A truly safe electric blanket that is fully protected against overheating

Abstract

The present invention relates to a completely high-temperature runaway-proof electric blanket, which is absolutely safe. The technical scheme adopted is: a temperature-sensitive diaphragm (7) is sandwiched between two parallel outer membrane electric heating wires (5) and inner membrane electric heating wires (6) as temperature sensing devices, a temperature detection and disconnection detection circuit (8) is connected in series between the two electric heating wires, and the temperature detection voltage outputted by the circuit is then used to connect and control an overheating and anti-flashover protection control circuit (9) and a zero-through temperature control circuit (10), and then the internal protection switch of the overheating and anti-flashover protection control circuit (9) is used for high-temperature protection control, and the zero-through temperature control circuit (10) is used to control the normal temperature of the electric heating wire. Therefore, the present invention has both the normal temperature control without interference and high-temperature protection control functions, and the protection control function of preventing the electric heating wire from breaking and flashing, ensuring reliable and effective control without runaway when the AC power supply needs to be disconnected, and absolutely safe.

Description

Technical Field

[0001] The present invention belongs to the field of household appliances or electric heating control, and particularly relates to an electric heating blanket that is fully protected against flash fire, high-heat protection failure, and runaway during the entire use process, whether in a normal state or an abnormal fault state, to ensure absolute safety, in short: an absolutely safe electric heating blanket that is fully protected against high-heat runaway. Since the electric heating blanket is a flexible electric heating body, the present invention is also particularly suitable as a must-safe controller for other electric heating bodies. Background Art

[0002] Electric blankets are the preferred heating device for warming the bed when it is cold. They not only make people feel warm and comfortable when sleeping and improve the quality of sleep, but also the infrared rays and low-frequency electromagnetic fields radiated by them have certain physical therapy and health care effects and rheumatism treatment effects on the human body. In addition, electric blankets are significantly more energy-efficient than other heating methods, economical and practical, so they are deeply loved by people. However, the early electric blanket technology was simple, and there were many fire accidents caused by local high temperature, which also brought safety hazards and threats to people. It can be seen that the safety performance of electric blankets is more important than the heating function. Therefore, people choose electric blankets with safety first, and the higher the safety performance, the better, and the more realistic, the better. Therefore, the high safety of electric blankets has become a mandatory technical requirement in national standards.

[0003] Since the development of electric blanket technology, its safety quality has gone from elementary to advanced, and has gone through the development stages of simple switch type, open-loop temperature control type, closed-loop temperature control type, local safety protection temperature control type, and full-line safety protection temperature control type. The electric heating temperature has gone from uncontrolled to controlled, from rough manual control to precise automatic control, and its safety performance has also been greatly improved, and it has long been balanced with foreign technology. At present, the mainstream full-line special safety temperature control electric blankets on the market are electric blankets that meet the current national technical standards. The technical principle is: the two ends of the temperature sensing wire are connected in parallel with the two ends of the two diodes, and the other two ends of the two diodes are separated and connected to the two ends of the heating wire. These two ends are respectively connected to the two poles of the AC power supply, and one end is connected in series with the AC power supply. The temperature sensing wire is wrapped around the insulating diaphragm on the surface of the heating wire. When the heating wire is partially overheated, the insulating diaphragm will melt or carbonize, causing the heating wire and the temperature sensing wire to short-circuit. The short-circuit current passes through the temperature sensing wire through the diode and the fuse. The fuse quickly melts and cuts off the AC power supply, protecting the electric blanket from the high temperature of the heating wire. However, if the series diode and the connection line between the temperature sensing wire and the fuse are broken, the fuse cannot cut off the AC power supply, and the continued high temperature of the heating wire will ignite the electric blanket. It can be seen that the current safety electric blankets still generally have fatal defects or technical difficulties such as failure of overheating protection function or high temperature out of control, which cause fires, and these are ignored. However, in reality, any electromechanical product has a certain life cycle, and abnormal failures are inevitable during use. It is inevitable that false safety will occur due to failure or out of control. Therefore, the special safety electric blanket has not completely eliminated the safety hazards, and can only achieve relatively high safety, but not real safety or absolute safety.

[0004] Perfecting and solving safety technology problems, completely and thoroughly eliminating safety hazards and defects, and raising electric blankets from "particularly safe" to "truly safe, absolutely safe" is necessary to promote supply-side improvements and meet consumers' high safety requirements. It is also the responsibility of the electric blanket manufacturing industry and an opportunity for innovative development. Consumer product safety is also a key factor that must be included in the formulation or revision of mandatory national standards. Therefore, the country supports the use of advanced safety technologies to promote the upgrading of national standards and then lead the upgrading of the industry. Summary of the invention

[0005] The purpose of the present invention is to design an electric blanket controller with adjustable electric temperature, overheat protection, and arc protection for electric heating wire (wire) breakage, and the overheat protection function of the entire circuit is effective regardless of normal and abnormal conditions, preventing runaway throughout the entire process, and ensuring real safety; to solve the technical problem of fire accidents caused by high-temperature runaway of existing electric blankets in abnormal faults, and completely eliminate the safety hazards and defects of existing electric blankets. Or simply put, the purpose of the present invention is to provide a real safety electric blanket that is fully protected against high-temperature runaway.

[0006] In order to achieve the above-mentioned purpose and solve the above-mentioned technical difficulties, the technical solution adopted by the present invention includes a fuse (1) and a power switch (2), characterized in that it also includes an outer membrane heating wire (5), an inner membrane heating wire (6), a temperature sensing diaphragm (7), a temperature detection and disconnection detection circuit (8), an overheating and flashover protection control circuit (9), and a zero-through temperature control circuit (10); the fuse (1) is connected in series between one power side (L1) of the power switch (2) and an input end (L) of the AC power supply, the other power side (N1) of the power switch (2) is directly connected to the other input end (N) of the AC power supply, a load side (L2) of the power switch (2) is connected to the protection switch K1 end of the overheating and flashover protection control circuit (9), and the other load side (N2) of the power switch (2) is connected to the tail end (b) of the inner membrane heating wire (6) and the zero-through temperature control circuit The AC input terminal (Z) of (10), the head end (A) of the outer membrane heating wire (5) is connected to the Y end of the terminal controller in the zero-through temperature control circuit (10) and the electric heating start end (Q) in the overheating and flash protection control circuit (9), the temperature sensing diaphragm (7) sandwiched between the outer membrane heating wire (5) and the inner membrane heating wire (6) is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperature, reduced impedance and increased leakage when the temperature rises, and melting and opening holes at high temperature to cause direct contact and short circuit between the two wires; an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) is connected to the head end (a) of the inner membrane heating wire (6), and the other AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) is connected to the tail end (B) of the outer membrane heating wire (5), and the detection output positive electrode (V +1 ) is connected in parallel to the positive input terminal (V + ) and the positive electrode (V +3 ), the temperature detection and disconnection detection circuit (8) detects the output negative pole (V -1 ) is connected in parallel to the negative input terminal (V - ) and the temperature control input terminal (V ki ); the protection switch K2 end of the protection control circuit (9) is connected to the H end of the terminal controller in the zero-through temperature control circuit (10).

[0007] As a preferred embodiment 1, the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a hot-melt film RMG fully sandwiched between the heating wire WR2 and the heating wire WR1; the temperature detection and disconnection detection circuit (8) includes diodes 2D1 to 2D4, a capacitor 2C1, a resistor 2R10, and a high-current light-emitting diode 2LED; the The overheat and flash protection control circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a phototransistor GMT, and a resistor 2R15, or the resistors 2R15 can be replaced by an electromagnetic relay J and a diode 2D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 2IC, a solid-state relay SSD2, a transistor 2VT1, a transistor 2VT2, voltage-stabilizing diodes 2WD1 to 2WD3, diodes 2D6 to 2D8, a potentiometer 2RP, resistors 2R1 to 2R3, resistors 2R5, 2R6, 2R8, 2R11, 2R12, capacitors 2C2, 2C3, 2C6, wherein the integrated circuit 2IC is used as a core The device uses an anti-failure and anti-control circuit module or a circuit module with equivalent functions; the circuit connection method is as follows: a fuse FS is connected in series between a power side (L1) of the power switch DK and an input end (L) of the AC power supply, another power side (N1) of the power switch DK is directly connected to another input end (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input end (Z) of the primary winding (n1) in the transformer BY, and another AC input end of the primary winding (n1) in the transformer BY is connected to the AC end (Y) of the bidirectional thyristor in the solid-state relay SSD2 and the heating wire WR2 The first end (A) of the transformer BY and the electric start end (Q) of the normally open button CKA, the temperature-sensitive diaphragm RMG sandwiched between the heating wire WR1 and the heating wire WR2 is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperature, reduced impedance and increased leakage when heated, and melting and opening holes at high temperature, resulting in direct contact and short circuit between the two wires; an AC output end of the secondary winding (n2) in the transformer BY is connected to an AC input end (~) of the rectifier bridge QD, the other AC output end of the secondary winding (n2) in the transformer BY is connected to the other AC input end (~) of the rectifier bridge QD, and the DC voltage positive pole (V +2 ) connects the anode of diode 2D6 and resistor 2R1, and the negative pole of the DC voltage output by the rectifier bridge QD (V -2) connects one end of capacitor 2C3 and the negative electrode of capacitor 2C2 and the positive electrode of voltage regulator diode 2WD3 as the ground terminal (GND) of the DC power supply in the zero-pass temperature control circuit (10); the positive electrode of diode 2D1 is connected to the negative electrode of diode 2D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 2D4 is connected to the negative electrode of diode 2D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 2D2 and 2D3 are connected to the negative electrode of capacitor 2C1 as the negative DC electrode (V -1 ) is then connected to the emitter of the phototransistor GMT and the cathode of the high current light emitting diode 2LED, and the cathodes of the diodes 2D1 and 2D4 are connected to the anode of the capacitor 2C1 as the DC positive electrode (V +1 ) and then connect the positive electrode of the light-emitting diode in the solid-state relay SSD1, one end of the resistor 2R10, and the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 2R15, the other end of the resistor 2R15 is connected to the collector of the phototransistor GMT, and the other end of the resistor 2R10 is connected to the anode of the high-current light emitting diode 2LED; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; or the solid-state relay SSD1, the phototransistor GMT, the high-current light emitting diode 2LED, the resistors 2R10 and 2R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 2D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the coil of the electromagnetic relay J and the anode of the diode 2D5 are connected in parallel to the negative DC pole (V -1), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, and the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; the cathode of the light-emitting diode in the solid-state relay SSD2 is connected to the collector of the transistor 2VT2, the anode of the light-emitting diode is connected to one end of the resistor 2R3, the other end of the resistor 2R3 is connected to the collector of the transistor 2VT1, the emitter of the transistor 2VT1 is connected to the anodes of the capacitors 2C2 and 2C1, the base of the transistor 2VT1 is connected to the cathode of the voltage-stabilizing transistor 2WD1, the anode of the voltage-stabilizing transistor 2WD1 is connected to one end of each of the resistors 2R1 and 2R11, and the other end of 2R1 is used as the zero-crossing trigger input end (V) of the zero-through temperature control circuit (10) m ) connects the anode of diode 2D6 and the DC voltage positive electrode (V +2 ), the emitter of transistor 2VT2 is connected to the DC power supply ground terminal (GND) of the zero-pass temperature control circuit (10), the base of transistor 2VT2 is connected to the positive electrode of voltage-stabilizing transistor 2WD2, the negative electrode of voltage-stabilizing transistor 2WD2 is connected to one end of resistor 2R12, and the other end of resistor 2R12 is connected to one end of resistor 2R6 and the inverting output terminal (V O2 ), the in-phase output terminal (V O1 ) connects the other end of 2R11, and the two input ends (V i1 、V i2 ) is connected in parallel to one end of the resistor 2R5, the other end of the resistor 2R5 is connected to one end of the capacitor 2C6 and the sliding arm of the potentiometer 2RP, one fixed end of the potentiometer 2RP is connected to the cathode of the diode 2D7, the other fixed end of the potentiometer 2RP is connected to the anode of the diode 2D8, the anode of the diode 2D7 and the cathode of the diode 2D8 are connected in parallel to the other end of the resistor 2R6 and the other end of the resistor 2R2, and the other end of the resistor 2R2 serves as the temperature control input end (V ki ) connects the two positive electrodes of diodes 2D2 and 2D3 and the negative electrode of capacitor 2C1; the negative electrode of diode 2D6 is connected to the other end of capacitor 2C3 and one end of resistor 2R8, and the other end of resistor 2R8 is connected in parallel to the negative electrode of voltage stabilizing diode 2WD3 and the positive electrode of capacitor 2C2 as the positive electrode (V) of the DC power supply of the zero-pass temperature control circuit (10) +3 ), and then connect the positive power input terminal (V + ) and the emitter of transistor 2VT1, the DC power supply positive electrode (V +3 ) is also connected to the positive electrode (V +1 ) and the two cathodes of diodes 2D1 and 2D4; the negative power input terminal (V- ) and the other end of the capacitor 2C6 are connected in parallel to the DC power ground terminal (GND) of the zero-pass temperature control circuit (10).

[0008] As a preferred embodiment 2, the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a temperature-sensitive diaphragm RMG fully sandwiched between the heating wires WR2 and WR1; the temperature detection and disconnection detection circuit (8) includes diodes 3D1 to 3D4, a capacitor 3C1, and a resistor 3R10; the overheating and flash protection circuit The fire protection control circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a varistor YR, a positive temperature coefficient thermistor PTC, resistors 3R13 and 3R15, or they can be replaced by an electromagnetic relay J and a diode 3D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 3IC, a photocoupler GDH, a bidirectional thyristor SCR, a transistor 3VT, a light-emitting diode 3LED, a voltage-stabilizing diode 3WD3, diodes 3D6 to 3D9, resistors 3R1 to 3R9, resistors 3R11 and 3R12, and capacitors 3C2 to 3C6, wherein the integrated circuit 3IC is selected as a core device. A time base circuit 555 or a circuit module with equivalent functions is used; the circuit connection method is as follows: a fuse FS is connected in series between a power side (L1) of the power switch DK and an input end (L) of the AC power supply, another power side (N1) of the power switch DK is directly connected to another input end (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input end (Z) of the primary winding (n1) in the transformer BY, and another AC input end of the primary winding (n1) in the transformer BY is connected to the AC end (Y) of the bidirectional thyristor SCR and the head end (A) of the heating wire WR2 and The electric heating start end (Q) of the normally open button CKA; the temperature-sensitive diaphragm RMG sandwiched between the heating wires WR1 and WR2 is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperatures, reduced impedance and increased leakage when heated, and melting and opening holes at high temperatures, resulting in direct contact and short circuit between the two wires; an AC output end of the secondary winding (n2) in the transformer BY is connected to an AC input end (~) of the rectifier bridge QD, the other AC output end of the secondary winding (n2) in the transformer (3) is connected to the other AC input end (~) of the rectifier bridge QD, and the DC voltage positive electrode (V +2) connects the anode of diode 3D6 and resistor 3R1, and the negative pole of the DC voltage output by rectifier bridge QD (V -2 ) connects one end of capacitor 3C3 and the negative electrode of capacitor 3C2 and the positive electrode of voltage regulator diode 3WD3 as the DC power ground terminal (GND) in the zero-pass temperature control circuit (10); the positive electrode of diode 3D1 is connected to the negative electrode of diode 3D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 3D4 is connected to the negative electrode of diode 3D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 3D2 and 3D3 are connected to the negative electrode of capacitor 3C1 as the DC negative electrode (V -1 ) and then connected to one end of the positive temperature coefficient thermistor PTC and one end of the resistor 3R10 and one end of the resistor 3R2, the cathodes of the diodes 3D1 and 3D4 are connected to the anode of the capacitor 3C1 as the DC anode (V +1 ) and then connected to the positive electrode of the light-emitting diode in the solid-state relay SSD1 and one end of the varistor YR and the other end of the resistor 3R10, and also connected to the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 3R15, the other end of the resistor 3R15 is connected to the other end of the varistor YR and one end of the resistor 3R13, and the other end of the resistor 3R13 is connected to the other end of the positive temperature coefficient thermistor PTC; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor SCR and one end of the resistor 3R9 and one end of the capacitor 3C4; or the solid-state relay SSD1, the varistor YR, the positive temperature coefficient thermistor PTC, the resistors 3R10, 3R13, 3R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 3D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the electromagnetic relay J coil and the anode of the diode 3D5 are connected in parallel to the negative DC pole (V -1), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor SCR, one end of the resistor 3R9 and one end of the capacitor 3C4; the other end of the capacitor 3C4 is connected to one end of the resistor 3R11, the other end of the resistor 3R9 is connected to an AC end of the bidirectional thyristor in the photoelectric coupler GDH, the other AC end of the bidirectional thyristor in the photoelectric coupler GDH is connected to one end of the resistor 3R12 and the control electrode (G) of the bidirectional thyristor SCR, the AC end (Y) of the bidirectional thyristor SCR is internally connected to the other end of the resistor 3R11 and the other end of the resistor 3R12 and the other AC input end of the primary winding (n1) in the transformer BY, and is externally connected. The first end (A) of the electric heating wire WR2 and the electric heating start end (Q) of the normally open button CKA are connected; the cathode of the light-emitting diode in the photoelectric coupler GDH is connected to the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the anode of the light-emitting diode in the photoelectric coupler GDH is connected to the cathode of the light-emitting diode 3LED; the anode of the light-emitting diode 3LED is connected to one end of the resistor 3R3 and the collector of the transistor 3VT; the emitter of the transistor 3VT is connected to one end of the resistor 3R4 and the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the other end of the resistor 3R4 is connected to one end of the resistor 3R1 and the anode of the diode 3D9; the cathode of the diode 3D9 is connected to the base of the transistor 3VT; the other end of the resistor 3R1 serves as the zero-crossing trigger input end (V m ) is connected to the positive DC voltage output by the rectifier bridge QD (V +2 ) and the anode of diode 3D6; the cathode of diode 3D6 is connected to the other end of capacitor 3C3 and one end of resistor 3R8, and the other end of resistor 3R8 is connected in parallel to the cathode of voltage-stabilizing diode 3WD3 and the anode of capacitor 3C2 as the positive electrode (V) of the DC power supply in the zero-pass temperature control circuit (10). +3 ), and then connect one end of the resistor 3R5 and the 8th and 4th pins of the time base circuit 555 and the DC positive electrode (V +1); the third pin of the time base circuit 555 is connected to the other end of the resistor 3R3, the fifth pin thereof is connected to one end of the capacitor 3C5, the first pin thereof is connected to the ground terminal (GND) of the DC power supply and the other end of the capacitor 3C5 and one end of the capacitor 3C6, the second and sixth pins thereof are connected in parallel to the other end of the capacitor 3C6 and the sliding arm of the potentiometer 3RP, the fixed end of the potentiometer 3RP is connected to the cathode of the diode 3D7, the other fixed end of the potentiometer 3RP is connected to one end of the resistor 3R6, the other end of the resistor 3R6 is connected to the anode of the diode 3D8, the cathode of the diode 3D8 is connected to the anode of the diode 3D7, and then connected to one end of each of the resistors 3R2 and 3R7 and the other end of the resistor 3R5, the other end of the resistor 3R7 is connected to the seventh pin of the time base circuit 555; the other end of the resistor 3R2 is used as the temperature control input end (V ki ) connects the anodes of diodes 3D2 and 3D3 and the cathode of capacitor 3C1.

[0009] The working principle of the technical solution used in the present invention is as follows:

[0010] Temperature control principle: When the electric blanket needs to be put into heating operation, first turn on the power switch (2), then press the normally open button in the overheating and flashover protection control circuit (9), connect the protection switch K1 end and the electric heating start end (Q) in the overheating and flashover protection control circuit (9), so that the AC current passes through the outer membrane heating wire (5) and the temperature detection and disconnection detection circuit (8) and the inner membrane heating wire (6), and also makes the AC input end (Z) and the final control end in the zero-through temperature control circuit (10) The Y end of the device receives AC power input, thereby starting the entire circuit to enter the working state: the outer membrane heating wire (5) and the inner membrane heating wire (6) are energized and start to heat up, and the temperature-sensitive diaphragm (7) sandwiched between the two heating wires naturally assumes the role of a temperature sensor. A temperature detection voltage is output between the positive and negative poles of the detection output of the temperature detection and disconnection detection circuit (8). On the one hand, it controls the conduction of the two ends of the protection switch K1 and K2 in the overheating and flashover protection control circuit (9), and on the other hand, the negative pole (V -1 ) controls the temperature control input terminal (V ki), so that the two ends H and Y of the final controller in the zero-through temperature control circuit (10) are also turned on; after the protection switch and the final controller are powered on at the same time, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) continue to obtain AC power, and then the protection switch in the overheating and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10) are simultaneously locked in a continuous power-on state. At this time, after releasing the normally open button, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) and the overheating and flash protection control circuit (9) can continue to obtain AC power, so that the protection switch and the final controller are still locked in a continuous power-on state. Therefore, the two heating wires can continue to generate heat after the alternating current passes through them stably, so that the working temperature of the electric blanket gradually increases. Subsequently, the temperature detection and disconnection detection circuit (8) outputs a detection voltage to control the pulse width in the zero-pass temperature control circuit (10) according to the temperature of the two heating wires detected by the temperature-sensitive diaphragm (7). Finally, the final controller controls the length of the power-on time in each cycle according to the pulse width, thereby automatically controlling the heating value or temperature of the two heating wires. At the beginning of power-on, the temperature of the two heating wires is relatively low, the impedance of the temperature sensing diaphragm (7) is relatively large, the leakage current is relatively small, the detection voltage difference output by the temperature detection and disconnection detection circuit (8) is relatively large, the pulse width of the zero-pass temperature control circuit (10) is widened in each cycle, and the power-on time of the final controller is extended, so that the heat generated by the two heating wires increases and the temperature rises; on the contrary, if the temperature of the two heating wires is relatively high, the impedance of the temperature sensing diaphragm (7) is relatively small, the leakage current is relatively large, the detection voltage difference output by the temperature detection and disconnection detection circuit (8) is relatively small, the pulse width of the zero-pass temperature control circuit (10) is narrowed in each cycle, and the power-on time of the final controller is shortened, so that the heat generated by the two heating wires decreases and the temperature drops; in this cycle, the temperature of the two heating wires is automatically controlled within the set range. In normal use, the working temperature of the electric blanket should be within the range that the human body feels comfortable. If the electric blanket is to stop working and not generate heat, pull out the power switch (2), disconnect the AC power supply, force the entire circuit to enter the unlocked power-off state, and the electric heating wires are also powered off and stop generating heat. At this time, if the power switch (2) is turned on again, the entire circuit is still in the unlocked state due to the self-locking function. If the electric blanket is to be powered on again to generate heat, the normally open button in the overheat and flash protection control circuit (9) needs to be activated again to put the entire circuit into the working state again and lock it in the continuous self-locking power-on state again.

[0011] Principle of high-temperature protection and control: When the electric blanket is in an abnormal state of non-normal use, the outer heating wire (5) and the inner heating wire (6) of the membrane are partially overheated, and the actual temperature will be much higher than the normal working temperature, causing the impedance of the temperature-sensing diaphragm (7) between the two heating wires to be very small (large leakage current), and finally quickly melt and open a hole, so that a short circuit is formed somewhere between the two heating wires, causing the voltage between the two AC detection input terminals (X1, X1) of the temperature detection and disconnection detection circuit (8) to disappear, and its detection output voltage also disappears, forcing the protection and control switches K1 and K2 in the overheat and flash protection control circuit (9) to be turned off and disconnect the AC power supply, and then the entire circuit enters the unlocked power-off state, and the two heating wires are also powered off and stop heating, and cannot be automatically powered on. Thus, the overheat protection and control of the electric blanket is realized.

[0012] Principle of preventing runaway: The AC power required for the normal heating of the electric blanket needs to be turned on simultaneously by the protection switch in the overheat and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10), and continuously self-locked in the locked power-on state, so as to maintain the connection of the AC power of the two heating wires. When an abnormal open circuit or a short circuit occurs somewhere in the power-on links of the two heating wires and the temperature detection and disconnection detection circuit (8) and the overheat and flash protection control circuit (9) and the zero-through temperature control circuit (10), the self-locking condition for maintaining the locked power is destroyed, and the power is automatically unlocked and cut off, so that the protection control circuit of the electric blanket will not lose control when it is overheated, and the overheat protection control function will never fail, completely eliminating the safety hazards and defects of the original electric blanket. Thus, the desire of providing users with a truly safe electric blanket that is fully protected against high-temperature runaway is realized.

[0013] Principle of preventing flash fire: When the outer heating wire (5) or the inner heating wire (6) breaks somewhere inside, it takes a certain time for the electric charge stored in the capacitor in the temperature detection and disconnection detection circuit (8) to discharge. Therefore, the overheating and flash fire protection control circuit (9) also needs to delay for a period of time after the heating wire breaks before cutting off the AC power supply. As long as the discharge time of the capacitor in the temperature detection and disconnection detection circuit (8) exceeds the cut-off power-off time of the final controller in each cycle of the zero-pass temperature control circuit (10), it will not affect the normal and stable power-on and heating of the outer heating wire (5) and the inner heating wire (6). If the break time of the outer heating wire (5) or the inner heating wire (6) exceeds the discharge time of the capacitor in the temperature detection and disconnection detection circuit (8), the overheating and flash fire protection control circuit (9) loses the maintenance current, forcing the protection switch in the overheating and flash fire protection control circuit (9) to cut off and disconnect the AC power supply, resulting in automatic unlocking and power off, and the device will always be locked in the unlocked state of power off. This technical measure is to prevent the arc flash (sparking) time from being too long after the two electric heating wires are broken, causing local overheating and igniting the electric blanket fabric, avoiding fire and ensuring personal and property safety. It can be seen that the wire break protection function in the present invention further thoroughly, reliably and effectively eliminates the safety hazards and defects of the electric blanket. Therefore, the present invention is a truly safe electric blanket that is fully protected against high-temperature runaway.

[0014] Beneficial effects and technical advantages of the present invention:

[0015] 1. After a temperature-sensing diaphragm is sandwiched between two parallel electric heating wires, a temperature detection and disconnection detection circuit (8) is connected in series downstream, and then the temperature detection voltage output by the temperature detection and disconnection detection circuit (8) is used to connect and control the overheating and flashover protection control circuit (9) and the zero-through temperature control circuit (10). The circuit structure is extremely simple, low in cost, and high in cost performance; the temperature detection or temperature sensing dedicated wire that must be used in the previous safety electric heating blanket is omitted, and only the temperature-sensing diaphragm is directly used as a temperature sensing device, and the two parallel electric heating wires also serve as temperature sensing signal sensors. The temperature detection and line break detection circuit (8) cooperates with the overheating and flashover protection control circuit (9), which not only has the overheating protection control function, but also has the protection control function of preventing the electric heating wire (wire) from breaking and flashing (sparking), and can also prevent these two protection control functions from being out of control or failing due to circuit failure; the overheating protection performance effect of each point in the entire electric heating line is consistent, and the overheating protection control response speed is extremely fast, and the anti-failure or anti-runaway performance is constant and reliable, ensuring that it will be effective when the AC power supply needs to be disconnected, and can always fully ensure the safety of people and property. Therefore, the present invention is a fully anti-high-temperature runaway electric blanket that is absolutely safe. The present invention can also be used as a must-safe controller for other electric heating bodies.

[0016] 2. The zero-pass temperature control circuit (10) also cleverly uses the temperature detection voltage output by the temperature detection and disconnection detection circuit (8) as the temperature control signal (Vki ), detect the temperature of the two heating wires, can simply modulate the pulse width according to the temperature control requirements, and synchronously adjust the power-on time of the two heating wires in each pulse cycle, so as to automatically control the temperature of the electric blanket on demand; adopt the method of zero-crossing triggering thyristor conduction (abbreviated as zero-through method), which does not generate harmonic interference to the use environment and power grid.

[0017] 3. The present invention thoroughly solves the technical problem that electric blankets in the past could not prevent abnormal faults and runaway, completely eliminates the hidden dangers and defects of false safety in electric blankets in the past, and perfectly realizes that the overheating protection control function of the entire circuit will never fail under various normal or abnormal conditions, or will never lose control during the entire life cycle, and can always truly ensure the safety of people and property. It can be seen that the present invention is a truly safe electric blanket that is fully protected against high-temperature runaway. Its superior performance and control principle have a wider range of versatility and can be applied to all technical fields that require safe control of electric heating bodies. The present invention ensures the safety of life and property of the majority of users, and is of course beneficial to public safety. It has important practical value and social benefits. It is expected to become a necessary patent required for the revision and upgrade of national mandatory technical standards in the field of electric blankets and electric heating safety control. There is also an opportunity for our country's national standards in the field of electric blankets and electric heating safety control to lead the upgrade of international standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the energy frame structure diagram of the present invention;

[0019] Figure 2 1 is a circuit diagram of a specific embodiment of the present invention;

[0020] Figure 3 It is a circuit schematic diagram of specific embodiment 2 of the present invention.

[0021] exist Figure 1 In it: (1) is a fuse, (2) is a power switch, (5) is an electric heating wire outside the membrane, (6) is an electric heating wire inside the membrane, (7) is a temperature sensing diaphragm, (8) is a temperature detection and disconnection detection circuit, (9) is an overheating and flash fire protection control circuit, and (10) is a zero-through temperature control circuit. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0023] 1. Specific description of the technical solution of the present invention:

[0024] The energy frame structure diagram of the present invention is as follows: Figure 1As shown, (1) is a fuse, (2) is a power switch, (5) is an electric heating wire outside the membrane, (6) is an electric heating wire inside the membrane, (7) is a temperature sensing diaphragm, (8) is a temperature detection and disconnection detection circuit, (9) is an overheating and flash fire protection control circuit, and (10) is a zero-through temperature control circuit. A fuse (1) is connected in series between one power side (L1) of the power switch (2) and one input end (L) of the AC power supply, the other power side (N1) of the power switch (2) is directly connected to the other input end (N) of the AC power supply, a load side (L2) of the power switch (2) is connected to the protection switch K1 end in the overheating and flashover protection control circuit (9), the other load side (N2) of the power switch (2) is connected to the tail end (b) of the membrane heating wire (6) and the AC input end (Z) of the zero-through temperature control circuit (10), and the head end (A) of the membrane heating wire (5) is connected to the terminal controller Y end in the zero-through temperature control circuit (10) and the overheating and flashover protection control circuit (9). The control circuit (9) has an electric heating start end (Q), and the temperature sensing diaphragm (7) sandwiched between the outer heating wire (5) and the inner heating wire (6) is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperature, reduced impedance and increased leakage when the temperature rises, and melting and opening holes at high temperature, resulting in direct contact and short circuit between the two wires; an AC detection input end (X1) of the temperature detection and disconnection detection circuit (8) is connected to the head end (a) of the inner heating wire (6), and another AC detection input end (X2) of the temperature detection and disconnection detection circuit (8) is connected to the tail end (B) of the outer heating wire (5), and the detection output positive electrode (V +1 ) is connected in parallel to the positive input terminal (V + ) and the positive electrode (V +3 ), the temperature detection and disconnection detection circuit (8) detects the output negative pole (V -1 ) is connected in parallel to the negative input terminal (V - ) and the temperature control input terminal (V ki ); the protection switch K2 end of the protection control circuit (9) is connected to the H end of the terminal controller in the zero-through temperature control circuit (10).

[0025] Figure 1 Here’s how it works:

[0026] Temperature control principle: When the electric blanket needs to be put into heating operation, first turn on the power switch (2), then press the normally open button in the overheating and flashover protection control circuit (9), connect the protection switch K1 end and the electric heating start end (Q) in the overheating and flashover protection control circuit (9), so that the AC current passes through the outer membrane heating wire (5) and the temperature detection and disconnection detection circuit (8) and the inner membrane heating wire (6), and also makes the AC input end (Z) and the final control end in the zero-through temperature control circuit (10) The Y end of the device receives AC power input, thereby starting the entire circuit to enter the working state: the outer membrane heating wire (5) and the inner membrane heating wire (6) are energized and start to heat up, and the temperature-sensitive diaphragm (7) sandwiched between the two heating wires naturally assumes the role of a temperature sensor. A temperature detection voltage is output between the positive and negative poles of the detection output of the temperature detection and disconnection detection circuit (8). On the one hand, it controls the conduction of the two ends of the protection switch K1 and K2 in the overheating and flashover protection control circuit (9), and on the other hand, the negative pole (V -1 ) controls the temperature control input terminal (V ki), so that the two ends H and Y of the final controller in the zero-through temperature control circuit (10) are also turned on; after the protection switch and the final controller are powered on at the same time, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) continue to obtain AC power, and then the protection switch in the overheating and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10) are simultaneously locked in a continuous power-on state. At this time, after releasing the normally open button, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) and the overheating and flash protection control circuit (9) can continue to obtain AC power, so that the protection switch and the final controller are still locked in a continuous power-on state. Therefore, the two heating wires can continue to generate heat after the alternating current passes through them stably, so that the working temperature of the electric blanket gradually increases. Subsequently, the temperature detection and disconnection detection circuit (8) outputs a detection voltage to control the pulse width in the zero-pass temperature control circuit (10) according to the temperature of the two heating wires detected by the temperature-sensitive diaphragm (7). Finally, the final controller controls the length of the power-on time in each cycle according to the pulse width, thereby automatically controlling the heating value or temperature of the two heating wires. At the beginning of power-on, the temperature of the two heating wires is relatively low, the impedance of the temperature sensing diaphragm (7) is relatively large, the leakage current is relatively small, the detection voltage difference output by the temperature detection and disconnection detection circuit (8) is relatively large, the pulse width of the zero-pass temperature control circuit (10) is widened in each cycle, and the power-on time of the final controller is extended, so that the heat generated by the two heating wires increases and the temperature rises; on the contrary, if the temperature of the two heating wires is relatively high, the impedance of the temperature sensing diaphragm (7) is relatively small, the leakage current is relatively large, the detection voltage difference output by the temperature detection and disconnection detection circuit (8) is relatively small, the pulse width of the zero-pass temperature control circuit (10) is narrowed in each cycle, and the power-on time of the final controller is shortened, so that the heat generated by the two heating wires decreases and the temperature drops; in this cycle, the temperature of the two heating wires is automatically controlled within the set range. In normal use, the working temperature of the electric blanket should be within the range that the human body feels comfortable. If the electric blanket is to stop working and not generate heat, pull out the power switch (2), disconnect the AC power supply, force the entire circuit to enter the unlocked power-off state, and the electric heating wires are also powered off and stop generating heat. At this time, if the power switch (2) is turned on again, the entire circuit is still in the unlocked state due to the self-locking function. If the electric blanket is to be powered on again to generate heat, the normally open button in the overheat and flash protection control circuit (9) needs to be activated again to put the entire circuit into the working state again and lock it in the continuous self-locking power-on state again.

[0027] Principle of high-temperature protection and control: When the electric blanket is in an abnormal state of non-normal use, the outer heating wire (5) and the inner heating wire (6) of the membrane are partially overheated, and the actual temperature will be much higher than the normal working temperature, causing the impedance of the temperature-sensing diaphragm (7) between the two heating wires to be very small (large leakage current), and finally quickly melt and open a hole, so that a short circuit is formed somewhere between the two heating wires, causing the voltage between the two AC detection input terminals (X1, X1) of the temperature detection and disconnection detection circuit (8) to disappear, and its detection output voltage also disappears, forcing the protection and control switches K1 and K2 in the overheat and flash protection control circuit (9) to be turned off and disconnect the AC power supply, and then the entire circuit enters the unlocked power-off state, and the two heating wires are also powered off and stop heating, and cannot be automatically powered on. Thus, the overheat protection and control of the electric blanket is realized.

[0028] Principle of preventing runaway: The AC power required for the normal heating of the electric blanket needs to be turned on simultaneously by the protection switch in the overheat and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10), and continuously self-locked in the locked power-on state, so as to maintain the connection of the AC power of the two heating wires. When an abnormal open circuit or a short circuit occurs somewhere in the power-on links of the two heating wires and the temperature detection and disconnection detection circuit (8) and the overheat and flash protection control circuit (9) and the zero-through temperature control circuit (10), the self-locking condition for maintaining the locked power is destroyed, and the power is automatically unlocked and cut off, so that the protection control circuit of the electric blanket will not lose control when it is overheated, and the overheat protection control function will never fail, completely eliminating the safety hazards and defects of the original electric blanket. Thus, the desire of providing users with a truly safe electric blanket that is fully protected against high-temperature runaway is realized.

[0029] Principle of preventing flash fire: When the outer heating wire (5) or the inner heating wire (6) breaks somewhere inside, it takes a certain time for the electric charge stored in the capacitor in the temperature detection and disconnection detection circuit (8) to discharge. Therefore, the overheating and flash fire protection control circuit (9) also needs to delay for a period of time after the heating wire breaks before cutting off the AC power supply. As long as the discharge time of the capacitor in the temperature detection and disconnection detection circuit (8) exceeds the cut-off power-off time of the final controller in each cycle of the zero-pass temperature control circuit (10), it will not affect the normal and stable power-on and heating of the outer heating wire (5) and the inner heating wire (6). If the break time of the outer heating wire (5) or the inner heating wire (6) exceeds the discharge time of the capacitor in the temperature detection and disconnection detection circuit (8), the overheating and flash fire protection control circuit (9) loses the maintenance current, forcing the protection switch in the overheating and flash fire protection control circuit (9) to cut off and disconnect the AC power supply, resulting in automatic unlocking and power off, and the device will always be locked in the unlocked state of power off. This technical measure is to prevent the arc flash (sparking) time from being too long after the two electric heating wires are broken, causing local overheating and igniting the electric blanket fabric, avoiding fire and ensuring personal and property safety. It can be seen that the wire break protection function in the present invention further thoroughly, reliably and effectively eliminates the safety hazards and defects of the electric blanket. Therefore, the present invention is a truly safe electric blanket that is fully protected against high-temperature runaway.

[0030] 2. Specific description of the preferred specific embodiment 1 of the present invention:

[0031] The preferred specific embodiment 1 of the present invention is a circuit diagram, as shown in FIG. Figure 2As shown, the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a hot-melt film RMG fully sandwiched between the heating wire WR2 and the heating wire WR1; the temperature detection and disconnection detection circuit (8) includes diodes 2D1 to 2D4, a capacitor 2C1, a resistor 2R10, and a high-current light-emitting diode 2LED; the overheating prevention and The anti-flash protection control circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a phototransistor GMT, and a resistor 2R15, or the resistors 2R15 can be replaced by an electromagnetic relay J and a diode 2D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 2IC, a solid-state relay SSD2, a transistor 2VT1, a transistor 2VT2, voltage-stabilizing diodes 2WD1 to 2WD3, diodes 2D6 to 2D8, a potentiometer 2RP, resistors 2R1 to 2R3, resistors 2R5, 2R6, 2R8, 2R11, 2R12, capacitors 2C2, 2C3, 2C6, wherein the integrated circuit 2IC is selected as a core component. A circuit module for preventing loss of control and preventing failure or a circuit module with equivalent functions is used; the circuit connection method is as follows: a fuse FS is connected in series between a power side (L1) of the power switch DK and an input end (L) of the AC power supply, another power side (N1) of the power switch DK is directly connected to another input end (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input end (Z) of the primary winding (n1) in the transformer BY, and another AC input end of the primary winding (n1) in the transformer BY is connected to the AC end (Y) of the bidirectional thyristor in the solid-state relay SSD2 and the first end (Y) of the heating wire WR2. The terminal (A) and the electric heating start terminal (Q) of the normally open button CKA, the temperature sensing diaphragm RMG sandwiched between the heating wire WR1 and the heating wire WR2 is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperature, reduced impedance and increased leakage when heated, and melting and opening holes at high temperature, resulting in direct contact and short circuit between the two wires; an AC output terminal of the secondary winding (n2) in the transformer BY is connected to an AC input terminal (~) of the rectifier bridge QD, the other AC output terminal of the secondary winding (n2) in the transformer BY is connected to the other AC input terminal (~) of the rectifier bridge QD, and the DC voltage positive electrode (V +2 ) connects the anode of diode 2D6 and resistor 2R1, and the negative pole of the DC voltage output by the rectifier bridge QD (V -2) connects one end of capacitor 2C3 and the negative electrode of capacitor 2C2 and the positive electrode of voltage regulator diode 2WD3 as the ground terminal (GND) of the DC power supply in the zero-pass temperature control circuit (10); the positive electrode of diode 2D1 is connected to the negative electrode of diode 2D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 2D4 is connected to the negative electrode of diode 2D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 2D2 and 2D3 are connected to the negative electrode of capacitor 2C1 as the negative DC electrode (V -1 ) is then connected to the emitter of the phototransistor GMT and the cathode of the high current light emitting diode 2LED, and the cathodes of the diodes 2D1 and 2D4 are connected to the anode of the capacitor 2C1 as the DC positive electrode (V +1 ) and then connect the positive electrode of the light-emitting diode in the solid-state relay SSD1, one end of the resistor 2R10, and the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 2R15, the other end of the resistor 2R15 is connected to the collector of the phototransistor GMT, and the other end of the resistor 2R10 is connected to the anode of the high-current light emitting diode 2LED; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; or the solid-state relay SSD1, the phototransistor GMT, the high-current light emitting diode 2LED, the resistors 2R10 and 2R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 2D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the coil of the electromagnetic relay J and the anode of the diode 2D5 are connected in parallel to the negative DC pole (V -1), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, and the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; the cathode of the light-emitting diode in the solid-state relay SSD2 is connected to the collector of the transistor 2VT2, the anode of the light-emitting diode is connected to one end of the resistor 2R3, the other end of the resistor 2R3 is connected to the collector of the transistor 2VT1, the emitter of the transistor 2VT1 is connected to the anodes of the capacitors 2C2 and 2C1, the base of the transistor 2VT1 is connected to the cathode of the voltage-stabilizing transistor 2WD1, the anode of the voltage-stabilizing transistor 2WD1 is connected to one end of each of the resistors 2R1 and 2R11, and the other end of 2R1 is used as the zero-crossing trigger input end (V) of the zero-through temperature control circuit (10) m ) connects the anode of diode 2D6 and the DC voltage positive electrode (V +2 ), the emitter of transistor 2VT2 is connected to the DC power supply ground terminal (GND) of the zero-pass temperature control circuit (10), the base of transistor 2VT2 is connected to the positive electrode of voltage-stabilizing transistor 2WD2, the negative electrode of voltage-stabilizing transistor 2WD2 is connected to one end of resistor 2R12, and the other end of resistor 2R12 is connected to one end of resistor 2R6 and the inverting output terminal (V O2 ), the in-phase output terminal (V O1 ) connects the other end of 2R11, and the two input ends (V i1 、V i2 ) is connected in parallel to one end of the resistor 2R5, the other end of the resistor 2R5 is connected to one end of the capacitor 2C6 and the sliding arm of the potentiometer 2RP, one fixed end of the potentiometer 2RP is connected to the cathode of the diode 2D7, the other fixed end of the potentiometer 2RP is connected to the anode of the diode 2D8, the anode of the diode 2D7 and the cathode of the diode 2D8 are connected in parallel to the other end of the resistor 2R6 and the other end of the resistor 2R2, and the other end of the resistor 2R2 serves as the temperature control input end (V ki ) connects the two positive electrodes of diodes 2D2 and 2D3 and the negative electrode of capacitor 2C1; the negative electrode of diode 2D6 is connected to the other end of capacitor 2C3 and one end of resistor 2R8, and the other end of resistor 2R8 is connected in parallel to the negative electrode of voltage stabilizing diode 2WD3 and the positive electrode of capacitor 2C2 as the positive electrode (V) of the DC power supply of the zero-pass temperature control circuit (10) +3 ), and then connect the positive power input terminal (V + ) and the emitter of transistor 2VT1, the DC power supply positive electrode (V +3 ) is also connected to the positive electrode (V +1 ) and the two cathodes of diodes 2D1 and 2D4; the negative power input terminal (V- ) and the other end of the capacitor 2C6 are connected in parallel to the DC power ground terminal (GND) of the zero-pass temperature control circuit (10).

[0032] Figure 2 The circuit works as follows:

[0033] Temperature control principle: when the electric blanket needs to be put into heating operation, first turn on the power switch DK, then press the normally open button CKA in the overheating and flash protection control circuit (9), turn on the protection switch K1 end and the electric heating start end (Q) in the overheating and flash protection control circuit (9), so that the AC current passes through the rectifier bridge composed of the heating wire WR2 and the diodes 2D1 to 2D4 and the heating wire WR1. On the one hand, the high-current light-emitting diode 2LED is energized to emit light, triggering the photosensitive transistor GMT to turn on, and then the light-emitting diode in the solid-state relay SSD1 is energized to emit light, triggering its bidirectional thyristor to turn on (the protection switch is energized), and on the other hand, the two AC input ends (Z, Y) of the primary winding (n1) of the transformer BY receive AC power, and the zero-pass temperature control circuit (10) is started to enter the working state: after the rectifier bridge QD receives the low-voltage AC power provided by the secondary winding (n2) of the transformer BY, it then outputs a DC fluctuating voltage (V +2 ) as the zero-crossing trigger input signal (V m ), through resistor 2R1 and voltage stabilizing diode 2WD1, transistor 2VT1 is driven to generate a DC fluctuation voltage (V m ) is turned on around zero, and the other path passes through diode 2D6 and resistor 2R8 to the positive electrode of capacitor 2C2 to establish a DC regulated power supply (V +3 ); At the beginning of power-on, due to the low potential of capacitor 2C6, the two input terminals of integrated circuit 2IC are also pulled down (V i1 、V i2 ) potential, so that the in-phase output terminal (V O1 ) output low level, inverting output terminal (V O2 ) outputs a high level, mainly because the resistor 2R6 starts charging the capacitor 2C6 through the diode 2D7 and the potentiometer 2RP sliding arm. When the potential of the capacitor 2C6 rises to 2 / 3 (V +3 ) is above, the state of the bistable circuit in the integrated circuit 2IC is triggered to flip, so that the in-phase output terminal (V O1 ) output high level, inverting output terminal (V O2 ) outputs a low level. At this time, the charge of capacitor 2C6 begins to pass through potentiometer 2RP, diode 2ID8, resistor 2R6, and the inverting output terminal (V O2 ) discharges to the ground terminal (GND). When the potential of capacitor 2C6 drops below 1 / 3 (V+3 ) is below, the state of the bistable circuit in the integrated circuit 2IC is flipped, and the in-phase output terminal (V O1 ) output low level, inverting output terminal (V O2 ) outputs a high level, so the resistor 2R6, the diode 2D7, and the potentiometer 2RP sliding arm can charge the capacitor 2C6. In this way, the rising and falling potentials formed by the charging and discharging of the capacitor 2C6 in a cycle continuously and alternately trigger the two input terminals of the integrated circuit 2IC, so that the state of the bistable circuit in the integrated circuit 2IC continuously flips to form an oscillation. O1 、V O2 ) will each continuously output alternating high and low levels, and the high levels at intervals form a periodic square wave. When the sliding arm of potentiometer 2RP moves up, charging speeds up and discharging slows down, which can narrow the square wave width; when the sliding arm of potentiometer 2RP moves down, charging slows down and discharging speeds up, which can widen the square wave width. It can be seen that moving the sliding arm of potentiometer 2RP up and down can only adjust the square wave width (or pulse width), but the oscillation period remains unchanged. The inverting output terminal (V O2 ) During the high level output period (pulse width), resistor 2R12 and voltage stabilizing diode 2WD2 push transistor 2VT2 to conduct, and then transistor 2VT1 is in the DC fluctuation voltage (V m ) is turned on around zero, then the light-emitting diode in the solid-state relay SSD2 lights up and triggers the bidirectional thyristor to turn on (the two ends of the final controller H and Y are turned on). At this point, the entire circuit has fully entered the working state: the outer membrane heating wire WR2 and the inner membrane heating wire WR1 are energized and start to heat up, and the temperature-sensitive diaphragm RMG sandwiched between the two heating wires naturally plays the role of a temperature sensor. The temperature detection and disconnection detection circuit (8) has a temperature detection voltage output at both ends of the capacitor 2C1. On the one hand, the high-current light-emitting diode 2LED triggers the phototransistor GMT to turn on, and then the light-emitting diode in the solid-state relay SSD1 lights up and triggers its bidirectional thyristor to turn on (the protection switch is energized). On the other hand, the detection output (V -1 ) is connected to the temperature control input terminal (V ki), the pulse width of the square wave oscillation circuit can also be appropriately controlled through the resistor 2R2. When the AC power source passes zero within the pulse width of each oscillation cycle, the light-emitting diode in the solid-state relay SSD2 is illuminated to trigger the bidirectional thyristor H and Y ends to be turned on (the ends of the final controller H and Y are turned on). After the protection switch and the final controller are powered on at the same time, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) continue to obtain the AC power supply, and then the protection switch in the overheating and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10) are simultaneously self-locked in a continuous power-on state. At this time, after releasing the normally open button CKA, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) and the overheating and flash protection control circuit (9) can continue to obtain the AC power supply, so that the protection switch and the final controller (the bidirectional thyristor in the solid-state relays SSD1 and SSD2) are still locked in a continuous power-on state. Therefore, the two heating wires can continue to generate heat after AC current passes through them stably, so that the working temperature of the electric blanket gradually increases. Then, the capacitor 2C1 in the temperature detection and disconnection detection circuit (8) outputs a detection voltage (V +1 ) controls the pulse width in the zero-pass temperature control circuit (10), and finally the final controller (bidirectional thyristor in the solid-state relay SSD2) controls the duration of the power-on time in each cycle according to the pulse width, so as to automatically control the heat generation or temperature of the two heating wires. At the beginning of power-on, the temperature of the two heating wires is relatively low, so that the impedance of the temperature sensing diaphragm RMG is relatively large, the leakage is relatively small, and the voltage difference detected by the capacitor 2C1 is relatively large, which is equivalent to the temperature control input terminal (V ki ) to the ground (GND) potential is reduced, and the pulse width of the integrated circuit 2IC is widened in each cycle through the resistor 2R2. Finally, the final controller (bidirectional thyristor in the solid-state relay SSD2) controls the power-on time in each cycle according to the pulse width, which increases the heat generated by the two heating wires and increases the temperature. On the contrary, if the temperature of the two heating wires is high, the impedance of the temperature-sensing diaphragm RMG is small, the leakage is large, and the voltage difference detected by the capacitor 2C1 is small, which is equivalent to the temperature control input terminal (V ki) The potential of the ground terminal (GND) increases, and the pulse width of the integrated circuit 2IC is narrowed in each cycle through the resistor 2R2. Finally, the final controller (bidirectional thyristor in the solid-state relay SSD2) controls the power-on time in each cycle according to the pulse width to shorten the power-on time, so that the heat generated by the two heating wires is reduced and the temperature is lowered; in this cycle, the temperature of the two heating wires is automatically controlled within the set range. In addition, by adjusting the potentiometer 2RP to change the pulse width, the temperature can be set or adjusted manually. By moving the potentiometer 2RP up and narrowing the pulse width, the set temperature can be lowered; conversely, by moving the potentiometer 2RP down and widening the pulse width, the set temperature can be increased. During normal use, the working temperature of the electric blanket should be within the range that the human body feels comfortable. If the electric blanket is to stop working and not generate heat, disconnect the power switch DK, cut off the AC power supply, force the entire circuit to enter the unlocked and power-off state, and the heating wire will also be powered off and stop generating heat. At this time, if the power switch DK is turned on again, the entire circuit is still in the unlocked state of power off due to the self-locking function. If the electric blanket is to be powered on again to generate heat, the normally open button CKA in the overheat and flash protection control circuit (9) needs to be activated again to put the entire circuit into working state again and lock it in the continuous self-locking power-on state again.

[0034] Principle of high-temperature protection and control: When the electric blanket is in an abnormal state of non-normal use, the heating wire WR1 and the heating wire WR2 are partially overheated, and the actual temperature will be much higher than the normal working temperature, causing the temperature sensing diaphragm RMG between the two heating wires to have a very small impedance (large leakage current), and finally quickly melt and open a hole, so that a short circuit is formed somewhere between the two heating wires, causing the voltage between the two AC detection input terminals (X1, X1) of the temperature detection and disconnection detection circuit (8) to disappear, and the detection output voltage of the capacitor 2C1 also disappears quickly, forcing the protection and control switch (bidirectional thyristor in the solid-state relay SSD1) in the overheating and flash protection control circuit (9) to cut off the AC current at both ends of K1 and K2, and then the entire circuit enters the unlocked power-off state, and the two heating wires are also powered off and stop heating, and cannot be automatically powered on. Thus, the overheat protection and control of the electric blanket is realized.

[0035] Principle of preventing runaway: The AC power required for the normal heating of the electric blanket needs to be turned on simultaneously by the protection switch (bidirectional thyristor in solid-state relay SSD1) in the overheat and flash protection control circuit (9) and the final controller (bidirectional thyristor in solid-state relay SSD2) in the zero-through temperature control circuit (10), and continuously self-locked in the locked power-on state, so as to maintain the connection of the AC power of the two heating wires. When an abnormal open circuit or a short circuit occurs somewhere in the power-on links of the two heating wires and the temperature detection and disconnection detection circuit (8) and the overheat and flash protection control circuit (9), the self-locking condition for maintaining the locked power-on is destroyed, and the power is automatically unlocked and cut off, so that the protection control circuit of the electric blanket will not lose control when it is overheated, and the overheat protection control function will never fail, completely eliminating the safety hazards and defects of the original electric blanket. Thus, the desire of providing users with a truly safe electric blanket that is fully protected against high-temperature runaway is realized.

[0036] Principle of preventing flashover: When a break occurs somewhere inside the heating wire WR1 and the heating wire WR2, it takes a certain amount of time for the electric charge stored in the capacitor 2C1 in the temperature detection and disconnection detection circuit (8) to discharge. Therefore, the protection switch (bidirectional thyristor in the solid-state relay SSD1) in the overheating and flashover protection control circuit (9) also needs to delay for a period of time before cutting off the AC power supply after the heating wire breaks. As long as the discharge time of the capacitor 2C1 in the temperature detection and disconnection detection circuit (8) exceeds the cut-off power-off time of the final controller (bidirectional thyristor in the solid-state relay SSD2) in the zero-through temperature control circuit (10) in each oscillation cycle, the heating wire WR1 and the heating wire WR2 will not be affected to be powered on and heated normally and stably. If the break time of the heating wire WR1 and the heating wire WR2 exceeds the discharge time of the capacitor 2C1 in the temperature detection and disconnection detection circuit (8), the light-emitting diode in the solid-state relay SSD1 in the overheat and flash protection control circuit (9) loses the light-emitting current, forcing the protection switch (bidirectional thyristor in the solid-state relay SSD2) in the overheat and flash protection control circuit (9) to cut off and disconnect the AC power supply, resulting in automatic unlocking and power failure, and the electric blanket will always be locked in the unlocked state of power failure. This technical measure is to prevent the arc flash (sparking) time from being too long after the two heating wires are broken, causing local overheating and igniting the electric blanket fabric, avoiding fire and ensuring personal and property safety. It can be seen that the disconnection protection function in the present invention further thoroughly, reliably and effectively eliminates the safety hazards and defects of the electric blanket. Therefore, the present invention is a truly safe electric blanket that is fully protected against high-temperature runaway.

[0037] 3. Specific description of the preferred specific embodiment 2 of the present invention: (optimized for 3.0 positive image)

[0038] The circuit diagram of the preferred embodiment 2 of the present invention is as follows: Figure 3As shown, the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a temperature-sensitive diaphragm RMG fully sandwiched between the heating wires WR2 and WR1; the temperature detection and disconnection detection circuit (8) includes diodes 3D1 to 3D4, a capacitor 3C1, and a resistor 3R10; the overheating and flashover protection control The circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a varistor YR, a positive temperature coefficient thermistor PTC, resistors 3R13 and 3R15, or they can be replaced by an electromagnetic relay J and a diode 3D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 3IC, a photocoupler GDH, a bidirectional thyristor SCR, a transistor 3VT, a light-emitting diode 3LED, a voltage-stabilizing diode 3WD3, diodes 3D6 to 3D9, resistors 3R1 to 3R9, resistors 3R11 and 3R12, and capacitors 3C2 to 3C6, wherein the integrated circuit 3IC is used as a core device to select a time base circuit. Circuit 555 or a circuit module with equivalent functions; circuit connection mode: a fuse FS is connected in series between a power side (L1) of the power switch DK and an input end (L) of the AC power supply, another power side (N1) of the power switch DK is directly connected to another input end (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input end (Z) of the primary winding (n1) in the transformer BY, and another AC input end of the primary winding (n1) in the transformer BY is connected to the AC end (Y) of the bidirectional thyristor SCR and the head end (A) of the heating wire WR2 and the normally open The electric heating start end (Q) of the button CKA; the temperature sensing diaphragm RMG sandwiched between the heating wires WR1 and WR2 is a hot-melt film made of semiconductor nylon thermoplastic material, which has the characteristics of insulation isolation at low temperatures, reduced impedance and increased leakage when heated, and melting and opening holes at high temperatures, resulting in direct contact and short circuit between the two wires; an AC output end of the secondary winding (n2) in the transformer BY is connected to an AC input end (~) of the rectifier bridge QD, the other AC output end of the secondary winding (n2) in the transformer (3) is connected to the other AC input end (~) of the rectifier bridge QD, and the DC voltage positive electrode (V +2 ) connects the anode of diode 3D6 and resistor 3R1, and the negative pole of the DC voltage output by rectifier bridge QD (V -2) connects one end of capacitor 3C3 and the negative electrode of capacitor 3C2 and the positive electrode of voltage regulator diode 3WD3 as the DC power ground terminal (GND) in the zero-pass temperature control circuit (10); the positive electrode of diode 3D1 is connected to the negative electrode of diode 3D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 3D4 is connected to the negative electrode of diode 3D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 3D2 and 3D3 are connected to the negative electrode of capacitor 3C1 as the DC negative electrode (V -1 ) and then connected to one end of the positive temperature coefficient thermistor PTC and one end of the resistor 3R10 and one end of the resistor 3R2, the cathodes of the diodes 3D1 and 3D4 are connected to the anode of the capacitor 3C1 as the DC anode (V +1 ) and then connected to the positive electrode of the light-emitting diode in the solid-state relay SSD1 and one end of the varistor YR and the other end of the resistor 3R10, and also connected to the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 3R15, the other end of the resistor 3R15 is connected to the other end of the varistor YR and one end of the resistor 3R13, and the other end of the resistor 3R13 is connected to the other end of the positive temperature coefficient thermistor PTC; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor SCR and one end of the resistor 3R9 and one end of the capacitor 3C4; or the solid-state relay SSD1, the varistor YR, the positive temperature coefficient thermistor PTC, the resistors 3R10, 3R13, 3R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 3D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the electromagnetic relay J coil and the anode of the diode 3D5 are connected in parallel to the negative DC pole (V -1), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor SCR, one end of the resistor 3R9 and one end of the capacitor 3C4; the other end of the capacitor 3C4 is connected to one end of the resistor 3R11, the other end of the resistor 3R9 is connected to an AC end of the bidirectional thyristor in the photoelectric coupler GDH, the other AC end of the bidirectional thyristor in the photoelectric coupler GDH is connected to one end of the resistor 3R12 and the control electrode (G) of the bidirectional thyristor SCR, the AC end (Y) of the bidirectional thyristor SCR is internally connected to the other end of the resistor 3R11 and the other end of the resistor 3R12 and the other AC input end of the primary winding (n1) in the transformer BY, and is externally connected. The first end (A) of the electric heating wire WR2 and the electric heating start end (Q) of the normally open button CKA are connected; the cathode of the light-emitting diode in the photoelectric coupler GDH is connected to the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the anode of the light-emitting diode in the photoelectric coupler GDH is connected to the cathode of the light-emitting diode 3LED; the anode of the light-emitting diode 3LED is connected to one end of the resistor 3R3 and the collector of the transistor 3VT; the emitter of the transistor 3VT is connected to one end of the resistor 3R4 and the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the other end of the resistor 3R4 is connected to one end of the resistor 3R1 and the anode of the diode 3D9; the cathode of the diode 3D9 is connected to the base of the transistor 3VT; the other end of the resistor 3R1 serves as the zero-crossing trigger input end (V m ) is connected to the positive DC voltage output by the rectifier bridge QD (V +2 ) and the anode of diode 3D6; the cathode of diode 3D6 is connected to the other end of capacitor 3C3 and one end of resistor 3R8, and the other end of resistor 3R8 is connected in parallel to the cathode of voltage-stabilizing diode 3WD3 and the anode of capacitor 3C2 as the positive electrode (V) of the DC power supply in the zero-pass temperature control circuit (10). +3 ), and then connect one end of the resistor 3R5 and the 8th and 4th pins of the time base circuit 555 and the DC positive electrode (V +1); the third pin of the time base circuit 555 is connected to the other end of the resistor 3R3, the fifth pin thereof is connected to one end of the capacitor 3C5, the first pin thereof is connected to the ground terminal (GND) of the DC power supply and the other end of the capacitor 3C5 and one end of the capacitor 3C6, the second and sixth pins thereof are connected in parallel to the other end of the capacitor 3C6 and the sliding arm of the potentiometer 3RP, the fixed end of the potentiometer 3RP is connected to the cathode of the diode 3D7, the other fixed end of the potentiometer 3RP is connected to one end of the resistor 3R6, the other end of the resistor 3R6 is connected to the anode of the diode 3D8, the cathode of the diode 3D8 is connected to the anode of the diode 3D7, and then connected to one end of each of the resistors 3R2 and 3R7 and the other end of the resistor 3R5, the other end of the resistor 3R7 is connected to the seventh pin of the time base circuit 555; the other end of the resistor 3R2 is used as the temperature control input end (V ki ) connects the anodes of diodes 3D2 and 3D3 and the cathode of capacitor 3C1.

[0039] Figure 3 The working principle of the circuit is as follows: (optimized for 3.0 positive diagram)

[0040] Temperature control principle: when the electric blanket needs to be put into heating operation, first turn on the power switch DK, then press the normally open button CKA in the overheating and flashover protection control circuit (9), turn on the protection switch K1 end and the electric heating start end (Q) in the overheating and flashover protection control circuit (9), so that the AC current passes through the rectifier bridge composed of the heating wire WR2 and the diodes 3D1 to 3D4 and the heating wire WR1. On the one hand, the light-emitting diode in the solid-state relay SSD1 is energized and illuminated to trigger its bidirectional thyristor to conduct (the protection switch is energized), and on the other hand, the two AC input ends (Z, Y) of the primary winding (n1) of the transformer BY receive AC power, and the zero-through temperature control circuit (10) is started to enter the working state: the rectifier bridge QD obtains the low-voltage AC power provided by the secondary winding (n2) of the transformer BY, and then outputs a DC fluctuating voltage (V +2 ) as the zero-crossing trigger input signal (V m ), through resistor 3R1 and diode 3D9, the transistor 3VT is driven to the DC fluctuation voltage (V m ) is cut off around zero, making the collector of transistor 3VT present a high potential, so that the light-emitting diode in the photocoupler GDH also emits light to trigger the small current thyristor, and then trigger the large current thyristor SCR to turn on; the other path goes through diode 3D6 and resistor 3R8 to the positive electrode of capacitor 3C2 to establish a DC regulated power supply (V +3) is used to power the integrated circuit 3IC and its input and output circuits. At the beginning of power-on, the potential of the capacitor 3C6 on the 2nd and 6th pins of the integrated circuit 3IC is low. At this time, the 3rd and 7th pins of the integrated circuit 3IC both output high levels, so the resistors 3R5, 3R2, the diode 3D7, and the potentiometer 3RP begin to charge the capacitor 3C6. When the potential of the capacitor 3C6 rises to 2 / 3 (V +3 ), the state of the bistable circuit in the integrated circuit 3IC is flipped, so that its 3rd and 7th pins both output low level. After that, the charge of the capacitor 3C6 begins to discharge directly to the ground terminal (GND) through the potentiometer 3RP, the resistor 3R6, the diode 3D8, and the resistor 3R7 to the 7th pin, causing the potential of the 2nd and 6th pins of the integrated circuit 3IC to drop. When this potential is lower than 1 / 3 (V +3 ), the state of the bistable circuit in the integrated circuit 3IC is flipped, so that its 3rd and 7th pins both output high level, so the resistors 3R5, 3R2, diode 3D7, and potentiometer 3RP can charge the capacitor 3C6 again, and the rising and falling potentials formed by the charging and discharging of the capacitor 3C6 in this cycle will continuously and alternately trigger the 2nd and 6th pins of the integrated circuit 3IC, so that the state of the bistable circuit in the integrated circuit 3IC is continuously flipped to form oscillation, and the 3rd and 7th pins of the integrated circuit 3IC continuously and alternately output high and low levels, and the interval high level forms a periodic square wave. When the sliding arm of the potentiometer 2RP moves up, the charging speed is accelerated and the discharging is slowed down, which can narrow the square wave width; when the sliding arm of the potentiometer 2RP moves down, the charging speed is slowed down and the discharging speed is accelerated, which can widen the square wave width. It can be seen that the square wave width (or pulse width) can be adjusted by moving the sliding arm of the potentiometer 2RP up and down, but the oscillation period remains unchanged. During the pulse width, if the collector of transistor 3VT is at a high potential, the light-emitting diode in the photocoupler GDH can emit light to trigger the small current thyristor, and then trigger the large current thyristor SCR to turn on (the two ends of the final controller H and Y are turned on). At this point, the entire circuit has fully entered the working state: the heating wire WR2 and the heating wire WR1 are energized and start to heat up, and the temperature-sensitive diaphragm RMG sandwiched between the two heating wires naturally plays the role of a temperature sensor; the temperature detection and disconnection detection circuit (8) has a temperature detection voltage output at both ends of the capacitor 3C1. On the one hand, the light-emitting diode in the solid-state relay SSD1 emits light to trigger its bidirectional thyristor to turn on (the protection switch is energized), and on the other hand, the negative electrode (V -1 ) is connected to the temperature control input terminal (V ki), the pulse width of the square wave oscillation circuit is controlled by resistor 3R2. When the AC power source passes through zero during the pulse width of each oscillation cycle, the light-emitting diode in the photocoupler GDH can emit light to trigger the small current thyristor, and then trigger the large current thyristor SCR to conduct (the two ends of the final controller H and Y are turned on). After the protection switch and the final controller are powered on at the same time, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-through temperature control circuit (10) continue to obtain AC power, and then the protection switch in the overheat and flash protection control circuit (9) and the final controller in the zero-through temperature control circuit (10) are simultaneously self-locked in a continuous power-on state. At this time, after releasing the normally open button CKA, the two electric heating wires and the temperature detection and disconnection detection circuit (8) and the zero-pass temperature control circuit (10) and the overheat and flash protection control circuit (9) can continue to obtain AC power, so that the protection switch (solid-state relay SSD1) and the final controller (large current bidirectional thyristor SCR) are still locked in the continuous power-on state. Therefore, the two electric heating wires can continue to heat up after the AC current passes through them stably, so that the working temperature of the electric blanket gradually increases. Then, the capacitor 3C1 in the temperature detection and disconnection detection circuit (8) outputs a detection voltage to control the pulse width in the zero-pass temperature control circuit (10) according to the temperature of the two electric heating wires detected by the temperature sensing diaphragm RMG. Finally, the final controller (large current bidirectional thyristor SCR) controls the length of the power-on time in each cycle according to the pulse width, so as to automatically control the heating value or temperature of the two electric heating wires. At the beginning of power-on, the temperature of the two heating wires is low, which makes the temperature sensing diaphragm RMG have a larger impedance and a smaller leakage current. The voltage difference detected by capacitor 3C1 is large, which is equivalent to the temperature control input terminal (V ki ) to the ground terminal (GND), the pulse width of the integrated circuit 3IC is widened in each cycle through the resistor 3R2, and finally the power-on time in each cycle is extended by the final controller (high current bidirectional thyristor SCR) according to the pulse width control, so that the heat generated by the two heating wires increases and the temperature rises; on the contrary, if the temperature of the two heating wires is high, the impedance of the temperature sensing diaphragm RMG is small, the leakage is large, and the voltage difference detected by the capacitor 3C1 is small, which is equivalent to the temperature control input terminal (V ki) The potential of the ground terminal (GND) increases, and the pulse width of the integrated circuit 3IC is narrowed in each cycle through the resistor 3R2. Finally, the final controller (high current bidirectional thyristor SCR) controls the power-on time in each cycle according to the pulse width to shorten the power-on time, so that the heat generated by the two heating wires is reduced and the temperature is lowered; in this cycle, the temperature of the two heating wires is automatically controlled within the set range. In addition, by adjusting the potentiometer 3RP to change the pulse width, the temperature can be manually set or adjusted. By moving the potentiometer 3RP up and narrowing the pulse width, the set temperature can be lowered; conversely, by moving the potentiometer 3RP down and widening the pulse width, the set temperature can be increased. During normal use, the working temperature of the electric blanket should be within the range that the human body feels comfortable. If the electric blanket is to stop working and not generate heat, pull out the power switch DK, disconnect the AC power supply, force the entire circuit to enter the unlocked and power-off state, and the heating wire will also be powered off and stop generating heat. At this time, if the power switch DK is turned on again, the entire circuit is still in the unlocked state of power off due to the self-locking function. If the electric blanket is to be powered on again to generate heat, the normally open button CKA in the overheat and flash protection control circuit (9) needs to be activated again to put the entire circuit into working state again and lock it in the continuous self-locking power-on state again.

[0041] Principle of high-temperature protection and control: When the electric blanket is in an abnormal state of non-normal use, the heating wire WR1 and the heating wire WR2 are partially overheated, and the actual temperature will be much higher than the normal working temperature, causing the temperature sensing diaphragm RMG between the two heating wires to have a very small impedance (large leakage current), and finally quickly melt and open a hole, so that a short circuit is formed somewhere between the two heating wires, causing the voltage between the two AC detection input terminals (X1, X1) of the temperature detection and disconnection detection circuit (8) to disappear, and the detection output voltage of the capacitor 3C1 also disappears quickly, forcing the protection and control switch (bidirectional thyristor in the solid-state relay SSD1) in the overheat and flash protection control circuit (9) to cut off the AC current at both ends of K1 and K2, and then the entire circuit enters the unlocked power-off state, and the two heating wires are also powered off and stop heating, and cannot be automatically powered on. Thus, the overheat protection and control of the electric blanket is realized.

[0042] Principle of preventing loss of control: The AC power required for the normal heating of the electric blanket requires the protection switch (bidirectional thyristor in the solid-state relay SSD1) in the overheat and flash protection control circuit (9) and the final controller (high current bidirectional thyristor SCR) in the zero-pass temperature control circuit (10) to be turned on at the same time and continuously locked in the locked power-on state to maintain the connection of the AC power of the two heating lines. When an abnormal open circuit or some short circuit occurs somewhere in the power-on links of the two electric heating wires, the temperature detection and disconnection detection circuit (8), and the overheating and flash protection control circuit (9), the self-locking condition for maintaining the lock power supply is destroyed (if the resistor 3R10 is open, the varistor YR is short-circuited. If the varistor YR is open, the thermistor PTC impedance is very large, which eventually causes the light-emitting tube in the solid-state relay SSD1 to be powered off and the bidirectional thyristor to be cut off), it will inevitably cause the entire circuit to automatically unlock and power off, so that the protection control circuit of the electric blanket will not lose control when it is overheated, and the overheating protection control function will never fail, completely eliminating the safety hazards and defects of the original electric blanket. Therefore, the desire of providing users with a truly safe electric blanket that is fully protected against high-temperature runaway is realized.

[0043] Principle of preventing flashover: When a break occurs somewhere inside the heating wire WR1 and the heating wire WR2, it takes a certain amount of time for the stored electricity in the capacitor 3C1 in the temperature detection and disconnection detection circuit (8) to discharge. Therefore, the protection switch (bidirectional thyristor in the solid-state relay SSD1) in the overheating and flashover protection control circuit (9) also needs to delay for a period of time before cutting off the AC power supply after the heating wire breaks. As long as the discharge time of the capacitor 3C1 in the temperature detection and disconnection detection circuit (8) exceeds the cut-off power-off time of the final controller (high current bidirectional thyristor SCR) in the zero-pass temperature control circuit (10) in each oscillation cycle, the heating wire WR1 and the heating wire WR2 will not be affected to be powered on and heated normally and stably. If the break time of the heating wire WR1 and the heating wire WR2 exceeds the discharge time of the capacitor 3C1 in the temperature detection and disconnection detection circuit (8), the light-emitting diode in the solid-state relay SSD1 in the overheat and flash protection control circuit (9) loses the light-emitting maintenance current, forcing the protection switch (high-current bidirectional thyristor SCR) in the overheat and flash protection control circuit (9) to cut off and disconnect the AC power supply, resulting in automatic unlocking and power failure, and the electric blanket will always be locked in the unlocked state of power failure. This technical measure is to prevent the arc flash (sparking) time from being too long after the two heating wires are broken, causing local overheating and igniting the electric blanket fabric, avoiding fire and ensuring personal and property safety. It can be seen that the disconnection protection function in the present invention further thoroughly, reliably and effectively eliminates the safety hazards and defects of the electric blanket. Therefore, the present invention is a truly safe electric blanket that is fully protected against high-temperature runaway.

[0044] 4. Additional explanation:

[0045] 1. The solid-state relays SSD1 and SSD2 used in the present invention are both TAC018 solid-state relays, which can directly control the load of 220V AC voltage and 1A current, and can fully meet the power requirement of the electric blanket (far less than 200W).

[0046] 2. The integrated circuit 2IC described in the present invention uses an anti-runaway and anti-failure circuit module or a circuit module with equivalent functions. For example, the anti-runaway circuit chip described in Patent Application No. 201620682543.0 is one of the anti-runaway and anti-failure circuit modules; for example, the stable and effective control circuit chip described in Patent Application No. 2015204058783 is also one of the anti-runaway and anti-failure circuit modules. The basic principle and function of the integrated circuit 2IC (hereinafter referred to as: IC) described in the present invention are as follows: When the two input terminals (V i1 、V i2 ) input is lower than the lower limit potential set in the IC, the IC works in the on state, and the IC's in-phase output terminal (V o1 ) outputs a low potential, the inverting output terminal of the IC (V o2 ) outputs a high potential, which can directly drive the subsequent execution circuit to connect the load power supply; when the two input terminals of the IC (V i1 、V i2 ) input external sensing signal potential is higher than the upper limit potential set in the IC, the IC works in the cut-off state, and the IC's in-phase output terminal (V o1 ) outputs a high potential, the inverting output terminal of the IC (V o2 ) outputs a low potential, which can directly drive the subsequent execution circuit to disconnect the load power supply; the difference between the upper and lower limit potentials is the action hysteresis of the IC switching between the two working states; when the two input terminals of the IC (V i1 、V i2 ) When the external sensing signal potential of the input is lower than the lower limit potential set in the IC due to an abnormal fault (the lower limit is much lower than the lower limit potential), the IC works in the anti-runaway or anti-failure state, and the IC's in-phase output terminal (V o1 ) outputs a high potential, the inverting output terminal of the IC (V o2 ) outputs a low potential, and can also directly drive the subsequent execution circuit to disconnect the power supply of the electric heating load, so that the IC can play an overheating protection role for the electric heating load. It is particularly noted that the stable and effective control circuit chip described in the patent application number 201520405878.3 also has two signal amplification input terminals (V F1 、V F2 ), when not in use, it should be connected to the negative input terminal of the power supply (V - ) together with the ground (GND), Figure 2 The reason why there is no mark in 2IC is because Figure 2The 2IC also needs to adapt to the selection of other non-signal amplification input terminals (V F1 、V F2 ) circuit modules such as anti-loss of control and anti-failure.

Claims

1. A fully thermally runaway-proof electric blanket, comprising a fuse (1) and a power switch (2), characterized in that: It also includes an outer membrane heating wire (5), an inner membrane heating wire (6), a temperature sensing diaphragm (7), a temperature detection and disconnection detection circuit (8), an overheating and flashover protection control circuit (9), and a zero-through temperature control circuit (10); a fuse (1) is connected in series between one power side (L1) of the power switch (2) and one input end (L) of the AC power supply, the other power side (N1) of the power switch (2) is directly connected to the other input end (N) of the AC power supply, a load side (L2) of the power switch (2) is connected to the protection switch K1 end of the overheating and flashover protection control circuit (9), and the other load side (N2) of the power switch (2) is connected to the tail end (b) of the inner membrane heating wire (6) and the zero-through temperature control circuit (10). ), the head end (A) of the outer membrane electric heating wire (5) is connected to the Y end of the terminal controller in the zero-through temperature control circuit (10) and the electric heating start end (Q) in the overheating and flashover protection control circuit (9), and the temperature sensing diaphragm (7) sandwiched between the outer membrane electric heating wire (5) and the inner membrane electric heating wire (6) is a hot-melt film made of semiconductor nylon thermoplastic material; an AC detection input end (X1) of the temperature detection and disconnection detection circuit (8) is connected to the head end (a) of the inner membrane electric heating wire (6), and the other AC detection input end (X2) of the temperature detection and disconnection detection circuit (8) is connected to the tail end (B) of the outer membrane electric heating wire (5), and the detection output positive pole (V +1 ) is connected in parallel to the positive input terminal (V + ) and the positive electrode (V +3 ), the temperature detection and disconnection detection circuit (8) detects the output negative pole (V -1 ) is connected in parallel to the negative input terminal (V - ) and the temperature control input terminal (V ki ); the protection switch K2 end in the overheat and flash protection control circuit (9) is connected to the terminal H end in the zero-through temperature control circuit (10); the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a hot-melt film RMG sandwiched between the heating wires WR2 and WR1; the temperature detection and disconnection detection circuit (8 ) includes diodes 2D1 to 2D4, capacitor 2C1, resistor 2R10, and high current light emitting diode 2LED; the overheat and flash protection control circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a phototransistor GMT, and a resistor 2R15, or it can be replaced by an electromagnetic relay J and a diode 2D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 2IC, a solid-state relay SSD2, a transistor 2VT1, a transistor 2VT2, a voltage regulator diode 2WD1 to 2WD3, diodes 2D6 to 2D8, a potentiometer 2RP, resistors 2R1 to 2R3, a resistor 2R5, and a diode 2D6 to 2D8. R6, 2R8, 2R11, 2R12, capacitors 2C2, 2C3, 2C6, wherein the integrated circuit 2IC is used as a core component to select an anti-failure and anti-control circuit module or a circuit module with equivalent functions; circuit connection method: a fuse FS is connected in series between a power side (L1) of the power switch DK and an input end (L) of the AC power supply, the other power side (N1) of the power switch DK is directly connected to the other input end (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input end (Z) of the primary winding (n1) in the transformer BY, the primary winding in the transformer BY Another AC input terminal of (n1) is connected to the AC terminal (Y) of the bidirectional thyristor in the solid-state relay SSD2, the first terminal (A) of the heating wire WR2, and the electric heating start terminal (Q) of the normally open button CKA. The temperature-sensitive diaphragm RMG sandwiched between the heating wire WR1 and the heating wire WR2 is a hot-melt film made of semiconductor nylon thermoplastic material; an AC output terminal of the secondary winding (n2) in the transformer BY is connected to an AC input terminal (~) of the rectifier bridge QD, and another AC output terminal of the secondary winding (n2) in the transformer BY is connected to another AC input terminal (~) of the rectifier bridge QD. The positive pole (V +2 ) connects the anode of diode 2D6 and resistor 2R1, and the negative pole of the DC voltage output by the rectifier bridge QD (V -2 ) connects one end of capacitor 2C3 and the negative electrode of capacitor 2C2 and the positive electrode of voltage regulator diode 2WD3 as the ground terminal (GND) of the DC power supply in the zero-pass temperature control circuit (10); the positive electrode of diode 2D1 is connected to the negative electrode of diode 2D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 2D4 is connected to the negative electrode of diode 2D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 2D2 and 2D3 are connected to the negative electrode of capacitor 2C1 as the negative DC electrode (V -1 ) is then connected to the emitter of the phototransistor GMT and the cathode of the high current light emitting diode 2LED, and the cathodes of the diodes 2D1 and 2D4 are connected to the anode of the capacitor 2C1 as the DC positive electrode (V +1 ) and then connect the positive electrode of the light-emitting diode in the solid-state relay SSD1, one end of the resistor 2R10, and the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 2R15, the other end of the resistor 2R15 is connected to the collector of the phototransistor GMT, and the other end of the resistor 2R10 is connected to the anode of the high-current light emitting diode 2LED; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; or the solid-state relay SSD1, the phototransistor GMT, the high-current light emitting diode 2LED, the resistors 2R10 and 2R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 2D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the coil of the electromagnetic relay J and the anode of the diode 2D5 are connected in parallel to the negative DC pole (V -1 ), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, and the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor in the solid-state relay SSD2; the cathode of the light-emitting diode in the solid-state relay SSD2 is connected to the collector of the transistor 2VT2, the anode of the light-emitting diode is connected to one end of the resistor 2R3, the other end of the resistor 2R3 is connected to the collector of the transistor 2VT1, the emitter of the transistor 2VT1 is connected to the anodes of the capacitors 2C2 and 2C1, the base of the transistor 2VT1 is connected to the cathode of the voltage-stabilizing transistor 2WD1, the anode of the voltage-stabilizing transistor 2WD1 is connected to one end of each of the resistors 2R1 and 2R11, and the other end of 2R1 is used as the zero-crossing trigger input end (V) of the zero-through temperature control circuit (10) m ) connects the anode of diode 2D6 and the DC voltage positive electrode (V +2 ), the emitter of transistor 2VT2 is connected to the DC power supply ground terminal (GND) of the zero-pass temperature control circuit (10), the base of transistor 2VT2 is connected to the positive electrode of voltage-stabilizing transistor 2WD2, the negative electrode of voltage-stabilizing transistor 2WD2 is connected to one end of resistor 2R12, and the other end of resistor 2R12 is connected to one end of resistor 2R6 and the inverting output terminal (V O2 ), the in-phase output terminal (V O1 ) connects the other end of 2R11, and the two input ends (V i1 、V i2 ) is connected in parallel to one end of the resistor 2R5, the other end of the resistor 2R5 is connected to one end of the capacitor 2C6 and the sliding arm of the potentiometer 2RP, one fixed end of the potentiometer 2RP is connected to the cathode of the diode 2D7, the other fixed end of the potentiometer 2RP is connected to the anode of the diode 2D8, the anode of the diode 2D7 and the cathode of the diode 2D8 are connected in parallel to the other end of the resistor 2R6 and the other end of the resistor 2R2, and the other end of the resistor 2R2 serves as the temperature control input end (V ki ) connects the two positive electrodes of diodes 2D2 and 2D3 and the negative electrode of capacitor 2C1; the negative electrode of diode 2D6 is connected to the other end of capacitor 2C3 and one end of resistor 2R8, and the other end of resistor 2R8 is connected in parallel to the negative electrode of voltage stabilizing diode 2WD3 and the positive electrode of capacitor 2C2 as the positive electrode (V) of the DC power supply of the zero-pass temperature control circuit (10) +3 ), and then connect the positive power input terminal (V + ) and the emitter of transistor 2VT1, the DC power supply positive electrode (V +3 ) is also connected to the positive electrode (V +1 ) and the two cathodes of diodes 2D1 and 2D4; the negative power input terminal (V - ) and the other end of the capacitor 2C6 are connected in parallel to the DC power ground terminal (GND) of the zero-pass temperature control circuit (10).

2. A fully thermally runaway-proof electric blanket, comprising a fuse (1) and a power switch (2), characterized in that: It also includes an outer membrane heating wire (5), an inner membrane heating wire (6), a temperature sensing diaphragm (7), a temperature detection and disconnection detection circuit (8), an overheating and flashover protection control circuit (9), and a zero-through temperature control circuit (10); a fuse (1) is connected in series between one power side (L1) of the power switch (2) and one input end (L) of the AC power supply, the other power side (N1) of the power switch (2) is directly connected to the other input end (N) of the AC power supply, a load side (L2) of the power switch (2) is connected to the protection switch K1 end of the overheating and flashover protection control circuit (9), and the other load side (N2) of the power switch (2) is connected to the tail end (b) of the inner membrane heating wire (6) and the zero-through temperature control circuit (10). ), the head end (A) of the outer membrane electric heating wire (5) is connected to the Y end of the terminal controller in the zero-through temperature control circuit (10) and the electric heating start end (Q) in the overheating and flashover protection control circuit (9), and the temperature sensing diaphragm (7) sandwiched between the outer membrane electric heating wire (5) and the inner membrane electric heating wire (6) is a hot-melt film made of semiconductor nylon thermoplastic material; an AC detection input end (X1) of the temperature detection and disconnection detection circuit (8) is connected to the head end (a) of the inner membrane electric heating wire (6), and the other AC detection input end (X2) of the temperature detection and disconnection detection circuit (8) is connected to the tail end (B) of the outer membrane electric heating wire (5), and the detection output positive pole (V +1 ) is connected in parallel to the positive input terminal (V + ) and the positive electrode (V +3 ), the temperature detection and disconnection detection circuit (8) detects the output negative pole (V -1 ) is connected in parallel to the negative input terminal (V - ) and the temperature control input terminal (V ki ); the protection switch K2 end in the overheat and flash protection control circuit (9) is connected to the terminal H end in the zero-through temperature control circuit (10); the fuse (1) is a fuse FS for preventing short-circuit current, the power switch (2) is a two-pole power switch DK, the outer heating wire (5) is a heating wire WR2 spirally wound on the outer surface of the temperature-sensitive diaphragm (7), the inner heating wire (6) is a heating wire WR1 spirally wound on the inner surface of the temperature-sensitive diaphragm (7), and the temperature-sensitive diaphragm (7) is a temperature-sensitive diaphragm RMG fully sandwiched between the heating wires WR2 and WR1; the temperature detection and disconnection circuit The detection circuit (8) includes diodes 3D1 to 3D4, a capacitor 3C1, and a resistor 3R10; the overheat and flash protection control circuit (9) includes a normally open button CKA, a solid-state relay SSD1, a varistor YR, a positive temperature coefficient thermistor PTC, resistors 3R13 and 3R15, or they can be replaced by an electromagnetic relay J and a diode 3D5; the zero-pass temperature control circuit (10) includes a transformer BY, a rectifier bridge QD, an integrated circuit 3IC, a photocoupler GDH, a bidirectional thyristor SCR, a transistor 3VT, a light-emitting diode 3LED, a voltage-stabilizing diode 3WD3, diodes 3D6 to 3D9, and a resistor 3R1 to 3R9, resistors 3R11, 3R12, capacitors 3C2 to 3C6, wherein the integrated circuit 3IC is used as a core device and is a time base circuit 555 or a circuit module with equivalent functions; circuit connection mode: a fuse FS is connected in series between a power supply side (L1) of the power switch DK and an input terminal (L) of the AC power supply, another power supply side (N1) of the power switch DK is directly connected to another input terminal (N) of the AC power supply, a load side (N2) of the power switch DK is connected to the tail end (b) of the heating wire WR1 and an AC input terminal (Z) of the primary winding (n1) in the transformer BY, and the primary winding ( The other AC input end of the transformer (n1) is connected to the AC end (Y) of the bidirectional thyristor SCR, the head end (A) of the heating wire WR2 and the electric heating start end (Q) of the normally open button CKA; the temperature sensing diaphragm RMG sandwiched between the heating wires WR1 and WR2 is a hot-melt film made of semiconductor nylon thermoplastic material; an AC output end of the secondary winding (n2) in the transformer BY is connected to an AC input end (~) of the rectifier bridge QD, the other AC output end of the secondary winding (n2) in the transformer (3) is connected to the other AC input end (~) of the rectifier bridge QD, and the DC voltage positive electrode (V +2 ) connects the anode of diode 3D6 and resistor 3R1, and the negative pole of the DC voltage output by rectifier bridge QD (V -2 ) connects one end of capacitor 3C3 and the negative electrode of capacitor 3C2 and the positive electrode of voltage regulator diode 3WD3 as the DC power ground terminal (GND) in the zero-pass temperature control circuit (10); the positive electrode of diode 3D1 is connected to the negative electrode of diode 3D2 as an AC detection input terminal (X1) of the temperature detection and disconnection detection circuit (8) and then connected to the head end (a) of the heating wire WR1; the positive electrode of diode 3D4 is connected to the negative electrode of diode 3D3 as another AC detection input terminal (X2) of the temperature detection and disconnection detection circuit (8) and then connected to the tail end (B) of the heating wire WR2; the positive electrodes of diodes 3D2 and 3D3 are connected to the negative electrode of capacitor 3C1 as the DC negative electrode (V -1 ) and then connected to one end of the positive temperature coefficient thermistor PTC and one end of the resistor 3R10 and one end of the resistor 3R2, the cathodes of the diodes 3D1 and 3D4 are connected to the anode of the capacitor 3C1 as the DC anode (V +1 ) and then connected to the positive electrode of the light-emitting diode in the solid-state relay SSD1, one end of the varistor YR and the other end of the resistor 3R10, and also connected to the positive electrode (V +3 ), the cathode of the light emitting diode in the solid-state relay SSD1 is connected to one end of the resistor 3R15, the other end of the resistor 3R15 is connected to the other end of the varistor YR and one end of the resistor 3R13, and the other end of the resistor 3R13 is connected to the other end of the positive temperature coefficient thermistor PTC; one AC end of the bidirectional thyristor in the solid-state relay SSD1 is connected to one end (K1) of the normally open button CKA and a load side (L2) of the power switch DK, and the other AC end (K2) of the bidirectional thyristor in the solid-state relay SSD1 is connected to the AC end (H) of the bidirectional thyristor SCR and one end of the resistor 3R9 and one end of the capacitor 3C4; or the solid-state relay SSD1, the varistor YR, the positive temperature coefficient thermistor PTC, the resistors 3R10, 3R13, 3R15 are replaced by an electromagnetic relay J and a diode 3D5, and one end of the coil of the electromagnetic relay J and the cathode of the diode 3D5 are connected in parallel to the DC positive pole (V +1 ), the other end of the electromagnetic relay J coil and the anode of the diode 3D5 are connected in parallel to the negative DC pole (V -1 ), one end (K1) of the normally open contact of the electromagnetic relay J is connected to one end of the normally open button CKA and a load side (L2) of the power switch DK, the other end (K2) of the normally open contact of the electromagnetic relay J is connected to the AC end (H) of the bidirectional thyristor SCR, one end of the resistor 3R9 and one end of the capacitor 3C4; the other end of the capacitor 3C4 is connected to one end of the resistor 3R11, the other end of the resistor 3R9 is connected to an AC end of the bidirectional thyristor in the photoelectric coupler GDH, the other AC end of the bidirectional thyristor in the photoelectric coupler GDH is connected to one end of the resistor 3R12 and the control electrode (G) of the bidirectional thyristor SCR, the AC end (Y) of the bidirectional thyristor SCR is internally connected to the other end of the resistor 3R11 and the other end of the resistor 3R12 and the other AC input end of the primary winding (n1) in the transformer BY, and is externally connected. The first end (A) of the electric heating wire WR2 and the electric heating start end (Q) of the normally open button CKA are connected; the cathode of the light-emitting diode in the photoelectric coupler GDH is connected to the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the anode of the light-emitting diode in the photoelectric coupler GDH is connected to the cathode of the light-emitting diode 3LED; the anode of the light-emitting diode 3LED is connected to one end of the resistor 3R3 and the collector of the transistor 3VT; the emitter of the transistor 3VT is connected to one end of the resistor 3R4 and the ground end (GND) of the DC power supply in the zero-pass temperature control circuit (10); the other end of the resistor 3R4 is connected to one end of the resistor 3R1 and the anode of the diode 3D9; the cathode of the diode 3D9 is connected to the base of the transistor 3VT; the other end of the resistor 3R1 serves as the zero-crossing trigger input end (V m ) is connected to the positive DC voltage output by the rectifier bridge QD (V +2 ) and the anode of diode 3D6; the cathode of diode 3D6 is connected to the other end of capacitor 3C3 and one end of resistor 3R8, and the other end of resistor 3R8 is connected in parallel to the cathode of voltage-stabilizing diode 3WD3 and the anode of capacitor 3C2 as the positive electrode (V) of the DC power supply in the zero-pass temperature control circuit (10). +3 ), and then connect one end of the resistor 3R5 and the 8th and 4th pins of the time base circuit 555 and the DC positive electrode (V +1 ); the third pin of the time base circuit 555 is connected to the other end of the resistor 3R3, the fifth pin thereof is connected to one end of the capacitor 3C5, the first pin thereof is connected to the ground terminal (GND) of the DC power supply and the other end of the capacitor 3C5 and one end of the capacitor 3C6, the second and sixth pins thereof are connected in parallel to the other end of the capacitor 3C6 and the sliding arm of the potentiometer 3RP, the fixed end of the potentiometer 3RP is connected to the cathode of the diode 3D7, the other fixed end of the potentiometer 3RP is connected to one end of the resistor 3R6, the other end of the resistor 3R6 is connected to the anode of the diode 3D8, the cathode of the diode 3D8 is connected to the anode of the diode 3D7, and then connected to one end of each of the resistors 3R2 and 3R7 and the other end of the resistor 3R5, the other end of the resistor 3R7 is connected to the seventh pin of the time base circuit 555; the other end of the resistor 3R2 is used as the temperature control input end (V ki ) connects the anodes of diodes 3D2 and 3D3 and the cathode of capacitor 3C1.

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