Constant-temperature heating control circuit, circuit board and device thereof

Abstract

The embodiment of the utility model provides a constant-temperature heating control circuit, a circuit board and a device thereof, and belongs to the technical field of heating circuits. The constant-temperature heating control circuit comprises a circuit control module, a heating module, a level detection module, a switch module, a temperature detection module and an alternating current power supply module. The control module, the switch module and the zero-cross detection module are combined, the heating temperature is detected through the temperature detection module, and when the temperature does not reach a preset temperature value, the control module controls the switch module to be switched on, and the temperature is increased by running at the maximum power; when the temperature reaches a preset temperature value, the control module detects the zero point of an alternating current signal through the zero-cross detection module, and sends a control signal to control the switch module to be switched on or switched off at the zero point, so that the heating circuit works by using unidirectional voltage, the control of constant-temperature heating is realized, meanwhile, the control is performed at the zero point, and the accurate sending of the control signal is ensured; the influence of voltage pulse fluctuation is reduced, and the problem of performance reduction caused by voltage pulse waves is avoided.

Description

Technical Field

[0001] This application relates to the technical field of heating circuits, and particularly to a constant-temperature heating control circuit, a circuit board and a device thereof. Background Art

[0002] The heating technology for a sealed small-space box is a technology for raising the internal temperature of the box in a closed environment through a specific method. This technology is widely used in many fields such as scientific experiments, chemical production, pharmaceutical manufacturing, and fine processing, aiming to meet the requirements of precise temperature control and high heating efficiency.

[0003] When using a heating element to heat a relatively sealed small-space box and making its internal temperature quickly reach a relatively stable constant temperature value, on the one hand, it is necessary to control the heating power of the heating element. The heating element requires a large power value so that the temperature can quickly reach the preset temperature value. However, due to the large power of the heating element, when maintaining the constant temperature after the temperature reaches the preset temperature value, the temperature change range value shows a large deviation; on the other hand, due to the large power of the heating element and the small internal space of the product, during the temperature control process, it will cause an increase in the voltage pulse fluctuation (Filcker) of the circuit to the product, which may cause problems such as product damage and performance degradation. Therefore, the requirements for the control circuit are relatively high. Summary of the Utility Model

[0004] The main purpose of the embodiments of this application is to propose a constant-temperature heating control circuit, a circuit board and a device thereof, aiming to improve the accuracy of constant-temperature control and reduce the voltage pulse fluctuation of the circuit to the product.

[0005] To achieve the above object, in the first aspect of the embodiments of this application, a constant-temperature heating control circuit is proposed. The constant-temperature heating control circuit includes:

[0006] A circuit control module, the circuit control module includes a circuit control chip;

[0007] An AC power supply module;

[0008] A heating module, the first pin of the heating module is connected to the live wire of the AC power supply module, and the heating function is realized through the heating module;

[0009] A switch module, the control signal input end of the switch module is connected to the control signal output pin of the circuit control chip, and the neutral wire of the AC power supply module is connected to the second pin of the heating module after passing through the power input end of the switch module;

[0010] A temperature detection module, the output end of the temperature detection module is connected to the temperature input pin of the circuit control chip;

[0011] A level detection module, the input end of the level detection module is connected to the AC power module, and the output end of the level detection module is connected to the level detection pin of the circuit control chip.

[0012] According to the constant temperature heating control circuit provided by some embodiments of the present application, the circuit further includes:

[0013] A first rectification module, the input pin of the first rectification module is connected to the AC power module;

[0014] According to the constant temperature heating control circuit provided by some embodiments of the present application, the circuit further includes:

[0015] A second rectification module, the input pin of the second rectification module is connected to the output pin of the first rectification module, and the output pin of the second rectification module is connected to the power input pin of the circuit control module.

[0016] According to the constant temperature heating control circuit provided by some embodiments of the present application, the circuit further includes:

[0017] A fan module, the input pin of the fan module is connected to the output pin of the first rectification module, the signal input pin of the fan module is connected to the fan control pin of the circuit control chip, and the output pin of the fan module is connected to the reference ground.

[0018] According to the constant temperature heating control circuit provided by some embodiments of the present application, the switch module includes:

[0019] A first optocoupler, the first pin of the first optocoupler serves as the control signal input pin of the switch module and is connected to the control signal output pin of the circuit control module, the second pin of the first optocoupler is connected to the reference ground, and the fourth pin of the first optocoupler is connected to the neutral wire of the AC power module;

[0020] A triac, the gate of the triac is connected to the third pin of the first optocoupler, the main anode of the triac is connected to the neutral wire of the AC power module, and the main cathode of the triac is connected to the second pin of the heating module.

[0021] According to the constant temperature heating control circuit provided by some embodiments of the present application, the switch module further includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor;

[0022] One end of the first resistor is connected to the first pin of the first optocoupler, and the other end of the first resistor is connected to the control signal output pin of the circuit control chip;

[0023] One end of the second resistor is connected to the fourth pin of the first optocoupler, and the other end of the second resistor is connected to the neutral line of the AC power supply module;

[0024] One end of the first capacitor is connected to the fourth pin of the first optocoupler, and the other end of the first capacitor is connected to the second pin of the heating module;

[0025] After the third resistor is connected in parallel with the second capacitor, one pin is connected to the second pin of the heating module, and the other end is connected to the gate of the triac;

[0026] One end of the fourth resistor is connected to the third pin of the first optocoupler, and the other end of the fourth resistor is connected to the gate of the triac.

[0027] According to the constant temperature heating control circuit provided by some embodiments of the present application, the level detection module includes:

[0028] A second optocoupler, a first level detection resistor, a second level detection resistor, a third level detection resistor, and a rectifier diode;

[0029] One end of the first level detection resistor is connected to the first pin of the second optocoupler, and the other end of the first level detection resistor is connected to the level detection pin of the circuit control chip;

[0030] The second pin of the second optocoupler is connected to the reference ground;

[0031] The third pin of the second optocoupler is connected to the neutral line of the AC power supply module;

[0032] The live wire of the AC power supply module is connected to the positive electrode of the rectifier diode. One end of the second level detection resistor is connected to the fourth pin of the second optocoupler, and one end and the other end of the second level detection resistor are connected in series with the third level detection resistor and then connected to the negative electrode of the rectifier diode.

[0033] According to the constant temperature heating control circuit provided by some embodiments of the present application, the temperature detection module includes:

[0034] A first temperature detection resistor, a second temperature detection resistor, and a thermistor;

[0035] One end of the first temperature detection resistor is connected to the output pin of the second rectification module, and the other end of the first temperature detection resistor is connected to the first pin of the thermistor;

[0036] One end of the second temperature detection resistor is connected to the first pin of the thermistor, and the other end of the second temperature detection resistor is connected to the temperature input pin of the circuit control chip;

[0037] The second pin of the thermistor is connected to the reference ground.

[0038] To achieve the above object, a third aspect of the embodiments of the present application provides a constant temperature heating control circuit board, and the constant temperature heating control circuit board includes the constant temperature heating control circuit described in the first aspect of the embodiments of the present application.

[0039] To achieve the above object, a fourth aspect of the embodiments of the present application provides a constant temperature heating control device, and the constant temperature heating control device includes the constant temperature heating control circuit board described in the third aspect of the embodiments of the present application.

[0040] The constant temperature heating control circuit, circuit board and device proposed by the present application combine a control module, a switch module and a zero-crossing detection module. The heating temperature is detected by a temperature detection module. When the temperature does not reach the preset temperature value, the control switch module is turned on to operate at the maximum power to quickly increase the temperature. When the temperature reaches the preset temperature value, the control module detects the zero point of the AC signal through the zero-crossing detection module, and sends a control signal to the switch module at the zero point to control the switch module to be turned on or off, so that the heating circuit works with a unidirectional voltage, realizing the control of constant temperature heating. At the same time, the control is carried out at the zero point to ensure the accurate sending of the control signal, reduce the influence of voltage pulse fluctuations, and avoid problems such as performance degradation caused by voltage pulse waves. Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of a constant temperature heating control circuit provided by an embodiment of the present application;

[0042] Figure 2 It is a partial structural diagram of the constant temperature heating control circuit provided by an embodiment of the present application;

[0043] Figure 3 It is a partial schematic diagram of a constant temperature heating control circuit provided by an embodiment of the present application;

[0044] Figure 4 It is a schematic structural diagram of a level detection module provided by an embodiment of the present application;

[0045] Figure 5 It is a schematic structural diagram of a temperature detection module provided by an embodiment of the present application. Detailed Embodiments

[0046] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] It should be noted that although the functional modules are divided in the schematic diagram of the device and the logical sequence is shown in the flowchart, in some cases, the steps shown or described can be executed in a different module division from that in the device or a different sequence from that in the flowchart. Terms such as "first" and "second" in the description, claims, and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0049] The heating technology for a sealed small-space box is a technology that raises the internal temperature of the box in a specific way within a closed environment. This technology is widely used in multiple fields such as scientific experiments, chemical production, pharmaceutical manufacturing, and precision processing, aiming to meet the requirements of precise temperature control and high heating efficiency.

[0050] When using a heating element to heat a relatively sealed small-space box and making its internal temperature quickly reach a relatively stable constant temperature value, on the one hand, it is necessary to control the heating power of the heating element. The heating element requires a relatively large power value so that the temperature can quickly reach the preset temperature value. However, due to the relatively large power of the heating element, after the temperature reaches the preset temperature value, during the process of maintaining a constant temperature, the range of temperature change shows a relatively large deviation; on the other hand, due to the relatively large power of the heating element and the limited internal space of the product, during the temperature control process, it will cause a larger voltage pulse fluctuation (Filcker) of the circuit to the product, which may cause problems such as product damage and performance degradation. Therefore, the requirements for the control circuit are relatively high.

[0051] Based on this, the embodiments of this application propose a constant-temperature heating control circuit, a circuit board, and its device, aiming to improve the accuracy of constant-temperature control and reduce the influence of voltage pulse fluctuations of the circuit on the product. Please refer to the following description for details.

[0052] For the convenience of subsequent narration, definitions are made here for the pins of all capacitors, resistors, diodes, switch devices, and other devices that appear in this application. From the left to the right of the circuit shown in the drawings, for devices with pins distributed horizontally, the first end is the left pin of the device, and the second end is the right pin of the device; for devices with pins distributed vertically, the first end is the upper pin of the device, and the second end is the lower pin of the device; for devices with pins distributed in all directions, the first end is the upper-right pin of the device, and the second end is the next pin along the clockwise direction of the device from the first end.

[0053] Please refer to Figure 1, which is a schematic structural diagram of a constant-temperature heating control circuit provided by an embodiment of the present application. As Figure 1 shown, the constant-temperature heating control circuit 100 provided by an embodiment of the present application may include, but is not limited to:

[0054] A circuit control module 110, the circuit control module 110 includes a circuit control chip; an AC power module 160; a heating module 120, the first pin of the heating module 120 is connected to the live wire 161 of the AC power module 160, and the heating function is realized through the heating module 120; a switch module 130, the control signal input end of the switch module 130 is connected to the control signal output pin of the circuit control chip, and the neutral wire 162 of the AC power module 160 is connected to the second pin of the heating module 120 after passing through the power input end of the switch module 130; a temperature detection module 150, the output end of the temperature detection module 150 is connected to the temperature input pin of the circuit control chip; a level detection module 140, the input end of the level detection module 140 is connected to the AC power module 160, and the output end of the level detection module 140 is connected to the level detection pin of the circuit control chip.

[0055] It should be noted that in the embodiment of the present application, when the temperature reaches the preset temperature, the constant-temperature control heating circuit is controlled to work with a unidirectional voltage to reduce the power of the constant-temperature control heating circuit and achieve the effect of constant-temperature control. Considering that zero-crossing detection can be accurately controlled, the AC power module 160 is subjected to zero-crossing detection through the level detection module 140. When the AC power signal passes through the zero point, the circuit control module 110 sends a control signal to the switch module 130. When the switch module 130 receives the control signal, the following operations are performed:

[0056] If the switch module 130 is in the conducting state, it is switched to the off state;

[0057] If the switch module 130 is in the off state, it is switched to the conducting state.

[0058] Circuit control is realized through zero-crossing detection, so that the heating power is maintained at the required magnitude, and zero-crossing detection can be accurately realized. The circuit ensures that when working with a unidirectional voltage, it can work for a complete cycle of the unidirectional voltage, and the temperature is maintained at the preset temperature value.

[0059] Exemplarily, in an embodiment of the present application, when the constant-temperature heating control circuit is powered on, heating work needs to be performed. The circuit control module 110 sends a control signal to the switch module 130 to make it conduct, and the temperature is detected through the temperature detection module 150;

[0060] When the temperature does not reach the preset temperature value, the switch module 130 is in a normally conducting state and is heated at full power to quickly raise the temperature;

[0061] When the temperature reaches the preset temperature value, the circuit control module 110 performs zero-crossing detection on the AC power supply module 160 through the level detection module 140. When the zero-crossing point of the AC power supply signal is reached, the circuit control module 110 sends a control signal to the switch module 130 to control the switch module 130 to switch on or off, so that the circuit operates with a unidirectional voltage and the heating power is reduced.

[0062] By combining the switch module 130, the level detection module 140, and the temperature detection module 150, after the detected temperature reaches the preset temperature value, the circuit control module 110 detects the zero point of the AC power supply signal through the level detection module 140 and controls the switch module 130, enabling the circuit to operate with a unidirectional voltage, improving the accuracy of constant temperature control, and reducing the impact of voltage pulse fluctuations of the circuit on the product.

[0063] Exemplarily, in an embodiment of the present application, the constant temperature heating control circuit further includes:

[0064] A first rectification module, the input pins of the first rectification module are connected to the AC power supply module;

[0065] A second rectification module, the input pins of the second rectification module are connected to the output pins of the first rectification module, and the output pins of the second rectification module are connected to the power input pins of the circuit control module 110.

[0066] It should be noted that the first rectification module in the embodiment of the present application is used to convert the AC power supply signal output by the AC power supply module into a DC signal. The output pins of the first rectification module are connected to the input pins of the second rectification module, and the output pins of the second rectification module are connected to the power input pins of the circuit control module 110. The DC signal is further voltage-stabilized and filtered by the second rectification module and input to the circuit control module 110, and the circuit control module 110 in the constant temperature heating control circuit is controlled using the DC power supply signal.

[0067] Specifically, please refer to Figure 2 which is a partial structural schematic diagram of the constant temperature heating control circuit provided by the embodiment of the present application. As Figure 2 shown, in a feasible embodiment of the present application, the first rectification module 171 uses an AC TO DC buck circuit, the second rectification module 172 uses a buck voltage stabilization circuit, and the input pins of the first rectification module 171 are connected to the live wire 161 and the neutral wire 162 of the AC power supply module 160. The AC power supply signal output by the AC power supply module 160 is converted into a 24V DC signal through the first rectification module 171;

[0068] The output pin of the first rectification module 171 is connected to the input pin of the second rectification module 172. The output pin of the second rectification module 172 is connected to the power input pin of the circuit control module 110. The 24V DC signal output by the first rectification module 171 is further stepped down and regulated by the second rectification module 172 and then converted into a 5V DC signal and input to the circuit control module 110.

[0069] In the embodiment of the present application, the first rectification module 171 and the second rectification module 172 step down and regulate the AC power signal output by the AC power module 160 to supply power to the circuit control module 110.

[0070] It should be noted that in the embodiment of the present application, the constant temperature heating control circuit further includes:

[0071] A fan module 180. The input pin of the fan module 180 is connected to the output pin of the first rectification module. The signal input pin of the fan module 180 is connected to the fan control pin of the circuit control chip in the circuit control module 110. The output pin of the fan module 180 is connected to the reference ground.

[0072] Exemplarily, in a feasible embodiment of the present application, the fan module ensures that the inside of the heating space is in a thermal circulation state. The fan module is connected to the output pin of the first rectification module and is powered by a 24V DC signal. The signal input pin of the fan module is connected to the circuit control module. When heating is turned on, the circuit control module outputs a control signal to control the fan module to turn on, realizing the internal thermal circulation of the heating space.

[0073] It can be understood that in the embodiment of the present application, the internal heat is circulated through the fan module to ensure that the inside of the heating space is in a thermal circulation state.

[0074] It should be noted that in the embodiment of the present application, the switch module 130 includes:

[0075] A first optocoupler. The first pin of the first optocoupler serves as the control signal input pin of the switch module and is connected to the control signal output pin of the circuit control module. The second pin of the first optocoupler is connected to the reference ground. The fourth pin of the first optocoupler is connected to the neutral line of the AC power module.

[0076] A triac. The gate of the triac is connected to the third pin of the first optocoupler. The main anode of the triac is connected to the neutral line of the AC power module. The main cathode of the triac is connected to the second pin of the heating module.

[0077] Please refer to Figures 3 - 5 , Figure 3 which is a partial schematic diagram of a constant temperature heating control circuit provided by the embodiment of the present application. Figure 4Schematic diagram of a level detection module provided by an embodiment of the present application Figure 5 Schematic diagram of a temperature detection module provided by an embodiment of the present application

[0078] Exemplarily, as Figure 3 shown, in the constant temperature heating control circuit of the embodiment of the present application, the AC power supply module is AC, AC_L is the live wire, AC_N is the neutral wire, the heating module is 3P, and the switch module is the part outlined by the virtual coil

[0079] Among them, the live wire AC_L and the neutral wire AC_N of AC are connected to the first filtering module, and the AC power supply signal is converted into a 24V DC signal through the first filtering module. The output end of the first filtering module is respectively connected to the input end of the second filtering module and the input end of the fan module; the 24V DC signal output through the first filtering module supplies power to the fan module

[0080] The output end of the second filtering module is connected to the circuit control module, and the 24V DC signal is further converted into a 5V DC signal to supply power to the circuit control module

[0081] In the circuit control module, the fan control pin is FanPort, the control signal output pin is PtcPort, the level detection pin is ACCheck, and the temperature input pin is NtcFb. Among them, the fan control pin FanPort of the circuit control chip is connected to the signal input pin of the fan module; the control signal output pin PtcPort is connected to the control signal input pin of the switch module; the level detection pin ACCheck is connected to the level detection module; the temperature input pin NtcFb is connected to the temperature detection module

[0082] The fan control signal is output through the fan control pin FanPort to control the switch of the fan module, the control signal is output through the control signal output pin PtcPort to control the opening and closing of the switch module, the AC power zero-crossing information detected by the level detection module is received through the level detection pin ACCheck, and the temperature information detected by the temperature detection module is received through the temperature input pin NtcFb

[0083] It should be noted that, as Figure 3 shown, the first optocoupler is U4 and the triac is Q2. In the embodiment of the present application, the switch module further includes: the first resistor R40, the second resistor R50, the third resistor R51, the fourth resistor R52, the first capacitor C10 and the second capacitor C11

[0084] One end of the first resistor R40 is connected to the first pin of the first optocoupler, and the other end of the first resistor R40 is connected to the control signal output pin of the circuit control chip

[0085] One end of the second resistor R50 is connected to the fourth pin of the first optocoupler, and the other end of the second resistor R50 is connected to the neutral line of the AC power supply module;

[0086] One end of the first capacitor C10 is connected to the fourth pin of the first optocoupler, and the other end of the first capacitor C10 is connected to the second pin of the heating module;

[0087] After the third resistor R51 is connected in parallel with the second capacitor C11, one end is connected to the second pin of the heating module, and the other end is connected to the gate of the triac;

[0088] One end of the fourth resistor R52 is connected to the third pin of the first optocoupler, and the other end of the fourth resistor R52 is connected to the gate of the triac.

[0089] Through the first resistor R40, the second resistor R50, the third resistor R51, the fourth resistor R52, the first capacitor C10 and the second capacitor C11, the first optocoupler U4 and the triac Q2 in the protection circuit are protected.

[0090] Exemplarily, as Figure 4 shown, in an embodiment of the present application, the level detection module includes:

[0091] A second optocoupler OC2, a first level detection resistor R53, a second level detection resistor R48, a third level detection resistor R49 and a rectifier diode D10;

[0092] One end of the first level detection resistor R53 is connected to the first pin of the second optocoupler OC2, and the other end of the first level detection resistor R53 is connected to the level detection pin ACCheck of the circuit control chip;

[0093] The second pin of the second optocoupler OC2 is connected to the reference ground;

[0094] The third pin of the second optocoupler OC2 is connected to the neutral line AC_N of the AC power supply module;

[0095] The live wire AC_L of the AC power supply module is connected to the positive pole of the rectifier diode D10. One end of the second level detection resistor R48 is connected to the fourth pin of the second optocoupler OC2, and the other end of the second level detection resistor R48 is connected in series with the third level detection resistor R49 and then connected to the negative pole of the rectifier diode D10.

[0096] In the embodiment of the present application, the level zero-crossing detection is realized through the level detection module. When the AC power signal passes through the zero point, the circuit control module can obtain the level detection signal sent by the level detection module, so that the circuit control can be performed according to the zero point of the AC signal.

[0097] It should be noted that, as Figure 5As shown, in the embodiment of the present application, the temperature detection module includes:

[0098] The first temperature detection resistor R30, the second temperature detection resistor R31, and the thermistor NTC;

[0099] One end of the first temperature detection resistor R30 is connected to the output pin of the second rectification module, and the other end of the first temperature detection resistor R30 is connected to the first pin of the thermistor NTC;

[0100] One end of the second temperature detection resistor R31 is connected to the first pin of the thermistor NTC, and the other end of the second temperature detection resistor is connected to the temperature input pin NtcFb of the circuit control chip;

[0101] The second pin of the thermistor NTC is connected to the reference ground.

[0102] It can be understood that the temperature detection module provided by the embodiment of the present application is powered by the 5V DC signal output by the second filtering module, detects the temperature through the NTC, and transmits the temperature information to the circuit control module in real time, so that the circuit control module can perform real-time control according to the temperature situation.

[0103] It should be noted that, in the embodiment of the present application, the circuit control module detects the internal temperature information in real time through the temperature detection module. When the temperature information does not reach the preset temperature value, the switch module remains conducting, and at this time, heating is performed at the maximum power, so that the temperature quickly reaches the preset temperature value;

[0104] When the temperature information reaches the preset temperature value, the circuit control module performs zero-crossing detection on the AC power supply module through the level detection module to detect the zero point of the AC power supply signal and achieve accurate signal positioning;

[0105] When the voltage of the AC power supply module passes through zero, the circuit control module outputs a control signal to the switch module, and controls the opening and closing of the switch module through the control signal.

[0106] It should be noted that since the light-emitting diode of the second optocoupler used in the level detection module necessarily requires a certain voltage, the zero-crossing detection detected by the circuit control module through this circuit will inevitably have a certain delay. However, due to component differences, the duration of this delay will vary. Therefore, it is necessary to specially select the first optocoupler of the switch module, which can be an optocoupler with the property of zero-crossing optocoupler, that is, the AC terminal control of the first optocoupler is affected by the working zero-crossing. When passing through zero, the control terminal is at a high level and is turned on, and when passing through zero, the control terminal is at a low level and is cut off. Since the circuit control module detects the zero-crossing of the AC signal with a slight delay, when the circuit control module detects the presence of a zero-crossing through the zero-crossing detection circuit, considering the fixed frequency of the power grid, it can be delayed to the next zero-crossing range and then provide a high level to the first optocoupler in the switch module, that is, it can ensure accurate zero-crossing in each working cycle, and can well adjust the working power, and will not increase the voltage pulse fluctuation of the product.

[0107] The embodiment of the present application also provides a constant temperature heating control circuit board, and the constant temperature heating control circuit board includes any constant temperature heating control circuit provided in the embodiment of the present application.

[0108] The embodiment of the present application also provides a constant temperature heating control device, and the constant temperature heating control device includes the constant temperature heating control circuit board provided in the embodiment of the present application.

[0109] The constant temperature heating control circuit, circuit board and device proposed by the present application combine a control module, a switch module and a zero-crossing detection module. The heating temperature is detected through a temperature detection module. When the temperature does not reach the preset temperature value, the switch module is controlled to conduct and operate at the maximum power to quickly increase the temperature; when the temperature reaches the preset temperature value, the control module detects the zero point of the AC signal through the zero-crossing detection module, and sends a control signal to the switch module at the zero point to control the switch module to conduct or turn off, so that the heating circuit works with a unidirectional voltage, realizing the control of constant temperature heating. At the same time, the control is carried out at the zero point to ensure accurate transmission of the control signal, reduce the influence of voltage pulse fluctuation, and avoid problems such as performance degradation caused by voltage pulse waves.

[0110] The embodiments described in the embodiments of the present application are for more clearly explaining the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0111] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art will know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0112] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and their appropriate combinations.

[0113] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0114] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and their appropriate combinations.

[0115] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0116] It should be understood that, in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously. Here, A and B can be singular or plural. The character " / " generally indicates an "or" relationship between the associated objects before and after. "At least one (one) of the following" or its similar expressions refer to any combination of these items, including any combination of single items (ones) or plural items (ones). For example, at least one (one) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0117] In several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of devices or units can be in electrical, mechanical, or other forms.

[0118] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0119] The preferred embodiments of the embodiments of the present disclosure have been described above with reference to the accompanying drawings. However, this does not limit the scope of the rights of the embodiments of the present disclosure. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present disclosure shall be within the scope of the rights of the embodiments of the present disclosure.

Claims

1. A constant temperature heating control circuit, characterized in that, The circuit includes: A circuit control module, which includes a circuit control chip; An AC power module; A heating module, the first pin of the heating module is connected to the live wire of the AC power module, and the heating function is realized through the heating module; A switch module, the control signal input end of the switch module is connected to the control signal output pin of the circuit control chip, and the neutral wire of the AC power module is connected to the second pin of the heating module after passing through the power input end of the switch module; A temperature detection module, the output end of the temperature detection module is connected to the temperature input pin of the circuit control chip; A level detection module, the input end of the level detection module is connected to the AC power module, and the output end of the level detection module is connected to the level detection pin of the circuit control chip.

2. The constant temperature heating control circuit according to claim 1, characterized in that The circuit further includes: A first rectification module, the input end of the first rectification module is connected to the AC power module.

3. The constant temperature heating control circuit according to claim 2, wherein, The circuit further includes: A second rectification module, the input end of the second rectification module is connected to the output end of the first rectification module, and the output end of the second rectification module is connected to the power input end of the circuit control module.

4. The constant temperature heating control circuit according to claim 3, wherein The circuit further includes: A fan module, the input end of the fan module is connected to the output end of the first rectification module, the signal input end of the fan module is connected to the fan control pin of the circuit control chip, and the output pin of the fan module is connected to the reference ground.

5. The constant temperature heating control circuit according to claim 4, characterized in that, The switch module includes: A first optocoupler, the first pin of the first optocoupler serves as the control signal input pin of the switch module, the second pin of the first optocoupler is connected to the reference ground, and the fourth pin of the first optocoupler is connected to the neutral wire of the AC power module; A triac, the gate of the triac is connected to the third pin of the first optocoupler, the main anode of the triac is connected to the neutral wire of the AC power module, and the main cathode of the triac is connected to the second pin of the heating module.

6. The constant temperature heating control circuit according to claim 5, characterized in that, The switch module further includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor; One end of the first resistor is connected to the first pin of the first optocoupler, and the other end of the first resistor is connected to the control signal output pin of the circuit control chip; One end of the second resistor is connected to the fourth pin of the first optocoupler, and the other end of the second resistor is connected to the neutral wire of the AC power module; One end of the first capacitor is connected to the fourth pin of the first optocoupler, and the other end of the first capacitor is connected to the second pin of the heating module; After the third resistor is connected in parallel with the second capacitor, one end is connected to the second pin of the heating module, and the other end is connected to the gate of the triac; One end of the fourth resistor is connected to the third pin of the first optocoupler, and the other end of the fourth resistor is connected to the gate of the triac.

7. The constant temperature heating control circuit according to claim 4, wherein The level detection module includes: A second optocoupler, a first level detection resistor, a second level detection resistor, a third level detection resistor and a rectifier diode; One end of the first level detection resistor is connected to the first pin of the second optocoupler, and the other end of the first level detection resistor is connected to the level detection pin of the circuit control chip; The second pin of the second optocoupler is connected to the reference ground; The third pin of the second optocoupler is connected to the neutral line of the AC power supply module; The live wire of the AC power supply module is connected to the positive electrode of the rectifier diode. One end of the second level detection resistor is connected to the fourth pin of the second optocoupler. One end and the other end of the second level detection resistor are connected in series with the third level detection resistor and then connected to the negative electrode of the rectifier diode.

8. The constant temperature heating control circuit according to claim 4, wherein, The temperature detection module includes: A first temperature detection resistor, a second temperature detection resistor, and a thermistor; One end of the first temperature detection resistor is connected to the output end of the second rectification module, and the other end of the first temperature detection resistor is connected to the first end of the thermistor; One end of the second temperature detection resistor is connected to the first end of the thermistor, and the other end of the second temperature detection resistor is connected to the temperature input pin of the circuit control chip; The second end of the thermistor is connected to the reference ground.

9. A constant temperature heating control circuit board, characterized in that, The constant temperature heating control circuit board includes the constant temperature heating control circuit according to any one of claims 1 to 8.

10. A constant temperature heating control device, characterized in that, The constant temperature heating control device includes the constant temperature heating control circuit board according to claim 9.

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