A dryer circuit and dryer

Abstract

The application relates to the technical field of electronic engineering, in particular to a dryer circuit and a dryer. The dryer circuit comprises a power module, a main control unit, a heating control unit, a temperature detection unit, a display driving unit, a fan control unit and an alarm unit which are connected with the main control unit. The output end of the power module provides power supply for the main control unit, the display driving unit, the temperature detection unit, the fan control unit, the heating control unit and the alarm unit. The dryer circuit of the application connects the main control unit with the heating control unit, the temperature detection unit, the display driving unit, the fan control unit and the alarm unit, thereby enhancing the anti-interference ability of the circuit and making the signal transmission more stable and reliable. In addition, the power module adopts an AC / DC conversion module and a linear voltage stabilizer, thereby ensuring the stability of power supply of each unit.

Description

Technical Field

[0001] This application relates to the field of electronic engineering technology, and in particular to a dryer circuit and a dryer. Background Technology

[0002] Drying equipment is widely used in many fields such as food processing, textiles, wood drying, and agricultural product dehydration. To achieve precise control of parameters such as temperature, heating power, and operating status during the drying process, it is typically equipped with modules including heaters, motors, and their control circuits. Traditional dryer control systems often rely on relay logic control or PLC modules, which have certain limitations in temperature acquisition, control response, and equipment protection. For example, they suffer from low control accuracy, large equipment size, poor system integration, and difficulty in achieving intelligent control and status feedback.

[0003] In terms of circuit structure, most existing dryers adopt a distributed design, that is, the power module, control module and actuator control circuit are distributed among different circuit boards, resulting in complex wiring and relatively weak system stability and anti-interference ability.

[0004] Especially in terms of safety, the existing drying control circuit still has certain gaps in over-temperature protection and motor abnormality protection, and lacks a unified and coordinated main control logic control unit. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a dryer circuit and a dryer.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, embodiments of this application provide a dryer circuit, including:

[0009] The power supply module 1, the main control unit 2, and the heating control unit 3, temperature detection unit 4, display drive unit 5, fan control unit 6, and alarm unit 7, which are respectively connected to the main control unit 2;

[0010] The output of the power module 1 provides power to the main control unit 2, the display driver unit 5, the temperature detection unit 4, the fan control unit 6, the heating control unit 3, and the alarm unit 7, respectively.

[0011] Preferably, the main control unit 2 is a microcontroller chip;

[0012] The power module 1 includes:

[0013] AC / DC conversion module, wherein the input terminal of the AC / DC conversion module is connected to a 220V AC power supply, and the output terminal outputs a 12V DC voltage;

[0014] A linear voltage regulator module, the input of which is connected to the output of the AC / DC converter module, and the output of which outputs a 5V DC voltage;

[0015] Several capacitors are connected in parallel to the output terminal of the AC / DC converter module, the input terminal and the output terminal of the linear regulator module, respectively, for filtering and stabilizing voltage;

[0016] The output of the linear voltage regulator module is connected to the VCC power supply pin of the microcontroller chip.

[0017] Preferably, the heating control unit 3 includes:

[0018] An optocoupler isolator, whose input is connected to the main control unit 2 via a control signal line, and whose output is connected to the control electrode of a bidirectional thyristor;

[0019] The output of the AC / DC conversion module of the power module 1 provides a 12V working power to the input of the optocoupler isolator.

[0020] A bidirectional thyristor, whose control electrode is connected to the output terminal of the optocoupler isolator, whose main electrode is connected in series with a heating wire and forms a closed loop with the AC power supply;

[0021] The main electrode of the bidirectional thyristor is directly connected to a 220V AC power supply;

[0022] The main control unit 2 outputs a control signal through the optocoupler isolator to turn the bidirectional thyristor on or off, thereby controlling the heating state of the heating wire.

[0023] Preferably, the temperature detection unit 4 includes:

[0024] Thermocouple, whose signal end is connected to the analog input pin of temperature acquisition chip through RC filter circuit;

[0025] The power supply pin of the temperature acquisition chip is connected to the 5V output terminal of the linear voltage regulator module, and its digital interface is connected to the main control unit 2 via the SPI bus.

[0026] Preferably, the display driving unit 5 includes:

[0027] Display driver chip, at least two LED digital tubes, and several status indicator lights;

[0028] The power supply pin of the display driver chip is connected to the output terminal of the linear voltage regulator module;

[0029] The display driver chip is connected to the main control unit 2 via clock lines, data signal lines and strobe signal lines;

[0030] The segment selection pin of the LED digital tube is connected to the segment drive output terminal of the display driver chip, and the bit selection pin is connected to the bit selection output terminal of the display driver chip.

[0031] The positive terminal of the status indicator light is connected to the independent control pin of the display driver chip through a current-limiting resistor, while the negative terminal is grounded.

[0032] Preferably, the fan control unit 6 includes:

[0033] The base of the first driving transistor is connected to the PWM output pin of the main control unit 2 through a current-limiting resistor;

[0034] A fan motor, one end of which is connected to the output terminal of the AC / DC conversion module, and the other end of which is connected to the collector of the first driving transistor;

[0035] A freewheeling diode, the anode of which is connected to the collector of the first driving transistor, and the cathode of which is connected to the 12V output terminal;

[0036] The emitter of the first driving transistor is connected to the power ground line;

[0037] The main control unit 2 controls the duty cycle of the first driving transistor through a PWM signal to adjust the speed of the fan motor.

[0038] Preferably, the alarm unit 7 includes:

[0039] A buzzer, one end of which is connected to the output of the linear voltage regulator module, and the other end of which is connected to the collector of the second driving transistor;

[0040] The base of the second driving transistor is connected to the output terminal of the main control unit 2, and the emitter is connected to the ground wire;

[0041] The main control unit 2 controls the start and stop of the buzzer by driving the second driving transistor to turn on or off.

[0042] Preferably, the dryer circuit further includes:

[0043] The indicator unit includes a power indicator light, the positive terminal of which is connected to the 5V output terminal of the linear voltage regulator module through a current-limiting resistor, and the negative terminal is grounded.

[0044] The button input unit includes multiple capacitive touch buttons. The sensing electrode of each button is connected to the 5V output terminal of the linear voltage regulator module through a pull-up resistor and is connected to the input pin of the main control unit 2 through a signal line.

[0045] Preferably, the microcontroller chip is an STC8H1K17 microcontroller;

[0046] The temperature acquisition chip is a MAX6675 chip, and it communicates with the main control unit 2 through the SPI interface.

[0047] The display driver chip is a TM1628 chip, and the LED digital tube is a common cathode type.

[0048] The optocoupler in the heating control unit 3 is of type MOC3063, and the bidirectional thyristor is of type BTA24-600CW.

[0049] The AC / DC conversion module in the power supply module 1 is an HLK-5M12 module, and the linear regulator module is an L78M05ABDT-TR chip.

[0050] On the other hand, this embodiment also provides a dryer, including the dryer circuit as described above.

[0051] (III) Beneficial Effects

[0052] The dryer circuit solution proposed in this application brings significant benefits in several aspects through innovative structural design and optimized connection relationships. First, the modular circuit architecture connects the main control unit with the heating control unit, temperature detection unit, display driver unit, fan control unit, and alarm unit, enhancing the circuit's anti-interference capability and making signal transmission more stable and reliable. Second, the power supply module, employing an AC / DC converter and a linear voltage regulator, ensures the stability of power supply to each unit, effectively avoiding reset problems caused by sudden load changes.

[0053] The heating control unit employs an optocoupler-based isolator coupled with a bidirectional thyristor drive scheme, thus achieving complete isolation between high and low voltage circuits and ensuring the safety of the control system. The temperature detection unit utilizes thermocouples and a dedicated acquisition chip, improving temperature measurement accuracy. The display and interaction unit controls the digital tube display via a dedicated driver chip, combined with capacitive touch buttons, enhancing both the human-machine interface and reliability in humid environments. Attached Figure Description

[0054] Figure 1 A circuit diagram of a dryer provided in an embodiment of this application;

[0055] Figure 2 This is a schematic diagram of the actual circuit of the HLK-5M12 module in the embodiments of this application;

[0056] Figure 3 This is a schematic diagram of the specific circuit included in the L78M05ABDT-TR chip in the embodiments of this application;

[0057] Figure 4This is a schematic diagram of the STC8H1K17 microcontroller in the embodiments of this application;

[0058] Figure 5 A detailed circuit diagram of the heating control unit provided in the embodiments of this application;

[0059] Figure 6 This is a schematic diagram of the actual circuit of the temperature detection unit provided in the embodiments of this application;

[0060] Figure 7 This is a schematic diagram of a display driver chip provided in an embodiment of this application;

[0061] Figure 8 This is a schematic diagram of the actual circuit in the fan control unit provided in the embodiments of this application;

[0062] Figure 9 This is a schematic diagram of the actual circuit of the alarm unit provided in the embodiments of this application.

[0063] [Explanation of Labels in the Attached Image]

[0064] 1: Power supply module; 2: Main control unit; 3: Heating control unit; 4: Temperature detection unit; 5: Display driver unit; 6: Fan control unit; 7: Alarm unit. Detailed Implementation

[0065] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0066] The dryer circuit technology proposed in this application addresses the problems of traditional drying equipment. Through innovative circuit architecture design and optimized connection methods, it achieves significant technical improvements. Traditional dryer circuits commonly employ a mechanical temperature controller combined with a relay control scheme. This structure not only results in complex installation and wiring but also leads to severe mutual interference between functional modules.

[0067] The technical solution of this application effectively solves the above-mentioned problems through circuit design. Specifically, the main control unit and each unit adopt a standardized digital signal connection method, which greatly simplifies circuit wiring. The power supply module adopts a multi-stage voltage regulation design, combined with a carefully arranged filter capacitor network, to provide a stable and reliable operating voltage for each unit. The heating control unit achieves safe isolation between strong and weak currents through optocoupler isolation devices, which not only improves the reliability of the circuit but also facilitates fault diagnosis and maintenance. The temperature detection unit adopts a digital transmission scheme, avoiding the interference problems in the traditional analog signal transmission process.

[0068] All improvements in this application are based on hardware circuit structure optimization and connection adjustments, without involving any program-level modifications. Through the aforementioned innovative design, this solution significantly improves the convenience of installation and maintenance, reduces operating costs, and provides a reliable hardware foundation for the intelligent upgrading of drying equipment while maintaining the integrity of system functionality. These improvements make this technical solution particularly suitable for commercial drying equipment applications requiring high reliability and ease of maintenance.

[0069] To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0070] This application provides a dryer circuit, such as... Figure 1 As shown, it includes:

[0071] The power supply module 1, the main control unit 2, and the heating control unit 3, temperature detection unit 4, display drive unit 5, fan control unit 6, and alarm unit 7, which are respectively connected to the main control unit 2;

[0072] The output of the power module 1 provides power to the main control unit 2, the display driver unit 5, the temperature detection unit 4, the fan control unit 6, the heating control unit 3, and the alarm unit 7, respectively.

[0073] In the practical application of this embodiment, the main control unit 2 is a microcontroller chip; specifically, the microcontroller chip is an STC8H1K17 microcontroller. Figure 4 (Schematic diagram of STC8H1K17 microcontroller);

[0074] The power module 1 includes:

[0075] AC / DC conversion module, wherein the input terminal of the AC / DC conversion module is connected to a 220V AC power supply, and the output terminal outputs a 12V DC voltage;

[0076] A linear voltage regulator module, the input of which is connected to the output of the AC / DC converter module, and the output of which outputs a 5V DC voltage;

[0077] Several capacitors are connected in parallel to the output terminal of the AC / DC converter module, the input terminal and the output terminal of the linear regulator module, respectively, for filtering and stabilizing the voltage.

[0078] The output of the linear voltage regulator module is connected to the VCC power supply pin of the microcontroller chip.

[0079] The AC / DC conversion module in power module 1 is an HLK-5M12 module (see...). Figure 2 (This is a schematic diagram of the actual circuit of the HLK-5M12 module), the linear regulator module is the L78M05ABDT-TR chip ( Figure 3 (A schematic diagram of the specific circuit contained in the L78M05ABDT-TR chip).

[0080] In this embodiment, the microcontroller chip used in the main control unit 2 is supplied with a precise and stable operating power by the linear voltage regulator module of the power supply module 1. This power supply system employs a two-stage conversion architecture: first, the 220V AC power is converted to 12V DC power via an AC / DC converter module; then, the voltage is further reduced to 5V DC output via a high-performance linear voltage regulator module (such as the L78M05ABDT-TR chip). The output terminal of the linear voltage regulator module is directly connected to the VCC power supply pin of the microcontroller chip, while its GND terminal is connected to the chip's ground pin, forming a complete power supply loop.

[0081] Preferably, in some embodiments of this application, the heating control unit 3 includes:

[0082] An optocoupler isolator, whose input is connected to the main control unit 2 via a control signal line, and whose output is connected to the control electrode of a bidirectional thyristor;

[0083] The output of the AC / DC conversion module of the power module 1 provides a 12V working power to the input of the optocoupler isolator.

[0084] A bidirectional thyristor, whose control electrode is connected to the output terminal of the optocoupler isolator, whose main electrode is connected in series with a heating wire and forms a closed loop with the AC power supply;

[0085] The main electrode of the bidirectional thyristor is directly connected to a 220V AC power supply;

[0086] The main control unit 2 outputs a control signal through the optocoupler isolator to turn the bidirectional thyristor on or off, thereby controlling the heating state of the heating wire.

[0087] The optocoupler in the heating control unit 3 is of type MOC3063, and the bidirectional thyristor is of type BTA24-600CW.

[0088] In the dryer circuit provided in this embodiment, the 220V AC mains power is first connected to the AC input terminal of the power module, and then splits into two independent branches: one branch enters the AC / DC converter module for step-down rectification, outputting 12V and 5V DC voltages to power the control system; the other branch is directly led to the bidirectional thyristor main electrode of the heating control unit, maintaining the original 220V AC voltage to power the heating wire. This design ensures stable operation of the dryer circuit while avoiding unnecessary energy conversion losses. See [link to relevant documentation]. Figure 5 This is a schematic diagram of the heating control unit.

[0089] The core component of the heating control unit employs an optimized combination of an optocoupler and a bidirectional thyristor. The T1 main electrode of the bidirectional thyristor is directly connected to the AC live wire, while the T2 main electrode is connected to the neutral wire via the heating wire, forming a complete heating circuit. The input side of the optocoupler is driven by the main control unit via a PWM signal, while the output side is directly connected to the control electrode of the thyristor. Specifically, when the main control unit issues a heating command, the internal LED of the optocoupler illuminates, triggering the output side to conduct. At the AC zero-crossing point, this automatically triggers the thyristor to conduct, energizing the heating wire. When heating stops, the optocoupler cuts off, causing the thyristor to automatically turn off at the current zero-crossing point. This control method not only achieves complete electrical isolation but also ensures precise control of the switching process.

[0090] In a specific embodiment of this application, Figure 6 This is a schematic diagram of the actual circuit of the temperature detection unit 4, which includes:

[0091] Thermocouple, whose signal end is connected to the analog input pin of temperature acquisition chip through RC filter circuit;

[0092] The temperature acquisition chip is a MAX6675 chip, and it communicates with the main control unit 2 through the SPI interface.

[0093] The power supply pin of the temperature acquisition chip is connected to the 5V output terminal of the linear voltage regulator module, and its digital interface is connected to the main control unit 2 via the SPI bus.

[0094] Specifically, the power module provides operating power to the temperature detection unit through its linear regulator module's output of 5V DC voltage. This 5V power supply first passes through parallel filter capacitors to filter out high-frequency noise before being directly connected to the VCC pin of the temperature acquisition chip (such as MAX6675), providing it with a stable operating voltage. Simultaneously, the signal terminal of the thermocouple is connected to the input terminal of the temperature acquisition chip, which connects to the main control unit via digital communication interfaces such as SPI to achieve digital transmission of temperature data. The connection method between the power module and the temperature detection unit in this application has several technical advantages: First, the 5V low-voltage power supply avoids the influence of high-voltage interference on the weak thermocouple signal; second, the digital communication interface replaces traditional analog signal transmission, effectively solving the signal attenuation problem caused by long-distance transmission.

[0095] Preferably, the display driving unit 5 includes:

[0096] Display driver chip;

[0097] At least two LED digital tubes are used to display operating temperature, time, or other parameters;

[0098] Several status indicator lights are used to display heating status, fan status, setting status, etc.;

[0099] The power supply pin of the display driver chip is connected to the output terminal of the linear voltage regulator module;

[0100] The display driver chip is connected to the main control unit 2 via clock lines, data signal lines and strobe signal lines;

[0101] The display driver chip is a TM1628 chip, and the LED digital tube is a common cathode type.

[0102] The segment selection pin of the LED digital tube is connected to the segment drive output terminal of the display driver chip, and the bit selection pin is connected to the bit selection output terminal of the display driver chip.

[0103] The positive terminal of the status indicator light is connected to the independent control pin of the display driver chip through a current-limiting resistor, and the negative terminal is grounded.

[0104] Figure 7 This is a schematic diagram of a display driver chip, in which the LED digital tube can be connected to the SEG1-SEG8 pins and GRID1-GRID4 pins of the display driver chip.

[0105] Specifically, the display driver unit uses a display driver chip as its core hub. This chip connects to the general-purpose I / O pins of the main control unit via a three-wire serial interface (clock line CLK, data line DIO, and strobe line STB), transmitting display data using a serial communication protocol. The power supply pins of the display driver chip are connected to a 5V regulated output provided by the power module to ensure stable operating voltage. The LED digital tubes adopt a common cathode connection, with their segment selection pins directly connected to the segment drive output of the display driver chip, and their digit selection pins connected to the digit selection output of the chip. Dynamic scanning technology enables the sequential display of multiple digits, a design that saves I / O resources and reduces overall power consumption. The status indicator lights are directly driven by the display driver chip, with each indicator light connected to an independent control pin of the chip via a current-limiting resistor, and their on / off states managed uniformly by the main control unit.

[0106] Preferably, the fan control unit 6 includes:

[0107] The base of the first driving transistor is connected to the PWM output pin of the main control unit 2 through a current-limiting resistor;

[0108] A fan motor, one end of which is connected to the output terminal of the AC / DC conversion module, and the other end of which is connected to the collector of the first driving transistor;

[0109] A freewheeling diode, the anode of which is connected to the collector of the first driving transistor, and the cathode of which is connected to the 12V output terminal;

[0110] The emitter of the first driving transistor is connected to the power ground line;

[0111] The main control unit 2 controls the duty cycle of the first driving transistor through a PWM signal to adjust the speed of the fan motor.

[0112] Figure 8 This is a schematic diagram of the actual circuit in the fan control unit.

[0113] In this embodiment, the fan motor is directly powered by a 12V DC voltage output from the AC / DC conversion module of the power supply module. Specifically, the 12V positive terminal is connected to one end of the fan motor, and the other end is connected to the collector of the first driving transistor (NPN type transistor). The emitter of this first driving transistor is grounded, and its base is connected to the PWM output pin of the main control unit through a current-limiting resistor, forming a complete control loop. This power supply architecture achieves electrical isolation between the power circuit and the control circuit, ensuring driving capability while avoiding mutual interference.

[0114] Preferably, Figure 9 This is a schematic diagram of the actual circuit of the alarm unit 7, which includes:

[0115] A buzzer, one end of which is connected to the output of the linear voltage regulator module, and the other end of which is connected to the collector of the second driving transistor;

[0116] The base of the second driving transistor is connected to the output terminal of the main control unit 2, and the emitter is connected to the ground wire;

[0117] The main control unit 2 controls the start and stop of the buzzer by driving the second driving transistor to turn on or off.

[0118] In this embodiment, the positive terminal of the buzzer is directly connected to the 5V power supply terminal of the linearly regulated power module, while the negative terminal is connected to the collector of the second driving transistor, forming a complete current loop. The power module ensures the stability of the 5V output through multi-stage filtering, providing a clean operating voltage for the alarm unit. Regarding control signal transmission, the GPIO pin of the main control unit is connected to the base of the second driving transistor through a current-limiting resistor. When an alarm is needed, a high-level signal is output to saturate and turn on the transistor, driving the buzzer to sound.

[0119] Preferably, the dryer circuit further includes: an indicator unit and a key input unit;

[0120] The button input unit includes multiple capacitive touch buttons, each of which is connected to the input pin of the main control unit 2 via a pull-up resistor.

[0121] The output terminal of the power module 1 also provides power to the key input unit;

[0122] In this embodiment, the power supply system of the button input unit adopts a highly efficient and stable design architecture, with a 5V DC operating voltage directly provided by the linear regulator output of the power module. Specifically, the L78M05 linear regulator in the power module steps down and regulates the 12V input to output a clean 5V voltage. This voltage first passes through a multi-stage filtering network composed of a 100nF ceramic capacitor and a 100μF electrolytic capacitor, and then is distributed to the pull-up resistor network of each capacitive touch button through a star topology wiring method. The sensing electrode of each touch button is connected to the 5V power supply through a 10kΩ precision pull-up resistor, and a 100pF high-frequency filter capacitor is connected in parallel at the signal input terminal to form a complete power supply and signal conditioning circuit.

[0123] The indicator unit includes a power indicator light, which is connected between the positive terminal of the power supply and ground through a current-limiting resistor to indicate whether the whole machine is powered on.

[0124] The power indicator light in this embodiment employs a simple and reliable circuit design to visually display the power-on status of the dryer. The indicator light consists of a light-emitting diode (LED) (serving as a power indicator) and a current-limiting resistor, connected in a basic series circuit: the positive terminal (anode) of the LED is connected to the 5V DC positive terminal output by the power module through a precisely calculated current-limiting resistor, while the negative terminal (cathode) of the LED is directly connected to the system ground. When the power module is working normally, a 5V DC voltage is applied across this circuit, driving the LED to illuminate, clearly indicating to the user that the equipment is in a power-on standby state; when the equipment is powered off or a power supply failure occurs, the LED immediately turns off, providing a clear power-off indication.

[0125] The dryer circuit provided in this application offers several advantages in terms of structural design and functional integration. Firstly, regarding the power supply system, it adopts a two-stage voltage conversion architecture of "AC / DC conversion + linear regulation," achieving not only efficient and stable conversion from 220V AC to 12V and 5V DC, but also effectively suppressing power ripple and noise with multi-stage filter capacitors, providing a clean and reliable operating voltage for the dryer circuit and enhancing the overall anti-interference capability and stability of the circuit. Secondly, in terms of the control structure, all functional units, such as heating control, fan drive, temperature detection, display, and alarm, are uniformly controlled by the main control unit. The control logic is centralized, the modules are clearly divided, and maintenance and expansion are convenient. Simultaneously, the circuit achieves effective isolation between high-voltage and low-voltage circuits through optocoupler isolators. Especially in the heating control section, the use of MOC3063 optocouplers and BTA24-600CW bidirectional thyristors enhances the overall safety and surge resistance of the circuit.

[0126] Furthermore, the fan control section outputs a PWM signal through the main control unit to control the drive transistors and adjust the fan speed, balancing heat dissipation efficiency with energy saving and noise reduction. Temperature detection utilizes the MAX6675 digital temperature acquisition chip combined with a thermocouple to achieve high-precision temperature measurement and SPI bus communication, avoiding errors and interference caused by analog signal transmission and improving the sensitivity and stability of the temperature control system. For human-machine interaction, the system is equipped with a TM1628 display driver chip, driving LED digital tubes and multiple status indicator lights to intuitively display the current operating status. This, combined with capacitive touch buttons, provides a highly sensitive input method without mechanical wear, enhancing ease of operation and equipment durability. The alarm function is controlled by the main control unit via a buzzer, providing audible and visual alerts for operational abnormalities, and working in conjunction with the power indicator light to provide real-time feedback on the overall power-on status.

[0127] In summary, the dryer circuit of this application has significant advantages in terms of power supply stability, control precision, safety isolation, anti-interference ability, and user interaction experience. It is suitable for various household or industrial small and medium-sized drying equipment and has good practicality and promotion value.

[0128] On the other hand, this embodiment also provides a dryer, including the dryer circuit as described above.

[0129] In the dryer of this application embodiment, the structural characteristics of traditional electric heating blast drying ovens and the advantages of a new electronic control system are combined to further optimize temperature control accuracy, airflow stability, and fault self-diagnosis capability. The whole machine adopts a front-to-back split layout: the power module and control circuit are centrally located in the control cavity at the bottom of the equipment, while the heating unit and circulating fan are arranged in the working cavity. The two are connected by a metal heat-conducting plate and an air guide shroud to achieve rapid and uniform heat distribution, thereby improving heat exchange efficiency.

[0130] Compared with traditional analog temperature control schemes, the control circuit design of this application significantly improves the system's intelligence level. It employs an STC8H1K17 microcontroller chip as the core control unit, working in conjunction with a MAX6675 digital temperature sensor to achieve real-time acquisition, digital processing, and closed-loop regulation control of the temperature inside the chamber. Combined with electric heating elements and a fan system, it can achieve precise temperature control within the range of 0–150℃, with temperature fluctuations controlled within ±1℃, meeting the requirements of applications with high thermal uniformity requirements, such as medical experiments and metal drying.

[0131] The controller's operation section employs a touch-screen human-machine interface. The internal display driver circuit uses a TM1628 chip to drive LED digital tubes and status indicator lights, displaying key parameters such as set temperature, current temperature, and timer duration. The user interface is simple and intuitive. The panel functions support temperature preset, heating timer, and alarm output. Heating and timer functions are accessed by pressing and holding the "Set" button to enter parameter setting mode, and then quickly inputting the target temperature and time using the "+" and "-" keys. After heating is complete, it can enter a heat preservation mode or automatically power off, improving ease of use and safety.

[0132] To enhance its self-diagnostic capabilities, this dryer's circuit design integrates multiple fault response mechanisms. Faults such as abnormal temperature sensor operation (open circuit or short circuit), fan malfunction, relay failure, and buzzer failure can all be identified by the main control unit through ADC sampling, level detection, or communication anomaly detection. The main control unit will then provide prompts through the controller interface or trigger an alarm via the buzzer, facilitating timely problem detection and resolution by the user.

[0133] In addition, to ensure the long-term stability and safety of the equipment, the system is designed with multiple electrical protection measures, including overvoltage protection, undervoltage protection, and drive tube overheat protection. Especially during the heating process, if the temperature exceeds the set threshold (such as 130℃), the system will actively open the top exhaust port and can activate the fan to run at high speed to quickly release heat and prevent overheating and burnout of the equipment.

[0134] In summary, the dryer circuit provided in this application combines modern control technology with the advantages of traditional structure, and has the advantages of precise temperature control, sensitive response, safety and reliability, and user-friendly human-machine interaction. It is particularly suitable for laboratory, medical institutions and industrial application scenarios with high requirements for heating uniformity and temperature stability.

[0135] It should be noted that in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0136] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dryer circuit, characterized in that, include: The power supply module (1), the main control unit (2), and the heating control unit (3), temperature detection unit (4), display drive unit (5), fan control unit (6), and alarm unit (7) respectively connected to the main control unit (2); The output of the power module (1) provides power to the main control unit (2), the display driver unit (5), the temperature detection unit (4), the fan control unit (6), the heating control unit (3), and the alarm unit (7), respectively. The main control unit (2) is a microcontroller chip; The power module (1) includes: AC / DC conversion module, wherein the input terminal of the AC / DC conversion module is connected to a 220V AC power supply, and the output terminal outputs a 12V DC voltage; A linear voltage regulator module, the input of which is connected to the output of the AC / DC converter module, and the output of which outputs a 5V DC voltage; Several capacitors are connected in parallel to the output terminal of the AC / DC converter module, the input terminal and the output terminal of the linear regulator module, respectively, for filtering and stabilizing voltage; The output of the linear voltage regulator module is connected to the VCC power supply pin of the microcontroller chip.

2. The dryer circuit according to claim 1, characterized in that, The heating control unit (3) includes: The optocoupler isolator has its input end connected to the main control unit (2) via a control signal line, and its output end connected to the control electrode of the bidirectional thyristor. The output of the AC / DC conversion module of the power module (1) provides 12V working power to the input of the optocoupler isolator; A bidirectional thyristor, whose control electrode is connected to the output terminal of the optocoupler isolator, whose main electrode is connected in series with a heating wire and forms a closed loop with the AC power supply; The main electrode of the bidirectional thyristor is directly connected to a 220V AC power supply; The main control unit (2) outputs a control signal through the optocoupler isolator to turn the bidirectional thyristor on or off, thereby controlling the heating state of the heating wire.

3. The dryer circuit according to claim 2, characterized in that, The temperature detection unit (4) includes: Thermocouple, whose signal end is connected to the analog input pin of temperature acquisition chip through RC filter circuit; The power supply pin of the temperature acquisition chip is connected to the 5V output terminal of the linear voltage regulator module, and its digital interface is connected to the main control unit (2) via the SPI bus.

4. The dryer circuit according to claim 3, characterized in that, The display driving unit (5) includes: Display driver chip, at least two LED digital tubes, and several status indicator lights; The power supply pin of the display driver chip is connected to the output terminal of the linear voltage regulator module; The display driver chip is connected to the main control unit (2) via clock lines, data signal lines and strobe signal lines; The segment selection pin of the LED digital tube is connected to the segment drive output terminal of the display driver chip, and the bit selection pin is connected to the bit selection output terminal of the display driver chip. The positive terminal of the status indicator light is connected to the independent control pin of the display driver chip through a current-limiting resistor, while the negative terminal is grounded.

5. The dryer circuit according to claim 4, characterized in that, The fan control unit (6) includes: The base of the first driving transistor is connected to the PWM output pin of the main control unit (2) through a current-limiting resistor; A fan motor, one end of which is connected to the output terminal of the AC / DC conversion module, and the other end of which is connected to the collector of the first driving transistor; A freewheeling diode, the anode of which is connected to the collector of the first driving transistor, and the cathode of which is connected to the 12V output terminal; The emitter of the first driving transistor is connected to the power ground line; The main control unit (2) controls the duty cycle of the first driving transistor through a PWM signal to adjust the speed of the fan motor.

6. The dryer circuit according to claim 5, characterized in that, The alarm unit (7) includes: A buzzer, one end of which is connected to the output of the linear voltage regulator module, and the other end of which is connected to the collector of the second driving transistor; The second driving transistor has its base connected to the output terminal of the main control unit (2) and its emitter connected to the ground wire; The main control unit (2) controls the start and stop of the buzzer by driving the second driving transistor to turn on or off.

7. The dryer circuit according to claim 1, characterized in that, The dryer circuit also includes: The indicator unit includes a power indicator light, the positive terminal of which is connected to the 5V output terminal of the linear voltage regulator module through a current-limiting resistor, and the negative terminal is grounded. The key input unit includes multiple capacitive touch keys. The sensing electrode of each key is connected to the 5V output terminal of the linear voltage regulator module through a pull-up resistor and is connected to the input pin of the main control unit (2) through a signal line.

8. The dryer circuit according to claim 6, characterized in that, The microcontroller chip is an STC8H1K17 single-chip microcomputer. The temperature acquisition chip is a MAX6675 chip, and it communicates with the main control unit (2) through the SPI interface; The display driver chip is a TM1628 chip, and the LED digital tube is a common cathode type. The optocoupler in the heating control unit (3) is of type MOC3063, and the bidirectional thyristor is of type BTA24-600CW. The AC / DC conversion module in the power supply module (1) is an HLK-5M12 module, and the linear regulator module is an L78M05ABDT-TR chip.

9. A dryer, characterized in that, It includes the dryer circuit as described in any one of claims 1-8.

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