CN207635444U - Automatic temperature control circuit - Google Patents

Abstract

A kind of automatic temperature control circuit.Function shows that (1) is electrically connected with function gear position operation (4), function gear position operation (4) amplification compared with data is electrically connected with output (2), temperature detecting head (3) amplification compared with data is electrically connected with output (2), data compare amplification with output (2) with or door drive (7) be electrically connected, overtemperature prote (5) with or door driving (7) be electrically connected, overpressure protection (6) with or door driving (7) be electrically connected, temperature detecting head (3) is electrically connected with overtemperature prote (5), voltage stabilizing provides DC voltage-stabilizing and reference voltage with reference voltage (8), or door driving (7) is electrically connected with heater (9), temperature detecting head (3) is connect with heater (9) at heat transfer.So that the automatic temperature control circuit has automatic heating object, operating temperature control accuracy is high, the smaller feature of fluctuation, having prevents from generating heat because ultra-voltage causes supercurrent and burning out the function of parts, have again and passes through luminescence display, it is intuitive to see that it is operated in the characteristics of what is using function, allows people to use safer, convenient and comfortable.

Description

Automatic temperature control circuit

Technical field

The utility model is related to a kind of heating temperature-control circuit, especially have smaller return difference temperature control curve and Temperature gear electroluminescence indicates the automatic temperature control circuit of function.

Background technology

Currently, a kind of 2014205410351 automatic temperature control device of the well-known patent No., NTC temperature probes (1) and heating Limit temperature circuit (4) is electrically connected, and heating limit temperature circuit (4) is electric with thermoregulator (6), micro-processor interface circuit (9) respectively Connection, NTC overtemperatures probe (2) limit circuit (5) with overtemperature prote and are electrically connected, and overtemperature prote limits circuit (5) and microprocessor electricity Road (9) is electrically connected, and micro-processor interface circuit (9) is electrically connected with power pull switch (7), protection switch (8) respectively, power pull switch (7) it is electrically connected with protection switch (8), power pull switch (7) is electrically connected with heater (3), power pull switch (7) and display Circuit (11) is electrically connected.Micro-processor interface circuit (9) is internal to be made of two time base circuits, when its work, there is bigger temperature Degree controlling curve return difference, that is, temperature fluctuation are bigger, give people to heat in this case, are easily brought to user uncomfortable Feeling used unwell complete without over voltage protection, besides people cannot be allowed to be intuitive to see automatic temperature control device work The range in what temperature made, inconvenience is used.

Invention content

When in order to overcome a kind of existing automatic temperature control device work, there is bigger temperature control curve return difference, that is, Temperature fluctuation is larger, gives people's heating in this case, easily brings uncomfortable feeling to user, without over voltage protection, It cannot besides be intuitive to see that automatic temperature control device is operated in the range gear of what temperature, use unwell complete, not side Just defect, the utility model provide a kind of automatic temperature control circuit, which automatically controls heating object, there is ratio Smaller temperature control curve return difference has operating temperature control accuracy high, fluctuates smaller feature, and have ultra-voltage guarantor Shield prevents from generating heat because ultra-voltage causes supercurrent and burning out the function of parts, and has through luminescence display, is intuitive to see its work The characteristics of range in what temperature made, what uses function in allows people to use safer, convenient and comfortable.

Technical solution adopted by the utility model to solve its technical problems is：Function shows (1) and function gear position operation (4) it is electrically connected, function gear position operation (4) amplification compared with data is electrically connected with output (2), temperature detecting head (3) and data ratio It is electrically connected with the in-phase input end of the operational amplifier U1 in output (2) compared with amplification, data compare amplification and export the operation of (2) Amplifier U2 output ends drive the input terminal A of the AND gate circuit U5 in (7) to be electrically connected with door, and the operation of overtemperature prote (5) is put Big device U3 output ends drive the input terminal C of the AND gate circuit U5 in (7) to be electrically connected with door, the operation amplifier of overpressure protection (6) Device U4 output ends drive the input terminal B of the AND gate circuit U5 in (7) to be electrically connected with door, temperature detecting head (3) and overtemperature prote (5) it is electrically connected, voltage stabilizing and the other end of resistance R12 in reference voltage (8) and the electric connecting terminal of one end of resistance R11 and data ratio Compared with amplification and the inverting input of operational amplifier U1, the in-phase input end of operational amplifier U2, the overtemperature prote in output (2) (5) in-phase input end of the operational amplifier U3 in, the operational amplifier U4 in overpressure protection (6) in-phase input end be electrically connected It connects, cathode of the voltage stabilizing with the zener diode D9 in reference voltage (8), the power end with the AND gate circuit U5 in door driving (7) It is electrically connected with one end resistance R2 NTC in temperature detecting head (3) and the one end NTC resistance R3 contact that is electrically connected, the field in (7) is driven with door The drain electrode of effect pipe D6 is electrically connected with heater (9) flexible sheet heating board R10 other ends, and temperature detecting head (3) is attached to hair The surfaces flexible sheet heating board R10 heat transfer connection in hot body (9).There are two groups of switches in function gear position operation (4), every group is opened Guan Jun contains a movable contact, multiple stationary contacts, and two groups of switch motions synchronize, and constitutes a manual double-pole and synchronizes multi gear Gear-shift switch The stationary contact terminals of K3, one group of switch are individually electrically connected light emitting diode D1, light emitting diode D2, light emitting diode The cathode of Dn, light emitting diode Dn+1, light emitting diode Dn+2, the stationary contact terminals of another group of switch individually with it is public The other end electrical connection on ground, divider resistance R5, divider resistance R4, divider resistance Rn, divider resistance Rn+1.Due to light emitting diode D1, light emitting diode D2, light emitting diode Dn, light emitting diode Dn+1, light emitting diode Dn+2 are connected to different stationary contacts Gear, therefore only there are one lumination of light emitting diode for each gear, and different range is in corresponding instruction heater (9) temperature Stationary contact gear.Light emitting diode D7, light emitting diode D8, which shine, indicates respectively that heater (9) is in cooling, temperature rise period. Temperature detecting head (3) is attached to fixed on the surfaces flexible sheet heating board R10 in heater (9), with flexible sheet heating board R10 Forming face contacts so that is connect in thermo-conducting manner between the temperature of heater (9) and temperature detecting head (3), direct detection Flexible sheet heating board R10 surface temperatures situation in heater (9) and variation.Temperature detecting head (3) by NTC resistance R2 and NTC resistance R3 is constituted, and NTC resistance R2 is adjusted for temperature and measured, and NTC resistance R3 is detected for temperature overtemperature.Data are relatively put Greatly with have operational amplifier U1, operational amplifier U2 in output (2), operational amplifier U1 undertake to by NTC resistance R2 conveyings Lai Temperature signal comparison amplify task, operational amplifier U2, which undertakes, compares the voltage signal of operational amplifier U1 output ends Amplify anti-phase output task, improves the precision of temperature adjusting control.When automatic temperature control circuit connects the straight of normal voltage range value Behind galvanic electricity source, voltage stabilizing provides a steady dc voltage, voltage stabilizing and benchmark electricity with reference voltage (8) to temperature detecting head (3) Pressure (8) compares amplification to data respectively and provides a stable benchmark electricity with (2), overtemperature prote (5) and overpressure protection (6) is exported Pressure.By taking the manual double-pole of function gear position operation (4) synchronizes first grade of multi gear Gear-shift switch K3 as an example, which starts When work, often ambient temperature and heater (9) surface temperature are relatively low, and the resistance value of NTC resistance reduces with temperature and increased, It is on the contrary then reduce, by the NTC resistance R2 in temperature detecting head (3) compared with data amplification and the divider resistance R5 in output (2) First grade of branch pressure voltage is formed on operational amplifier U1 in-phase input ends with divider resistance R4, it is defeated with operational amplifier U1 reverse phases The reference voltage entered on end is compared, this branch pressure voltage is less than reference voltage, and gained voltage difference is negative, through operational amplifier U1 After amplification, is inputted from the inverting input of operational amplifier U2, compare amplification, operational amplifier for the second time through operational amplifier U2 U2 will export high level so that data compare amplification and output (2) output high level；Since heater (9) is no super at this time Temperature, the anti-phase input of the NTC resistance R3 and resistance R6 in overtemperature prote (5) in temperature detecting head (3) in operational amplifier U3 The branch pressure voltage less than reference voltage will be formed on end, operational amplifier U3 exports high level so that overtemperature prote (5) exports High level；And supply voltage is not above setting value, the resistance R8 in overpressure protection (6) and resistance R7 is operational amplifier U4's The branch pressure voltage less than reference voltage is formed on inverting input, operational amplifier U4 exports high level so that overpressure protection (6) Export high level；When data compare amplification and to export (2), the output end of overtemperature prote (5) and overpressure protection (6) respectively while defeated When going out high level, it is high level to drive input terminal A, input terminal B, the input terminal C of the AND gate circuit U5 of (7) with door, with door electricity The output end Y of road U5 exports high level, and the grid of field-effect tube D6 obtains high level, field-effect tube D6 conductings, and electric current flows through hair Hot body (9), heater (9) heating；When the flexible sheet heating board R10 surface temperatures in heater (9) rise to setting value, number It is more than on its inverting input with the voltage obtained on the in-phase input end of the operational amplifier U1 in output (2) according to amplification is compared Reference voltage, operational amplifier U2 output ends export low level, with door drive (7) in AND gate circuit U5 output end Y it is defeated Go out low level, the grid of field-effect tube D6 is in low level, and field-effect tube D6 ends, and heater (9) no electric current flows through, heater (9) cool down, when the flexible sheet heating board R10 surface temperatures in heater (9) are less than setting value, field-effect tube D6 is led again Logical, electric current flows through heater (9), and heater (9) heating recycles repeatedly.It is used with output (2) since data compare amplification Two-stage calculation enhanced processing temperature change signal has temperature very high control accuracy, only the temperature curve return difference of very little, makes The temperature of heater (9) fluctuates within the scope of very little, stablizes within the temperature range set at first grade, heater (9) It can emit and conduct thermal energy outward, when heater (9) is come close to or in contact with user's body, can stablize to user and heat, allow User feels comfortable；When the manual double-pole in function gear position operation (4), which synchronizes multi gear Gear-shift switch K3, is in first grade, Light emitting diode D1 is lighted, and luminescence display goes out the set temperature range that equipment is in first grade；When in function gear position operation (4) When manual double-pole synchronizes multi gear Gear-shift switch K3 and is allocated to second gear, light emitting diode D2 is lighted, and luminescence display goes out equipment and is in the Two grades of set temperature range, NTC resistance R2 in temperature detecting head (3) amplification and the partial pressure in output (2) compared with data Resistance R4 forms second of intrinsic standoff ratio on operational amplifier U1 in-phase input ends so that this intrinsic standoff ratio is less than first grade of partial pressure Than the set temperature range of equipment second gear is higher than first grade, and heater (9) temperature is stablized in second gear setting value；It uses Person can synchronize in the manual double-pole in function gear position operation (4) and independently select different gears on multi gear Gear-shift switch K3 so that Equipment operating temperature is presented within different temperature ranges, is heated to user, is allowed user to be warmed oneself or physical therapy is most suitable Or comfortable temperature；When temperature is more than safety value, temperature change value is through the NTC resistance in heat transfer to temperature detecting head (3) The resistance value of R3, NTC resistance R3 are increased with temperature and are reduced, NTC resistance R3 and the electricity after the resistance R6 partial pressures in overtemperature prote (5) Pressure is more than reference voltage, and the output end of overtemperature prote (5) is in low level, and the input terminal C of the AND gate circuit U5 in (7) is driven with door In low level, the output end Y of AND gate circuit U5 exports low level, and the grid of field-effect tube D6 is in low level, and field-effect tube D6 is cut Only, heater (9) cools down, and plays the role of overtemperature prote；When the direct current power source voltage value for connecting Vcc is more than permissible value, surpass Resistance R8 in pressure protection (6) is more than reference voltage with the voltage after resistance R7 partial pressures, and the output end of overpressure protection (6) is in low electricity Flat, it is in low level to drive the input terminal B of the AND gate circuit U5 in (7) with door, and the output end Y of AND gate circuit U5 exports low level, The grid of field-effect tube D6 is in low level, and field-effect tube D6 ends, and heater (9) no electric current flows through, the work of whole device Electric current will be reduced to 1 percent hereinafter, since the electric current of DC power supply current supply circuit is greatly decreased, to prevent because of ultra-voltage Cause supercurrent and generate heat and burn out the possibility of parts, plays the role of overpressure protection；Since automatic temperature control circuit is transported using two-stage Control of the enhanced processing to temperature is calculated, temperature control return difference is not only reduced, improves to temperature controlled precision, and further through Its luminescence display is intuitive to see that device is operated in the gear of what temperature range, what uses function in, reaches and allows people Use safer, convenient and comfortable purpose.

The utility model has the beneficial effects that the automatic temperature control circuit not only has heating object, to temperature control precision What high feature, overpressure protection feature, and energy luminous display unit be in and use function, and people is allowed to use safer, side Just and comfortably.

Description of the drawings

The utility model is further illustrated with reference to the accompanying drawings and examples.

Fig. 1 is the circuit block diagram of the utility model.

Fig. 2 is two grades of temperature adjustment function mode circuit schematic diagrams of automatic temperature control circuit one embodiment.

Fig. 3 is two grades of temperature adjustment function mode circuit schematic diagrams of second embodiment of automatic temperature control circuit.

Fig. 4 is the multi gear position temperature adjustment part schematic diagram in Fig. 2, Fig. 3.

Fig. 5 is heater schematic diagram.

Fig. 6 is temperature detecting head and its element layout drawing.

Fig. 7 is temperature detecting head and heater relative position schematic diagram.

1. functions are shown in figure, and 2. data compare amplification and output, and 3. temperature detecting heads, 4. function gear position operations 5. surpass Temperature protection, 6. overpressure protections, 7. drive with door, 8. voltage stabilizings and reference voltage, 9. heaters, 10. wiring boards, 11. NTC resistance R2,12. NTC resistance R3.

Specific implementation mode

In Fig. 1, function shows that (1) is electrically connected with function gear position operation (4), and function gear position operation (4) is compared with data Amplification with output (2) be electrically connected, temperature detecting head (3) compared with data amplification with export (2) in operational amplifier U1 it is same Phase input terminal be electrically connected, data compare amplification with export (2) operational amplifier U2 output ends with door drive (7) in door The input terminal A electrical connection of circuit U 5, the operational amplifier U3 output ends of overtemperature prote (5) with door drive in (7) with door electricity The input terminal C electrical connections of road U5, the operational amplifier U4 output ends of overpressure protection (6) and the AND gate circuit driven with door in (7) The input terminal B electrical connections of U5, temperature detecting head (3) are electrically connected with overtemperature prote (5), voltage stabilizing and resistance R12 in reference voltage (8) The other end and resistance R11 one end electric connecting terminal compared with data amplification with output (2) in operational amplifier U1 it is anti- The in-phase input end, super of phase input terminal, the in-phase input end of operational amplifier U2, operational amplifier U3 in overtemperature prote (5) The in-phase input end electrical connection of operational amplifier U4 in pressure protection (6), voltage stabilizing and the zener diode D9 in reference voltage (8) Cathode, electric with the one end resistance R2 NTC and NTC in the power end of the AND gate circuit U5 in door driving (7) and temperature detecting head (3) Resistance R3 one end is electrically connected contact electrical connection, drives the drain electrode of the field-effect tube D6 in (7) to generate heat with heater (9) flexible sheet with door The plate R10 other ends are electrically connected, and temperature detecting head (3) is attached to the surfaces the flexible sheet heating board R10 heat transfer in heater (9) Connection.Temperature detecting head (3) is attached to fixed on the surfaces flexible sheet heating board R10 in heater (9), generates heat with flexible sheet Plate R10 forming faces contact so that are connect in thermo-conducting manner between the temperature of heater (9) and temperature detecting head (3).Attachment There are two types of fixed structures：First, the flexible sheet heating board R10 tables in heater (9) that temperature detecting head (3) is adhesively fixed Face；Second is that temperature detecting head (3) suture, riveted or fastener are fixed on the flexible sheet heating board R10 tables in heater (9) Face.NTC resistance R2 (11), NTC resistance R3 (12) in temperature detecting head (3) are respectively welded in fixed assist side (10).

In Fig. 2, Fig. 5, Fig. 6 and Fig. 7, function shows (1) by resistance R1, light emitting diode D1, light emitting diode D2 structures At one end of resistance R1 is electrically connected with the anode of light emitting diode D1, light emitting diode D2 respectively；Temperature detecting head (3) is by NTC Resistance R2, NTC resistance R3 is constituted, and one end of NTC resistance R2 is electrically connected with one end of NTC resistance R3；In function gear position operation (4) There are two groups of switches, every group of switch to contain a movable contact, multiple stationary contacts, two groups of switch motions synchronize, and constitute one manual pair Knife synchronizes multi gear Gear-shift switch K3, the movable contact terminals in one group of contact, the movable contact terminals in another group of contact, another Group contact in a stationary contact terminals respectively be publicly electrically connected；Data compare amplification with output (2) by operation amplifier Device U1, operational amplifier U2 and divider resistance R4, divider resistance R5 are constituted, in-phase input end and the partial pressure electricity of operational amplifier U1 The electrical connection of the one end R4 is hindered, the inverting input of operational amplifier U1 is electrically connected with the in-phase input end of operational amplifier U2, operation The inverting input of amplifier U2 is electrically connected with the output end of operational amplifier U1, the other end and divider resistance of divider resistance R4 One end of R5 is electrically connected, the other end of divider resistance R5 be publicly electrically connected；Overtemperature prote (5) is by operational amplifier U3 and electricity It hinders R6 to constitute, the inverting input of operational amplifier U3 is electrically connected with one end of resistance R6, the other end of resistance R6 and publicly Electrical connection；Overpressure protection (6) is made of operational amplifier U4 and resistance R7, resistance R8, the inverting input of operational amplifier U4 Be electrically connected respectively with one end of resistance R7, resistance R8, the other end of resistance R7 be publicly electrically connected；With door driving (7) by with Gate circuit U5, field-effect tube D6 are constituted, and the output end Y of AND gate circuit U5 is electrically connected with the grid of field-effect tube D6, AND gate circuit It the ground terminal of U5, the source electrode of field-effect tube D6 and is publicly electrically connected；Voltage stabilizing with reference voltage (8) by zener diode D9, move back Coupling capacitance C1, decoupling capacitance C2 and resistance R11, resistance R12, resistance R13 are constituted, the cathode of zener diode D9 respectively with decoupling One end electrical connection of one end of capacitance C1, one end of resistance R12, resistance R13, the other end of resistance R12 is respectively with resistance R11's One end, decoupling capacitance C2 one end electrical connection, the anode of zener diode D9, the other end of decoupling capacitance C1, resistance R11 it is another One end, decoupling capacitance C2 the other end respectively be publicly electrically connected；Heater (9) is made of flexible sheet heating board R10；Work( It can show in the other end, the resistance R8 other ends in overpressure protection (6), voltage stabilizing and the reference voltage (8) of the resistance R1 in (1) One end of flexible sheet heating board R10 in the resistance R13 other ends, heater (9) is electrically connected through Vcc and DC power anode respectively Connect, function show light emitting diode D1 in (1), light emitting diode D2 cathode respectively in function gear position operation (4) manually Double-pole synchronizes two stationary contact terminals in one group of contact of multi gear Gear-shift switch K3 and is electrically connected, one in another group of contact Stationary contact terminals amplification and other end of the divider resistance R4 in output (2) and one end electricity of divider resistance R5 compared with data Tie point is electrically connected, the other end of the NTC resistance R2 in temperature detecting head (3) with data compared with amplification with export the electricity in (2) Hinder one end electrical connection of R4, the other end of NTC resistance R3 and the inverting input electricity of the operational amplifier U3 in overtemperature prote (5) Connection, the output end of operational amplifier U3 drive the input terminal C of the AND gate circuit U5 in (7) to be electrically connected with door, overpressure protection (6) output end of the operational amplifier U4 in drives the input terminal B of the AND gate circuit U5 in (7) to be electrically connected with door, data ratio Compared with the input terminal A of amplification and the output end and the AND gate circuit U5 driven with door in (7) of the operational amplifier U2 in output (2) The drain electrode of field-effect tube D6 in electrical connection, with door driving (7) is another with the flexible sheet heating board R10's in heater (9) End electrical connection, data compare amplification and the inverting input for exporting the operational amplifier U1 in (2), the same phase of operational amplifier U2 Input terminal, the in-phase input end of operational amplifier U3 in overtemperature prote (5), operational amplifier U4 in overpressure protection (6) In-phase input end is electrically connected with voltage stabilizing with one end of the decoupling capacitance C2 in reference voltage (8).

In an alternative embodiment as shown in fig. 3, only there are differences with door driving (7) with upper one embodiment.It is driven with door Dynamic (7) are made of AND gate circuit U5, field-effect tube D6, light emitting diode D7, light emitting diode D8 and resistance R14, resistance R15, The output end Y of AND gate circuit U5 is electrically connected with the grid of field-effect tube D6, the anode of light emitting diode D7, light emitting diode D8 Cathode is electrically connected with the drain electrode of field-effect tube D6, and the cathode of light emitting diode D7 is electrically connected with one end of resistance R15, light-emitting diodes The anode of pipe D8 is electrically connected with one end of resistance R14, the other end of resistance R15, the ground terminal of AND gate circuit U5, field-effect tube D6 Source electrode be publicly electrically connected, the resistance R14 other ends are electrically connected through Vcc with DC power anode.

In Fig. 4, function shows (1) by light emitting diode D1, light emitting diode D2, light emitting diode Dn, light-emitting diodes Pipe Dn+1, light emitting diode Dn+2 and resistance R1 are constituted, and light emitting diode D1, light emitting diode D2, light emitting diode Dn, are shone Diode Dn+1, the positive of light emitting diode Dn+2 are electrically connected with the one end resistance R1；Data compare amplification with output (2) by operation Amplifier U1, operational amplifier U2 and divider resistance R4, divider resistance R5, divider resistance Rn, divider resistance Rn+1, divider resistance Rn+2 is constituted, and the in-phase input end of operational amplifier U1 is electrically connected with the one end divider resistance Rn+2, the reverse phase of operational amplifier U1 Input terminal is electrically connected with the in-phase input end of operational amplifier U2, inverting input and the operational amplifier U1 of operational amplifier U2 Output end electrical connection, the one end divider resistance R5 and be publicly electrically connected, the divider resistance R5 other ends and the one end divider resistance R4 Electrical connection, the divider resistance R4 other ends are electrically connected with the one end divider resistance Rn, the divider resistance Rn other ends and divider resistance Rn+1 One end is electrically connected, and the divider resistance Rn+1 other ends are electrically connected with the one end divider resistance Rn+2, the divider resistance Rn+2 other ends and fortune Calculate the in-phase input end electrical connection of amplifier U1；Manual double-pole in function gear position operation (4) synchronize multi gear Gear-shift switch K3 by There are two groups of switches, every group of switch to contain a movable contact, multiple stationary contacts, two groups of switch motions, which synchronize, to be constituted；One group of switch Stationary contact terminals are individually electrically connected light emitting diode D1, light emitting diode D2, light emitting diode Dn, light emitting diode Dn + 1, the cathode of light emitting diode Dn+2, multiple stationary contact terminals of another group of switch individually with publicly, divider resistance The other end electrical connection of R5, divider resistance R4, divider resistance Rn, divider resistance Rn+1, it is the movable contact terminals of one group of switch, another The movable contact terminals of one group of switch be publicly electrically connected.Manual double-pole synchronize multi gear Gear-shift switch K3 can have two grades, three Shelves or even multi gear form exist, to adapt to the needs of the embodiment of different temperatures gear.

Claims (7)

1. a kind of automatic temperature control circuit, temperature probe, control circuit, heater electrical connection, it is characterized in that：Function show (1) with Function gear position operation (4) is electrically connected, and function gear position operation (4) amplification compared with data is electrically connected with output (2), temperature detecting head (3) amplification be electrically connected with the in-phase input end of operational amplifier U1 in output (2) compared with data, data compare amplify with it is defeated The operational amplifier U2 output ends for going out (2) drive the input terminal A of the AND gate circuit U5 in (7) to be electrically connected with door, overtemperature prote (5) operational amplifier U3 output ends drive the input terminal C of the AND gate circuit U5 in (7) to be electrically connected with door, overpressure protection (6) Operational amplifier U4 output ends drive the input terminal B of AND gate circuit U5 in (7) to be electrically connected with door, temperature detecting head (3) It is electrically connected with overtemperature prote (5), voltage stabilizing is electrically connected with one end of the other end and resistance R11 of resistance R12 in reference voltage (8) Hold amplification and the inverting input of the operational amplifier U1 in output (2), the homophase input of operational amplifier U2 compared with data End, the in-phase input end of operational amplifier U3 in overtemperature prote (5), operational amplifier U4 in overpressure protection (6) same phase Input terminal is electrically connected, and voltage stabilizing drives the AND gate circuit in (7) with the cathode of the zener diode D9 in reference voltage (8), with door The one end resistance R2 NTC and the one end NTC resistance R3 contact that is electrically connected are electrically connected in the power end and temperature detecting head (3) of U5, are driven with door The drain electrode of field-effect tube D6 in dynamic (7) is electrically connected with heater (9) flexible sheet heating board R10 other ends, temperature detecting head (3) surfaces the flexible sheet heating board R10 heat transfer connection being attached in heater (9).

2. automatic temperature control circuit according to claim 1, heater (9), it is characterized in that：Flexible sheet heating board R10.

3. automatic temperature control circuit according to claim 1, temperature detecting head (3), it is characterized in that：Temperature detecting head (3) stitches Conjunction, riveted or fastener are fixed on the surfaces flexible sheet heating board R10 in heater (9), with flexible sheet heating board R10 shapes It is contacted at face so that connect in thermo-conducting manner between the temperature of heater (9) and temperature detecting head (3).

4. automatic temperature control circuit according to claim 1, it is characterized in that：Temperature detecting head (3) is adhesively fixed in heater (9) surfaces flexible sheet heating board R10 in, contact so that the temperature of heater (9) with flexible sheet heating board R10 forming faces It spends and is connect in thermo-conducting manner between temperature detecting head (3).

5. automatic temperature control circuit according to claim 1, data compare amplification and output (2), it is characterized in that：It is put by operation Big device U1, U2 and resistance R4, R5, Rn, Rn+1, Rn+2 are constituted, in-phase input end and the one end resistance Rn+2 of operational amplifier U1 Electrical connection, the inverting input of operational amplifier U1 are electrically connected with the in-phase input end of operational amplifier U2, operational amplifier U2 Inverting input be electrically connected with the output end of operational amplifier U1, the one end resistance R5 be publicly electrically connected, resistance R5 is another End is electrically connected with the one end resistance R4, and the resistance R4 other ends are electrically connected with the one end resistance Rn, the resistance Rn other ends and resistance Rn+1 mono- End electrical connection, the resistance Rn+1 other ends are electrically connected with the one end resistance Rn+2, and the resistance Rn+2 other ends are same with operational amplifier U1's Phase input terminal is electrically connected.

6. automatic temperature control circuit according to claim 1 drives (7) with door, it is characterized in that：It is imitated by AND gate circuit U5, field Should pipe D6 constitute, the output end Y of AND gate circuit U5 is electrically connected with the grid of field-effect tube D6, the ground terminal of AND gate circuit U5, field The source electrode of effect pipe D6 be publicly electrically connected.

7. automatic temperature control circuit according to claim 1 drives (7) with door, it is characterized in that：It is imitated by AND gate circuit U5, field It should pipe D6, light emitting diode D7, light emitting diode D8 and resistance R14, resistance R15 compositions, the output end Y of AND gate circuit U5 and field The grid of effect pipe D6 is electrically connected, the drain electrode of the anode of light emitting diode D7, the cathode and field-effect tube D6 of light emitting diode D8 Electrical connection, the cathode of light emitting diode D7 are electrically connected with one end of resistance R15, and the anode of light emitting diode D8 is with resistance R14's One end be electrically connected, the other end of resistance R15, the ground terminal of AND gate circuit U5, field-effect tube D6 source electrode be publicly electrically connected.