Heating safety protection circuit, controller and electric blanket

Abstract

The utility model provides a heating safety protection circuit, including a first heating control circuit, a second heating control circuit, a controller circuit, a temperature sensing control circuit and a power supply circuit; after the live wire end is connected to the first fuse, it is respectively connected to the power supply circuit and the second heating control circuit; the neutral wire end is respectively connected to the power supply circuit and the first heating control circuit, and is also electrically connected to the first temperature sensing wire end, and is electrically connected to the power supply circuit through the second fuse, and the second temperature sensing wire end is electrically connected to the temperature sensing control circuit; the first heating control circuit and the second heating control circuit are respectively electrically connected to the first heating wire end and the second heating wire end, and are also respectively electrically connected to the two control ends of the controller circuit, and the temperature sensing control circuit is electrically connected to the controller circuit. When the protection circuit is used for an electric blanket, it can quickly cut off the power when the electric blanket loses control and generates high temperature, ensuring the safety of electricity use and avoiding the danger caused by the continued high temperature of the electric blanket. A controller and an electric blanket are also disclosed.

Description

Technical Field

[0001] The utility model relates to the field of heating circuit safety, in particular to a heating safety protection circuit, a controller and an electric blanket. Background Art

[0002] In the prior art, for flexible heating silk fabrics such as electric blankets and electric heating pads that are heated by power supply, the problem of heating runaway often occurs, resulting in excessive heating temperature inside the electric blanket and causing safety accidents such as smoke and fire in the electric blanket. This has become a common problem in this technical field but is difficult to fundamentally solve. Utility Model Content

[0003] In order to solve the above technical problems, a technical solution adopted by the utility model is to provide a heating safety protection circuit, including a first heating control circuit, a second heating control circuit, a controller circuit and a temperature sensing control circuit, and a power supply circuit connected to the live wire end and the neutral wire end of the AC power; after the live wire end is connected to the first fuse, two branches are separated, the first branch is connected to the power supply circuit, and the second branch is connected to the second heating control circuit; the neutral wire end is respectively connected to the power supply circuit and the first heating control circuit, and is also electrically connected to the first temperature sensing wire end, and is electrically connected to the power supply circuit through the second fuse, and the second temperature sensing wire end is electrically connected to the temperature sensing control circuit; the first heating control circuit and the second heating control circuit are respectively electrically connected to the first heating wire end and the second heating wire end, and are also respectively electrically connected to the two control ends of the controller circuit, and the temperature sensing control circuit is electrically connected to the controller circuit.

[0004] In some embodiments, the first heating control circuit includes a first thermal control chip and a first thyristor; the input end of the first heating control chip is electrically connected to the controller circuit; the first control end of the first heating control chip is electrically connected to the control electrode of the first thyristor; the second electrode of the first thyristor is electrically connected to the first heating wire end; the first electrode is electrically connected to the neutral line end, and is also connected to the second fuse, and then connected to the power supply circuit, and the first electrode is also electrically connected to the first temperature sensing wire end.

[0005] In some embodiments, the second heating control circuit includes a second thermal control chip and a second thyristor; the input end of the second heating control chip is electrically connected to the controller circuit; the first control end of the second heating control chip is electrically connected to the control electrode of the second thyristor; the first electrode of the second thyristor is electrically connected to the second heating wire end; and the second electrode is electrically connected to the first fuse.

[0006] In some embodiments, the temperature sensing control circuit includes a first diode, a second diode, a first resistor, a second resistor and a first capacitor; the cathode of the first diode is electrically connected to the second temperature sensing wire end, the anode is electrically connected to the first end of the first capacitor and is grounded, and the second end of the first capacitor is electrically connected to the controller circuit; the cathode of the second diode is also electrically connected to the second temperature sensing wire end, the anode is electrically connected to the first resistor and then connected to the power supply circuit, and the anode of the second diode is electrically connected to the second resistor at the electrical connection point with the first resistor, and then electrically connected to the second end of the first capacitor.

[0007] In some embodiments, the controller circuit includes a control chip, and two pins of the control chip are respectively used to connect the first heating control circuit and the second heating control circuit, and to output pulse width control signals to the first heating control circuit and the second heating control circuit; the control chip also has a pin electrically connected to the temperature sensing control circuit, and is used to receive a voltage analog signal from the temperature sensing control circuit to collect the temperature of the temperature sensing wire; the control chip also has another pin connected in series with a resistor and electrically connected to the first fuse.

[0008] In some embodiments, the control chip is also electrically connected to two control switches, and electrically connected to a digital tube and / or an LED lamp.

[0009] In some embodiments, the power supply circuit includes a rectifier circuit, an anti-interference circuit, and a transformer and low-voltage circuit, wherein the transformer and low-voltage circuit provides a DC power supply for the first heating control circuit, the second heating control circuit, the controller circuit, and the temperature sensing control circuit.

[0010] In some embodiments, the first branch is connected to the rectifier circuit in the power supply circuit, the neutral line terminal is also connected to the rectifier circuit in the power supply circuit, and the second fuse is connected to the transformer and low voltage circuit in the power supply circuit.

[0011] A controller is also provided, which includes the aforementioned heating safety protection circuit.

[0012] An electric blanket is also provided, comprising the aforementioned controller.

[0013] The beneficial effects of the utility model are as follows: the utility model provides a heating safety protection circuit, including a first heating control circuit, a second heating control circuit, a controller circuit, a temperature sensing control circuit and a power supply circuit; after the live wire end is connected to the first fuse, it is respectively connected to the power supply circuit and the second heating control circuit; the neutral wire end is respectively connected to the power supply circuit and the first heating control circuit, and is also electrically connected to the first temperature sensing wire end, and is electrically connected to the power supply circuit through the second fuse, and the second temperature sensing wire end is electrically connected to the temperature sensing control circuit; the first heating control circuit and the second heating control circuit are respectively electrically connected to the first heating wire end and the second heating wire end, and are also respectively electrically connected to the two control ends of the controller circuit, and the temperature sensing control circuit is electrically connected to the controller circuit. When the protection circuit is used for an electric blanket, it can quickly cut off the power when the electric blanket loses control and generates high temperature, ensuring the safety of electricity use and avoiding the danger caused by the continued high temperature of the electric blanket. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the electric heating cable according to the utility model;

[0015] Figure 2 It is a schematic diagram of the arrangement of the electric heating cable in the electric blanket according to the utility model;

[0016] Figure 3 It is a composition principle diagram of the heating safety protection circuit in the utility model;

[0017] Figure 4 It is a principle diagram of a controller circuit in a heating safety protection circuit according to the utility model;

[0018] Figure 5 It is a composition principle diagram of the first heating control circuit in the heating safety protection circuit of the utility model;

[0019] Figure 6 It is a composition principle diagram of the second heating control circuit in the heating safety protection circuit of the utility model;

[0020] Figure 7 It is a composition principle diagram of the temperature sensing control circuit in the heating safety protection circuit of the utility model;

[0021] Figure 8 It is a composition principle diagram of the rectifier circuit in the heating safety protection circuit of the utility model;

[0022] Fig. 9 It is a composition principle diagram of the anti-interference circuit in the heating safety protection circuit of the utility model;

[0023] Fig.10 The utility model discloses a composition principle diagram of a voltage transformer and a low-voltage circuit in a heating safety protection circuit. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. The accompanying drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0026] In the field of electric blanket technology, the reasons why the heating of electric blankets runs away (i.e., the heating cannot be performed according to the normal controlled settings, causing the heating to lose normal control and become out of control) leading to excessive heating temperatures, smoke, and fire are not directly conclusive and obvious. This is related to factors such as the length of service life of the electric blanket, whether there is abnormal use (such as folding, heavy objects pressing on it), and the structural composition and materials of the internal heating cable. However, these factors do not necessarily lead to the runaway heating of the electric blanket. Therefore, the runaway heating of electric blankets has become a chronic disease in this field, or a natural defect in this field that is difficult to overcome.

[0027] In this application, a dedicated electric heating cable is usually provided inside the electric blanket. Figure 1 As shown, the electric heating cable generally includes a reinforcing fiber 101 arranged at the inner center position, and the reinforcing fiber has both flexibility and elasticity, can withstand a certain degree of folding and bending, and can also recover from a bent state to a straight state. The outer surface of the reinforcing fiber is surrounded by a heating wire 101, which is used to release heat to produce a heating effect when powered on, and is an effective component of electric heating. Further, an internal insulating layer 302 is arranged on the periphery of the heating wire 101, and the internal insulating layer 302 is used to insulate and protect the heating wire to prevent the heating wire 101 from leaking electricity when powered on. The outer surface of the internal insulating layer 302 is surrounded by a temperature sensing wire 201, which is used to sense and measure the heating temperature of the heating wire 101. An external insulating layer 303 is arranged on the periphery of the temperature sensing wire 201, which is used to insulate and protect the temperature sensing wire 201 and other components inside the cable, and belongs to the outermost insulating protective layer of the electric heating cable.

[0028] Further, such as Figure 2As shown, the electric heating cable is arranged in a ring in the electric blanket, and the two ends of the cable respectively include two ends of the heating wire 101: a first heating wire end 11 and a second heating wire end 12, and two ends of the temperature sensing wire 201: a first temperature sensing wire end 21 and a second temperature sensing wire end 22. Usually, the first heating wire end 11, the second heating wire end 12, the first temperature sensing wire end 21 and the second temperature sensing wire end 22 are all connected to the heating control circuit in the heating controller for heating control and temperature sensing measurement.

[0029] for Figure 1 and Figure 2 The electric heating cable shown is used in electric blankets. Since the heating wire is long, when the heating wire has a short circuit or other faults at different positions, the fuse in the heating control circuit will have different blowing times in the prior art. That is to say, although the heating wire in the electric blanket has a short circuit or other fault, which will cause the electric blanket to overheat, get hot, or even smoke, the fuse in the prior art cannot be blown quickly immediately after the heating wire has a short circuit or other fault. Instead, it will show different blowing times due to different fault locations of the heating wire. Even after heating, smoking, and burning, the fuse has not yet blown, making the safety not meet the requirements. For this reason, the present application makes technical improvements and innovations to the heating control circuit to solve the problems in this industry.

[0030] Specific, combined Figure 3 The heating safety protection circuit includes a first heating control circuit A4, a second heating control circuit A5, a controller circuit A6 and a temperature sensing control circuit A7, and a power supply circuit A8 connected to two terminals of AC power, namely, the live wire terminal 01 and the neutral wire terminal 02. The power supply circuit specifically includes a rectifier circuit A1, an anti-interference circuit A2 and a transformer and low-voltage circuit A3, wherein the transformer and low-voltage circuit A3 provides a DC power supply for the first heating control circuit A4, the second heating control circuit A5, the controller circuit A6 and the temperature sensing control circuit A7.

[0031] Furthermore, after the live wire terminal 01 is connected to the first fuse F1, two branches are generated, the first branch is connected to the rectifier circuit A1 in the power circuit A8, and the second branch is connected to the second heating control circuit A5; the neutral wire terminal 02 is respectively connected to the rectifier circuit A1 and the first heating control circuit A4 in the power circuit A8, and is also electrically connected to the first temperature sensing wire terminal 21, and is electrically connected to the transformer and low voltage circuit A3 in the power circuit A8 through the second fuse F2. The second temperature sensing wire terminal 22 is electrically connected to the temperature sensing control circuit A7.

[0032] It can also be seen that the first heating control circuit A4 and the second heating control circuit A5 are electrically connected to the first heating wire end 11 and the second heating wire end 12, respectively, and are also electrically connected to the two control ends of the controller circuit A6, respectively, mainly to control the heating power between the first heating wire end 11 and the second heating wire end 12 under the control of the controller circuit A6, thereby adjusting different heating temperatures. Specifically, the controller circuit A6 controls the on-off frequency and on-off duty ratio between the neutral wire end 02 and the first heating wire end 11 through the first heating control circuit A4, and the controller circuit A6 controls the on-off frequency and on-off duty ratio between the live wire end 01 and the second heating wire end 12 through the second heating control circuit A5, thereby jointly realizing the power level control of the alternating current connected to the two ends of the heating wire, thereby adjusting the heating speed and heating temperature.

[0033] In actual application, when the first unexpected situation occurs, that is, the first heating control circuit A4 and the second heating control circuit A5 both lose control of the AC power supply input to the first heating wire end 11 and the second heating wire end 12, it is equivalent to that the two heating control circuits are short-circuited, and the two ends of the heating wire are directly connected to the live wire end 01 and the neutral wire end 02 of the AC power respectively. The heating wire works at full power. When the heating wire touches the temperature sensing wire, the input current increases, the power increases, the resistance of the temperature sensing wire is connected in parallel with the resistance of the heating wire, and the current will flow from the neutral wire end 02 through the very small resistance of the temperature sensing wire to the live wire end 01, melting the first fuse F1 and cutting off the output, thereby playing a protective role.

[0034] In actual application, when the first heating control circuit A4 and the second heating control circuit A5 are working normally, due to abnormal use or other reasons, when the heating wire inside the electric blanket generates high temperature and collides with the temperature sensing wire after a short circuit, the current flows from the neutral wire terminal 02 and the first temperature sensing wire terminal 21, through the second fuse F2, the transformer and low voltage circuit A3 and the temperature sensing control circuit A7, and then through the second temperature sensing wire terminal 22 back to the live wire terminal 01 to form a loop, thereby melting the second fuse F2 and cutting off the output, thereby playing a protective role.

[0035] Therefore, in the present application, by providing the second fuse F2 and the corresponding connection circuit, when the heating wire inside the electric blanket generates high temperature and short-circuits the temperature-sensitive wire, a current loop passing through the second fuse F2 can be formed in the heating safety protection circuit. The second fuse F2 is preferably a current fuse. When the temperature-sensitive wire inside the electric blanket and the heating wire are short-circuited, the current in the circuit loop formed in the heating safety protection circuit is very large, and the current fuse can be instantly blown.

[0036] In the prior art, a temperature fuse is usually used in series with a resistor to control the operation. When the first heating control circuit A4 and the second heating control circuit A5 are both directly connected and lose the on-off control, the electric blanket works at full power, and the current flowing through the first fuse is too large, causing the resistor to heat up, and the temperature is then transmitted to the temperature fuse, causing it to melt. In addition, in specific practical applications, there is also the problem of setting the distance between the resistor and the temperature fuse. If the distance between the two is too far, it is difficult to melt. If the distance between the two is too close, it will cause a certain degree of false alarm and the fuse will melt, although there will be no accident, affecting the user experience.

[0037] like Figure 4 As shown, the controller circuit A6 includes a control chip U2. In this embodiment, the model of the control chip U2 is OB38S08A1W20GP.

[0038] Specifically, two pins of the control chip U2 are connected to two control switches for adjusting the temperature of heating up or down, so there is an upward control switch for increasing the heating temperature and a downward control switch for decreasing the heating temperature. Specifically, the second terminal P3.1 of the control chip U2 is electrically connected to the first touch switch UP and then grounded, and the third terminal P3.0 of the control chip U2 is electrically connected to the second touch switch DOWN and then grounded.

[0039] The control chip U2 has two other pins as two control terminals, which are respectively used to connect the first heating control circuit A4 and the second heating control circuit A5, and output pulse width control signals to the first heating control circuit A4 and the second heating control circuit A5, so as to adjust the duty cycle of the two circuits in powering the heating wire, thereby adjusting the heating power of the heating wire. Specifically, the 8th terminal P1.0 / TXD of the control chip U2 is connected to Figure 5 The input terminal AN of the first heating control chip U3 is electrically connected, and the eighth terminal P1.0 / TXD is also electrically connected to a resistor R22 and then grounded; the seventh terminal P1.1 / T2EX / RXD of the control chip U2 is electrically connected to the Figure 6 The input terminal AN of the second heating control chip U4 is electrically connected, and the seventh terminal P1.1 / T2EX / RXD is also electrically connected to a resistor R21 and then grounded.

[0040] The control chip U2 also has multiple pins for connecting digital tubes and / or LED lights, which are used to cooperate with the aforementioned control switch to display the heating gear or level. For example, the heating temperature range corresponding to the first gear is 41-43°C, the heating temperature range corresponding to the second gear is 43-46°C, the heating temperature range corresponding to the third gear is 46-50°C, the heating temperature range corresponding to the fourth gear is 50-54°C, the heating temperature range corresponding to the fifth gear is 54-58°C, and the heating temperature range corresponding to the sixth gear is 58-62°C. The specific pins are the 12th terminal ADC4 / P0.4 of the control chip U2, the 13th terminal ADC3 / T2 / KBI 3 / P0.3, the 14th terminal ADC2 / KBI2 / P0.2, the 15th terminal ADC1 / KB I 1 / P0.1, the 16th terminal KB I 0 / SPI CLK / P0.0, the 17th terminal CC2 / MOS I / PWM1 / P1.7, the 18th terminal CC1 / MI SO / PWM0 / P1.6, the 19th terminal P1.5, the 10th terminal P0.6 / ADC6 and the 9th terminal P0.7 / PWM3 / CC3 / ADC7T1.

[0041] The control chip U2 also has a pin for collecting an analog voltage value, which reflects the heating temperature of the electric blanket. Therefore, this pin is electrically connected to the temperature sensing control circuit A7 and is used to receive the voltage analog signal from the temperature sensing control circuit A7 to collect the temperature of the temperature sensing wire. Specifically, the 11th terminal PWM2 / CC0 / ADC5 / P0.5 of the control chip U2 is connected to Figure 7 The resistor R20 and the capacitor C8 in the temperature sensing control circuit A7 are electrically connected.

[0042] The control chip U2 also has a pin for connecting a resistor RN in series and electrically connecting to an end of the first fuse F1 close to the rectifier circuit A1 (combined with Figure 3 Specifically, the fourth terminal P1.4 / I NT1 of the control chip U2 is electrically connected to a resistor RN and then electrically connected to an end of the first fuse F1 close to the rectifier circuit A1. The fifth terminal P1.3 / I NT0 / I ICSDA and the sixth terminal P1.2 / T0 / II CSCL of the control chip U2 are used to connect to a crystal oscillator.

[0043] like Figure 5 As shown, the first heating control circuit includes a first heating control chip U3 and a first thyristor VT1. Specifically, the input terminal AN of the first heating control chip U3 is electrically connected to a resistor R11 and then Figure 4The output terminal P1.0 / TXD of the middle control chip U2 is electrically connected; the first control terminal MA IN TERM (pin 4) of the first heating control chip U3 is electrically connected to the control electrode of the first thyristor VT1; the second electrode of the first thyristor VT1 is electrically connected to the first heating wire end; the first electrode of the first thyristor VT1 is electrically connected to the neutral line end, and is also connected to the second fuse F2-1A, and then connected to the transformer and low-voltage rectifier circuits respectively, and the first electrode of the first thyristor VT1 is also electrically connected to the first temperature sensing wire end. The first electrode of the first thyristor VT1 is also electrically connected to two series resistors, namely resistors R13 and R12, and then connected to the second control terminal MA I NTERM (pin 6) of the first heating control chip U3.

[0044] like Figure 6 As shown, the second heating control circuit includes a second heating control chip U4 and a second thyristor VT2. Specifically, the input terminal AN of the second heating control chip U4 is electrically connected to a resistor R14 and then Figure 4 The output terminal P1.1 / T2EX / RXD of the middle control chip U2 is electrically connected; the first control terminal MA IN TERM (pin 4) of the second heating control chip U4 is electrically connected to the control electrode of the second thyristor VT2, the first electrode of the second thyristor VT2 is electrically connected to the second heating wire end, and the second electrode of the second thyristor VT2 is electrically connected to the end L1 of the first fuse F1 close to the rectifier circuit A1. The second control terminal MA IN TERM (pin 6) of the second heating control chip U4 is electrically connected to two series resistors, namely resistors R15 and R16, and then electrically connected to the second heating wire end.

[0045] Specifically, the first heating control chip U3 and the second heating control chip U4 are both optocoupler relays, such as MOC3021.

[0046] like Figure 7 As shown, the temperature sensing control circuit includes a first diode D4, a second diode D5, a first resistor R19, a second resistor R20 and a first capacitor C8.

[0047] Specifically, the cathode of the first diode D4 is electrically connected to the second temperature sensing wire end, the anode of the first diode D4 is electrically connected to the first end of the first capacitor C8 and grounded, and the second end of the first capacitor C8 is electrically connected to Figure 4The input terminal PWM2 / CC0 / ADC5 / P0.5 of the control chip U2. The cathode of the second diode D5 is also electrically connected to the second temperature-sensitive wire end. The anode of the second diode D5 is electrically connected to the first resistor R19 and then connected to the first DC power supply VCC. The anode of the second diode D5 is also electrically connected to the first resistor R20 at the electrical connection point between the anode of the second diode D5 and the first resistor R19, and then electrically connected to the second end of the first capacitor C8. As mentioned above, the first temperature-sensitive wire end here is electrically connected to the neutral line end, and is also connected to the second fuse.

[0048] like Figure 8 As shown, the rectifier circuit includes a bridge rectifier circuit BD1 composed of four diodes connected in series and a toggle switch J1. Specifically, the second end 2 and the fourth end 4 of the bridge rectifier circuit BD1 are electrically connected to the two input ends of the anti-interference circuit respectively; the third end 3 of the bridge rectifier circuit BD1 is connected to the neutral line terminal, and the third end 3 of the bridge rectifier circuit BD1 is also connected to the Figure 5 The first electrode of the first thyristor VT1 is electrically connected; the first end 1 of the bridge rectifier circuit BD1 is electrically connected to the first output end of the first switch J1, the input end of the first switch J1 is electrically connected to the first fuse F1-1A and then connected to the live wire end L, and the electrical connection between the first end 1 of the bridge rectifier circuit BD1 and the first output end of the first switch J1 is also electrically connected Figure 6 The second electrode of the second thyristor VT2.

[0049] like Fig. 9 As shown, the anti-interference circuit includes a power chip U1, a power terminal 1 of the power chip U1 is connected to a first filter circuit, a feedback terminal 2 and a chip select terminal 4 are connected to a second filter circuit, and two control terminals 5 and 6 are connected to a third filter circuit. The power chip U1 is preferably a chip CSC7136B, which is an AC-DC switching power supply driver chip.

[0050] Specifically, the first filtering circuit includes a polarity capacitor C1, whose positive and negative ends are electrically connected to the rectifier circuit as two input ends of the anti-interference circuit respectively, the negative end of the polarity capacitor C1 is also electrically connected to the negative end of another polarity capacitor C3, the positive end of the polarity capacitor C3 is connected to a resistor R5 and then connected to the power supply terminal 1 of the power chip U1, the positive end of the polarity capacitor C3 is also electrically connected to two resistors R2 and R1 connected in series and then connected to the positive end of the polarity capacitor C1.

[0051] The second filter circuit includes a diode D2 and an inductor T1B, wherein the cathode of the diode D2 is electrically connected to the anode terminal of the polarity capacitor C3, the anode of the diode D2 is connected to the first terminal of the inductor T1B, and is also electrically connected to a resistor R6 and then connected to the feedback terminal 2 of the power chip U1, and the second terminal of the inductor T1B is electrically connected to a resistor R8 and then connected to the chip select terminal 4 of the power chip U1. In addition, a resistor R7 and a capacitor C4 are connected in parallel between the second terminal of the inductor T1B and the feedback terminal 2 of the power chip U1.

[0052] The third filtering circuit includes a diode D1, the positive electrode of which is electrically connected to the two control terminals 5 and 6 of the power chip U1, and the negative electrode of which is electrically connected to the resistor R4 and the resistor R3, and then to the positive terminal of the polar capacitor C1. A capacitor C2 is also connected in parallel at both ends of the resistor R3. Here, the positive terminal of the polar capacitor C1 and the positive electrode of the diode D1 are respectively used as the two output terminals of the entire anti-interference circuit, and Fig.10 The first input terminal 1 and the second input terminal 3 of the transformer T1A in the medium-voltage transformation and low-voltage rectification circuit are connected.

[0053] like Fig.10 As shown, the transformer and low voltage rectifier circuit includes a transformer T1A and a fifth diode D3. Specifically, the first input terminal 1 and the second input terminal 3 of the transformer T1A are respectively connected to Fig. 9 The two output ends of the anti-interference circuit in the transformer are electrically connected; the first output end 8 of the transformer T1A is electrically connected to the second fuse F2-1A and then Figure 5 The first electrode of the first thyristor VT1 in the transformer T1A is electrically connected, the first output terminal 8 of the transformer T1A is also connected in series with a resistor R10 and then electrically connected to the first DC power supply VCC, the negative electrode of the polarity capacitor C6 is also electrically connected to the electrical connection between the first output terminal 8 of the transformer T1A and the resistor R10 and grounded, the positive electrode of the polarity capacitor C6 is electrically connected to the negative electrode of the fifth diode D3 and serves as the first DC power supply VCC; the second output terminal 10 of the transformer T1A is electrically connected to the positive electrode of the fifth diode D3, and a resistor R9 and a capacitor C5 are also connected in series between the second output terminal 10 of the transformer T1A and the positive electrode of the polarity capacitor C6.

[0054] It can be seen that the utility model provides a heating safety protection circuit, including a first heating control circuit, a second heating control circuit, a controller circuit, a temperature sensing control circuit and a power supply circuit; after the live wire end is connected to the first fuse, it is connected to the power supply circuit and the second heating control circuit respectively; the neutral wire end is connected to the power supply circuit and the first heating control circuit respectively, and is also electrically connected to the first temperature sensing wire end, and is electrically connected to the power supply circuit through the second fuse, and the second temperature sensing wire end is electrically connected to the temperature sensing control circuit; the first heating control circuit and the second heating control circuit are electrically connected to the first heating wire end and the second heating wire end respectively, and are also electrically connected to the two control ends of the controller circuit respectively, and the temperature sensing control circuit is electrically connected to the controller circuit. When the protection circuit is used for an electric blanket, it can quickly cut off the power when the electric blanket loses control and generates high temperature, ensuring the safety of electricity use and avoiding the danger caused by the continued high temperature of the electric blanket.

[0055] Based on the same utility model concept, the utility model also provides a heating safety protection method, which adopts the aforementioned heating safety protection circuit. When the first heating control circuit and the second heating control circuit lose control of the AC power supply input to the first heating wire end and the second heating wire end, the two ends of the heating wire are directly connected to the live wire end and the neutral wire end of the AC power. When the heating wire works at full power, the heating wire touches the temperature sensing wire, and the current will flow from the neutral wire end through the temperature sensing wire to the live wire end, blowing the first fuse and cutting off the power supply.

[0056] Furthermore, when the first heating control circuit and the second heating control circuit are working normally, when the heating wire inside the electric blanket generates high temperature and collides with the temperature-sensitive wire due to a short circuit, the current flows from the neutral wire end and the first temperature-sensitive wire end, through the second fuse, the power supply circuit and the temperature-sensitive control circuit, and then returns to the live wire end through the second temperature-sensitive wire end to form a loop, thereby blowing the second fuse and cutting off the power supply.

[0057] The utility model also provides a controller, including the heating safety protection circuit provided by the utility model, and provides an electric blanket, including the controller.

[0058] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, is also included in the patent protection scope of the present invention.

Claims

1. A heating safety protection circuit, characterized in that: It includes a first heating control circuit, a second heating control circuit, a controller circuit and a temperature sensing control circuit, and a power supply circuit connected to the live wire terminal and the neutral wire terminal of the AC power; After the live wire end is connected to the first fuse, two branches are separated, the first branch is connected to the power supply circuit, and the second branch is connected to the second heating control circuit; the neutral wire end is respectively connected to the power supply circuit and the first heating control circuit, and is also electrically connected to the first temperature sensing wire end, and is electrically connected to the power supply circuit through the second fuse, and the second temperature sensing wire end is electrically connected to the temperature sensing control circuit; The first heating control circuit and the second heating control circuit are electrically connected to the first heating wire end and the second heating wire end respectively, and are also electrically connected to two control ends of the controller circuit respectively, and the temperature sensing control circuit is electrically connected to the controller circuit.

2. The heating safety protection circuit according to claim 1, characterized in that: The first heating control circuit includes a first heating control chip and a first thyristor; the input end of the first heating control chip is electrically connected to the controller circuit; the first control end of the first heating control chip is electrically connected to the control electrode of the first thyristor; the second electrode of the first thyristor is electrically connected to the first heating wire end; the first electrode is electrically connected to the neutral line end, and is also connected to the second fuse, and then connected to the power supply circuit, and the first electrode is also electrically connected to the first temperature sensing wire end.

3. The heating safety protection circuit according to claim 1, characterized in that: The second heating control circuit includes a second heating control chip and a second thyristor; the input end of the second heating control chip is electrically connected to the controller circuit; the first control end of the second heating control chip is electrically connected to the control electrode of the second thyristor; the first electrode of the second thyristor is electrically connected to the second heating wire end; and the second electrode is electrically connected to the first fuse.

4. The heating safety protection circuit according to claim 1, characterized in that: The temperature sensing control circuit includes a first diode, a second diode, a first resistor, a second resistor and a first capacitor; The cathode of the first diode is electrically connected to the second temperature-sensing wire end, the anode is electrically connected to the first end of the first capacitor and is grounded, and the second end of the first capacitor is electrically connected to the controller circuit; the cathode of the second diode is also electrically connected to the second temperature-sensing wire end, the anode is electrically connected to the first resistor and then connected to the power supply circuit, and the anode of the second diode is electrically connected to the first resistor at the electrical connection point with the first resistor, and then electrically connected to the second end of the first capacitor.

5. The heating safety protection circuit according to claim 1, characterized in that: The controller circuit includes a control chip, two pins of the control chip are respectively used to connect the first heating control circuit and the second heating control circuit, and are used to output pulse width control signals to the first heating control circuit and the second heating control circuit; The control chip also has a pin electrically connected to the temperature sensing control circuit, which is used to receive a voltage analog signal from the temperature sensing control circuit to collect the temperature of the temperature sensing wire; The control chip has another pin which is connected in series with a resistor and is electrically connected to the first fuse.

6. The heating safety protection circuit according to claim 5, characterized in that: The control chip is also electrically connected to the two control switches, and is electrically connected to the digital tube and / or the LED lamp.

7. The heating safety protection circuit according to claim 1, characterized in that: The power supply circuit includes a rectifier circuit, an anti-interference circuit and a transformer and low-voltage circuit, wherein the transformer and low-voltage circuit provides a DC power supply for the first heating control circuit, the second heating control circuit, the controller circuit and the temperature sensing control circuit.

8. The heating safety protection circuit according to claim 7, characterized in that: The first branch is connected to the rectifier circuit in the power supply circuit, the neutral line end is also connected to the rectifier circuit in the power supply circuit, and the second fuse is connected to the transformer and low voltage circuit in the power supply circuit.

9. A controller, characterized in that: The controller comprises the heating safety protection circuit according to any one of claims 1-8.

10. An electric blanket, characterized in that: The electric blanket comprises the controller of claim 9.

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