to lack of drive current, with the output terminal presenting a high level through the pull-up resistor. This process converts the analog current change of the phototransistor into a standard high / low level digital signal output to the main control circuit 43.
[0079] In one embodiment, such as Figure 3 As shown, the power supply circuit 01 includes:
[0080] The power conversion circuit 11 has its input terminal electrically connected to an external power source and is used to convert and output the external power source. The zero-crossing detection circuit 12 has its input terminal electrically connected to an external power source and its output terminal electrically connected to the main control circuit 43. It is used to detect the zero-crossing signal of the external power source and output it to the main control circuit 43 to synchronize the control signal of the main control circuit 43 with the phase of the external power source.
[0081] The power module provides power to the soldering iron tip and includes a zero-crossing signal detection circuit, a thyristor output, and MCU power supply. The zero-crossing detection circuit 12 is a key sensor for AC phase synchronization. Its input is connected in parallel to the external AC power supply live wire to capture the zero-crossing moment of the AC current in real time. It uses a high-impedance voltage divider network to reduce the high-voltage AC to a safe range and a high-speed comparator to convert the sine wave into a square wave signal. The comparator jumps when the AC voltage crosses zero, generating a steep-edge pulse. The output is connected to the interrupt pin of the main control circuit 43. Each rising / falling edge of the pulse corresponds to the precise zero-crossing point of the AC current, providing a time reference for power control.
[0082] After capturing the zero-crossing pulse, the main control circuit 43 uses it as the time origin to start the internal timer. When heating power needs to be adjusted, the thyristor is triggered only after a specific delay after the zero-crossing point, ensuring that the conduction start point is strictly synchronized with the power supply phase. If full power output is required, it is triggered immediately at the zero-crossing point, causing the thyristor to conduct for the entire half-cycle. If reduced power output is required, the trigger time is delayed, shortening the effective conduction time and achieving stepless power adjustment. When the main control issues a turn-off command, it does not immediately cut off, but waits for the next zero-crossing point to allow the thyristor to turn off naturally. This eliminates voltage and current surges during turn-off, significantly reducing electromagnetic interference and device stress.
[0083] In one embodiment, it further includes:
[0084] The temperature input circuit, with its output terminal electrically connected to the input terminal of the main control circuit 43, is used to respond to the operator's input of a preset temperature and output it to the main control circuit 43. It establishes an input channel for temperature setting commands, converting the operator's physical actions into digital signals. This can be implemented using various methods, including rotary encoders and key matrix schemes.
[0085] Furthermore, to achieve the above objectives, this application also proposes a soldering iron device, including a soldering iron tip and a control circuit as described above. The control circuit includes: a power supply circuit 01 for processing and outputting the input power; a pin detection circuit 02 for detecting whether the soldering iron tip is in use and generating a first detection signal output; a personnel detection circuit 03 for detecting whether the operator is within a preset range and generating a second detection signal output; and a soldering iron control circuit 04 connected to the output terminals of the pin detection circuit 02 and the personnel detection circuit 03. The power supply input terminal of the soldering iron control circuit 04 is connected to the output terminal of the power supply circuit 01. The soldering iron control circuit 04 receives and controls the soldering iron tip to enter a corresponding mode based on the first and second detection signals.
[0086] The soldering iron control circuit 04 is further configured to continuously receive a detection signal indicating that the soldering iron tip is not in use within a preset time, and control the soldering iron tip to enter a low-temperature standby mode; the soldering iron control circuit 04 is also configured to continuously receive a detection signal indicating that the operator is not within a preset range within a preset time while the soldering iron tip is in the low-temperature standby mode, and control the soldering iron tip to enter a power-off mode.
[0087] This application monitors the usage status of the soldering iron tip through a tube detection circuit 02 and a personnel detection circuit 03 to detect in real time whether the operator is within a preset range. Based on this, the soldering iron control circuit 04 continuously detects that the soldering iron tip is not in use within a preset time and controls the soldering iron tip to enter a low-temperature standby mode; in the low-temperature standby mode, if it continuously detects that the operator is not within a preset range within a preset time, it controls the soldering iron tip to enter a power-off mode. By automatically entering the low-temperature standby and complete power-off modes, the equipment significantly reduces power consumption when idle or unattended, effectively saving energy and reducing operating costs, and preventing the soldering iron tip from oxidizing due to prolonged dry burning at high temperatures, effectively extending the service life of the soldering iron tip and reducing replacement frequency and maintenance costs. At the same time, the low-temperature standby state itself significantly reduces the temperature of the soldering iron tip, combined with the complete power-off guarantee after personnel leave, the dual effect makes the equipment extremely difficult to ignite surrounding flammable materials, improving the safety of the operating environment.
[0088] The above embodiments are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.
Claims
1. A control circuit applied to a soldering iron device, the soldering iron device including a soldering tip, characterized in that, include: A power supply circuit is used to process the input power and output it. The transistor detection circuit is used to detect whether the soldering iron tip is in use and generate a first detection signal. The personnel detection circuit is used to detect whether the operator is within a preset range and generate a second detection signal. The soldering iron control circuit is connected to the output terminals of the tube detection circuit and the personnel detection circuit. The power supply input terminal of the soldering iron control circuit is connected to the output terminal of the power supply circuit. The soldering iron control circuit is used to receive and control the soldering iron tip to enter the corresponding mode according to the first detection signal and the second detection signal. The soldering iron control circuit is further configured to continuously receive a detection signal indicating that the soldering iron tip is not in use within a preset time, and control the soldering iron tip to enter a low-temperature standby mode; the soldering iron control circuit is also configured to continuously receive a detection signal indicating that the operator is not within a preset range within a preset time while the soldering iron tip is in the low-temperature standby mode, and control the soldering iron tip to enter a power-off mode.
2. The control circuit as described in claim 1, characterized in that, The soldering iron control circuit is also used to receive a detection signal indicating that the soldering iron tip is in use within a preset time, and control the soldering iron tip to enter the working mode; the soldering iron control circuit is also used to receive a detection signal from the operator within a preset range when the soldering iron tip is in the power-off mode, and control the soldering iron tip to enter the low-temperature standby mode.
3. The control circuit as described in claim 2, characterized in that, In working mode, the soldering iron tip operates and maintains a first preset temperature; In low-temperature standby mode, the soldering tip maintains a second preset temperature and remains in standby mode; In power-off mode, the soldering tip is inactive.
4. The control circuit as described in claim 1, characterized in that, The soldering iron control circuit includes: Temperature detection circuit is used to detect the temperature of the soldering iron tip and output a temperature detection signal; The soldering iron output circuit has its input terminal electrically connected to an external power supply and is used to adjust the temperature of the soldering iron tip. The main control circuit has its input terminal electrically connected to the output terminal of the temperature detection circuit, and its control terminal electrically connected to the controlled terminal of the soldering iron output circuit. It is used to output corresponding control signals to the soldering iron output circuit according to the received first detection signal, second detection signal and temperature detection signal, so as to dynamically adjust the temperature of the soldering iron tip.
5. The control circuit as described in claim 4, characterized in that, The temperature detection circuit includes a thermistor, one end of which is electrically connected to the input terminal of the main control circuit and the output terminal of the power supply circuit, and the other end is grounded. A capacitor is connected in parallel across the two ends of the thermistor.
6. The control circuit as described in claim 4, characterized in that, The soldering iron tip is equipped with a heating element, and the soldering iron output circuit includes: A bidirectional thyristor, with its input terminal electrically connected to an external power supply, and its output terminal connected to one end of a heating element via an inductor, while the other end of the heating element is electrically connected to an external power supply; The first switching transistor has its input terminal electrically connected to the controlled terminal of the bidirectional thyristor, the controlled terminal electrically connected to the main control circuit, and its output terminal grounded.
7. The control circuit as described in claim 4, characterized in that, The transistor detection circuit includes: Light-emitting diode; The second switching transistor has its input terminal electrically connected to the output terminal of the power supply circuit via the light-emitting diode, its controlled terminal electrically connected to the control terminal of the main control circuit, and its output terminal grounded. The phototransistor's input terminal is electrically connected to the output terminal of the power supply circuit, and its output terminal is grounded. The third switching transistor has its input terminal electrically connected to the output terminal of the power supply circuit and the input terminal of the main control circuit, its controlled terminal electrically connected to the output terminal of the power supply circuit, and its output terminal grounded.
8. The control circuit as described in claim 4, characterized in that, The power supply circuit includes: The power conversion circuit has its input terminal electrically connected to an external power source, and is used to convert and output the external power source. The zero-crossing detection circuit has its input terminal electrically connected to an external power supply and its output terminal electrically connected to the main control circuit. It is used to detect the zero-crossing signal of the external power supply and output it to the main control circuit to synchronize the control signal of the main control circuit with the phase of the external power supply.
9. The control circuit as described in claim 4, characterized in that, Also includes: The temperature input circuit has its output terminal electrically connected to the input terminal of the main control circuit. It is used to respond to the operator's input of a preset temperature and output it to the main control circuit.
10. A soldering iron device, characterized in that, It includes a soldering iron tip and a control circuit as described in any one of claims 1-9.