CN214621521U - PTC electric heating piece detection circuit and electric blanket - Google Patents
PTC electric heating piece detection circuit and electric blanket Download PDFInfo
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- CN214621521U CN214621521U CN202120433867.1U CN202120433867U CN214621521U CN 214621521 U CN214621521 U CN 214621521U CN 202120433867 U CN202120433867 U CN 202120433867U CN 214621521 U CN214621521 U CN 214621521U
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Abstract
The utility model relates to an electric warming appliance field discloses a PTC electric heating element detection circuitry and electric blanket. The PTC electric heating piece detection circuit comprises a PTC electric heating piece, a thermistor, a voltage detection circuit, a first switch circuit and a controller, wherein the controller is respectively connected with the first switch circuit and the voltage detection circuit, the voltage detection circuit is connected with two ends of the thermistor, the first switch circuit is used for switching on or off the connection between the PTC electric heating piece and the controller, when the first switch circuit is switched on through the controller to switch on the connection between the PTC electric heating piece and the controller, a preset voltage output by the controller is applied to the PTC electric heating piece, and then the controller is used for judging whether the voltage detection circuit detects the voltage at two ends of the thermistor, so that whether the PTC electric heating piece and the thermistor are short-circuited or not is judged.
Description
Technical Field
The utility model relates to a warm utensil technical field of electricity, especially relate to a PTC electric heat spare detection circuitry and electric blanket.
Background
PTC electric heating elements, such as PTC electric heating sheets, are electric heating elements that convert electric energy into heat energy, and thus are widely used in electric heating appliances such as electric blankets. In the application of the PTC heaters, the PTC heaters are usually heated by applying commercial power, and the temperature of the PTC heaters will rise continuously when the commercial power is continuously applied. Since it is not desirable that the PTC electric heating element is overheated and temperature control of the PTC electric heating element is to be achieved, it is usually necessary to add a temperature measuring circuit to detect the temperature of the PTC electric heating element, for example, the thermistor is in close contact with the PTC electric heating element and the thermistor and the PTC electric heating element are isolated by an insulating material, so that the temperature of the PTC electric heating element can be detected by the thermistor in real time and accurately and fed back to the temperature control system instantly, and then the temperature control system controls the commercial power to be applied to the PTC electric heating element in a preset manner according to the temperature condition, so that the temperature of the PTC electric heating element is controlled, or the temperature is controlled within a preset range.
Because the thermistor and the PTC electric heating piece are in close contact and are only isolated by the insulating material, when some factors cause the thermistor and the PTC electric heating piece to be in direct contact, the thermistor and the PTC electric heating piece are electrically connected, at the moment, the thermistor and the PTC electric heating piece are in short circuit, and the situation of burning out internal elements is easily caused during short circuit, even a fire disaster is caused, and unnecessary loss is caused. Therefore, in practical applications, it is required to have a short-circuit detection function, so that when the thermistor and the PTC electric heating element are found to be short-circuited, corresponding protection measures can be taken in time to avoid unnecessary loss.
At present, whether a power grid signal exists on a thermistor is detected through voltage division by a singlechip to detect whether the thermistor is short-circuited with a PTC electric heating piece, namely: when the thermistor and the PTC electric heating piece are short-circuited, a power grid signal on the thermistor can be detected, and when the thermistor and the PTC electric heating piece are not short-circuited, a power grid signal on the thermistor can be detected. However, this kind of detection method has some disadvantages, on one hand, because the AD sampling port of the single chip can only be input with a voltage lower than 5V, then, because there is a power grid signal at both ends of the thermistor, it is necessary to be able to divide the power grid signal to within 5V, so that the single chip can normally detect, and there is a huge difference in the voltage at both ends of the thermistor in two cases without the power grid signal, so when there is no power grid signal on the thermistor, the voltage detected by the single chip is extremely low, thereby affecting the detection accuracy; on the other hand, when the temperature of the PTC electric heating element is high, the internal resistance of the thermistor is low, and at the moment, even if the thermistor and the PTC electric heating element are not short-circuited, the voltage at two ends of the thermistor is close to the voltage of a power grid, so that the detection result obtained by the single chip microcomputer is inconsistent with the actual situation, and misjudgment is caused.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, an embodiment of the utility model provides a PTC electric heating element detection circuitry and electric blanket can solve among the prior art and have no electric wire netting voltage to judge PTC electric heating element and thermistor short circuit through detecting the thermistor both ends when, detects the technical problem that the precision is low or the testing result is inconsistent with actual conditions.
The embodiment of the utility model provides a for solving above-mentioned technical problem provides following technical scheme:
in a first aspect, an embodiment of the present invention provides a PTC electrical heating element detection circuit, including a PTC electrical heating element, a thermistor, a voltage detection circuit, a first switch circuit, and a controller; the PTC electric heating piece comprises a first end and a second end, wherein the first end of the PTC electric heating piece is used for being applied with commercial power, the second end of the PTC electric heating piece is used for being grounded, and the PTC electric heating piece is used for being applied with the commercial power for heating; the voltage detection circuit is connected with the thermistor and is used for detecting the voltage at two ends of the thermistor; the first switch circuit is respectively connected with the first end of the PTC electric heating piece and the controller and is used for switching on or off the connection between the first end of the PTC electric heating piece and the controller; the controller is respectively connected with the first switch circuit and the voltage detection circuit, and is used for controlling the on and off of the first switch circuit and applying a preset voltage to the first end of the PTC electric heating piece when controlling the on of the first switch circuit.
In some embodiments, the first switching circuit comprises a first optocoupler and a first resistor; the first optocoupler comprises a first bidirectional thyristor and a first light-emitting diode; one end of the first bidirectional controllable silicon is connected with the first end of the PTC electric heating piece, the other end of the first bidirectional controllable silicon is connected with the controller, the anode of the first light emitting diode is connected with one end of the first resistor, the other end of the first resistor is connected with the controller, and the cathode of the first light emitting diode is used for grounding.
In some embodiments, a second switching circuit is also included; the second switch circuit is used for being respectively connected with a power grid, the first end of the PTC electric heating piece and the controller and is used for switching on or switching off the connection between the power grid and the first end of the PTC electric heating piece.
In some embodiments, a third switching circuit is further included; the third switch circuit is used for being respectively connected with the auxiliary power supply, the controller and the voltage detection circuit.
In some embodiments, the third switch circuit comprises a PMOS transistor, a second resistor, and a third resistor; one end of the second resistor and a source electrode of the PMOS tube are used for being connected with an auxiliary power supply, the other end of the second resistor, a grid electrode of the PMOS tube and one end of the third resistor are connected together, the other end of the third resistor is connected with the controller, and a drain electrode of the PMOS tube is connected with the voltage detection circuit.
In some embodiments, the voltage detection circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first operational amplifier and a capacitor; one end of the fourth resistor is connected with the drain electrode of the first PMOS tube, the other end of the fourth resistor, one end of the fifth resistor and one end of the thermistor are connected together, the other end of the fifth resistor, one end of the sixth resistor and the non-inverting input end of the first operational amplifier are connected together, the other end of the sixth resistor is used for grounding, the inverting input end of the first operational amplifier, one end of the seventh resistor and one end of the eighth resistor are connected together, the other end of the seventh resistor is connected with the other end of the thermistor, the other end of the eighth resistor, the output end of the first operational amplifier and one end of the ninth resistor are connected together, the other end of the ninth resistor, one end of the capacitor and the controller are connected together, and the other end of the capacitor is used for grounding.
In some embodiments, the voltage detection circuit further comprises a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a second operational amplifier; one end of the tenth resistor, one end of the eleventh resistor and one end of the seventh resistor are commonly connected, the other end of the tenth resistor is used for grounding, the other end of the eleventh resistor is connected with the non-inverting input end of the second operational amplifier, the inverting input end of the operational amplifier, one end of the twelfth resistor and one end of the thirteenth resistor are commonly connected, the other end of the twelfth resistor is used for grounding, the other end of the thirteenth resistor, the output end of the second operational amplifier and one end of the fourteenth resistor are connected, and the other end of the fourteenth resistor is connected with the controller.
In some embodiments, the second switching circuit comprises a control terminal, a first terminal, and a second terminal; the first end of the second switch circuit is used for being connected with a power grid, the second end of the second switch circuit is connected with the first end of the PTC electric heating piece, and the control end of the second switch circuit is connected with the controller.
In some embodiments, the second switching circuit comprises a second triac, a second optocoupler, a fifteenth resistor, and a sixteen resistor; the second bidirectional controllable silicon comprises a control end, a first end and a second end, and the second optocoupler comprises a third bidirectional controllable silicon and a second light-emitting diode; the control end of the second bidirectional controllable silicon is connected with one end of the third bidirectional controllable silicon, the first end of the second bidirectional controllable silicon is used for being connected with a power grid and one end of the fifteenth resistor respectively, the second end of the second bidirectional controllable silicon is connected with the first end of the PTC electric heating element, the other end of the third bidirectional controllable silicon is connected with the other end of the fifteenth resistor, the anode of the second light-emitting diode is connected with one end of the sixteenth resistor, the other end of the sixteenth resistor is connected with the controller, and the cathode of the second light-emitting diode is used for being grounded.
In a second aspect, the present invention provides an electric blanket comprising the PTC electric heating element detection circuit as described above.
The embodiment of the utility model provides a beneficial effect is: different from the related technology, the PTC electric heating element detection circuit and the electric blanket are provided. The PTC electric heating piece detection circuit comprises a PTC electric heating piece, a thermistor, a voltage detection circuit, a first switch circuit and a controller, wherein the controller is respectively connected with the first switch circuit and the voltage detection circuit, the voltage detection circuit is connected with two ends of the thermistor, the first switch circuit is used for switching on or off the connection between the PTC electric heating piece and the controller, when the first switch circuit is switched on through the controller to switch on the connection between the PTC electric heating piece and the controller, a preset voltage output by the controller is applied to the PTC electric heating piece, and then the controller is used for judging whether the voltage detection circuit detects the voltage at two ends of the thermistor, so as to judge whether the PTC electric heating piece and the thermistor are short-circuited.
Drawings
The embodiments are illustrated by way of example only in the accompanying drawings, in which like reference numerals refer to similar elements and which are not to be construed as limiting the embodiments, and in which the figures are not to scale unless otherwise specified.
Fig. 1 is a schematic structural diagram of a detection circuit for a PTC electrical heating element according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a detection circuit for a PTC electrical heating element according to another embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of a first switch circuit provided in FIG. 1;
fig. 4 is a schematic circuit diagram of a circuit for detecting PTC electrical heating elements according to an embodiment of the present invention.
Detailed Description
To facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and detailed description. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a detection circuit for a PTC electrical heating element according to an embodiment of the present invention. As shown in fig. 1, the PTC electrical heating element detection circuit 100 includes a PTC electrical heating element 10, a thermistor 20, a voltage detection circuit 30, a first switching circuit 40, and a controller 50.
The PTC electric heating element 10 includes a first end 10a and a second end 10b, the first end 10a of the PTC electric heating element 10 is connected to a power grid through a wire, so that a commercial power can be applied, the second end 10b of the PTC electric heating element is grounded through a wire, and when the commercial power is applied to the first end 10a of the PTC electric heating element 10, the PTC electric heating element 10 itself converts electric energy into heat energy, so that heating can be performed.
The thermistor 20 is a temperature sensitive element, and when the thermistor 20 senses different temperatures, the resistance value thereof will change, and the change of the resistance value has a predetermined relationship with the change of the temperature, so that when the thermistor 20 is used as one of the voltage dividing resistors connected in series in a loop, then when a fixed voltage is applied to the loop, the resistance value of the thermistor 20 can be calculated by detecting the voltage across the thermistor 20, and then the temperature of the thermistor 20 can be converted according to a relationship table between the resistance value and the temperature. The present embodiment can detect the temperature of the PTC heaters 10 through the thermistor 20 (the wires of both the thermistor 20 and the PTC heaters 10 are in close contact and separated by an insulating material, independently from each other), but is not limited thereto. In some embodiments, the thermistor 20 is a Negative Temperature Coefficient (NTC) thermistor, which is a thermistor having a Negative Temperature Coefficient with an exponentially decreasing resistance to Temperature rise.
The voltage detection circuit 30 is connected to the thermistor 20 and the controller 50, respectively, and the voltage detection circuit 30 can detect the voltage across the thermistor 20 and output a voltage signal corresponding to the voltage to a sampling port of the controller 50, so that the controller 50 can convert the temperature information from the received voltage signal, but the present embodiment is not limited thereto, and the controller 50 can also be used for other detection, such as short circuit detection, from the received voltage signal.
The first switching circuit 40 is connected between the first end 10a of the PTC electrothermal device 10 and the controller 50, and is controlled by the controller 50: when the controller 50 applies a preset voltage (for example, 5V) to the first switching circuit 40, the first switching circuit 40 is turned on, so as to connect the first end 10a of the PTC electric heating element 10 to the controller 50, and at this time, the preset voltage output by the controller 50 is applied to the first end 10a of the PTC electric heating element 10 through the first switching circuit 40; when the controller 50 does not apply the preset voltage to the first switching circuit 40, the first switching circuit 40 is turned off, thereby turning off the connection of the first end 10a of the PTC electrothermal device 10 to the controller 50.
The controller 50 may be any general purpose processor, Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), single chip, arm (acorn RISC machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. Also, the controller 50 may be any conventional processor, controller, microcontroller, or state machine. The controller 50 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP, and/or any other such configuration.
In the present embodiment, when detecting a short circuit between the PTC electrical heating element 10 and the thermistor 20, the commercial power is controlled not to be applied to the first end 10a of the PTC electrical heating element 10, at this time, no current flows through the PTC electrical heating element 10, then the first switching circuit 40 is controlled to be turned on, at this time, a preset voltage output by the controller 50 is applied to the first end 10a of the PTC electrical heating element 10, so that a current flows through the PTC electrical heating element 10, and if the PTC electrical heating element 10 and the thermistor 20 are short-circuited, a current flows through the thermistor 20, conversely, if the PTC electrical heating element 10 and the thermistor 20 are not short-circuited, no current flows through the thermistor 20, and thus, whether a voltage is present at both ends of the thermistor 20 is detected by the voltage detection circuit 30 (if a voltage is detected, the controller 50 receives a corresponding voltage signal), so that whether a current flows through the thermistor 20 can be detected, and then, it is determined whether the PTC electrical heating elements 10 and the thermistor 20 are short-circuited.
Therefore, the present embodiment can conveniently and effectively detect whether the PTC electrical heating element 10 and the thermistor 20 are short-circuited, and take corresponding protection measures in time when detecting the short-circuit, thereby avoiding unnecessary loss.
In some embodiments, as shown in fig. 2, the first switch circuit 40 includes a first optical coupler OPT1 and a first resistor R1, wherein the first optical coupler OPT1 includes a first triac T1 and a first light emitting diode D1. One end of the first triac T1 is connected to the first end 10a of the PTC electric heating element 10, the other end of the first triac T1 is connected to the controller 50, the anode of the first light emitting diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the controller 50, and the cathode of the first light emitting diode D1 is grounded. The first triac T1 and the first resistor R1 may be connected to the same IO port of the controller 50, or may not be connected to the same IO port of the controller 50.
In this embodiment, the first triac T1 and the first resistor R1 are connected to the same IO port of the controller 50, and when a preset voltage is inputted to the IO port of the controller 50, the preset voltage is applied between the anode and the cathode of the first led D1, so that the first led D1 has current flowing through it to emit light, and the first triac T1 is turned on after receiving light, and then the preset voltage is applied to the first end 10a of the PTC heater 10 through the first triac T1. It is understood that when the IO port of the controller 50 does not input a preset voltage, the first triac T1 is turned off.
In some embodiments, the first optocoupler OPT1 is model MOC 3021.
In some embodiments, as shown in fig. 3, the PTC thermistor detection circuit 100 further includes a second switch circuit 60. The second switch circuit is used for being connected with an electric network, the first end 10a of the PTC electric heating element 10 and the controller 50 respectively, and is used for switching on or off the connection between the electric network and the first end 10a of the PTC electric heating element 10 under the control of the controller 50.
Specifically, as shown in fig. 3, the second switch circuit 60 includes a control terminal 60a, a first terminal 60b and a second terminal 60 c. The first end 60b of the second switch circuit 60 is connected to the power grid, the second end 60c of the second switch circuit 60 is connected to the first end 10a of the PTC electrothermal element 10, and the control end 60a of the second switch circuit 60 is connected to the controller 50. It is worth mentioning that the second switching circuit 60 may comprise any suitable controllable switching component, such as a transistor switch or the like.
In some embodiments, as shown in fig. 4, the second switch circuit 60 includes a second triac T2, a second optical coupler OPT2, a fifteenth resistor R15 and a sixteen resistor R16, wherein the second triac T2 includes a control terminal G, a first terminal and a second terminal, and the second optical coupler OPT2 includes a third triac T3 and a second light emitting diode D2.
The control end G of the second bidirectional thyristor T2 is connected with one end of a third bidirectional thyristor T3, the first end of the second bidirectional thyristor T2 is respectively connected with the power grid and one end of a fifteenth resistor R15, the second end of the second bidirectional thyristor T2 is connected with the first end 10a of the PTC electric heating element 10, the other end of the third bidirectional thyristor T3 is connected with the other end of a fifteenth resistor R15, the anode of the second light-emitting diode D2 is connected with one end of a sixteenth resistor R16, the other end of the sixteenth resistor R16 is connected with the controller 50, and the cathode of the second light-emitting diode D2 is grounded.
In this embodiment, when the IO port of the controller 50 connected to one end of the sixteenth resistor R16 outputs a high level, the third triac T3 is turned on, so that the second triac T2 is turned on, at this time, the power grid is connected to the first end 10a of the PTC electric heating element 10, and the PTC electric heating element 10 is heated by the commercial power. It is understood that when the IO port of the controller 50 outputs a low level, both the third triac T3 and the second triac T2 are turned off.
In some embodiments, the second optocoupler OPT2 is model MOC 3021.
Referring to fig. 3 again, in some embodiments, the PTC thermistor detection circuit 100 further includes a third switch circuit 70. The third switch circuit 70 is connected to the auxiliary power source VCC, the controller 50, and the voltage detection circuit 30, respectively.
Specifically, as shown in fig. 4, the third switch circuit 70 includes a PMOS transistor Q1, a second resistor R2, and a third resistor R3. One end of the second resistor R2 and the source of the PMOS transistor Q1 are both connected to the auxiliary power source VCC, the other end of the second resistor R2, the gate of the PMOS transistor Q1 and one end of the third resistor R3 are commonly connected, the other end of the third resistor R3 is connected to the controller 50, and the drain of the PMOS transistor Q1 is connected to the voltage detection circuit 30.
In this embodiment, when the IO port of the controller 50 connected to one end of the third resistor R3 outputs a high level, the PMOS transistor Q1 is turned off, and when the IO port outputs a low level, the PMOS transistor Q1 is turned on, and at this time, the voltage of the auxiliary power VCC is applied to the voltage detection circuit 30 through the PMOS transistor Q1.
In some embodiments, as shown in fig. 4, the voltage detection circuit 30 includes a first operational amplifier a1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a capacitor C1.
One end of a fourth resistor R4 is connected to the drain of the PMOS transistor Q1, the other end of the fourth resistor R4, one end of the fifth resistor R5 and one end of the thermistor 20 are connected together, the other end of the fifth resistor R5, one end of the sixth resistor R6 and the non-inverting input terminal of the operational amplifier a1 are connected together, the other end of the sixth resistor R6 is grounded, the inverting input terminal of the operational amplifier a1, one end of the seventh resistor R7 and one end of the eighth resistor R8 are connected together, the other end of the seventh resistor R7 is connected to the other end of the thermistor 20, the other end of the eighth resistor R8, the output terminal of the operational amplifier a1 and one end of the ninth resistor R9 are connected together, the other end of the ninth resistor R9, one end of the capacitor C1 and the controller 50 are connected together, and the other end of the capacitor C1 is grounded.
In some embodiments, as shown in fig. 4, the voltage detection circuit 30 further includes a second operational amplifier a2, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14.
One end of a tenth resistor R10, one end of an eleventh resistor R11 and one end of a seventh resistor R7 are commonly connected, the other end of the tenth resistor R10 is grounded, the other end of the eleventh resistor R11 is connected to the non-inverting input terminal of the second operational amplifier a2, the inverting input terminal of the second operational amplifier a2, one end of the twelfth resistor R12 and one end of the thirteenth resistor R13 are commonly connected, the other end of the twelfth resistor R12 is grounded, the other end of the thirteenth resistor R13, the output terminal of the second operational amplifier a2 and one end of the fourteenth resistor R14 are connected, and the other end of the fourteenth resistor R14 is connected to the controller 50.
The working process of the embodiment of the present invention will be described in detail with reference to fig. 4.
And (5) time-sharing operation of temperature measurement and short circuit measurement.
During temperature measurement, as shown in fig. 4, the controller 50 controls the second triac T2 to be turned on, the PTC electrical heating element 10 is heated by applying commercial power, and the controller 50 controls the PMOS transistor Q1 to be turned on and controls the first triac T1 to be turned off, a 5V voltage is applied to one end of the thermistor 20 after passing through the PMOS transistor Q1 and the seventh resistor R7, since the resistance value of the thermistor 20 changes with the temperature change of the PTC electrical heating element 10, the voltage at the two ends of the thermistor 20 also changes correspondingly, and then the controller 50 can obtain corresponding temperature information by obtaining the voltage signal output by the first operational amplifier a1 or the second operational amplifier a 2.
When detecting a short circuit, as shown in fig. 4, the controller 50 controls the second triac T2 to turn off to stop the PTC electric heating element 10 from being supplied with the commercial power, and the controller 50 controls the PMOS transistor Q1 to turn off and controls the first triac T1 to turn on, and the 5V voltage output by the controller 50 is applied to the first end 10a of the PTC electric heating element 10 through the first triac T1, if the PTC electric heating element 10 and the thermistor 20 are short-circuited at this time, the controller 50 may acquire a voltage signal through the first operational amplifier a1 or the second operational amplifier a2, and if the PTC electric heating element 10 and the thermistor 20 are not short-circuited at this time, the controller 50 may not acquire a voltage signal through the first operational amplifier a1 or the second operational amplifier a2, thereby achieving short circuit detection.
In addition, in this embodiment, the controller 50 may control the first bidirectional thyristor T1 and the PMOS transistor Q1 through only one IO port at the same time, that is, the PMOS transistor Q1 is controlled to be turned off while the first bidirectional thyristor T1 is controlled to be turned on, or the PMOS transistor Q1 is controlled to be turned on while the first bidirectional thyristor T1 is controlled to be turned off, so that two processes of switching temperature measurement and short circuit measurement by using one IO port are implemented.
As another aspect of the present invention, an embodiment of the present invention further provides an electric blanket, which includes the PTC electric heating element detection circuit 100 as described above. By adopting the PTC electric heating element detection circuit 100, the electric blanket has the functions of heating, temperature measurement, short circuit detection and the like.
Finally, it is to be understood that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, which are intended as additional limitations on the scope of the invention, as these embodiments are provided so that the disclosure will be thorough and complete. In addition, under the idea of the present invention, the above technical features are combined with each other continuously, and many other variations of the present invention in different aspects as described above are considered as the scope of the present invention; further, modifications and variations will occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A PTC electric heating element detection circuit is characterized by comprising a PTC electric heating element, a thermistor, a voltage detection circuit, a first switch circuit and a controller;
the PTC electric heating piece comprises a first end and a second end, wherein the first end of the PTC electric heating piece is used for being applied with commercial power, the second end of the PTC electric heating piece is used for being grounded, and the PTC electric heating piece is used for being applied with the commercial power for heating;
the voltage detection circuit is connected with the thermistor and is used for detecting the voltage at two ends of the thermistor;
the first switch circuit is respectively connected with the first end of the PTC electric heating piece and the controller and is used for switching on or off the connection between the first end of the PTC electric heating piece and the controller;
the controller is respectively connected with the first switch circuit and the voltage detection circuit, and is used for controlling the on and off of the first switch circuit and applying a preset voltage to the first end of the PTC electric heating piece when controlling the on of the first switch circuit.
2. The PTC electrothermal element detection circuit according to claim 1, wherein the first switch circuit comprises a first optical coupler and a first resistor;
the first optocoupler comprises a first bidirectional thyristor and a first light-emitting diode;
one end of the first bidirectional controllable silicon is connected with the first end of the PTC electric heating piece, the other end of the first bidirectional controllable silicon is connected with the controller, the anode of the first light emitting diode is connected with one end of the first resistor, the other end of the first resistor is connected with the controller, and the cathode of the first light emitting diode is used for grounding.
3. The PTC electrothermal element detection circuit according to claim 1, further comprising a second switching circuit;
the second switch circuit is used for being respectively connected with a power grid, the first end of the PTC electric heating piece and the controller and is used for switching on or switching off the connection between the power grid and the first end of the PTC electric heating piece.
4. The PTC electrothermal element detection circuit according to claim 3, further comprising a third switching circuit;
the third switch circuit is used for being respectively connected with the auxiliary power supply, the controller and the voltage detection circuit.
5. The PTC heater detection circuit according to claim 4, wherein the third switch circuit comprises a PMOS tube, a second resistor and a third resistor;
one end of the second resistor and a source electrode of the PMOS tube are connected with an auxiliary power supply, the other end of the second resistor, a grid electrode of the PMOS tube and one end of the third resistor are connected together, the other end of the third resistor is connected with the controller, and a drain electrode of the PMOS tube is connected with the voltage detection circuit.
6. The PTC electrothermal element detection circuit according to claim 5, wherein the voltage detection circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first operational amplifier and a capacitor;
one end of the fourth resistor is connected with the drain electrode of the PMOS tube, the other end of the fourth resistor, one end of the fifth resistor and one end of the thermistor are connected together, the other end of the fifth resistor, one end of the sixth resistor and the non-inverting input end of the first operational amplifier are connected together, the other end of the sixth resistor is used for grounding, the inverting input end of the first operational amplifier, one end of the seventh resistor and one end of the eighth resistor are connected together, the other end of the seventh resistor is connected with the other end of the thermistor, the other end of the eighth resistor, the output end of the first operational amplifier and one end of the ninth resistor are connected together, the other end of the ninth resistor, one end of the capacitor and the controller are connected together, and the other end of the capacitor is used for grounding.
7. The PTC electrothermal element detection circuit according to claim 6, wherein the voltage detection circuit further comprises a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a second operational amplifier;
one end of the tenth resistor, one end of the eleventh resistor and one end of the seventh resistor are connected together, the other end of the tenth resistor is used for grounding, the other end of the eleventh resistor is connected with the non-inverting input end of the second operational amplifier, the inverting input end of the second operational amplifier, one end of the twelfth resistor and one end of the thirteenth resistor are connected together, the other end of the twelfth resistor is used for grounding, the other end of the thirteenth resistor, the output end of the second operational amplifier and one end of the fourteenth resistor are connected, and the other end of the fourteenth resistor is connected with the controller.
8. A PTC heater detecting circuit according to any one of claims 3 through 7, wherein the second switch circuit includes a control terminal, a first terminal and a second terminal;
the first end of the second switch circuit is used for being connected with a power grid, the second end of the second switch circuit is connected with the first end of the PTC electric heating piece, and the control end of the second switch circuit is connected with the controller.
9. A PTC heater detecting circuit according to any one of claims 3 through 7, wherein the second switch circuit includes a second triac, a second optocoupler, a fifteenth resistor and a sixteenth resistor;
the second bidirectional controllable silicon comprises a control end, a first end and a second end, and the second optocoupler comprises a third bidirectional controllable silicon and a second light-emitting diode;
the control end of the second bidirectional controllable silicon is connected with one end of the third bidirectional controllable silicon, the first end of the second bidirectional controllable silicon is used for being connected with a power grid and one end of the fifteenth resistor respectively, the second end of the second bidirectional controllable silicon is connected with the first end of the PTC electric heating element, the other end of the third bidirectional controllable silicon is connected with the other end of the fifteenth resistor, the anode of the second light-emitting diode is connected with one end of the sixteenth resistor, the other end of the sixteenth resistor is connected with the controller, and the cathode of the second light-emitting diode is used for being grounded.
10. An electric blanket including a PTC electric heating element detection circuit according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120433867.1U CN214621521U (en) | 2021-02-26 | 2021-02-26 | PTC electric heating piece detection circuit and electric blanket |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120433867.1U CN214621521U (en) | 2021-02-26 | 2021-02-26 | PTC electric heating piece detection circuit and electric blanket |
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| Publication Number | Publication Date |
|---|---|
| CN214621521U true CN214621521U (en) | 2021-11-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120433867.1U Active CN214621521U (en) | 2021-02-26 | 2021-02-26 | PTC electric heating piece detection circuit and electric blanket |
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| Country | Link |
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| CN (1) | CN214621521U (en) |
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- 2021-02-26 CN CN202120433867.1U patent/CN214621521U/en active Active
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