Temperature control circuit and electronic equipment

Abstract

The utility model discloses a temperature control circuit and electronic equipment, the temperature control circuit comprises at least three heating wires, at least three control circuits and a control chip, one control circuit corresponds to one heating wire, one end of each control circuit is connected with the heating wire, and the other end of each control circuit is connected with the control chip. According to the scheme, a circuit structure with at least three heating wires is used, so that the problem of consistent power under different voltages is solved, and the problem of large instantaneous power variation during PWM (Pulse Width Modulation) is solved.

Description

Technical Field

[0001] This utility model relates to the field of hair dryer technology, specifically to a temperature control circuit and electronic device. Background Technology

[0002] Currently, existing hair dryers are usually labeled with a specific rated voltage, and most do not have a globally universal full-voltage function. This not only limits the versatility of hair dryers, but may also affect their performance under different voltage environments.

[0003] In existing technologies, many full-voltage hair dryers use pulse width modulation (PWM) to regulate the temperature of the heating element in order to control power output. However, PWM regulation can cause instantaneous power fluctuations, which in turn can cause fluctuations in the grid voltage, potentially failing voltage fluctuation and flicker tests. Utility Model Content

[0004] This application discloses a temperature control circuit and electronic device. By using a circuit structure with at least three heating wires, it not only satisfies the problem of consistent power under different voltages, but also solves the problem of large instantaneous power changes during PWM modulation.

[0005] The first aspect of this application discloses a temperature control circuit, including at least three heating wires, at least three control circuits, and a control chip. One control circuit corresponds to one heating wire. One end of each control circuit is connected to the heating wire, and the other end of each control circuit is connected to the control chip.

[0006] The control chip is used to detect the power supply voltage connected to the temperature control circuit, and, when the power supply voltage is detected, to control the target control circuit to be in a conducting state, wherein the target control circuit is at least one of the at least three control circuits;

[0007] The control circuit is used to supply operating current to the corresponding heating wire according to the power supply voltage when the circuit is in the on state.

[0008] The heating wire is used to be in a heating state under the action of the working current.

[0009] As an optional implementation, in a first aspect of the embodiments of this application, the at least three heating wires include a first portion and a second portion, the first portion including at least one heating wire, and the second portion including at least two heating wires, wherein:

[0010] At least two heating wires in the second part are connected in series;

[0011] The first part and the second part are connected in parallel.

[0012] As an optional implementation, in a first aspect of the embodiments of this application, the first portion includes a first heating wire, and the second portion includes a second heating wire and a third heating wire, wherein,

[0013] The first end of the first heating wire is connected to the first end of the second heating wire; the second end of the first heating wire is connected to the second end of the third heating wire and the neutral wire, and the second end of the third heating wire is also connected to the neutral wire.

[0014] The second end of the second heating wire is connected to the first end of the third heating wire.

[0015] As an optional implementation, in a first aspect of the embodiments of this application, the at least three control circuits include a first control circuit, a second control circuit, and a third control circuit, wherein,

[0016] One end of the first control circuit is connected to the first end of the first heating wire, one end of the second control circuit is connected to the first end of the second heating wire, and one end of the third control circuit is connected to the third heating wire.

[0017] The other ends of the first control circuit, the second control circuit, and the third control circuit are connected to the control chip.

[0018] As an optional implementation, in a first aspect of the embodiments of this application, the control circuit includes a silicon controlled rectifier (SCR) and an optocoupler. The control circuit is connected to the control chip through the optocoupler. The SCR is connected to the optocoupler. The optocoupler is also connected to the live wire and the at least three heating wires. The SCR is also connected to the live wire and the at least three heating wires.

[0019] The optocoupler is used to send an electrical signal to the thyristor when it receives a control command from the control chip.

[0020] The thyristor is used to be in a conducting state when the electrical signal is received, so that the control circuit is in an open state.

[0021] As an optional implementation, in a first aspect of the embodiments of this application, the control circuit further includes a first resistor, a second resistor, a third resistor, and a fourth resistor; the optocoupler includes a first terminal, a second terminal, a third terminal, and a fourth terminal; and the thyristor includes a gate, an anode, and a cathode, wherein:

[0022] The first end is connected to the power supply; the second end is connected to the control chip through the first resistor to receive signals from the control chip; the third end is connected to the live wire and the anode of the thyristor through the second resistor and the third resistor respectively; the fourth end is connected to the gate of the thyristor respectively, and is also connected to the cathode of the thyristor and the at least three heating wires through the fourth resistor respectively.

[0023] The anode is connected to the third terminal and the live wire respectively; the cathode is connected to the fourth terminal and the at least three heating wires respectively;

[0024] The optocoupler is used to receive signals from the control chip through the second terminal, and to send electrical signals to the gate through the fourth terminal;

[0025] The thyristor is used to turn on the anode 53 and the cathode when the gate receives an electrical signal, so that the control circuit is in a conducting state.

[0026] As an optional implementation, in a first aspect of the embodiments of this application, the resistance of the first heating wire is in the range of 90Ω to 100Ω, the resistance of the second heating wire is in the range of 70Ω to 80Ω, and the resistance of the third heating wire is in the range of 10Ω to 20Ω.

[0027] As an optional implementation, in a first aspect of the embodiments of this application, the parameters of the optocouplers in the at least three control circuits are the same, and the parameters of the thyristors in the at least three control circuits are the same.

[0028] As an optional implementation, in the first aspect of the embodiments of this application, the resistance value of the first resistor is in the range of 300Ω~400Ω, the resistance value range of the second resistor and the third resistor is both in the range of 200Ω~300Ω, and the resistance value range of the fourth resistor is 100kΩ~300kΩ.

[0029] A second aspect of this application discloses an electronic device including any of the temperature control circuits described above.

[0030] Compared with related technologies, the embodiments of this application have at least the following beneficial effects:

[0031] The temperature control circuit disclosed in this application includes at least three heating wires, at least three control circuits, and a control chip. Each control circuit corresponds to one heating wire. One end of each control circuit is connected to a heating wire, and the other end is connected to the control chip. The control chip is used to detect the power supply voltage connected to the temperature control circuit, and, when the power supply voltage is detected, to control a target control circuit to be in a conducting state. This target control circuit is at least one of the at least three control circuits. When in the conducting state, the control circuit supplies operating current to the corresponding heating wire according to the power supply voltage. The heating wire is used to be in a heating state under the action of the operating current. By using a circuit structure with at least three heating wires, this application not only satisfies the problem of consistent power under different voltages but also solves the problem of large instantaneous power changes during PWM modulation. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a structural schematic diagram of a temperature control circuit provided in an embodiment of this application;

[0034] Figure 2 A schematic diagram of the structure of another temperature control circuit provided in the embodiments of this application;

[0035] Figure 3 This is a structural schematic diagram of a control circuit provided in an embodiment of this application;

[0036] Figure 4 A schematic diagram of the structure of another temperature control circuit provided in the embodiments of this application;

[0037] Figure 5 This is a schematic structural diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] It should be noted that the terms "first, second, third" used in the embodiments of this application are used to distinguish similar or different objects and do not represent a specific order of objects. It can be understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0040] It should be noted that the terms "comprising" and "having," and any variations thereof, in the embodiments and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0041] As a common household appliance, the voltage compatibility of hair dryers is crucial for sales and user experience in the global market. Most hair dryers are typically labeled with their rated voltage, and their electrical design is often tailored to specific voltage standards. Therefore, the performance and stability of hair dryers can vary significantly under different voltage conditions. For example, in environments with low mains voltage, hair dryers may malfunction due to insufficient voltage, resulting in unstable airflow or even failure to start. Conversely, in environments with excessively high mains voltage, the power output of the hair dryer may exceed its design capacity, leading to overheating of the heating element, equipment damage, and even electrical safety hazards. Such voltage mismatch issues not only affect the performance of hair dryers but also limit their global versatility, causing inconvenience for consumers and preventing them from fully utilizing the device's functions. In severe cases, it can even affect the lifespan of the device and user safety.

[0042] To meet the demands of the global market, some hair dryers have adopted a so-called "all-voltage" design, supporting a wide range of voltage inputs, such as 100V to 240V. However, this design is not without its drawbacks. Many all-voltage hair dryers use Pulse Width Modulation (PWM) to regulate the temperature and power output of the heating element. Through PWM technology, the hair dryer can adjust the current duty cycle according to different usage conditions, thereby controlling the power output. This regulation method has certain advantages in controlling temperature and airflow, but it also brings some significant problems. PWM current regulation causes instantaneous power fluctuations. When these fluctuations are transmitted through the power grid, they can lead to rapid voltage changes or fluctuations. These voltage fluctuations can not only affect the efficiency of the hair dryer but also interfere with the power grid itself. For example, voltage instability in the power grid can cause flickering lights, malfunctions of other household appliances, and even electrical fires. Furthermore, excessive current fluctuations can lead to unbalanced grid loads, affecting the stability of the entire power grid and increasing the difficulty of maintenance and management for power companies. More seriously, these unstable current fluctuations may cause hair dryers to fail international safety certification standards, thus affecting their distribution and sales in the global market. To ensure these certifications, hair dryers must be designed to meet stringent electromagnetic compatibility (EMC) requirements. If voltage and instantaneous power fluctuations are not effectively controlled, electromagnetic interference will exceed limits, failing to meet certification requirements and ultimately impacting the manufacturer's market competitiveness. Therefore, hair dryers sold globally need to fully consider factors such as voltage adaptability, power output stability, and EMC to ensure they not only function normally in different voltage environments but also comply with international safety and environmental standards.

[0043] This application discloses a temperature control circuit and electronic device. By using a circuit structure with at least three heating wires, it not only satisfies the problem of consistent power under different voltages, but also solves the problem of large instantaneous power changes during PWM modulation. These will be described in detail below.

[0044] The temperature control circuit disclosed in this application is not only applicable to hair dryers, but can also play an important role in a variety of other scenarios and devices. For example, electric water heaters, electric heaters, electric ovens, microwave ovens, electric vehicles, hot air guns, hot air furnaces, heating pads, and heat therapy devices, etc., without specific limitations.

[0045] In electric water heaters, this temperature control circuit monitors water temperature to ensure it reaches the user-set value and prevents overheating that could cause scalding or damage. In electric heaters, it regulates the temperature of the heating element to prevent overheating, maintain a comfortable room temperature, and provide safety protection. In ovens and microwaves, it ensures food is heated evenly and baked at the set temperature. It adjusts the power output of the heating element in real time to prevent overheating or burning. In electric vehicle battery management systems, it helps regulate battery temperature, ensuring it operates within the optimal range and preventing performance degradation or damage from overheating or cooling. In hot air guns and ovens, it precisely controls temperature to prevent overheating that could damage materials or equipment. In heating pads or heat therapy devices, it ensures the device remains within the ideal heating range for a safe and comfortable treatment experience.

[0046] Please see Figure 1 , Figure 1 This is a schematic circuit diagram of a temperature control circuit provided in an embodiment of this application. The diagram includes at least three heating wires 11, at least three control circuits 21, and a control chip 31. Each control circuit corresponds to one heating wire, one end of each control circuit is connected to the heating wire, and the other end of each control circuit is connected to the control chip 31.

[0047] Among them, the control chip 31 is used to detect the power supply voltage connected to the temperature control circuit, and, when the power supply voltage is detected, to control the target control circuit to be in a conducting state, wherein the target control circuit is at least one of at least three control circuits 21.

[0048] The control circuit is used to supply operating current to the corresponding heating wire according to the power supply voltage when the circuit is in the on state.

[0049] Heating wire is used to generate heat under the action of working current.

[0050] The control chip 31, also known as a controller chip or control circuit chip, is an integrated circuit specifically designed to perform control tasks. It typically processes input signals and outputs signals according to predetermined rules or algorithms, ensuring the normal operation of other parts of the control system.

[0051] The main functions of the control chip 31 include, but are not limited to, signal processing, decision-making and control, data storage and calculation.

[0052] Signal processing refers to the process by which the control chip 31 receives external input signals, such as sensor data and button inputs, and processes these signals. It typically performs filtering, amplification, and conversion, and then makes decisions or control outputs based on the processing results.

[0053] Decision-making and control refer to the decision-making process of the control chip 31 based on preset algorithms, control rules, or logic. For example, in the temperature control circuit of this application embodiment, the control chip 31 detects the power supply voltage connected to the temperature control circuit based on the voltage detection sensor, and determines which control circuit to activate based on the voltage signal input from the sensor.

[0054] Data storage and computation refer to the fact that the control chip 31 integrates units such as a processor and memory to store program code and runtime data, and to perform calculations. This enables it to execute complex computational tasks and ensures the efficient operation of the system.

[0055] Optionally, the controller can be a microcontroller unit (MCU), a digital signal processor (DSP), a field-programmable gate array (FPGA), a system on chip (SoC), or a digital controller chip (DCC), etc., which can be selected according to actual needs, and no specific restrictions are made here.

[0056] Among them, an MCU is a microcomputer that integrates a microprocessor, memory, input / output interfaces, timers, and communication modules. A DSP (Digital Signal Processor) is a processor specifically designed for efficient digital signal processing. An FPGA (FPGA Programmable Logic Controller) allows users to configure hardware functions according to their needs. It supports parallel computing and is suitable for applications requiring high performance and flexibility. A SoC (System-on-a-Chip) is a control chip that integrates multiple functional modules on a single chip, typically including a processor, memory, and input / output interfaces. A DCC (Digital Control Center) is used to process digital signals and is usually combined with a digital signal processor to perform specific control tasks.

[0057] In this embodiment, in order to achieve power consistency under different voltage conditions by controlling the control circuit when the power supply voltage is detected, and to enable the temperature control circuit to adjust the PWM duty cycle time according to the power of the low-power heating wire by using PWM to adjust the power at different levels, the control chip 31 may implement the above control logic through several steps including but not limited to hardware architecture design, software programming and control algorithm, real-time and interrupt management, and peripheral interaction.

[0058] In this context, hardware architecture design refers to the fact that the control chip 31 typically includes multiple hardware modules to support different functions and control logic. The selection and design of hardware modules are the foundation for implementing the control logic. These hardware modules may include, but are not limited to, a central processing unit (CPU) microprocessor, memory, and input / output interfaces.

[0059] The central processing unit (CPU) is responsible for executing the computational tasks in the control logic. It controls the operation of various peripherals according to the program's instruction flow. The memory stores the control program and data. The program is stored in read-only memory (ROM) or flash memory and loaded into random access memory (RAM) during execution. Control algorithms are typically stored in ROM, while data and variables are stored in RAM.

[0060] Input / output interfaces are used to receive input signals from external devices and send output signals to external devices.

[0061] Software programming and control algorithms are the core of the control chip 31. This program code defines how to process input signals and, based on these signals, how to control the output. When writing the control program, several logical structures can be used for logic control, such as input signal acquisition, control algorithms, switch control, and output signal processing.

[0062] Real-time performance and interrupt management refer to the need for the control chip 31 to respond in real time to changes in external events or internal tasks. Therefore, an interrupt system needs to be designed to handle interrupt events. This includes an interrupt mechanism and a timer. The interrupt mechanism means that the control chip 31 can respond to requests from external devices through hardware interrupts, promptly interrupting the current task for processing. The timer refers to the ability of the control chip 31 to periodically execute certain tasks through a timer module, such as periodically reading sensor data or controlling the periodic actions of peripherals, such as the PWM output in the embodiments of this application.

[0063] Peripheral interaction refers to the interaction between the control chip 31 and external devices through different communication interfaces to execute control logic. These interfaces include, but are not limited to, GPIO interfaces, analog input / output, and communication interfaces. GPIO interfaces are used for interaction with simple peripherals. Analog input / output refers to the use of analog-to-digital converters or digital-to-analog converters if the control chip 31 needs to interact with analog signal devices, such as temperature sensors and analog voltage signals. Communication interfaces, such as UART, SPI, and I2C, are used for data exchange with other microcontrollers, sensors, displays, memory, and other devices.

[0064] The control circuit in this embodiment can be connected to the GPIO interface of the control chip 31.

[0065] In this embodiment, one control circuit corresponds to one heating wire, and one end of each control circuit is connected to the control chip 31, while the other end is connected to the heating wire.

[0066] Optionally, the control circuit can be a switch control circuit, a proportional control circuit, a PID control circuit, an adaptive control circuit, a digital control circuit, or a relay control circuit, etc. There are no specific restrictions here, and the choice can be made according to actual needs.

[0067] The core idea of ​​a control circuit is to control changes in current or voltage through input signals, thereby controlling the behavior of the load or external device. A control circuit includes, but is not limited to, several basic components such as input signals, control components, and output signals.

[0068] The input signal refers to the signal received by the control circuit from external sensors, switches, or control devices. These signals can be analog signals, such as sensor signals for temperature and pressure, or digital signals, such as the on / off state of a switch or encoder output. The control section refers to the hardware or program that processes the input signals to calculate control commands. These control commands determine the characteristics of the output signal. The output signal refers to the signal generated by the control circuit 20 and outputted to the actuator, such as a motor, light, or heater, to drive the external load. This output signal may be a voltage, current, or PWM signal.

[0069] The heating wire connected to each control circuit 20 is a metal wire that generates heat due to resistance when an electric current passes through it. It is typically made of a high-resistivity metal material, and its working principle is based on the Joule effect: when current flows through a conductor, the conductor's resistance causes some electrical energy to be converted into heat energy. This heat energy raises the temperature of the conductor, thus achieving the heating effect. Specifically, when current flows through the heating wire, free electrons inside the wire collide with metal atoms, causing the electrons' kinetic energy to be converted into heat energy. The resistance of the heating wire determines its efficiency in converting heat and the rate of heating. The higher the resistance, the more heat is generated; therefore, the material of the heating wire usually has high resistance.

[0070] The material of the heating wire must have high resistance and be able to withstand high temperatures without melting.

[0071] Optionally, the heating wire can be made of nickel-chromium alloy, iron-chromium-aluminum alloy, copper alloy, or tungsten, etc., without specific restrictions, and can be selected according to actual needs. The selection of these materials is based on their characteristics such as high temperature resistance, oxidation resistance, corrosion resistance, and fatigue resistance, enabling the heating wire to maintain its stability and effectiveness during long-term high-temperature operation.

[0072] In this embodiment, to ensure the heating wire generates heat efficiently while maintaining a long service life and safety, its diameter, length, shape, and density all require precise design.

[0073] The resistance of a heating wire is directly proportional to its length and inversely proportional to its cross-sectional area. This results in a thin, long heating wire having a higher resistance than a thick, short heating wire, thus generating more heat.

[0074] Optionally, the heating wire can be straight or spiral. Preferably, the spiral design helps to increase the contact area with air and optimize heat transfer.

[0075] The density of the heating element is designed, i.e., the resistance per unit length. A balance needs to be struck between the heat output and the lifespan of the heating wire.

[0076] This solution uses at least three heating wires 11 connected to at least three control circuits 21. Based on the control algorithm in the control chip 31, when the control chip 31 detects the power supply voltage, it controls the corresponding control circuit to be in the conducting state according to the control logic for different voltages. This satisfies the problem of consistent power under different voltages. Furthermore, since at least three heating wires 11 are used, the PWM duty cycle time can be adjusted according to the heating wire with the lowest heating power when adjusting the gear. This solves the problem of large instantaneous power changes during PWM modulation, thereby avoiding the problem of unstable mains voltage and light flickering caused by large power changes. This meets the relevant FCC / CE / CCC and other safety certifications.

[0077] In some embodiments, the at least three heating wires 11 are connected in series and parallel; see [link to relevant documentation]. Figure 2 , Figure 2 This is a schematic structural diagram of a heating wire structure provided in an embodiment of this application. The structural diagram includes a first part 12, a second part 13, and a neutral wire 62. The first part 12 includes at least one heating wire, and the second part 13 includes at least two heating wires connected in series. The first part 12 and the second part 13 are connected in parallel.

[0078] In some embodiments, please refer to further information. Figure 2 The first part 12 in the structural diagram includes a first heating wire 121, and the second part 13 includes a second heating wire 131 and a third heating wire 132. The first end of the first heating wire 121 is connected to the first end of the second heating wire 131; the second end of the first heating wire 121 is connected to the second end of the third heating wire 132 and the neutral wire 62, respectively; the second end of the third heating wire 132 is also connected to the neutral wire 62; and the second end of the second heating wire 131 is connected to the first end of the third heating wire 132.

[0079] For further information, please refer to the following: Figure 2 The structural diagram also includes a first control circuit 22, a second control circuit 23 and a third control circuit 24, wherein one end of the first control circuit 22 is connected to the first end of the first heating wire 121, one end of the second control circuit 23 is connected to the first end of the second heating wire 131, and one end of the third control circuit 24 is connected to the third heating wire 132.

[0080] The other ends of the first control circuit 22, the second control circuit 23, and the third control circuit 24 are connected to the control chip 31.

[0081] In some embodiments, please refer to Figure 3 , Figure 3 This is a schematic structural diagram of a control circuit provided in an embodiment of this application. The control circuit 20 includes an optocoupler 41, a silicon controlled rectifier 51, and a live wire 61. The control circuit 20 is connected to the control chip 31 through the optocoupler 41, the silicon controlled rectifier 51 is connected to the optocoupler 41, the optocoupler 41 is also connected to the live wire 61 and one of the at least three heating wires 11, and the silicon controlled rectifier 51 is also connected to the live wire 61 and the at least three heating wires 11.

[0082] Optocoupler 41 is used to send an electrical signal to the silicon controlled rectifier 51 when it receives a control command from the control chip 31;

[0083] The thyristor 51 is used to be in a conducting state when the electrical signal is received, so that the control circuit 20 is in an open state.

[0084] An optocoupler (also known as an opto-isolator or optocoupler) is an electronic component used to achieve electrical isolation, signal transmission, and interference suppression. It can transmit signals between two circuits without a direct electrical connection, thus avoiding interference from electrical noise, ground potential differences, or electrical surges, ensuring signal integrity and circuit safety.

[0085] The working principle of the optocoupler 41 is based on the photoelectric effect. Simply put, the optocoupler 41 converts an electrical signal into an optical signal, which is then transmitted to the receiving end and finally to another circuit. The basic components of the optocoupler 41 include a light-emitting diode (LED), a photosensitive element, and an isolation layer, which transmit signals via light. The light-emitting end refers to the LED portion, which is driven by the input electrical signal. Once excited, the LED emits light, and the optical signal is transmitted to the receiving end through the optical isolation layer. Optionally, the LED can be an LED, etc., without specific limitations.

[0086] The receiving end refers to the photosensitive element, which converts the received optical signal into an electrical signal. Optionally, the photosensitive element includes a photodiode, a phototransistor, or a photosensitive three-terminal device, etc., without specific limitations.

[0087] An isolation layer refers to a transparent physical barrier (such as glass or plastic) between the light-emitting and receiving ends to facilitate the transmission of optical signals. This isolation layer ensures that there is no direct electrical connection between the two circuits, thereby achieving electrical isolation and effectively suppressing interference from high-voltage surges, ground potential differences, and electrical noise. Optionally, the isolation layer can be glass or plastic; no specific limitation is made here.

[0088] Optionally, the optocoupler 41 can be a photodiode type optocoupler 41, a phototransistor type optocoupler 41, a photosensitive three-terminal element type optocoupler 41, a high-frequency type optocoupler 41, a fiber optic optocoupler 41, or a bidirectional optocoupler 41, etc. There are no specific restrictions here, and the selection can be made according to actual needs.

[0089] Among them, the photodiode-type optocoupler 41 uses a photodiode as the receiving element to convert optical signals into electrical signals. The phototransistor-type optocoupler 41 uses a phototransistor as the receiving element, offering higher response speed and stronger output capability compared to the photodiode-type optocoupler 41. The photosensitive three-terminal element-type optocoupler 41 integrates a phototransistor and a three-terminal element, providing higher driving capability. The high-frequency optocoupler 41 is used for high-frequency signal transmission. This type of optocoupler 41 features high bandwidth and high-speed response characteristics. The fiber optic optocoupler 41 is based on the principle of fiber optic transmission, using fiber optics as the signal transmission medium, and has extremely high anti-interference capability. The bidirectional optocoupler 41 can support signal transmission in both directions.

[0090] The thyristor 51 is connected to the optocoupler 41 and is used to be in a conducting state when it receives an electrical signal sent by the optocoupler 41, so that the control circuit 20 is in an open state.

[0091] Optionally, the thyristor 51 can be a standard thyristor 51, a bidirectional thyristor 51, a gate 52 turn-off type thyristor 51, a light-controlled thyristor 51, an adjustable gate 52 type thyristor 51, a silicon controlled rectifier, a four-port thyristor 51, a Schottky thyristor 51, and a dynamic thyristor 51, etc. There are no specific restrictions here, and the selection can be made according to actual needs.

[0092] The SCR51 is an important semiconductor device, belonging to the category of SCR51 rectifiers. It can control the conduction and cutoff of current. The SCR51 is a four-layer triple-junction semiconductor device, usually composed of four alternating layers of P-type and N-type materials, forming a PNPN structure.

[0093] The basic function of a SCR (Semiconductor Controlled Rectifier) ​​51 is to control the conduction and cutoff of current. Its conduction state is controlled by an external current. When no external trigger current signal is applied, the SCR 51 is in the off state, i.e., it does not conduct. When a suitable trigger current signal is applied externally, the first PN junction of the SCR 51 is activated, causing the SCR 51 to conduct. Once turned on, the SCR 51 will remain in the conducting state until the current drops below a certain threshold or the external circuit is disconnected, at which point it will turn off.

[0094] The thyristor 51 includes a gate, a cathode 54, and an anode 53. When the potential of the anode 53 of the thyristor 51 is higher than that of the cathode 54, it is in a forward-biased state. In this state, current can flow through the thyristor 51 until the current falls below the holding current, at which point it will turn off. When the potential of the anode 53 of the thyristor 51 is lower than that of the cathode 54, the device is in a reverse-biased state and will not conduct electricity, similar to the reverse cutoff state of a diode. The thyristor 51 is triggered to conduct by the gate 52; the magnitude and direction of the current at the gate 52 determine whether conduction is initiated.

[0095] Optionally, the parameters of the optocouplers 41 in the at least three control circuits 21 are the same, and the parameters of the thyristors 51 in the at least three control circuits 21 are the same.

[0096] In some embodiments, please refer to further information. Figure 3 The control circuit 20 also includes a power supply 63, a first resistor 25, a second resistor 26, a third resistor 27, and a fourth resistor 28. The optocoupler 41 includes a first terminal 42, a second terminal 43, a third terminal 44, and a fourth terminal 45. The silicon controlled rectifier 51 includes a gate 52, an anode 53, and a cathode 54.

[0097] The first terminal 42 is connected to the power supply 63; the second terminal 43 is connected to the control chip 31 through the first resistor 25 to receive signals from the control chip 31; the third terminal 44 is connected to the live wire 61 and the anode 53 of the silicon controlled rectifier 51 through the second resistor 26 and the third resistor 27 respectively; the fourth terminal 45 is connected to the gate 52 of the silicon controlled rectifier 51 respectively, and is also connected to the cathode 54 of the silicon controlled rectifier 51 and the at least three heating wires 11 through the fourth resistor 28 respectively.

[0098] Anode 53 is connected to the third terminal 44 and live wire 61 respectively; cathode 54 is connected to the fourth terminal 45 and at least three heating wires 11 respectively.

[0099] Optocoupler 41 is used to receive signals from control chip 31 through second terminal 43, and to send electrical signals to gate 52 through fourth terminal 45.

[0100] The thyristor 51 is used to turn on the anode 53 and cathode 54 when the gate 52 receives an electrical signal, so that the control circuit 20 is in a conducting state.

[0101] Optionally, the at least three control circuits 21 have the same circuit structure.

[0102] In some embodiments, to accommodate different voltage levels, the resistance of the first heating wire 121 is in the range of 90Ω to 100Ω, the resistance of the second heating wire 131 is in the range of 70Ω to 80Ω, and the resistance of the third heating wire 132 is in the range of 10Ω to 20Ω.

[0103] In some embodiments, in order to enable the control circuit 20 to perform better control and protect the stability of the circuit structure, the first resistor 25 in the control circuit 20 has a resistance range of 300Ω~400Ω, the second resistor 26 and the third resistor 27 both have a resistance range of 200Ω~300Ω, and the fourth resistor 28 has a resistance range of 100kΩ-300kΩ.

[0104] For example, please refer to Figure 4 , Figure 4 This is a schematic diagram of another temperature control circuit disclosed in an embodiment of this application. In this circuit structure, the parameters of optocouplers U1, U2, and U3 are the same, and the parameters of thyristors BT1, BT2, and BT3 are the same. The power supply 63 connected to the first terminal 42 of optocoupler 41 is 5V. The resistance R1 of the first heating wire 121 is 96Ω, the resistance R2 of the second heating wire 131 is 79.5Ω, and the resistance R3 of the third heating wire 132 is 16.5Ω. The first resistor 25 is 330Ω, the second resistor 26 and the third resistor 27 are both 220Ω, and the fourth resistor 28 is 100kΩ.

[0105] When the control chip 31 of the temperature control circuit detects that the power supply voltage U is 240V, it sends a control signal to the first control circuit 22, the second control circuit 23, and the third control circuit 24. The first and second control circuits 22 and 23 are in a conducting state according to the control signal, while the third control circuit 24 is in a de-energized state. Since the second heating wire 131 and the third heating wire 132 are connected in series, all three heating wires receive the control current sent by the control circuit 20. Therefore, all three heating wires begin to heat up. The total power of the three heating wires is = U*U / R1 + U*U / (R2+R3) = 240*240 / 96 + 240*240 / 96 = 1200W. Here, "*" represents multiplication and " / " represents division.

[0106] When the control chip 31 of the temperature control circuit detects that the power supply voltage U is 130V, it sends a control signal to the first control circuit 22, the second control circuit 23, and the third control circuit 24. The first control circuit 22 and the third control circuit 24 are in the conducting state according to the control signal, and the second control circuit 23 is in the conducting state according to the control signal. Therefore, at this time, the first heating wire 121 and the third heating wire 132 receive the control current sent by the control circuit 20, while the second heating wire 131 does not receive the control current from the control circuit 20. The first heating wire 121 and the third heating wire 132 are heating, while the second heating wire 131 is not heating. At this time, the total power of the three heating wires is =U*U / R1+U*U / (R2+R3)=240*240 / 96+240*240 / 96=1200W.

[0107] Additionally, when adjusting the power level, the PWM duty cycle time can be adjusted according to the heating wire with the lowest heating power. For example, when the power supply voltage is 240V, the heating wire with the lowest power is the first heating wire 121. The heating power of the first heating wire 121 is 240*240 / 96=600W1. Therefore, the power change of the PWM duty cycle time can be adjusted by adjusting the power level according to the heating wire power of the first heating wire 121, which is 1200-600=600W.

[0108] When the power supply voltage is 130V, the lowest power heating wire is the third heating wire 132. The heating power of the third heating wire 132 is 130*130 / 16.5=1024W. Therefore, the power change of the PWM duty cycle time is adjusted by adjusting the power of the total heating wires according to the power of the third heating wire 132, which is 1200-1024=176W.

[0109] Therefore, it effectively avoids the problem of unstable mains voltage and lamp flickering caused by large power fluctuations, and meets relevant international safety certification standards.

[0110] Based on the temperature control circuit 10 described above, this application also discloses an electronic device, such as... Figure 5 As shown, Figure 5 This is a structural schematic diagram of an electronic device disclosed in this application, including an electronic device 30 and any of the above-mentioned temperature control circuits 10.

[0111] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0112] In the various embodiments of this application, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0113] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they can be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0114] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0115] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0116] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0117] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0118] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0119] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0120] The temperature control circuit disclosed in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A temperature control circuit, characterized by, The control circuit comprises a control chip, at least three control circuits and at least three heating wires, one control circuit corresponds to one heating wire, one end of each control circuit is connected with the heating wire, and the other end of each control circuit is connected with the control chip, wherein: The control chip is used for detecting a power supply voltage connected to the temperature control circuit, and controlling a target control circuit to be in a conduction state when the power supply voltage is detected, wherein the target control circuit is at least one of the at least three control circuits; The control circuit is used for delivering working current to the corresponding heating wire according to the power supply voltage in the conduction state; The heating wire is used for being in a heating state under the action of the working current.

2. The temperature control circuit of claim 1, wherein, The at least three heating wires comprise a first part and a second part, the first part comprises at least one heating wire, and the second part comprises at least two heating wires, wherein: The at least two heating wires in the second part are connected in series; The first part and the second part are connected in parallel.

3. The temperature control circuit of claim 2, wherein, The first part comprises a first heating wire, and the second part comprises a second heating wire and a third heating wire, wherein: The first end of the first heating wire is connected with the first end of the second heating wire, the second end of the first heating wire is respectively connected with the second end of the third heating wire and a zero line, and the second end of the third heating wire is also connected with the zero line; The second end of the second heating wire is connected with the first end of the third heating wire.

4. The temperature control circuit of claim 3, wherein, The at least three control circuits comprise a first control circuit, a second control circuit and a third control circuit, wherein: One end of the first control circuit is connected with the first end of the first heating wire, one end of the second control circuit is connected with the first end of the second heating wire, and one end of the third control circuit is connected with the third heating wire; The other end of the first control circuit, the second control circuit and the third control circuit is connected with the control chip.

5. The temperature control circuit of claim 4, wherein, The control circuit comprises a silicon controlled rectifier and an optocoupler, the control circuit is connected with the control chip through the optocoupler, the silicon controlled rectifier is connected with the optocoupler, the optocoupler is also connected with a live wire and the at least three heating wires respectively, and the silicon controlled rectifier is also connected with the live wire and the at least three heating wires respectively; The optocoupler is used for sending an electric signal to the silicon controlled rectifier when receiving a control instruction of the control chip; The silicon controlled rectifier is used for being in a conduction state to make the control circuit in an open state when receiving the electric signal.

6. The temperature control circuit of claim 5, wherein, The control circuit further comprises a first resistor, a second resistor, a third resistor and a fourth resistor, the optocoupler comprises a first end, a second end, a third end and a fourth end, and the silicon controlled rectifier comprises a gate, an anode and a cathode, wherein: The first end is connected with a power supply; the second end is connected with the control chip through a first resistor for receiving a signal of the control chip; the third end is connected with a firewire and an anode of the thyristor through a second resistor and a third resistor respectively; the fourth end is connected with gates of the thyristor respectively and is further connected with cathodes of the thyristor and the at least three heating wires through a fourth resistor respectively; The anode is connected with the third end and the firewire respectively; the cathode is connected with the fourth end and the at least three heating wires respectively; The optocoupler is used for receiving the signal of the control chip through the second end and sending an electric signal to the gate through the fourth end; The thyristor is used for conducting the anode and the cathode when the gate receives the electric signal, so that the control circuit is in a conducting state.

7. The temperature control circuit of claim 4, wherein, The resistance value of the first heating wire ranges from 90Ω to 100Ω, the resistance value of the second heating wire ranges from 70Ω to 80Ω, and the resistance value of the third heating wire ranges from 10Ω to 20Ω.

8. The temperature control circuit of claim 6, wherein, The parameters of the optocoupler in the at least three control circuits are the same, and the parameters of the thyristor in the at least three control circuits are the same.

9. The temperature control circuit of claim 6, wherein, The resistance value of the first resistor ranges from 300Ω to 400Ω, the resistance value of the second resistor and the third resistor both ranges from 200Ω to 300Ω, and the resistance value of the fourth resistor ranges from 100kΩ to 300kΩ.

10. An electronic device, comprising: The temperature control circuit comprises the temperature control circuit according to any one of claims 1-9.

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