An over-temperature protection circuit and heating device with self-locking function

Abstract

The present invention relates to an over-temperature protection circuit and a heating device with a self-locking function, comprising a temperature acquisition device, which comprises at least one temperature acquisition unit, wherein the at least one temperature acquisition unit comprises a first temperature acquisition unit, a first over-temperature comparison circuit connected to the first temperature acquisition unit, a first switch circuit connected to the first over-temperature comparison circuit, a heating unit connected to the first switch circuit, and a self-locking circuit connected to the first over-temperature comparison circuit and the first switch circuit; the first temperature acquisition unit acquires first real-time temperature information of a first measured object group; the first over-temperature comparison circuit outputs a first over-temperature comparison signal when the first measured object group is over-temperature, the first switch circuit turns off the heating unit according to the first over-temperature comparison signal, and the self-locking circuit locks the power supply of the first switch circuit according to the first over-temperature comparison signal. When the temperature is over-temperature, the heating unit can be effectively disconnected, the current state of the circuit can be locked, automatic restart can be avoided, and reliability and service life can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heating products, and more particularly to an over-temperature protection circuit and a heating device with a self-locking function. Background Art

[0002] Existing heating products must be equipped with a fuse circuit according to the safety regulations of heating products. The traditional approach is to connect a temperature protection device in series with the heating wire on each detection circuit, so that the temperature of the circuit / product during the heating process can be detected in real time through the temperature protection device, and corresponding protection actions can be taken. In particular, in a double-fuse circuit, two detection circuits need to be set up, and the two detection circuits can detect the heating status of the product simultaneously and in parallel.

[0003] However, the traditional method is generally to use mechanical disconnection protection, that is, when the heating temperature is too high, the temperature protection device automatically disconnects, and when the temperature drops, the temperature protection device automatically reopens. Repeated operations may damage related circuits or electronic components in the product, affecting the reliability of the product and reducing the service life of the product. Moreover, the traditional method is inflexible, complex in structure and high in cost. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an over-temperature protection circuit and a heating device with a self-locking function in view of the above-mentioned defects of the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide an over-temperature protection circuit with a self-locking function, comprising: a temperature acquisition device, the temperature acquisition device comprising at least one temperature acquisition unit, the at least one temperature acquisition unit comprising a first temperature acquisition unit, a first over-temperature comparison circuit connected to the first temperature acquisition unit, a first switch circuit connected to the first over-temperature comparison circuit, a heating unit connected to the first switch circuit, and a self-locking circuit connected to the first over-temperature comparison circuit and the first switch circuit;

[0006] The first temperature acquisition unit is used to acquire first real-time temperature information of the first measured object group;

[0007] The first over-temperature comparison circuit receives the first real-time temperature information, and outputs a first over-temperature comparison signal to the self-locking circuit and the first switching circuit when the first measured object group is over-temperature, the first switching circuit turns off the heating unit according to the first over-temperature comparison signal, and the self-locking circuit locks the power supply of the first switching circuit according to the first over-temperature comparison signal.

[0008] Preferably, it also includes: a second temperature acquisition unit for acquiring second real-time temperature information of the second measured object group, a second over-temperature comparison circuit connected to the second temperature acquisition unit, and a second switch circuit connected to the second over-temperature comparison circuit, wherein the second switch circuit is also connected to the self-locking circuit and the heating unit respectively;

[0009] The second over-temperature comparison circuit receives the second real-time temperature information, and outputs a second over-temperature comparison signal to the self-locking circuit and the second switch circuit when the second measured object group is over-temperature, the second switch circuit turns off the heating unit according to the second over-temperature comparison signal, and the self-locking circuit locks the power supply of the second switch circuit according to the second over-temperature comparison signal.

[0010] Preferably, the first over-temperature comparison circuit includes: a first high-temperature comparison circuit connected to the first temperature acquisition unit, receiving the first real-time temperature information, and outputting the first over-temperature comparison signal when the first measured object group has an over-temperature.

[0011] Preferably, the first high temperature comparison circuit comprises: a first resistor, a second resistor, a third resistor, a fifth resistor, a first capacitor and a first high temperature comparator;

[0012] The positive input terminal of the first high temperature comparator is connected to the working voltage through the second resistor and is also grounded through the third resistor. The negative input terminal of the first high temperature comparator is connected to the output terminal of the first temperature acquisition unit through the fifth resistor. The first resistor is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator. The first capacitor is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator. The output terminal of the first high temperature comparator is connected to the input terminal of the first switch circuit and the first input terminal of the self-locking circuit.

[0013] Preferably, the first over-temperature comparison circuit comprises: a first high temperature comparison circuit and a first low temperature comparison circuit connected to the first temperature acquisition unit, and a first logic circuit connected to the first high temperature comparison circuit and the first low temperature comparison circuit respectively;

[0014] The first high temperature comparison circuit is used to receive the first real-time temperature information and output the first over-temperature comparison signal when the first measured object group is over-temperature;

[0015] The first low temperature comparison circuit is used to receive the first real-time temperature information and output a first low temperature comparison signal to the first logic circuit when the first measured object group is too low temperature;

[0016] The first logic circuit outputs a shutdown signal to the first switch circuit according to the first over-temperature comparison signal or the first low-temperature comparison signal, so that the first switch circuit shuts off the heating unit according to the shutdown signal.

[0017] Preferably, the first high temperature comparison circuit includes: a first resistor, a second resistor, a third resistor, a fifth resistor, a first capacitor and a first high temperature comparator; the first low temperature comparison circuit includes: a tenth resistor, a thirteenth resistor, a fifteenth resistor, a sixteenth resistor, a second capacitor and a first low temperature comparator; the first logic circuit includes: a first AND gate, a seventh resistor and a ninth resistor;

[0018] The positive input terminal of the first high temperature comparator is connected to the working voltage through the second resistor and is also grounded through the third resistor. The negative input terminal of the first high temperature comparator is connected to the output terminal of the first temperature acquisition unit through the fifth resistor. The first resistor is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator. The first capacitor is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator. The output terminal of the first high temperature comparator is connected to the first input terminal of the first AND gate and the first input terminal of the self-locking circuit.

[0019] The positive input terminal of the first low temperature comparator is connected to the output terminal of the first temperature acquisition unit through the thirteenth resistor, the tenth resistor is connected in parallel to the positive input terminal and the output terminal of the first low temperature comparator, the first low temperature comparator is connected to the working voltage through the sixteenth resistor and is also grounded through the fifteenth resistor, and the output terminal of the first low temperature comparator is connected to the second input terminal of the first AND gate;

[0020] The power supply end of the first AND gate is connected to the working voltage, the output end of the first AND gate is connected to the input end of the first switch circuit through the ninth resistor, one end of the seventh resistor is connected to the output end of the first AND gate, and the other end is connected to the working voltage.

[0021] Preferably, the first temperature acquisition unit comprises: a first temperature sensor and an eighth resistor;

[0022] A first end of the first temperature sensor is connected to a working voltage, a second end of the first temperature sensor is connected to a first end of the eighth resistor, and a second end of the eighth resistor is grounded;

[0023] A connection end between the second end of the first temperature sensor and the first end of the eighth resistor is an output end of the first temperature acquisition unit and is connected to the first over-temperature comparison circuit.

[0024] Preferably, the first switch circuit comprises: a first triode, a second triode, a third triode, a first relay, a fourth resistor, a sixth resistor, an eleventh resistor, a twelfth resistor, a fourteenth resistor and a first diode;

[0025] The emitter of the first transistor is connected to the power output of the self-locking circuit as the power input of the first switch circuit, the base of the first transistor is connected to the collector of the second transistor through the sixth resistor, the base of the second transistor is connected to the output of the first over-temperature comparison circuit as the input of the first switch circuit, the eleventh resistor is connected between the base and the emitter of the second transistor, the emitter of the second transistor is grounded, the fourth resistor is connected between the emitter and the base of the first transistor, and the collector of the first transistor is connected to the base of the third transistor through the twelfth resistor;

[0026] The emitter of the third transistor is grounded, the fourteenth resistor is connected between the base and the emitter of the third transistor, the collector of the third transistor is connected to the second end of the first relay, the anode of the first diode is connected to the second end of the first relay, the cathode of the first diode is connected to the first end of the first relay, the first end of the first relay is connected to the power supply voltage, and the control end of the first relay is respectively connected to the first end of the heating unit and the first end of the AC input power supply.

[0027] Preferably, the second temperature acquisition unit comprises: a second temperature sensor and a second fifth resistor;

[0028] A first end of the second temperature sensor is connected to a working voltage, a second end of the second temperature sensor is connected to a first end of the second fifth resistor, and a second end of the second fifth resistor is grounded;

[0029] A connection end between the second end of the second temperature sensor and the first end of the second fifth resistor is an output end of the second temperature acquisition unit and is connected to the second over-temperature comparison circuit.

[0030] Preferably, the second over-temperature comparison circuit includes: a second high-temperature comparison circuit connected to the output end of the second temperature acquisition unit, receiving the second real-time temperature information, and outputting the second over-temperature comparison signal when the second measured object group is over-temperature.

[0031] Preferably, the second high temperature comparison circuit comprises: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twenty-first resistor, a third capacitor and a second high temperature comparator;

[0032] The positive input terminal of the second high temperature comparator is connected to the working voltage through the eighteenth resistor and is also grounded through the nineteenth resistor. The negative input terminal of the second high temperature comparator is connected to the output terminal of the second temperature acquisition unit through the twenty-first resistor. The seventeenth resistor is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator. The third capacitor is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator. The output terminal of the second high temperature comparator is connected to the input terminal of the second switch circuit and the second input terminal of the self-locking circuit.

[0033] Preferably, the second over-temperature comparison circuit comprises: a second high temperature comparison circuit and a second low temperature comparison circuit connected to the second temperature acquisition unit, and a second logic circuit connected to the second high temperature comparison circuit and the second low temperature comparison circuit respectively;

[0034] The second high temperature comparison circuit is used to receive the second real-time temperature information and output the second over-temperature comparison signal when the second measured object group is over-temperature.

[0035] The second low temperature comparison circuit is used to receive the second real-time temperature information and output a second low temperature comparison signal to the second logic circuit when the second measured object group is too low temperature;

[0036] The second logic circuit outputs a shutdown signal to the second switch circuit according to the second over-temperature comparison signal or the second low-temperature comparison signal, so that the second switch circuit shuts off the heating unit according to the shutdown signal.

[0037] Preferably, the second high temperature comparison circuit includes: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twenty-first resistor, a third capacitor, and a second high temperature comparator; the second low temperature comparison circuit includes: a twenty-eighth resistor, a thirtieth resistor, a thirty-first resistor, a fourth capacitor, a thirty-fourth resistor, and a second low temperature comparator; the second logic circuit includes a second AND gate, a twenty-third resistor, and a twenty-sixth resistor;

[0038] The positive input terminal of the second high temperature comparator is connected to the working voltage through the eighteenth resistor and is also grounded through the nineteenth resistor. The negative input terminal of the second high temperature comparator is connected to the output terminal of the second temperature acquisition unit through the twenty-first resistor. The seventeenth resistor is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator. The third capacitor is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator. The output terminal of the second high temperature comparator is connected to the first input terminal of the second AND gate and the second input terminal of the self-locking circuit.

[0039] The positive input terminal of the second low temperature comparator is connected to the output terminal of the second temperature acquisition unit through the 30th resistor, the positive input terminal of the second low temperature comparator is also connected to its output terminal through the 28th resistor, the negative input terminal of the second low temperature comparator is grounded through the 31st resistor and is also connected to the working voltage through the 34th resistor, the fourth capacitor is connected between the positive input terminal and the negative input terminal of the second low temperature comparator, and the output terminal of the second low temperature comparator is connected to the second input terminal of the second AND gate;

[0040] The power supply end of the second AND gate is connected to the working voltage, the output end of the second AND gate is connected to the input end of the second switch circuit through the twenty-sixth resistor, one end of the twenty-third resistor is connected to the output end of the second AND gate, and the other end is connected to the working voltage.

[0041] Preferably, the second switch circuit comprises: a fourth transistor, a fifth transistor, a sixth transistor, a second relay, a twentieth resistor, a twenty-second resistor, a twenty-ninth resistor, a twenty-fourth resistor, a twenty-seventh resistor and a second diode;

[0042] The emitter of the fourth transistor is connected to the power output of the self-locking circuit as the power input of the second switch circuit, the base of the fourth transistor is connected to the collector of the sixth transistor through the twenty-second resistor, the twenty-tenth resistor is connected to the emitter and base of the fourth transistor respectively, the emitter of the sixth transistor is grounded, the base of the sixth transistor is connected to the output of the second over-temperature comparison circuit as the input of the second switch circuit, and the base of the sixth transistor is also grounded through the twenty-ninth resistor;

[0043] The collector of the fourth transistor is connected to the base of the fifth transistor through the twenty-fourth resistor, the base of the fifth transistor is grounded through the twenty-seventh resistor, the emitter of the fifth transistor is grounded, the collector of the fifth transistor is respectively connected to the second end of the second relay and the anode of the second diode, the cathode of the second diode is connected to the first end of the second relay, the first end of the second relay is connected to the power supply voltage, and the control end of the second relay is respectively connected to the second end of the heating unit and the second end of the AC input power supply.

[0044] Preferably, it further comprises: a control circuit and a third switch circuit; the control circuit is respectively connected to the output end of the first temperature acquisition unit, the output end of the second temperature acquisition unit and the control end of the self-locking circuit, and the third switch circuit is respectively connected to the control circuit and the second end of the heating unit;

[0045] The control circuit is used to receive the first real-time temperature information and the second real-time temperature information, and output an over-temperature control signal to the third switch circuit and the self-locking circuit when the first measured object group or the second measured object group is over-temperature;

[0046] The third switch circuit turns off the heating unit according to the over-temperature control signal, and the self-locking circuit locks the power supply of the first switch circuit or the power supply of the second switch circuit according to the over-temperature control signal.

[0047] Preferably, the control circuit includes a controller; the third switch circuit includes: a thirty-third resistor, a seventh transistor, a thirty-sixth resistor, a thirty-eighth resistor, a photocoupler, a thirty-second resistor, a thirty-fifth resistor, a thyristor, and a varistor;

[0048] The first acquisition end of the controller is connected to the output end of the first temperature acquisition unit through a thirty-seventh resistor, the second acquisition end of the controller is connected to the output end of the second temperature acquisition unit through a forty-sixth resistor, the first control end of the controller is connected to the second end of the thirty-sixth resistor, and the second control end of the controller is connected to the control end of the self-locking circuit;

[0049] The first end of the thirty-sixth resistor is connected to the base of the seventh transistor, the thirty-eighth resistor is respectively connected to the base of the seventh transistor and the ground, the emitter of the seventh transistor is grounded, the collector of the seventh transistor is connected to the second end of the photoelectric coupler, and the first end of the photoelectric coupler is connected to the working voltage through the thirty-third resistor;

[0050] The third end of the photoelectric coupler is connected to the control end of the thyristor through the thirty-second resistor, the first end of the thyristor is connected to the second end of the AC power supply, the second end of the thyristor is connected to the first end of the thirty-fifth resistor and the second end of the heating unit, the second end of the thirty-fifth resistor is connected to the fourth end of the photoelectric coupler, the first end of the varistor is connected to the first end of the thyristor and the second end of the AC power supply, and the second end of the varistor is connected to the second end of the heating unit.

[0051] Preferably, the self-locking circuit includes: a third AND gate, a thirty-ninth resistor, a forty-second resistor, a forty-first resistor, a forty-fourth resistor, a tenth transistor, a ninth transistor, a fourth diode, a fortieth resistor, a third diode, a fifth diode, a forty-third resistor, an eighth transistor, an electrolytic capacitor, a seventh capacitor and a sixth capacitor;

[0052] The first input end of the third AND gate is connected to the output end of the first over-temperature comparison circuit and the output end of the second over-temperature comparison circuit as the first input end of the self-locking circuit, the power supply end of the third AND gate is connected to the working voltage, the thirty-ninth resistor is respectively connected to the working voltage and the output end of the third AND gate, and the output end of the third AND gate is connected to the base of the ninth transistor through the forty-second resistor and the forty-first resistor in sequence;

[0053] The emitter of the ninth triode is connected to the working voltage, the collector of the ninth triode is connected to the anode of the fourth diode, the collector of the tenth triode is connected between the forty-first resistor and the forty-second resistor, the emitter of the tenth triode is grounded, and the base of the tenth triode is respectively connected to the collector of the ninth triode and the anode of the fourth diode through the forty-fourth resistor;

[0054] The cathode of the fourth diode is connected to the cathode of the third diode, the anode of the third diode is connected to the cathode of the fifth diode, the anode of the fifth diode is respectively connected to the base of the eighth transistor and the second end of the forty-third resistor, the first end of the forty-third resistor and the emitter of the eighth transistor are connected to the working voltage, the collector of the eighth transistor is respectively connected to the first end of the electrolytic capacitor and the first end of the seventh capacitor, the second end of the electrolytic capacitor and the second end of the seventh capacitor are grounded, and the first end of the electrolytic capacitor is connected to the power input end of the first switch circuit and the power input end of the second switch circuit as the power output end of the self-locking circuit;

[0055] The first end of the 40th resistor is connected to the cathode of the third diode, the second end of the 40th resistor is connected to the first end of the sixth capacitor, the second end of the sixth capacitor is grounded, and the connection end between the second end of the 40th resistor and the first end of the sixth capacitor is connected to the second control end of the controller as the control end of the self-locking circuit.

[0056] The present invention also provides a heating device, comprising the above-mentioned over-temperature protection circuit with self-locking function.

[0057] The implementation of the over-temperature protection circuit with a self-locking function of the present invention has the following beneficial effects: the over-temperature protection circuit with a self-locking function of the present invention collects the real-time temperature of the first measured object group by setting a first temperature collection unit, and the first over-temperature comparison circuit performs real-time monitoring according to the first real-time temperature of the first measured object group. When the first measured object group overheats, the heating unit is promptly turned off by the first switching circuit to avoid overheating of the heating unit and damage to the product or circuit. At the same time, the self-locking circuit automatically locks the current state of the circuit to avoid repeated operation and damage to the product or circuit, effectively improving the reliability of the product and extending the service life of the product. The over-temperature protection of the present invention is turned off by the circuit, and the control is flexible, and the structure is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0059] Figure 1 It is a structural schematic diagram of an over-temperature protection circuit with a self-locking function provided by an embodiment of the present invention;

[0060] Figure 2 is a structural schematic diagram of an over-temperature protection circuit with a self-locking function provided by another embodiment of the present invention;

[0061] Figure 3 is a schematic diagram of a partial circuit of an over-temperature protection circuit with a self-locking function provided by an embodiment of the present invention;

[0062] Figure 4 It is a circuit principle diagram of a self-locking circuit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] The present invention provides an over-temperature protection circuit with a self-locking function. The over-temperature protection circuit can be applied to heating products such as heaters, automatic cooking machines, etc.

[0065] refer to Figure 1 , which is a structural schematic diagram of an over-temperature protection circuit with a self-locking function provided by an embodiment of the present invention.

[0066] like Figure 1As shown, the over-temperature protection circuit with self-locking function comprises: a temperature acquisition device, the temperature acquisition device comprises at least one temperature acquisition unit, the at least one temperature acquisition unit comprises a first temperature acquisition unit 101, a first over-temperature comparison circuit 102 connected to the first temperature acquisition unit 101, a first switch circuit 103 connected to the first over-temperature comparison circuit 102, a heating unit 501 connected to the first switch circuit 103, and a self-locking circuit 401 connected to the first over-temperature comparison circuit 102 and the first switch circuit 103. The first temperature acquisition unit 101 is used to acquire the first real-time temperature information of the first measured object group; the first over-temperature comparison circuit 102 receives the first real-time temperature information, and outputs a first over-temperature comparison signal to the self-locking circuit 401 and the first switch circuit 103 when the first measured object group is over-temperature, the first switch circuit 103 turns off the heating unit 501 according to the first over-temperature comparison signal, and the self-locking circuit 401 locks the power supply of the first switch circuit 103 according to the first over-temperature comparison signal.

[0067] It can be understood that the first measured object group of the embodiment of the present invention can be at least one detection position in the same measured object. When there are multiple detection positions, the multiple detection positions are different detection positions of the measured object; or it can also be at least one measured object. When the first measured object group includes multiple measured objects, the multiple measured objects are different objects. Among them, the first temperature acquisition unit 101 is set corresponding to the first measured object group, that is, when the first measured object group is at least one detection position in the same measured object, the first temperature acquisition unit 101 is set in a one-to-one correspondence with at least one detection position of the measured object to respectively detect the real-time temperature information of the at least one detection position; when the first measured object group is one measured object or multiple different measured objects, the first temperature acquisition unit 101 is set in a one-to-one correspondence with the one measured object or the multiple different measured objects to detect the real-time temperature information of one measured object or multiple different measured objects. Therefore, the first real-time temperature information of the embodiment of the present invention can be any one or more of the real-time temperature information of a detection position of a measured object, multiple real-time temperature information of multiple different detection positions of a measured object, real-time temperature information of a measured object, and multiple real-time temperature information of multiple different measured objects, depending mainly on the circuit design.

[0068] Furthermore, if Figure 1As shown, the over-temperature protection circuit with a self-locking function of the embodiment of the present invention also includes: a second temperature acquisition unit 201 for acquiring second real-time temperature information of the second measured object group, a second over-temperature comparison circuit 202 connected to the second temperature acquisition unit 201, and a second switch circuit 203 connected to the second over-temperature comparison circuit 202, and the second switch circuit 203 is also connected to the self-locking circuit 401 and the heating unit 501 respectively; the second over-temperature comparison circuit 202 receives the second real-time temperature information, and outputs a second over-temperature comparison signal to the self-locking circuit 401 and the second switch circuit 203 when the second measured object group is over-temperature, the second switch circuit 203 turns off the heating unit 501 according to the second over-temperature comparison signal, and the self-locking circuit 401 locks the power supply of the second switch circuit 203 according to the second over-temperature comparison signal.

[0069] It can be understood that the second measured object group of the embodiment of the present invention can be at least one detection position in the same measured object. When there are multiple detection positions, the multiple detection positions are different detection positions of the measured object; or it can also be at least one measured object. When the second measured object group includes multiple measured objects, the multiple measured objects are different objects. Among them, the second temperature acquisition unit 201 is set corresponding to the second measured object group, that is, when the second measured object group is at least one detection position in the same measured object, the second temperature acquisition unit 201 is set in a one-to-one correspondence with at least one detection position of the measured object to respectively detect the real-time temperature information of the at least one detection position; when the second measured object group is one measured object or multiple different measured objects, the second temperature acquisition unit 201 is set in a one-to-one correspondence with the one measured object or the multiple different measured objects to detect the real-time temperature information of one measured object or multiple different measured objects. Therefore, the second real-time temperature information of the embodiment of the present invention can be any one or more of the real-time temperature information of a detection position of a measured object, multiple real-time temperature information of multiple different detection positions of a measured object, real-time temperature information of a measured object, and multiple real-time temperature information of multiple different measured objects, depending mainly on the circuit design.

[0070] like Figure 1As shown, the present invention is respectively provided with a first temperature acquisition unit 101, a first over-temperature comparison circuit 102, a first switch circuit 103, a self-locking circuit 401, a first switch circuit 103, and a second temperature acquisition unit 201, a second over-temperature comparison circuit 202, a second switch circuit 203, a self-locking circuit 401, and a second switch circuit 203, thereby forming two parallel and mutually independent over-temperature protection circuits, thereby realizing double protection of the circuit. When any over-temperature protection circuit has an over-temperature phenomenon, the over-temperature protection will be triggered to ensure that over-temperature damage cannot be carried out. Now it also has a self-locking function. When over-temperature occurs, the current state can be automatically locked to lock the current circuit to avoid repeated operations and damage to the circuit. Optionally, the self-locking function of the embodiment of the present invention is to automatically trigger the self-locking function when the high temperature is over-temperature.

[0071] It should be noted that, in the embodiment of the present invention, the first temperature acquisition unit 101 and the second temperature acquisition unit 201 acquire data of two different measured objects, that is, the first measured object group and the second measured object group are two different measured object groups.

[0072] like Figure 1 As shown, the first temperature acquisition unit 101 acquires the temperature of the first measured object group in real time to obtain the first real-time temperature information, and the first real-time temperature information is transmitted to the first over-temperature comparison circuit 102. The first over-temperature comparison circuit 102 monitors the first real-time temperature information in real time. When the first measured object group has an over-temperature, that is, when the temperature of the first real-time temperature information exceeds the high temperature reference value, the first over-temperature comparison circuit 102 outputs a first over-temperature comparison signal from its output end, and the first over-temperature comparison signal is sent to the input end of the first switch circuit 103. The first switch circuit 103 outputs a shutdown signal according to the first over-temperature comparison signal to shut down the heating. At the same time, the first over-temperature comparison signal is transmitted to the first input terminal of the self-locking circuit 401, and the self-locking circuit 401 outputs a self-locking signal from its power output terminal to the power input terminal of the first switch circuit 103 according to the first over-temperature comparison signal of the first input terminal, so as to lock the power supply of the first switch circuit 103, thereby realizing the self-locking function, and avoiding that when the temperature is restored to the workable range, the first switch circuit 103 automatically recovers and the heating unit 501 (HEATER) automatically resumes the heating action, so as to avoid the phenomenon of repeated heating of the heating unit 501, and effectively protect the circuit and the product. Optionally, the first over-temperature comparison signal is a comparison signal output when the temperature is too high.

[0073] Furthermore, if Figure 1As shown, the second temperature acquisition unit 201 acquires the temperature of the second measured object group in real time to obtain the second real-time temperature information, and the second real-time temperature information is transmitted to the second over-temperature comparison circuit 202. The second over-temperature comparison circuit 202 monitors the second real-time temperature information in real time. When the second measured object group has an over-temperature, that is, when the temperature of the second real-time temperature information exceeds the high temperature reference value, the second over-temperature comparison circuit 202 outputs a second over-temperature comparison signal from its output end, and the second over-temperature comparison signal is sent to the input end of the second switch circuit 203. The second switch circuit 203 outputs a shutdown signal according to the second over-temperature comparison signal. The heating unit 501 is turned off to realize over-temperature protection; at the same time, the second over-temperature comparison signal is transmitted to the second input end of the self-locking circuit 401), and the self-locking circuit 401 outputs a self-locking signal from its power output end to the power input end of the second switch circuit 203 according to the second over-temperature comparison signal of the second input end, so as to lock the power supply of the second switch circuit 203, thereby realizing the self-locking function, and preventing the second switch circuit 203 from automatically recovering when the temperature is restored to the workable temperature range, so as to prevent the heating unit 501 from being heated repeatedly, and effectively protecting the circuit and the product. Optionally, the second over-temperature comparison signal is a comparison signal output when the temperature is too high.

[0074] Furthermore, if Figure 1 As shown, the over-temperature protection circuit with a self-locking function in the embodiment of the present invention also includes: a control circuit 301 and a third switch circuit 302; the control circuit 301 is respectively connected to the output end of the first temperature acquisition unit 101, the output end of the second temperature acquisition unit 201 and the control end of the self-locking circuit 401, and the third switch circuit 302 is respectively connected to the control circuit 301 and the second end of the heating unit 501; the control circuit 301 is used to receive the first real-time temperature information and the second real-time temperature information, and output an over-temperature control signal to the third switch circuit 302 when the first measured object group or the second measured object group is over-temperature; the third switch circuit 302 turns off the heating unit 501 according to the over-temperature control signal, and the self-locking circuit 401 locks the first switch circuit 103 or the second switch circuit 203 according to the over-temperature control signal.

[0075] like Figure 1 As shown, when the temperature of any one of the first real-time temperature information and the second real-time temperature information collected by the first temperature acquisition unit 101 and the second temperature acquisition unit 201 exceeds the over-temperature reference value, the control circuit 301 will output an over-temperature control signal to the first switch circuit 103 or the second switch circuit 203, so as to shut down the heating unit 501 through the first switch circuit 103 or shut down the heating unit 501 through the second switch circuit 203, and at the same time output the over-temperature control signal to the self-locking circuit 401, so as to lock the power supply of the first switch circuit 103 or the power supply of the second switch circuit 203 through the self-locking circuit 401.

[0076] As can be seen from Figure 1, the present invention combines hardware and software. When overtemperature occurs, the heating unit 501 can be shut down by hardware or by software, and the current state of the circuit can be automatically locked, thereby effectively protecting the circuit and the product and improving the reliability of overtemperature protection.

[0077] refer to Figure 2 , is an over-temperature protection circuit with a self-locking function provided by another embodiment of the present invention. In this embodiment, the first over-temperature comparison circuit 102 includes: a first high temperature comparison circuit 1021 and a first low temperature comparison circuit 1022 connected to the first temperature acquisition unit 101, and a first logic circuit 104 connected to the first high temperature comparison circuit 1021 and the first low temperature comparison circuit 1022 respectively.

[0078] The first high temperature comparison circuit 1021 is used to receive the first real-time temperature information, and output a first over-temperature comparison signal when the first measured object group is too high; the first low temperature comparison circuit 1022 is used to receive the first real-time temperature information, and output a first low temperature comparison signal to the first logic circuit 104 when the first measured object group is too low; the first logic circuit 104 outputs a shutdown signal to the first switch circuit 103 according to the first over-temperature comparison signal or the first low temperature comparison signal, so that the first switch circuit 103 shuts off the heating unit 501 according to the shutdown signal.

[0079] The second over-temperature comparison circuit 202 includes: a second high temperature comparison circuit 2021 and a second low temperature comparison circuit 2022 connected to the second temperature acquisition unit 201 , and a second logic circuit 204 connected to the second high temperature comparison circuit 2021 and the second low temperature comparison circuit 2022 , respectively.

[0080] The second high temperature comparison circuit 2021 is used to receive the second real-time temperature information, and output a second over-temperature comparison signal when the second measured object group is too high; the second low temperature comparison circuit 2022 is used to receive the second real-time temperature information, and output a second low temperature comparison signal to the second logic circuit 204 when the second measured object group is too low; the second logic circuit 204 outputs a shutdown signal to the second switch circuit 203 according to the second over-temperature comparison signal or the second low temperature comparison signal, so that the second switch circuit 203 shuts off the heating unit 501 according to the shutdown signal.

[0081] By adding the first low temperature comparison circuit 1022 and the second low temperature comparison circuit 2022, when an excessively low temperature occurs in any one of the first measured object group and the second measured object group, the first switch circuit 103 or the second switch circuit 203 can be controlled to shut down the heating unit 501, thereby preventing the heating unit 501 from operating in an excessively low temperature environment and damaging the heating unit 501 and / or related components in the circuit.

[0082] refer to Figure 3 and Figure 4 , is a circuit schematic diagram of a specific embodiment of an over-temperature protection circuit with a self-locking function of the present invention.

[0083] like Figure 3 As shown, in this embodiment, the first temperature acquisition unit 101 includes: a first temperature sensor NTC1 and an eighth resistor R8.

[0084] The first end of the first temperature sensor NTC1 is connected to the working voltage (+3.3V), the second end of the first temperature sensor NTC1 is connected to the first end of the eighth resistor R8, and the second end of the eighth resistor R8 is grounded; the connection end between the second end of the first temperature sensor NTC1 and the first end of the eighth resistor R8 is the output end of the first temperature acquisition unit 101, and is connected to the first over-temperature comparison circuit 102 (i.e., Figure 3 As shown, the negative input terminal of the first high temperature comparator U1B is connected through the fifth resistor R5 and the positive input terminal of the first low temperature comparator U1A is connected through the thirteenth resistor R13).

[0085] Optionally, in the embodiment of the present invention, the second temperature sensor NTC2 includes but is not limited to a thermistor.

[0086] The first high temperature comparison circuit includes: a first resistor R1, a second resistor R2, a third resistor R3, a fifth resistor R5, a first capacitor C1 and a first high temperature comparator U1B; the first low temperature comparison circuit 1022 includes: a tenth resistor R10, a thirteenth resistor R13, a fifteenth resistor R15, a sixteenth resistor R16, a second capacitor C2 and a first low temperature comparator U1A; the first logic circuit 104 includes: a first AND gate U3, a seventh resistor R7 and a ninth resistor R9.

[0087] The positive input terminal of the first high temperature comparator U1B is connected to the working voltage (+3.3V) through the second resistor R2 and is also grounded through the third resistor R3. The negative input terminal of the first high temperature comparator U1B is connected to the output terminal of the first temperature acquisition unit 101 through the fifth resistor R5. The first resistor R1 is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator U1B. The first capacitor C1 is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator U1B. The output terminal of the first high temperature comparator U1B is connected to the first input terminal of the first AND gate U3 and the first input terminal (High Temp-1); the positive input terminal of the first low temperature comparator U1A is connected to the output terminal of the first temperature acquisition unit 101 through the thirteenth resistor R13, the tenth resistor R10 is connected in parallel to the positive input terminal and the output terminal of the first low temperature comparator U1A, the first low temperature comparator U1A is connected to the working voltage (+3.3V) through the sixteenth resistor R16 and is also grounded through the fifteenth resistor R15, the output terminal of the first low temperature comparator U1A is connected to the second input terminal of the first AND gate U3; the power supply terminal of the first AND gate U3 is connected to the working voltage (+3.3V), the output terminal of the first AND gate U3 is connected to the input terminal of the first switch circuit 103 through the ninth resistor R9, one end of the seventh resistor R7 is connected to the output terminal of the first AND gate U3, and the other end is connected to the working voltage (+3.3V).

[0088] Among them, the negative input end of the first high temperature comparator U1B and the positive input end of the first low temperature comparator U1A are the input ends of the first over-temperature comparison circuit 102 , and the output end of the first high temperature comparator U1B and the output end of the first low temperature comparator U1A are the output ends of the first over-temperature comparison circuit 102 .

[0089] The first switch circuit 103 includes: a first transistor Q1, a second transistor Q3, a third transistor Q4, a first relay (RELAY1), a fourth resistor R4, a sixth resistor R6, an eleventh resistor R11, a twelfth resistor R12, a fourteenth resistor R14 and a first diode D1.

[0090] The emitter of the first transistor Q1 is connected to the power output end (VCC-OUT) of the self-locking circuit 401 as the power input end of the first switch circuit 103, the base of the first transistor Q1 is connected to the collector of the second transistor Q3 through the sixth resistor R6, the base of the second transistor Q3 is connected to the output end of the first over-temperature comparison circuit 102 as the input end of the first switch circuit 103, the eleventh resistor R11 is connected between the base and the emitter of the second transistor Q3, the emitter of the second transistor Q3 is grounded, the fourth resistor R4 is connected between the emitter and the base of the first transistor Q1, the collector of the first transistor Q1 is connected to the collector of the third transistor Q3 through the twelfth resistor R12 base; the emitter of the third transistor Q3 is grounded, the fourteenth resistor R14 is connected between the base and the emitter of the third transistor Q3, the collector of the third transistor Q3 is connected to the second end of the first relay (RELAY1), the anode of the first diode D1 is connected to the second end of the first relay (RELAY1), the cathode of the first diode D1 is connected to the first end of the first relay (RELAY1), the first end of the first relay (RELAY1) is connected to the power supply voltage (+12V), and the control end of the first relay (RELAY1) is respectively connected to the first end of the heating unit 501 (HEATER) and the first end of the AC input power supply (ACPower).

[0091] The second temperature acquisition unit 201 includes: a second temperature sensor NTC2 and a twenty-fifth resistor R25.

[0092] The first end of the second temperature sensor NTC2 is connected to the working voltage (+3.3V), the second end of the second temperature sensor NTC2 is connected to the first end of the twenty-fifth resistor R25, and the second end of the twenty-fifth resistor R25 is grounded; the connection end between the second end of the second temperature sensor NTC2 and the first end of the twenty-fifth resistor R25 is the output end of the second temperature acquisition unit 201, and is connected to the second over-temperature comparison circuit 202 (i.e., Figure 3 As shown, the negative input terminal of the second high temperature comparator U2B is connected through a twenty-first resistor R21 and the positive input terminal of the second low temperature comparator U2A is connected through a thirtieth resistor R30). Optionally, in the embodiment of the present invention, the second temperature sensor NTC2 includes but is not limited to a thermistor.

[0093] like Figure 3As shown, the second high temperature comparison circuit 2021 includes: a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twenty-first resistor R21, a third capacitor C3 and a second high temperature comparator U2B; the second low temperature comparison circuit 2022 includes: a twenty-eighth resistor R28, a thirtieth resistor R30, a thirty-first resistor R31, a fourth capacitor C4, a thirty-fourth resistor R34 and a second low temperature comparator U2A; the second logic circuit 204 includes a second AND gate U4, a twenty-third resistor R23 and a twenty-sixth resistor R26.

[0094] The positive input terminal of the second high temperature comparator U2B is connected to the working voltage (+3.3V) through the eighteenth resistor R18, and is also grounded through the nineteenth resistor R19. The negative input terminal of the second high temperature comparator U2B is connected to the output terminal of the second temperature acquisition unit 201 through the twenty-first resistor R21. The seventeenth resistor R17 is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator U2B. The third capacitor C3 is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator U2B. The output terminal of the second high temperature comparator U2B is connected to the first input terminal of the second AND gate U4 and the second input terminal (High Temp-2); the positive input terminal of the second low temperature comparator U2A is connected to the output terminal of the second temperature acquisition unit 201 through the 30th resistor R30, the positive input terminal of the second low temperature comparator U2A is also connected to its output terminal through the 28th resistor R28, the negative input terminal of the second low temperature comparator U2A is grounded through the 31st resistor R31, and is also connected to the working voltage (+3.3V) through the 34th resistor R34, the fourth capacitor C4 is connected between the positive input terminal and the negative input terminal of the second low temperature comparator U2A, and the output terminal of the second low temperature comparator U2A is connected to the second input terminal of the second AND gate U4; the power supply terminal of the second AND gate U4 is connected to the working voltage (+3.3V), the output terminal of the second AND gate U4 is connected to the input terminal of the second switch circuit 203 through the 26th resistor R26, one end of the 23rd resistor R23 is connected to the output terminal of the second AND gate U4, and the other end is connected to the working voltage (+3.3V).

[0095] Among them, the negative input end of the second high temperature comparator U2B and the positive input end of the second low temperature comparator U2A are the input ends of the second over-temperature comparison circuit 202, and the output end of the second high temperature comparator U2B and the output end of the second low temperature comparator U2A are the output ends of the second over-temperature comparison circuit 202.

[0096] like Figure 3 As shown, the second switch circuit 203 includes: a fourth transistor Q4, a fifth transistor Q5, a sixth transistor Q6, a second relay (RELAY2), a twentieth resistor R20, a twenty-second resistor R22, a twenty-ninth resistor R29, a twenty-fourth resistor R24, a twenty-seventh resistor R27 and a second diode D2.

[0097] The emitter of the fourth transistor Q4 is connected to the power output end (VCC-OUT) of the self-locking circuit 401 as the power input end of the second switch circuit 203, the base of the fourth transistor Q4 is connected to the collector of the sixth transistor Q6 through the twenty-second resistor R22, the twentieth resistor R20 is connected to the emitter and base of the fourth transistor Q4 respectively, the emitter of the sixth transistor Q6 is grounded, the base of the sixth transistor Q6 is connected to the output end of the second over-temperature comparison circuit as the input end of the second switch circuit 203, and the base of the sixth transistor Q6 is also grounded through the twenty-ninth resistor R29; the collector of the fourth transistor Q4 is connected to the collector of the sixth transistor Q6 through the twenty-fourth resistor R29. Resistor R24 ​​is connected to the base of the fifth transistor Q5, the base of the fifth transistor Q5 is grounded through the twenty-seventh resistor R27, the emitter of the fifth transistor Q5 is grounded, the collector of the fifth transistor Q5 is respectively connected to the second end of the second relay (RELAY2) and the anode of the second diode D2, the cathode of the second diode D2 is connected to the first end of the second relay (RELAY2), the first end of the second relay (RELAY2) is connected to the power supply voltage (+12V), and the control end of the second relay (RELAY2) is respectively connected to the second end of the heating unit 501 (HEATER) and the second end of the AC input power supply (AC Power).

[0098] like Figure 3 As shown, the control circuit 301 includes a controller U8; the third switch circuit 302 includes: a thirty-third resistor R33, a seventh transistor Q7, a thirty-sixth resistor R36, a thirty-eighth resistor R38, a photocoupler U5, a thirty-second resistor R32, a thirty-fifth resistor R35, a thyristor SR1, and a varistor ZR1.

[0099] The first acquisition terminal (ADC1) of the controller U8 is connected to the output terminal of the first temperature acquisition unit 101 through the thirty-seventh resistor R37, the second acquisition terminal (ADC2) of the controller U8 is connected to the output terminal of the second temperature acquisition unit 201 through the forty-sixth resistor R46, the first control terminal (I / O-1) of the controller U8 is connected to the second end of the thirty-sixth resistor R36, and the second control terminal (I / O-2) of the controller U8 is connected to the control end of the self-locking circuit 401; the first end of the thirty-sixth resistor R36 is connected to the base of the seventh transistor Q7, the thirty-eighth resistor R38 is respectively connected to the base and ground of the seventh transistor Q7, the emitter of the seventh transistor Q7 is grounded, the collector of the seventh transistor Q7 is connected to the second end of the photoelectric coupler U5, and the first end of the photoelectric coupler U5 is connected to the working voltage (+3.3V) through the thirty-third resistor R33.

[0100] The third end of the photocoupler U5 is connected to the control end of the thyristor SR1 through the thirty-second resistor R32, the first end of the thyristor SR1 is connected to the second end of the AC power supply, the second end of the thyristor SR1 is connected to the first end of the thirty-fifth resistor R35 and the second end of the heating unit 501 (HEATER), the second end of the thirty-fifth resistor R35 is connected to the fourth end of the photocoupler U5, the first end of the varistor ZR1 is connected to the first end of the thyristor SR1 and the second end of the AC power supply, and the second end of the varistor ZR1 is connected to the second end of the heating unit 501 (HEATER).

[0101] like Figure 4 As shown, the self-locking circuit 401 includes: a third AND gate U6, a thirty-ninth resistor R39, a forty-second resistor R42, a forty-first resistor R41, a forty-fourth resistor R44, a tenth transistor Q10, a ninth transistor Q9, a fourth diode D4, a fortieth resistor R40, a third diode D3, a fifth diode D5, a forty-third resistor R43, an eighth transistor Q8, an electrolytic capacitor EC1, a seventh capacitor C7 and a sixth capacitor C6.

[0102] The first input terminal of the third AND gate U6 is connected to the output terminal of the first over-temperature comparison circuit 102 and the output terminal of the second over-temperature comparison circuit 202 as the first input terminal (High Temp-1) of the self-locking circuit 401, the power supply terminal of the third AND gate U6 is connected to the working voltage (+3.3V), the thirty-ninth resistor R39 is respectively connected to the working voltage (+3.3V) and the output terminal of the third AND gate U6, and the output terminal of the third AND gate U6 is connected to the base of the ninth transistor Q9 through the forty-second resistor R42 and the forty-first resistor R41 in sequence; the emitter of the ninth transistor Q9 is connected to the working voltage (+3.3V), the collector of the ninth transistor Q9 is connected to the anode of the fourth diode D4, the collector of the tenth transistor Q10 is connected between the forty-first resistor R41 and the forty-second resistor R42, the emitter of the tenth transistor Q10 is grounded, and the base of the tenth transistor Q10 is respectively connected to the collector of the ninth transistor Q9 and the anode of the fourth diode D4 through the forty-fourth resistor R44.

[0103] The cathode of the fourth diode D4 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the cathode of the fifth diode D5, the anode of the fifth diode D5 is connected to the base of the eighth triode Q8 and the second end of the forty-third resistor R43 respectively, the first end of the forty-third resistor R43 and the emitter of the eighth triode Q8 are connected to the working voltage (+3.3V), the collector of the eighth triode Q8 is connected to the first end of the electrolytic capacitor EC1 and the first end of the seventh capacitor C7 respectively, the second end of the electrolytic capacitor EC1 and the second end of the seventh capacitor C7 are grounded, and the electrolytic capacitor The first end of the capacitor EC1 is connected to the power input end of the first switch circuit 103 and the power input end of the second switch circuit 203 as the power output end (VCC-OUT) of the self-locking circuit 401; the first end of the 40th resistor R40 is connected to the cathode of the third diode D3, the second end of the 40th resistor R40 is connected to the first end of the sixth capacitor C6, the second end of the sixth capacitor C6 is grounded, and the connection end of the second end of the 40th resistor R40 and the first end of the sixth capacitor C6 is connected to the second control end (I / O-2) of the controller U8 as the control end of the self-locking circuit 401. The first input end of the third AND gate U6 is the first input end of the self-locking circuit 401, and the second input end of the third AND gate U6 is the second input end of the self-locking circuit 401.

[0104] like Figure 3 As shown, when the first measured object group has an overtemperature, the first high temperature comparator U1B outputs a first overtemperature comparison signal to the first AND gate U3, and the first AND gate U3 outputs a low level signal (0V), so that the second transistor Q3 is turned off, and the first transistor Q1 and the third transistor Q3 are also turned off, thereby disconnecting the first relay (RELAY1), disconnecting the heating unit from the AC input power supply (AC Power), and realizing the shutdown control of the heating unit 501 (HEATER); at the same time, the first overtemperature comparison signal output by the first high temperature comparator U1B is sent to the first input end of the third AND gate U6, so that the power output end (VCC-OUT) of the self-locking circuit outputs a self-locking signal (0V), thereby locking the power input end of the first switch circuit 103, so that the first switch circuit 103 has no power input, thereby achieving the purpose of locking the power supply of the first switch circuit 103. Alternatively, when the first group of measured objects has an excessively low temperature, the first low temperature comparator U1A outputs a first low temperature comparison signal to the first AND gate U3, and the first AND gate U3 outputs a low level signal (0V), so that the second transistor Q3 is cut off, and the first transistor Q1 and the third transistor Q3 are also cut off, thereby disconnecting the first relay (RELAY1), disconnecting the heating unit from the AC input power supply (AC Power), and realizing the shutdown control of the heating unit 501 (HEATER).

[0105] Alternatively, when the first test object group has an overtemperature, the second control terminal (I / O-2) of the controller U8 outputs an overtemperature control signal to the control terminal of the self-locking circuit 401, and controls the power output terminal (VCC-OUT) of the self-locking circuit 401 to output a self-locking signal (0V), thereby locking the power input terminal of the first switch circuit 103, so that the first switch circuit 103 has no power input, thereby achieving the purpose of locking the power supply of the first switch circuit 103; at the same time, the first control terminal (I / O-1) of the controller U8 outputs an overtemperature control signal to the input terminal of the third switch circuit 302, so that the photocoupler U5 is turned off, and then the thyristor SR1 is turned off, so that the heating unit is disconnected from the AC input power supply (AC Power), and the heating unit 501 (HEATER) is turned off.

[0106] When the second measured object group has an over-temperature, the second high-temperature comparator U2B outputs a second over-temperature comparison signal to the second AND gate U4, and the second AND gate U4 outputs a low-level signal (0V), so that the sixth transistor Q6 is turned off, and the fourth transistor Q4 and the fifth transistor Q5 are also turned off, thereby disconnecting the second relay (RELAY2), disconnecting the heating unit from the AC input power supply (ACPower), and realizing the shutdown control of the heating unit 501; at the same time, the second over-temperature comparison signal output by the second high-temperature comparator U2B is sent to the second input end of the third AND gate U6, so that the power output end (VCC-OUT) of the self-locking circuit 401 outputs a self-locking signal (0V), thereby locking the power input end of the second switch circuit, so that the second switch circuit 203 has no power input, thereby achieving the purpose of locking the power supply of the second switch circuit 202. Alternatively, when the second group of measured objects has an excessively low temperature, the second low temperature comparator U2A outputs a second low temperature comparison signal to the second AND gate U4, and the first and second AND gates U4 output a low level signal (0V), turning off the sixth transistor Q6, and also turning off the fourth transistor Q4 and the fifth transistor Q5, thereby disconnecting the second relay (RELAY2), disconnecting the heating unit 501 (HEATER) from the AC input power supply (AC Power), and realizing the shutdown control of the heating unit 501 (HEATER).

[0107] Alternatively, when the second measured object group has an over-temperature, the second control terminal (I / O-2) of the controller U8 outputs an over-temperature control signal to the control terminal of the self-locking circuit 401, and controls the power output terminal (VCC-OUT) of the self-locking circuit 401 to output a self-locking signal (0V), thereby locking the power input terminal of the second switch circuit 203, so that the second switch circuit 203 has no power input, thereby achieving the purpose of locking the power supply of the second switch circuit 203; at the same time, the first control terminal (I / O-1) of the controller U8 outputs an over-temperature control signal to the input terminal of the third switch circuit 302, so that the photocoupler U5 is turned off, and then the thyristor SR1 is turned off, so that the heating unit 501 (HEATER) is disconnected from the AC input power supply (AC Power), and the heating unit is turned off.

[0108] Of course, it can be understood that in some other embodiments, the first over-temperature comparison circuit 102 may also only include: a first high temperature comparison circuit 1021, in which case, it is not necessary to set the first low temperature comparison circuit 1022 and the first logic circuit 104. Its specific circuit structure is: the input end of the first high temperature comparison circuit 1021 is connected to the output end of the first temperature acquisition unit 101, and the output end of the first high temperature comparison circuit 1021 is respectively connected to the input end of the first switch circuit 103 and the first input end (High Temp-1) of the self-locking circuit 401, for over-temperature monitoring; when the first measured object group is over-temperature, the first high temperature comparison circuit 1021 outputs a first high temperature comparison signal (i.e., a first over-temperature comparison signal) to the first switch circuit 103 and the self-locking circuit 401, and the first switch circuit 103 turns off the heating unit 501 (HEATER) according to the first high temperature comparison signal, and the self-locking circuit 401 locks the power supply of the first switch circuit 103 according to the first high temperature comparison signal.

[0109] Specifically, Figure 3 As shown, similarly, at this time, the first high temperature comparison circuit includes: a first resistor R1, a second resistor R2, a third resistor R3, a fifth resistor R5, a first capacitor C1 and a first high temperature comparator U1B.

[0110] The positive input terminal of the first high temperature comparator U1B is connected to the working voltage (+3.3V) through the second resistor R2 and is also grounded through the third resistor R3. The negative input terminal of the first high temperature comparator U1B is connected to the output terminal of the first temperature acquisition unit 101 through the fifth resistor R5. The first resistor R1 is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator U1B. The first capacitor C1 is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator U1B. The output terminal of the first high temperature comparator U1B is connected to the input terminal of the first switch circuit 103 and the first input terminal (High Temp-1) of the self-locking circuit 401.

[0111] In this embodiment, the negative input terminal of the first high temperature comparator U1B is the input terminal of the first high temperature comparison circuit 1021 , and the output terminal of the first high temperature comparator U1B is the output terminal of the first high temperature comparison circuit 1021 .

[0112] Similarly, in some other embodiments, the second over-temperature comparison circuit 202 may also only include: a second high temperature comparison circuit 2021 connected to the second temperature acquisition unit 201, receiving the second real-time temperature information, and outputting a second over-temperature comparison signal when the second measured object group is over-temperature. In this embodiment, the input end of the second high temperature comparison circuit 2021 is connected to the output end of the second temperature acquisition unit 201, and the output end of the second high temperature comparison circuit 2021 is respectively connected to the input end of the second switch circuit 203 and the second input end (High Temp-2) of the self-locking circuit 401, for over-temperature monitoring; when the second measured object group is over-temperature, the second high temperature comparison circuit 2021 outputs a second high temperature comparison signal (i.e., a second over-temperature comparison signal) to the second switch circuit 203 and the self-locking circuit 401, and the second switch circuit 203 turns off the heating unit 501 (HEATER) according to the second high temperature comparison signal, and the self-locking circuit 401 locks the power supply of the second switch circuit 203 according to the second high temperature comparison signal.

[0113] Specifically, in this embodiment, the second high temperature comparison circuit 2021 includes: a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twenty-first resistor R21, a third capacitor C3 and a second high temperature comparator U2B.

[0114] The positive input terminal of the second high temperature comparator U2B is connected to the working voltage (+3.3V) through the eighteenth resistor R18, and is also grounded through the nineteenth resistor R19. The negative input terminal of the second high temperature comparator U2B is connected to the output terminal of the second temperature acquisition unit 201 through the twenty-first resistor R21. The seventeenth resistor R17 is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator U2B. The third capacitor C3 is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator U2B. The output terminal of the second high temperature comparator U2B is connected to the input terminal of the second switch circuit 203 and the second input terminal (High Temp-2) of the self-locking circuit 401.

[0115] At this time, the negative input terminal of the second high temperature comparator U2B is the input terminal of the second high temperature comparison circuit 2021 , and the output terminal of the second high temperature comparator U2B is the output terminal of the second high temperature comparison circuit 2021 .

[0116] The present invention also provides a heating device, which includes the aforementioned over-temperature protection circuit with a self-locking function, wherein the heating device can be a heating product such as a heater, an automatic cooking machine, etc.

[0117] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

[0118] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. An over-temperature protection circuit with a self-locking function, characterized in that: include: A temperature acquisition device, the temperature acquisition device comprising at least one temperature acquisition unit, the at least one temperature acquisition unit comprising a first temperature acquisition unit, a first over-temperature comparison circuit connected to the first temperature acquisition unit, a first switch circuit connected to the first over-temperature comparison circuit, a heating unit connected to the first switch circuit, and a self-locking circuit connected to the first over-temperature comparison circuit and the first switch circuit; The first temperature acquisition unit is used to acquire first real-time temperature information of the first measured object group; the first over-temperature comparison circuit receives the first real-time temperature information, and outputs a first over-temperature comparison signal to the self-locking circuit and the first switch circuit when the first measured object group is over-temperature, the first switch circuit turns off the heating unit according to the first over-temperature comparison signal, and the self-locking circuit locks the power supply of the first switch circuit according to the first over-temperature comparison signal; The first over-temperature comparison circuit includes: a first high-temperature comparison circuit and a first low-temperature comparison circuit connected to the first temperature acquisition unit, and a first logic circuit connected to the first high-temperature comparison circuit and the first low-temperature comparison circuit respectively; the first high-temperature comparison circuit is used to receive the first real-time temperature information, and output the first over-temperature comparison signal when the first measured object group is too high; the first low-temperature comparison circuit is used to receive the first real-time temperature information, and output the first low-temperature comparison signal to the first logic circuit when the first measured object group is too low; the first logic circuit outputs a shutdown signal to the first switch circuit according to the first over-temperature comparison signal or the first low-temperature comparison signal, so that the first switch circuit shuts down the heating unit according to the shutdown signal; It also includes: a second temperature acquisition unit for acquiring second real-time temperature information of a second measured object group, a second over-temperature comparison circuit connected to the second temperature acquisition unit, and a second switch circuit connected to the second over-temperature comparison circuit, wherein the second switch circuit is also connected to the self-locking circuit and the heating unit respectively; The second over-temperature comparison circuit receives the second real-time temperature information, and outputs a second over-temperature comparison signal to the self-locking circuit and the second switch circuit when the second measured object group is over-temperature, the second switch circuit turns off the heating unit according to the second over-temperature comparison signal, and the self-locking circuit locks the power supply of the second switch circuit according to the second over-temperature comparison signal; It also includes: a control circuit and a third switch circuit; the control circuit is respectively connected to the output end of the first temperature acquisition unit, the output end of the second temperature acquisition unit and the control end of the self-locking circuit, and the third switch circuit is respectively connected to the control circuit and the second end of the heating unit; The control circuit is used to receive the first real-time temperature information and the second real-time temperature information, and output an over-temperature control signal to the third switch circuit and the self-locking circuit when the first measured object group or the second measured object group is over-temperature; The third switch circuit turns off the heating unit according to the over-temperature control signal, and the self-locking circuit locks the power supply of the first switch circuit or the power supply of the second switch circuit according to the over-temperature control signal; The over-temperature protection circuit with a self-locking function has a self-locking function, and the self-locking function is automatically triggered when the temperature is too high.

2. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The first high temperature comparison circuit includes: a first resistor, a second resistor, a third resistor, a fifth resistor, a first capacitor and a first high temperature comparator; The positive input terminal of the first high temperature comparator is connected to the working voltage through the second resistor and is also grounded through the third resistor. The negative input terminal of the first high temperature comparator is connected to the output terminal of the first temperature acquisition unit through the fifth resistor. The first resistor is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator. The first capacitor is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator. The output terminal of the first high temperature comparator is connected to the input terminal of the first switch circuit and the first input terminal of the self-locking circuit.

3. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The first high temperature comparison circuit includes: a first resistor, a second resistor, a third resistor, a fifth resistor, a first capacitor and a first high temperature comparator; the first low temperature comparison circuit includes: a tenth resistor, a thirteenth resistor, a fifteenth resistor, a sixteenth resistor, a second capacitor and a first low temperature comparator; the first logic circuit includes: a first AND gate, a seventh resistor and a ninth resistor; The positive input terminal of the first high temperature comparator is connected to the working voltage through the second resistor and is also grounded through the third resistor. The negative input terminal of the first high temperature comparator is connected to the output terminal of the first temperature acquisition unit through the fifth resistor. The first resistor is connected in parallel between the positive input terminal and the negative input terminal of the first high temperature comparator. The first capacitor is connected in series between the positive input terminal and the negative input terminal of the first high temperature comparator. The output terminal of the first high temperature comparator is connected to the first input terminal of the first AND gate and the first input terminal of the self-locking circuit. The positive input terminal of the first low temperature comparator is connected to the output terminal of the first temperature acquisition unit through the thirteenth resistor, the tenth resistor is connected in parallel to the positive input terminal and the output terminal of the first low temperature comparator, the first low temperature comparator is connected to the working voltage through the sixteenth resistor and is also grounded through the fifteenth resistor, and the output terminal of the first low temperature comparator is connected to the second input terminal of the first AND gate; The power supply end of the first AND gate is connected to the working voltage, the output end of the first AND gate is connected to the input end of the first switch circuit through the ninth resistor, one end of the seventh resistor is connected to the output end of the first AND gate, and the other end is connected to the working voltage.

4. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The first temperature acquisition unit includes: a first temperature sensor and an eighth resistor; A first end of the first temperature sensor is connected to a working voltage, a second end of the first temperature sensor is connected to a first end of the eighth resistor, and a second end of the eighth resistor is grounded; A connection end between the second end of the first temperature sensor and the first end of the eighth resistor is an output end of the first temperature acquisition unit and is connected to the first over-temperature comparison circuit.

5. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The first switch circuit includes: a first triode, a second triode, a third triode, a first relay, a fourth resistor, a sixth resistor, an eleventh resistor, a twelfth resistor, a fourteenth resistor and a first diode; The emitter of the first transistor is connected to the power output of the self-locking circuit as the power input of the first switch circuit, the base of the first transistor is connected to the collector of the second transistor through the sixth resistor, the base of the second transistor is connected to the output of the first over-temperature comparison circuit as the input of the first switch circuit, the eleventh resistor is connected between the base and the emitter of the second transistor, the emitter of the second transistor is grounded, the fourth resistor is connected between the emitter and the base of the first transistor, and the collector of the first transistor is connected to the base of the third transistor through the twelfth resistor; The emitter of the third transistor is grounded, the fourteenth resistor is connected between the base and the emitter of the third transistor, the collector of the third transistor is connected to the second end of the first relay, the anode of the first diode is connected to the second end of the first relay, the cathode of the first diode is connected to the first end of the first relay, the first end of the first relay is connected to the power supply voltage, and the control end of the first relay is respectively connected to the first end of the heating unit and the first end of the AC input power supply.

6. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The second temperature acquisition unit includes: a second temperature sensor and a second resistor; A first end of the second temperature sensor is connected to a working voltage, a second end of the second temperature sensor is connected to a first end of the second fifth resistor, and a second end of the second fifth resistor is grounded; A connection end between the second end of the second temperature sensor and the first end of the second fifth resistor is an output end of the second temperature acquisition unit and is connected to the second over-temperature comparison circuit.

7. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The second over-temperature comparison circuit includes: a second high-temperature comparison circuit connected to the output end of the second temperature acquisition unit, receiving the second real-time temperature information, and outputting the second over-temperature comparison signal when the second measured object group has an over-temperature.

8. The over-temperature protection circuit with self-locking function according to claim 7, characterized in that: The second high temperature comparison circuit includes: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twenty-first resistor, a third capacitor and a second high temperature comparator; The positive input terminal of the second high temperature comparator is connected to the working voltage through the eighteenth resistor and is also grounded through the nineteenth resistor. The negative input terminal of the second high temperature comparator is connected to the output terminal of the second temperature acquisition unit through the twenty-first resistor. The seventeenth resistor is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator. The third capacitor is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator. The output terminal of the second high temperature comparator is connected to the input terminal of the second switch circuit and the second input terminal of the self-locking circuit.

9. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The second over-temperature comparison circuit includes: a second high temperature comparison circuit and a second low temperature comparison circuit connected to the second temperature acquisition unit, and a second logic circuit connected to the second high temperature comparison circuit and the second low temperature comparison circuit respectively; The second high temperature comparison circuit is used to receive the second real-time temperature information and output the second over-temperature comparison signal when the second measured object group is over-temperature; The second low temperature comparison circuit is used to receive the second real-time temperature information and output a second low temperature comparison signal to the second logic circuit when the second measured object group is too low temperature; The second logic circuit outputs a shutdown signal to the second switch circuit according to the second over-temperature comparison signal or the second low-temperature comparison signal, so that the second switch circuit shuts off the heating unit according to the shutdown signal.

10. The over-temperature protection circuit with self-locking function according to claim 9, characterized in that: The second high temperature comparison circuit includes: a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twenty-first resistor, a third capacitor, and a second high temperature comparator; the second low temperature comparison circuit includes: a twenty-eighth resistor, a thirtieth resistor, a thirty-first resistor, a fourth capacitor, a thirty-fourth resistor, and a second low temperature comparator; the second logic circuit includes a second AND gate, a twenty-third resistor, and a twenty-sixth resistor; The positive input terminal of the second high temperature comparator is connected to the working voltage through the eighteenth resistor and is also grounded through the nineteenth resistor. The negative input terminal of the second high temperature comparator is connected to the output terminal of the second temperature acquisition unit through the twenty-first resistor. The seventeenth resistor is connected in parallel between the positive input terminal and the negative input terminal of the second high temperature comparator. The third capacitor is connected in series between the positive input terminal and the negative input terminal of the second high temperature comparator. The output terminal of the second high temperature comparator is connected to the first input terminal of the second AND gate and the second input terminal of the self-locking circuit. The positive input terminal of the second low temperature comparator is connected to the output terminal of the second temperature acquisition unit through the 30th resistor, the positive input terminal of the second low temperature comparator is also connected to its output terminal through the 28th resistor, the negative input terminal of the second low temperature comparator is grounded through the 31st resistor and is also connected to the working voltage through the 34th resistor, the fourth capacitor is connected between the positive input terminal and the negative input terminal of the second low temperature comparator, and the output terminal of the second low temperature comparator is connected to the second input terminal of the second AND gate; The power supply end of the second AND gate is connected to the working voltage, the output end of the second AND gate is connected to the input end of the second switch circuit through the twenty-sixth resistor, one end of the twenty-third resistor is connected to the output end of the second AND gate, and the other end is connected to the working voltage.

11. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The second switch circuit includes: a fourth transistor, a fifth transistor, a sixth transistor, a second relay, a twentieth resistor, a twenty-second resistor, a twenty-ninth resistor, a twenty-fourth resistor, a twenty-seventh resistor and a second diode; The emitter of the fourth transistor is connected to the power output of the self-locking circuit as the power input of the second switch circuit, the base of the fourth transistor is connected to the collector of the sixth transistor through the twenty-second resistor, the twenty-tenth resistor is connected to the emitter and base of the fourth transistor respectively, the emitter of the sixth transistor is grounded, the base of the sixth transistor is connected to the output of the second over-temperature comparison circuit as the input of the second switch circuit, and the base of the sixth transistor is also grounded through the twenty-ninth resistor; The collector of the fourth transistor is connected to the base of the fifth transistor through the twenty-fourth resistor, the base of the fifth transistor is grounded through the twenty-seventh resistor, the emitter of the fifth transistor is grounded, the collector of the fifth transistor is respectively connected to the second end of the second relay and the anode of the second diode, the cathode of the second diode is connected to the first end of the second relay, the first end of the second relay is connected to the power supply voltage, and the control end of the second relay is respectively connected to the second end of the heating unit and the second end of the AC input power supply.

12. The over-temperature protection circuit with self-locking function according to claim 1, characterized in that: The control circuit includes a controller; the third switch circuit includes: a thirty-third resistor, a seventh transistor, a thirty-sixth resistor, a thirty-eighth resistor, a photocoupler, a thirty-second resistor, a thirty-fifth resistor, a thyristor, and a varistor; The first acquisition end of the controller is connected to the output end of the first temperature acquisition unit through a thirty-seventh resistor, the second acquisition end of the controller is connected to the output end of the second temperature acquisition unit through a forty-sixth resistor, the first control end of the controller is connected to the second end of the thirty-sixth resistor, and the second control end of the controller is connected to the control end of the self-locking circuit; The first end of the thirty-sixth resistor is connected to the base of the seventh transistor, the thirty-eighth resistor is respectively connected to the base of the seventh transistor and the ground, the emitter of the seventh transistor is grounded, the collector of the seventh transistor is connected to the second end of the photoelectric coupler, and the first end of the photoelectric coupler is connected to the working voltage through the thirty-third resistor; The third end of the photoelectric coupler is connected to the control end of the thyristor through the thirty-second resistor, the first end of the thyristor is connected to the second end of the AC power supply, the second end of the thyristor is connected to the first end of the thirty-fifth resistor and the second end of the heating unit, the second end of the thirty-fifth resistor is connected to the fourth end of the photoelectric coupler, the first end of the varistor is connected to the first end of the thyristor and the second end of the AC power supply, and the second end of the varistor is connected to the second end of the heating unit.

13. The over-temperature protection circuit with self-locking function according to claim 12, characterized in that: The self-locking circuit includes: a third AND gate, a thirty-ninth resistor, a forty-second resistor, a forty-first resistor, a forty-fourth resistor, a tenth transistor, a ninth transistor, a fourth diode, a fortieth resistor, a third diode, a fifth diode, a forty-third resistor, an eighth transistor, an electrolytic capacitor, a seventh capacitor and a sixth capacitor; The first input end of the third AND gate is connected to the output end of the first over-temperature comparison circuit and the output end of the second over-temperature comparison circuit as the first input end of the self-locking circuit, the power supply end of the third AND gate is connected to the working voltage, the thirty-ninth resistor is respectively connected to the working voltage and the output end of the third AND gate, and the output end of the third AND gate is connected to the base of the ninth transistor through the forty-second resistor and the forty-first resistor in sequence; The emitter of the ninth triode is connected to the working voltage, the collector of the ninth triode is connected to the anode of the fourth diode, the collector of the tenth triode is connected between the forty-first resistor and the forty-second resistor, the emitter of the tenth triode is grounded, and the base of the tenth triode is respectively connected to the collector of the ninth triode and the anode of the fourth diode through the forty-fourth resistor; The cathode of the fourth diode is connected to the cathode of the third diode, the anode of the third diode is connected to the cathode of the fifth diode, the anode of the fifth diode is respectively connected to the base of the eighth transistor and the second end of the forty-third resistor, the first end of the forty-third resistor and the emitter of the eighth transistor are connected to the working voltage, the collector of the eighth transistor is respectively connected to the first end of the electrolytic capacitor and the first end of the seventh capacitor, the second end of the electrolytic capacitor and the second end of the seventh capacitor are grounded, and the first end of the electrolytic capacitor is connected to the power input end of the first switch circuit and the power input end of the second switch circuit as the power output end of the self-locking circuit; The first end of the 40th resistor is connected to the cathode of the third diode, the second end of the 40th resistor is connected to the first end of the sixth capacitor, the second end of the sixth capacitor is grounded, and the connection end between the second end of the 40th resistor and the first end of the sixth capacitor is connected to the second control end of the controller as the control end of the self-locking circuit.

14. A heating device, characterized in that: The invention comprises an over-temperature protection circuit with a self-locking function as described in any one of claims 1 to 13.

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