Over-temperature protection circuit

Abstract

The embodiment of the utility model provides an over-temperature protection circuit. The over-temperature protection circuit comprises an over-temperature detection module and a control module, the output end of the over-temperature detection module is connected with the input end of the control module, the output end of the control module is connected with a heater, and the over-temperature detection module can detect the real-time temperature of equipment to be detected and detect whether the real-time temperature exceeds a temperature threshold value or not. The control module can control the heater to stop working when the real-time temperature exceeds a temperature threshold value, and control whether the heater works or not according to a software control signal of the heater when the real-time temperature does not exceed the temperature threshold value, so that over-temperature protection on hardware is achieved, the response speed of over-temperature protection can be increased, the risk of heating out of control is reduced, and the service life of the heater is prolonged. And the safety and the reliability of the equipment are improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the technical field of temperature control, and particularly relate to an over-temperature protection circuit. BACKGROUND

[0002] In a chromatograph application, certain parts of the equipment, such as a column box, a sample injector and a detector, need to be heated and temperature-controlled. Usually, the temperature is adjusted by software, but if the software is abnormal, the temperature control cannot be correctly identified and judged, which may cause a heating out-of-control problem, resulting in continuous and rapid temperature rise of the equipment, and even burning the equipment or causing a fire, greatly affecting the safety and reliability of the equipment. CONTENT OF THE INVENTION

[0003] The over-temperature protection circuit provided by the embodiments of the present disclosure realizes over-temperature protection in hardware, can improve the response speed of over-temperature protection, and improves the safety and reliability of the equipment.

[0004] The present disclosure provides an over-temperature protection circuit, comprising: an over-temperature detection module and a control module, the output end of the over-temperature detection module is connected to the input end of the control module, and the output end of the control module is connected to a heater.

[0005] The over-temperature detection module is configured to detect a real-time temperature of a to-be-tested equipment and detect whether the real-time temperature exceeds a temperature threshold. The control module is configured to control the heater to stop working when the real-time temperature exceeds the temperature threshold, and control whether the heater works according to a software control signal of the heater when the real-time temperature does not exceed the temperature threshold.

[0006] In some embodiments of the present disclosure, the over-temperature detection module comprises a temperature detection unit, a voltage generation unit and a comparator, the output end of the temperature detection unit is connected to the first input end of the comparator, the output end of the voltage generation unit is connected to the second input end of the comparator, and the output end of the comparator is connected to the input end of the control module.

[0007] The temperature detection unit is configured to detect the real-time temperature to obtain a temperature voltage. The voltage generation unit is configured to generate a voltage threshold, and the voltage threshold is used to represent the temperature threshold. The comparator is configured to output a first level signal when the temperature voltage is higher than the voltage threshold, and output a second level signal when the temperature voltage is not higher than the voltage threshold.

[0008] In some embodiments of the present disclosure, the temperature detection unit comprises a first voltage dividing resistor and a thermistor, the first voltage dividing resistor and the thermistor are connected in series between a reference power supply and a ground, and a connection point of the first voltage dividing resistor and the thermistor is connected to a first input terminal of the comparator.

[0009] In some embodiments of the present disclosure, the voltage generation unit comprises a second voltage dividing resistor and a third voltage dividing resistor, a first end of the second voltage dividing resistor is connected to a reference power supply, a second end of the second voltage dividing resistor is connected to a first end of the third voltage dividing resistor and a second input terminal of the comparator, and a second end of the third voltage dividing resistor is grounded.

[0010] In some embodiments of the present disclosure, the over-temperature detection module further comprises a hysteresis resistor, the hysteresis resistor is connected between a positive input terminal of the comparator and an output terminal of the comparator.

[0011] In some embodiments of the present disclosure, the over-temperature detection module further comprises a first current limiting resistor, an output terminal of the comparator is connected to an input terminal of the control module through the first current limiting resistor.

[0012] In some embodiments of the present disclosure, the control module comprises a solid state relay, a second current limiting resistor, a voltage limiting resistor and a transistor, a first end of the second current limiting resistor is configured to receive the software control signal, a second end of the second current limiting resistor is connected to a first end of the voltage limiting resistor and a base of the transistor, a second end of the voltage limiting resistor and an emitter of the transistor are grounded, a collector of the transistor is connected to a negative input terminal of the solid state relay, a positive input terminal of the solid state relay is connected to an output terminal of the over-temperature detection module, and an output terminal of the solid state relay is connected to a power supply terminal of the heater.

[0013] In some embodiments of the present disclosure, the thermistor is a positive temperature coefficient thermistor, a first end of the thermistor is connected to a first end of the first voltage dividing resistor and an inverting input terminal of the comparator, a second end of the thermistor is grounded, and a second end of the first voltage dividing resistor is connected to the reference power supply.

[0014] In some embodiments of the present disclosure, the thermistor is a negative temperature coefficient thermistor, a first end of the thermistor is connected to a first end of the first voltage dividing resistor and an inverting input terminal of the comparator, a second end of the thermistor is connected to the reference power supply, and a second end of the first voltage dividing resistor is grounded.

[0015] In some embodiments of the present disclosure, the thermistor is a negative temperature coefficient thermistor, a first end of the thermistor is connected to a first end of the first voltage dividing resistor and a positive input end of the comparator, a second end of the thermistor is grounded, and a second end of the first voltage dividing resistor is connected to the reference power supply.

[0016] In the technical solution of the embodiments of the present disclosure, the over-temperature protection circuit includes an over-temperature detection module and a control module, an output end of the over-temperature detection module is connected to an input end of the control module, and an output end of the control module is connected to the heater. The over-temperature detection module can detect the real-time temperature of the device under test and detect whether the real-time temperature exceeds the temperature threshold. The control module can control the heater to stop working when the real-time temperature exceeds the temperature threshold, and control whether the heater works according to the software control signal of the heater when the real-time temperature does not exceed the temperature threshold. The over-temperature protection on the hardware is realized, the response speed of the over-temperature protection is improved, the risk of heating out of control is reduced, and the safety and reliability of the device are improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 A structural schematic diagram of an over-temperature protection circuit is provided for the embodiments of the present disclosure.

[0019] Figure 2 A circuit schematic diagram of an over-temperature protection circuit is provided for the embodiments of the present disclosure.

[0020] Figure 3 Another circuit schematic diagram of an over-temperature protection circuit is provided for the embodiments of the present disclosure.

[0021] Figure 4 Another circuit schematic diagram of an over-temperature protection circuit is provided for the embodiments of the present disclosure. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor also belong to the scope of protection of the present disclosure.

[0023] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. As used herein, the statement that two or more parts or components are "coupled" together shall mean that the parts are joined or operate together either directly or through one or more intermediate parts or components.

[0024] Reference to "an embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" or "in the embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily referring to a common or identical embodiment, although they can be.

[0025] In addition, the terms "first", "second", and the like, in the description of the present disclosure and claims or above-described accompanying drawings, are used to distinguish different objects, and are not used to describe a particular order, and can explicitly or implicitly include one or more of the features.

[0026] The term "and / or", in the present disclosure, is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of existence of A, existence of A and B, and existence of B. In addition, the character " / " in this paper generally represents an "or" relationship between the front and rear associated objects.

[0027] In the description of the present disclosure, unless otherwise specified, the meaning of "a plurality of" and "at least two" is two or more (including two), and similarly, "a plurality of groups" and "at least two groups" means two groups or more (including two groups).

[0028] In order for those skilled in the art to better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings.

[0029] Figure 1 A structure schematic diagram of an over-temperature protection circuit provided by an embodiment of the present disclosure is shown in Figure 1 As shown, the over-temperature protection circuit 100 includes an over-temperature detection module 110 and a control module 120, the output end of the over-temperature detection module 110 is connected to the input end of the control module 120, and the output end of the control module 120 is connected to the heater 200.

[0030] The over-temperature detection module 110 is configured to detect the real-time temperature of the device under test and detect whether the real-time temperature exceeds the temperature threshold. The control module 120 is configured to control the heater 200 to stop working when the real-time temperature exceeds the temperature threshold, and control whether the heater 200 works according to the software control signal CTL of the heater when the real-time temperature does not exceed the temperature threshold.

[0031] Exemplarily, Figure 2 A circuit schematic diagram of an over-temperature protection circuit provided for the disclosed embodiment is shown in Figure 2 As shown, the over-temperature detection module 110 includes a temperature detection unit 111, a voltage generation unit 112, and a comparator CMP, the output end of the temperature detection unit 111 is connected to the first input end of the comparator CMP, the output end of the voltage generation unit 112 is connected to the second input end of the comparator CMP, and the output end of the comparator CMP is connected to the input end of the control module 120.

[0032] As shown in Figure 2 The temperature detection unit 111 includes a thermistor Rt and a first voltage dividing resistor Rv1, the first voltage dividing resistor Rv1 and the thermistor Rt are connected in series between a reference power supply VCC and the ground, and the connection point of the first voltage dividing resistor Rv1 and the thermistor Rt is connected to the first input end of the comparator CMP. The voltage generation unit 112 includes a second voltage dividing resistor Rv2 and a third voltage dividing resistor Rv3, the first end of the second voltage dividing resistor Rv2 is connected to the reference power supply VCC, the second end of the second voltage dividing resistor Rv2 is connected to the first end of the third voltage dividing resistor Rv3 and the second input end of the comparator CMP, and the second end of the third voltage dividing resistor Rv3 is grounded.

[0033] The voltage provided by the reference power supply VCC is divided by the first voltage dividing resistor Rv1 and the thermistor Rt, and the resistance value of the thermistor Rt affects the voltage division of the thermistor Rt. The thermistor Rt can be arranged in the area near the device under test, and the resistance value of the thermistor Rt changes with the real-time temperature. Obviously, the voltage division of the thermistor Rt can reflect the real-time temperature of the device under test, i.e., the voltage division of the thermistor Rt is the temperature voltage.

[0034] The voltage provided by the reference power supply VCC is divided by the second voltage dividing resistor Rv2 and the third voltage dividing resistor Rv3, and the voltage division of the third voltage dividing resistor Rv3 is input to the comparator CMP as the voltage threshold. The voltage threshold is related to the temperature threshold and can reflect the temperature threshold. In actual application, the temperature threshold is first determined, then the temperature threshold is converted into the corresponding voltage threshold, and finally the resistance values of the second voltage dividing resistor Rv2 and the third voltage dividing resistor Rv3 are adjusted so that the voltage division of the third voltage dividing resistor Rv3 is equal to the voltage threshold.

[0035] In this way, the temperature detection unit 111 can detect the real-time temperature of the device under test to obtain a temperature voltage, and the voltage generation unit 112 can generate a voltage threshold value for representing the temperature threshold value.

[0036] For example, the thermistor Rt is a positive temperature coefficient thermistor, such as Figure 2 As shown, the first end of the thermistor Rt is connected to the first end of the first voltage dividing resistor Rv1 and the inverting input terminal of the comparator CMP, the second end of the thermistor Rt is grounded, the second end of the first voltage dividing resistor Rv1 is connected to the reference power supply VCC, and the second end of the second voltage dividing resistor Rv2 is connected to the first end of the third voltage dividing resistor Rv3 and the non-inverting input terminal of the comparator CMP.

[0037] The non-inverting input voltage of the comparator CMP is the voltage threshold value, and the inverting input voltage of the comparator CMP is the temperature voltage. When the real-time temperature rises, the resistance of the thermistor Rt increases, the voltage dividing of the thermistor Rt increases, and the temperature voltage increases. When the real-time temperature drops, the resistance of the thermistor Rt decreases, the voltage dividing of the thermistor Rt decreases, and the temperature voltage decreases.

[0038] When the temperature voltage is less than the voltage threshold value, the real-time temperature is less than the temperature threshold value, and the comparator CMP outputs a high level signal. As the heater 200 continues to work, the real-time temperature continues to rise. When the real-time temperature rises to the temperature threshold value, the temperature voltage is greater than the voltage threshold value, and the output of the comparator CMP flips from a high level signal to a low level signal. In this way, the level signal output by the comparator CMP can represent whether the real-time temperature exceeds the temperature threshold value, i.e., whether the device under test is overheated.

[0039] In other embodiments, the thermistor Rt is a negative temperature coefficient thermistor, the first end of the thermistor Rt is connected to the first end of the first voltage dividing resistor Rv1 and the inverting input terminal of the comparator CMP, the second end of the thermistor Rt is connected to the reference power supply VCC, the second end of the first voltage dividing resistor Rv1 is grounded, and the second end of the second voltage dividing resistor Rv2 is connected to the first end of the third voltage dividing resistor Rv3 and the non-inverting input terminal of the comparator CMP, as shown in Figure 3 Figure 3 Another circuit schematic diagram of an over-temperature protection circuit provided by an embodiment of the present disclosure.

[0040] The non-inverting input voltage of the comparator CMP is the voltage threshold value, and the inverting input voltage of the comparator CMP is the temperature voltage. When the real-time temperature rises, the resistance of the thermistor Rt decreases, the voltage dividing of the thermistor Rt decreases, and the temperature voltage increases. When the real-time temperature drops, the resistance of the thermistor Rt increases, the voltage dividing of the thermistor Rt increases, and the temperature voltage decreases.

[0041] ​When the temperature voltage is less than the voltage threshold, the real-time temperature is less than the temperature threshold, the comparator CMP outputs a high level signal, and the real-time temperature continues to rise with the continuous work of the heater 200. When the real-time temperature rises to the temperature threshold, the temperature voltage is greater than the voltage threshold, and the output of the comparator CMP flips from the high level signal to the low level signal.

[0042] In some other embodiments, the thermistor Rt is a positive temperature coefficient thermistor, the first end of the thermistor Rt is connected to the first end of the first voltage dividing resistor Rv1 and the non-inverting input end of the comparator CMP, the second end of the thermistor Rt is connected to the reference power supply VCC, the second end of the second voltage dividing resistor Rv2 is connected to the first end of the third voltage dividing resistor Rv3 and the inverting input end of the comparator CMP, and the second end of the third voltage dividing resistor Rv3 is connected to the ground. Figure 4 Figure 4 A circuit schematic diagram of another over-temperature protection circuit provided by the embodiments of the present disclosure is shown.

[0043] The non-inverting input voltage of the comparator CMP is the temperature voltage, and the inverting input voltage of the comparator CMP is the voltage threshold. When the real-time temperature rises, the resistance of the thermistor Rt decreases, the voltage dividing of the thermistor Rt decreases, that is, the temperature voltage decreases, and when the real-time temperature drops, the resistance of the thermistor Rt increases, the voltage dividing of the thermistor Rt increases, that is, the temperature voltage decreases.

[0044] When the temperature voltage is greater than the voltage threshold, the real-time temperature is less than the temperature threshold, the comparator CMP outputs a high level signal, and the real-time temperature continues to rise with the continuous work of the heater 200. When the real-time temperature rises to the temperature threshold, the temperature voltage is greater than the voltage threshold, and the output of the comparator CMP flips from the high level signal to the low level signal.

[0045] Thus, when the temperature voltage is higher than the voltage threshold, the comparator CMP outputs a first level signal, and when the temperature voltage is not higher than the voltage threshold, the comparator CMP outputs a second level signal.

[0046] Continuing to refer to Figures 2 to 4 , the control module 120 includes a solid state relay SSR, a second current limiting resistor Rc2, a voltage limiting resistor Ru, and a transistor Q. The first end of the second current limiting resistor Rc2 is configured to receive a software control signal CTL, the second end of the second current limiting resistor Rc2 is connected to the first end of the voltage limiting resistor Ru and the base of the transistor Q, the second end of the voltage limiting resistor Ru and the emitter of the transistor Q are connected to the ground, the collector of the transistor Q is connected to the negative input end of the solid state relay SSR, the positive input end of the solid state relay SSR is connected to the output end of the over-temperature detection module 110, and the output end of the solid state relay SSR is connected to the power supply end of the heater 200.

[0047] ​For example, when the device is powered on, the heater 200 has not started working, the actual temperature at this time is low, the comparator CMP outputs a high level signal, and the positive input end of the solid state relay SSR receives the high level signal. The software control signal CTL is connected to the base of the transistor Q through the second current limiting resistor Rc2 and the voltage limiting resistor Ru.

[0048] When the software control signal CTL is a high level signal, the transistor Q1 is turned on, the negative input end of the solid state relay SSR is grounded, at this time, the solid state relay SSR is powered on, the power supply of the heater 200 can be turned on to control the heater 200 to work normally, so that the heater 200 heats normally.

[0049] When the software control signal CTL is a low level signal, the transistor Q1 is turned off, the negative input end of the solid state relay SSR is suspended, at this time, the solid state relay SSR is not powered on, the power supply of the heater 200 can be turned off to control the heater 200 to stop working, so that the heater 200 stops heating.

[0050] If the software of the heater 200 loses control, the software control signal CTL is no longer controlled by the software program, and the software control signal CTL may be just at a high level, so that the heater 200 will always heat, so that the temperature of the device under test always rises until the output of the over-temperature detection module 110 flips from a high level signal to a low level signal when the temperature threshold is reached.

[0051] At this time, the positive input end of the solid state relay SSR is connected to a low level, so that even if the software control signal CTL is a high level signal, the solid state relay SSR will not be powered on, the power supply of the heater 200 can be turned off to control the heater 200 to stop working, so that the heater 200 stops heating, to avoid over-temperature of the device, and improve the safety and reliability of the device.

[0052] In the embodiment of the present disclosure, the over-temperature protection circuit includes an over-temperature detection module and a control module, the output end of the over-temperature detection module is connected to the input end of the control module, and the output end of the control module is connected to the heater. The over-temperature detection module can detect the real-time temperature of the device under test and detect whether the real-time temperature exceeds the temperature threshold. The control module can control the heater to stop working when the real-time temperature exceeds the temperature threshold, and control whether the heater works according to the software control signal of the heater when the real-time temperature does not exceed the temperature threshold. The over-temperature protection of the hardware is realized, the response speed of the over-temperature protection is improved, the risk of heating out of control is reduced, and the safety and reliability of the device are improved.

[0053] In some embodiments, continuing to refer to Figures 2 to 4 , the over-temperature detection module 110 further includes a hysteresis resistor Rh, which is connected between the positive input end of the comparator CMP and the output end of the comparator CMP.

[0054] For example, the second input of the comparator CMP is a positive input, as shown in Figure 2 and Figure 3 The second end of the second voltage divider resistor Rv2 is connected to the second end of the hysteresis resistor Rh, and the first end of the hysteresis resistor Rh is connected to the output of the comparator CMP.

[0055] When the actual temperature is lower than the temperature threshold, the comparator CMP outputs a high-level signal, and the first end of the hysteresis resistor Rh is equivalent to being connected to the reference power supply VCC. It can be understood that the second voltage divider resistor Rv2 and the hysteresis resistor Rh are connected in parallel, and the parallel equivalent resistance of the second voltage divider resistor Rv2 and the hysteresis resistor Rh is R. The voltage provided by the reference power supply VCC is divided by the parallel equivalent resistance R and the third voltage divider resistor Rv3, and the voltage divided by the third voltage divider resistor Rv3 is input to the comparator CMP until the output of the comparator CMP flips from a high-level signal to a low-level signal.

[0056] Once the comparator CMP outputs a low-level signal, the first end of the hysteresis resistor Rh is equivalent to being connected to ground. Then, the hysteresis resistor Rh is no longer connected in parallel with the second voltage divider resistor Rv2, but is connected in parallel with the third voltage divider resistor Rv3, and the parallel equivalent resistance of the third voltage divider resistor Rv3 and the hysteresis resistor Rh is R'. The voltage provided by the reference power supply VCC is divided by the second voltage divider resistor Rv2 and the parallel equivalent resistance R', and the voltage divided by the parallel equivalent resistance R' is input to the comparator CMP until the output of the comparator CMP flips from a low-level signal to a high-level signal.

[0057] Because the resistance of the parallel equivalent resistance R' is smaller than the resistance of the third voltage divider resistor Rv3, and the resistance of the second voltage divider resistor Rv2 is greater than the resistance of the parallel equivalent resistance R, the voltage threshold will decrease after the output of the comparator CMP flips from a high-level signal to a low-level signal.

[0058] After the over-temperature protection is started, when the temperature voltage is less than this smaller voltage threshold, the actual temperature is less than the temperature threshold corresponding to this smaller voltage threshold, and the output of the comparator CMP will only flip from a low-level signal to a high-level signal, thereby achieving the hysteresis effect of the comparator CMP. The hysteresis amount of the comparator CMP can be adjusted by adjusting the resistances of the second voltage divider resistor Rv2, the third voltage divider resistor Rv3, and the hysteresis resistor Rh.

[0059] For example, the voltage threshold before the over-temperature protection is started is denoted as a first voltage threshold, and the corresponding temperature threshold is denoted as a first temperature threshold. When the actual temperature is greater than the first temperature threshold, the output of the comparator CMP flips from a high-level signal to a low-level signal to start the over-temperature protection.

[0060] The voltage threshold after the over-temperature protection is started is denoted as a second voltage threshold, and the corresponding temperature threshold is denoted as a second temperature threshold. The second voltage threshold is smaller than the first voltage threshold, and the second temperature threshold is smaller than the first temperature threshold. When the actual temperature is smaller than the second temperature threshold, the output of the comparator CMP is flipped from a low-level signal to a high-level signal to exit the over-temperature protection.

[0061] In other embodiments, the first input terminal of the comparator CMP is a positive input terminal, as shown in FIG. 4. The first terminal of the thermistor Rt is connected to the second terminal of the hysteresis resistor Rh, and the first terminal of the hysteresis resistor Rh is connected to the output terminal of the comparator CMP. The hysteresis resistor Rh has a hysteresis effect on the comparator CMP, and the principle is similar to the above embodiments, which will not be described herein. Figure 4

[0062] In this way, the hysteresis resistor Rh has a hysteresis effect on the comparator CMP, avoids frequent flipping of the comparator CMP, improves the stability of the over-temperature protection circuit, and improves the over-temperature protection effect.

[0063] In some embodiments, the over-temperature detection module 110 further includes a first current-limiting resistor Rc1, and the output terminal of the comparator CMP is connected to the input terminal of the control module 120 through the first current-limiting resistor Rc1.

[0064] For example, the first terminal of the first current-limiting resistor Rc1 is connected to the output terminal of the comparator CMP, and the second terminal of the first current-limiting resistor Rc1 is connected to the input terminal of the control module 120, which can limit the size of the current flowing into the control module 120.

[0065] Unless the context clearly indicates otherwise, as used herein and in the appended claims, the singular form "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Accordingly, the use of the term "a" or "an" herein and in the following claims is intended to be interpreted to include the singular form "a" or "an" as well as the plural forms "a" or "an," unless the context clearly indicates otherwise. Similarly, the word "or" is intended to mean either or both of the words "by" or "and" unless the context clearly indicates otherwise. Also, the use of the term "including," as well as other forms such as "include," "includes," and "includes," is intended to be broad and encompassed the terms "comprising" and "comprises," unless the context clearly indicates otherwise. Similarly, the use of the term "comprising" is intended to mean "including," "comprising," or "including the recited elements but not excluding others," unless the context clearly indicates otherwise.

[0066] Further aspects and scope of applicability will become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific examples herein are intended for illustrative purposes only and are not intended to limit the scope of the present application.

[0067] ​The above detailed description of several embodiments of the disclosure sets forth both the permitted and specific modifications and variations. It is to be understood that those skilled in the art can make various modifications and variations without departing from the spirit and scope of the disclosure. The scope of protection of the disclosure is defined by the appended claims.

Claims

1. An over-temperature protection circuit, characterized by, The application relates to an over-temperature detection module and a control module, wherein the output end of the over-temperature detection module is connected to the input end of the control module, and the output end of the control module is connected to a heater. The over-temperature detection module is configured to detect the real-time temperature of a device to be detected and detect whether the real-time temperature exceeds a temperature threshold value. The control module is configured to control the heater to stop working when the real-time temperature exceeds the temperature threshold value, and control whether the heater works according to a software control signal of the heater when the real-time temperature does not exceed the temperature threshold value. The over-temperature detection module comprises a temperature detection unit, a voltage generation unit and a comparator.

2. The over-temperature protection circuit of claim 1, wherein, The output end of the temperature detection unit is connected to the first input end of the comparator, the output end of the voltage generation unit is connected to the second input end of the comparator, and the output end of the comparator is connected to the input end of the control module. The temperature detection unit is configured to detect the real-time temperature and obtain a temperature voltage. The voltage generation unit is configured to generate a voltage threshold value, which is used to represent the temperature threshold value. The comparator is configured to output a first level signal when the temperature voltage is higher than the voltage threshold value, and output a second level signal when the temperature voltage is not higher than the voltage threshold value. The temperature detection unit comprises a first voltage dividing resistor and a thermistor.

3. The over-temperature protection circuit of claim 2, wherein, The first voltage dividing resistor and the thermistor are connected in series between a reference power supply and the ground, and the connection point of the first voltage dividing resistor and the thermistor is connected to the first input end of the comparator. The voltage generation unit comprises a second voltage dividing resistor and a third voltage dividing resistor.

4. Over-temperature protection circuit according to claim 2 or 3, characterized in that The first end of the second voltage dividing resistor is connected to the reference power supply, the second end of the second voltage dividing resistor is connected to the first end of the third voltage dividing resistor and the second input end of the comparator, and the second end of the third voltage dividing resistor is grounded. The over-temperature detection module further comprises a hysteresis resistor.

5. The over-temperature protection circuit of claim 4, wherein, The hysteresis resistor is connected between the non-inverting input end of the comparator and the output end of the comparator. The over-temperature detection module further comprises a first current limiting resistor.

6. The over-temperature protection circuit of claim 2, wherein, The output end of the comparator is connected to the input end of the control module through the first current limiting resistor. The control module comprises a solid-state relay, a second current limiting resistor, a voltage limiting resistor and a triode.

7. The over-temperature protection circuit of any one of claims 1-3, wherein, The first end of the second current limiting resistor is used for receiving the software control signal, the second end of the second current limiting resistor is connected to the first end of the voltage limiting resistor and the base of the triode, the second end of the voltage limiting resistor and the emitter of the triode are grounded, the collector of the triode is connected to the negative input end of the solid-state relay, the positive input end of the solid-state relay is connected to the output end of the over-temperature detection module, and the output end of the solid-state relay is connected to the power supply end of the heater. The thermistor is a positive temperature coefficient thermistor.

8. The over-temperature protection circuit of claim 3, wherein, The first end of the thermistor is connected to the first end of the first voltage dividing resistor and the inverting input end of the comparator, the second end of the thermistor is grounded, and the second end of the first voltage dividing resistor is connected to the reference power supply. The thermistor is a negative temperature coefficient thermistor.

9. The over-temperature protection circuit of claim 3, wherein, ​ The first end of the thermistor is connected to the first end of the first voltage dividing resistor and the inverting input of the comparator, and the second end of the thermistor is connected to the reference power supply, and the second end of the first voltage dividing resistor is grounded.

10. The over-temperature protection circuit of claim 3, wherein, The thermistor is a negative temperature coefficient thermistor. The first end of the thermistor is connected to the first end of the first voltage dividing resistor and the non-inverting input of the comparator, and the second end of the thermistor is grounded, and the second end of the first voltage dividing resistor is connected to the reference power supply.

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