Disclosure of Invention
The invention provides a temperature detection circuit for solving the problems, which comprises a power input end and a grounding end, wherein a reference circuit and a strain circuit which are connected in parallel are arranged between the power input end and the grounding end, the reference circuit comprises a first resistor and a second resistor which are connected in series, a reference contact is arranged between the first resistor and the second resistor, the strain circuit comprises a third resistor and a thermistor which are connected in series, and a diode of which the cathode is connected with the strain contact, the strain contact is arranged between the third resistor and the thermistor, the anode of the diode is connected with the reference contact, and when the diode is conducted, the second resistor is connected with the thermistor in parallel.
Preferably, the thermistor is a negative temperature coefficient thermistor.
Preferably, the first resistor and/or the second resistor are adjustable resistors.
Preferably, the detection circuit further comprises a plurality of strain circuits connected in parallel with the reference circuit.
The invention also provides a temperature detection control system, which comprises the temperature detection circuit, a voltage detection unit and a temperature controller, wherein the voltage detection unit detects the voltage of the reference contact, and transmits a detection result signal to the temperature controller.
And the temperature detection control device comprises a wire module, a reference module, a detection module, a voltage detection unit and a temperature controller, wherein the reference module comprises a reference circuit, the detection module comprises a strain circuit, the wire module comprises three wires, a first wire and a third wire are used for connecting a power input end and a grounding end of the reference circuit and the strain circuit, a second wire is connected with a reference contact and a diode anode, the voltage detection unit detects the voltage of the reference contact, and the voltage detection unit transmits a detection result signal to the temperature controller.
Preferably, the wire module is a flexible circuit board.
Preferably, the wire module is a wire harness.
Preferably, the detection module is provided with a heat conducting sheet connected with the thermistor.
Preferably, the temperature controller further comprises another group of wire modules, a reference module, a detection module and voltage detection units, and the two voltage detection units transmit detection result signals to the temperature controller.
The invention has the following beneficial effects: the temperature detection circuit is provided, the temperature detection of the planar heating product is realized by matching a simple series-parallel resistor circuit with a diode and the temperature change induction of a thermistor, and the production cost can be well controlled; meanwhile, the temperature detection control system and device are provided, the installation is convenient, and the production and processing difficulty is low.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.
In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
As shown in fig. 1 to 5, a temperature detection circuit includes a power input terminal and a ground terminal, a reference circuit 10 and a strain circuit 20 are disposed between the power input terminal and the ground terminal in parallel, the reference circuit 10 includes a first resistor 11 and a second resistor 12 connected in series, a reference contact 13 is disposed between the first resistor 11 and the second resistor 12, the strain circuit 20 includes a third resistor 21 and a thermistor 22 connected in series and a diode 23 having a cathode connected to a strain contact 24, the strain contact 24 is disposed between the third resistor 21 and the thermistor 22, an anode of the diode 23 is connected to the reference contact 13, when the diode 23 is turned on, the second resistor 12 is connected in parallel to the thermistor 22, the thermistor 22 is a negative temperature coefficient thermistor, such as a ceramic thermistor, the thermistor 22 increases in temperature, decreases in resistance, decreases in potential at the strain contact 24, when the voltage difference between the reference contact 13 and the strain contact 24 reaches the value of conducting the diode 23, the diode 23 is conducted, the thermistor 22 is connected in parallel with the second resistor 12, the first resistor 11 is connected in series with the thermistor 22 and the second resistor 12 which are connected in parallel, the resistance after the series connection is lower than the resistance value of the second resistor 12, at this time, the potential difference between the reference contact 13 and the ground potential is correspondingly reduced, namely, the voltage is reduced to form a link with the temperature rise, the link between the voltage and the temperature rise can be obtained through limited experiments or physical quantity deduction, so that the temperature detection is realized, the specific experimental process or the deduction means is the prior art, and details are not repeated herein.
Preferably, the first resistor 11 and/or the second resistor 12 are adjustable resistors, that is, the two resistors connected in series on the reference circuit 10 can adjust the voltage dividing capability of the two resistors, that is, adjust the potential at the reference contact 13, the potential at the reference contact 13 is an important influence factor for determining the conduction of the diode 23, for the same group of products, the higher the potential at the reference contact 13 is, the less the potential at the strain contact 24 required for conducting the diode 23 is reduced, the higher the sensitivity to temperature is, and vice versa, and corresponding adjustment can be performed for different application scenarios of the heat-generating product, so that the application range of the temperature detection circuit is wider, and a production operator can widen the market and bring greater economic value.
Preferably, the detection circuit further comprises a plurality of strain circuits 20 connected in parallel with the reference circuit 10, the plurality of strain circuits 20 realize multipoint detection, and the added strain circuits 20 are only two resistors, so that cost can be well controlled, and the practicability of the strain circuits is enhanced.
The invention also provides a temperature detection control system, which comprises the temperature detection circuit, a voltage detection unit and a temperature controller, wherein the voltage detection unit detects the voltage of the reference contact 13, the voltage detection unit transmits a detection result signal to the temperature controller, the voltage detection unit detects the potential at the reference contact 13 by taking the earth potential as the reference, namely the voltage at two ends of the second resistor 12 is detected, the voltage at two ends after the second resistor 12 and the thermistor 22 are connected in parallel is detected after the diode 23 is conducted, a voltage change signal caused by temperature change is transmitted to the temperature controller, the temperature controller carries out corresponding temperature control according to the voltage change, for example, when a high temperature point appears and ignition is possibly caused, the power supply is cut off, and the like And the third resistor and the thermistor realize temperature detection.
The design can also be carried out by adopting a positive temperature coefficient thermistor, the anode strain contact 24 of the diode 23 is connected, the cathode is connected with the reference contact 13, the temperature of the thermistor 22 rises, the resistance rises, the potential at the strain contact 24 correspondingly rises, the potential difference between the strain contact 24 and the reference contact 13 reaches the critical value of the conducting diode 23, the diode 23 is conducted, the first resistor 11 and the third resistor 22 are connected in series 12 after being connected in parallel, the potential at the reference contact 13 changes, if the voltage detection unit detects the voltage of two sections of the parallel circuit of the first resistor 11 and the third resistor 21 by taking the potential at the power supply input end as the reference, the voltage is reduced, and if the voltage detection unit detects the voltage at two ends of the second resistor 12 by taking the earth potential as the reference, the voltage is increased.
The voltage change at the reference contact 13 detected by the voltage detection unit is caused by the conduction of the diode 23, that is, the conduction condition of the diode 23 is reached, and the potential change of the strain contact 24 is caused by the resistance change of the thermistor 22 caused by the temperature rise of the heating element, so that the detection system firstly detects the highest temperature of the heating element.
For a temperature detection system, in order to improve the accuracy of temperature measurement, the actual temperature of each measurement point can be tested to be compared with the temperature detected by the temperature detection control system, and corresponding calibration is provided by a software algorithm, for example, if the deviation between the actual temperature and the detected temperature is positive and the deviation values of the actual temperature and the detected temperature are close to each other in different temperature ranges, corresponding compensation is directly performed; if the deviation amounts are different in different temperature ranges, differential compensation can be performed in different temperature ranges, that is, a proper compensation calculation method is selected by summarizing the rule of the difference between the actual temperature and the detected temperature, different influence factors can be differentially compensated, the aim is to improve the accuracy of temperature detection, and certainly, control and correction can be performed by an external correction circuit.
One embodiment is as follows: the voltage of 5V is input at the power input end, the resistance values of the first resistor 11 and the second resistor 12 are adjusted, the potential difference between the reference contact 13 and the ground is 3.6V, the conduction voltage of the diode 23 is 1.6V, when the temperature of the thermistor 22 is 40 ℃, the potential difference between the strain contact 24 and the ground is 2V, and the diode 23 is conducted at the moment.
And the temperature detection control device comprises a wire module, a reference module 40, a detection module 50, a voltage detection unit and a temperature controller, wherein the reference module 40 comprises a reference circuit 10, the detection module 50 comprises a strain circuit 20, the wire module comprises three wires, a first wire 31 and a third wire 33 are used for connecting a power input end and a grounding end of the reference circuit 10 and the strain circuit 20, a second wire 32 is connected with a reference contact 13 and an anode of a diode 23, the voltage detection unit detects the voltage of the reference contact 13, and the voltage detection unit transmits a detection result signal to the temperature controller.
The first wire 31 is used as a wire of a power input end to provide power input for the reference circuit 10 and the strain circuit 20, the third wire 33 is used as a grounding end connecting wire, and the grounding ends of the reference circuit 10 and the strain circuit 20 form a common ground through the third wire 33, so that the ground wire of a heating product can be directly accessed, the product installation and assembly process is simplified, and the production efficiency is improved.
The components of the temperature detection circuit are made into modules, so that on one hand, the production and processing are convenient, the requirements of assembly line operation are met, the requirements of manual intervention are reduced, a production operator can only produce corresponding modules, can be independent of manufacturers such as electric blankets, heating pads and the like, and can provide original components as the suppliers according to the requirements, and the manufacturers of heating products purchase the modules of a complete set or part of temperature detection control devices to carry out simple assembly so as to complete the production; on the other hand is convenient for maintain, and the part breaks down, only need through finished product module change can.
Preferably, the lead module is a flexible circuit board 30, and the reference circuit 10 and the strain circuit 20 in the reference module 40 and the detection module 50 are respectively provided with a corresponding welding head at each connection point, for example, the welding heads are respectively arranged at the ends of the first resistor 11 and the second resistor 12 for connecting with the first lead 31 and the third lead 33, and one welding head is led out from the reference contact 13 for welding with the second lead 32; the ends of the third resistor 21 and the thermistor 22 are respectively provided with a welding head for connecting with the first lead 31 and the third lead 33, the anode end of the diode 23 is led out to form a welding head for connecting with the second lead 32, and the flexible circuit board 30 has the characteristics of light weight, thin thickness, free bending and folding and good heat dissipation, is applied to the circuit connection of the temperature detection control device, and is arranged by multi-point detection, so that the robustness of the whole temperature detection control system is improved.
As a preferred scheme, the wire module is a wire harness, three wires are arranged in the form of the wire harness, the reference module 40 and the detection module 50 are hung on the wire harness, and then the assembly can be completed, for example, pins are respectively led out at the first resistor 11, the second resistor 12 and the reference contact 13, and the insulating layer of the wire harness is directly pierced to complete the circuit connection, so that the plasticity of the wire harness is extremely strong, and the requirement of arranging the measuring points at any position can be met.
The graphene electric heating product is different from the traditional electric heating wire electric heating product, the graphene heating principle is based on the characteristic of single-layer graphene, under the condition that electrodes at two ends of a graphene heating film are electrified, carbon molecules in the electric heating film generate phonons, ions and electrons in a resistor, heat energy is generated by mutual friction and collision (also called Brownian motion) between generated carbon molecular groups, the heating is more uniform, the temperature control can be more refined, the temperature detection control device is applied to the graphene electric heating product and used as the condition for controlling the temperature of the graphene electric heating product, the further market of the Xinxing product is facilitated, and the development of the electric heating product industry is promoted.
Preferably, the detection module 50 is provided with a heat conduction sheet connected with the thermistor 22, for the whole temperature detection control device, the accuracy and timeliness of temperature detection determine that the whole control system effectively and accurately responds, the thermistor 22 is provided with the heat conduction sheet, the capability of the thermistor 22 for sensing temperature changes nearby the thermistor is enhanced, the sensitivity of system response is improved, the heat conduction sheet can be in a form of covering the thermistor 22, for example, metal with good heat conductivity and the like, the arrangement positions of other elements do not substantially influence temperature detection, the structure of the thermistor 22 for sensing temperature changes can be expanded as much as possible, and the heat conduction sheet can even directly cover the whole detection module 50.
The device has the advantages that the metal or nonmetal heat conduction layer or the graphene composite material heat conduction layer is added, heat conduction and simultaneous detection are carried out on planar heating, the device can play a role in overall monitoring, the heat conduction layer is specifically arranged to transfer heat to the thermistor, for example, a single heat conduction layer is set to be 20cm multiplied by 20cm, and the whole planar heating product is covered and monitored; the setting size of a single heat conduction layer can be determined according to the temperature drop change of the heat conduction layer material, the smaller the drop is, the larger the coverage area of the single heat conduction layer can be set, and the factors such as the influence of the size of the heat conduction layer on the comfort level of a heating product can also be used as reference conditions.
The surface of the heat conducting sheet is coated with the graphene in a rolling mode, so that the omnidirectional heat conduction is realized, the detection is more comprehensive, the directivity of the heat conducting sheet does not need to be considered during installation, the requirement on a production line is reduced, special production equipment does not need to be provided, and the production cost and threshold of an enterprise are reduced.
Preferably, the temperature controller further comprises another group of wire modules, a reference module 40, a detection module 50 and voltage detection units, and the two voltage detection units transmit detection result signals to the temperature controller.
Two groups of wire modules, a reference module 40, detection modules 50 and voltage detection units are arranged in parallel, for example, interdigital measurement points are arranged, two detection modules 50 are arranged near the same detection point, the detection modules 50 can be grouped by adjusting the conduction voltage parameter of the diode 23, the voltage detection signal results of the detection modules 50 of the same group jointly determine the control logic of the temperature controller, and the control strategy of logical AND is adopted to avoid the false detection and the false operation caused by the characteristic drift of components; the measuring point intervals of the plurality of detection modules can be set at random, for example, the intervals are 5cm, 10cm and 15cm, and corresponding adjustment can be carried out according to the characteristics of the heating product, so that the intervals are larger or smaller.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.