Self-constant-temperature heating unit based on Hilbert curve

Abstract

The invention discloses a self-constant-temperature heating unit based on a Hilbert curve, relates to temperature-controlled high-precision electronic equipment, and aims to solve the problems that the existing heating mode cannot fundamentally solve the problems of non-uniform heating and low space utilization efficiency. The conductive heating sheet is printed in the heating zone according to the path of the Hilbert curve; the control circuit is arranged in the circuit area; the temperature sensor is used for monitoring the temperature change of the heating area in real time and outputting a temperature sensing signal; a temperature sensing signal output end of the temperature sensor is connected with a temperature sensing signal input end of the control circuit; the control circuit compares a preset temperature curve with the temperature sensing signal and generates an adjusting signal according to a comparison result, and the output end of the adjusting signal acts on the conductive heating piece. The heating device has the beneficial effects that the heating uniformity is remarkably improved, and the space utilization rate is increased.

Description

Technical Field

[0001] The invention relates to a temperature-controlled high-precision electronic device. Background Art

[0002] With the continuous development of electronic equipment, the requirements for high-precision and controllable temperature are increasing; the existing printed circuit board (PCB) heating technology mainly relies on simple resistive heating elements or existing serpentine heating circuits; however, these heating methods have certain shortcomings in heating uniformity, heating efficiency and heating accuracy.

[0003] For example, due to its linear path design, the existing serpentine heating circuit is prone to hot spots and cold spots during the heating process, resulting in uneven heating and a short service life of the serpentine heating circuit. In addition, within the limited PCB area, the existing heating circuit design is difficult to balance heating uniformity and space utilization. These defects make it difficult for existing technologies to meet the temperature control requirements of high-precision electronic equipment.

[0004] To solve the above problems, researchers have proposed some improvement methods, such as improving the heating effect by optimizing circuit layout or material selection, but they still cannot fundamentally solve the problems of uneven heating and inefficient space utilization. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing heating method cannot fundamentally solve the problem of uneven heating and low space utilization efficiency, and proposes a self-constant temperature heating unit based on the Hilbert curve.

[0006] The self-constant temperature heating unit based on the Hilbert curve of the present invention comprises a control circuit, a conductive heating sheet and a temperature sensor;

[0007] The temperature sensor is used to monitor the temperature change of the conductive heating plate in real time and output a temperature sensing signal; the temperature sensing signal output end of the temperature sensor is connected to the temperature sensing signal input end of the control circuit;

[0008] The control circuit compares the temperature sensing signal with the preset temperature curve, generates an adjustment signal according to the comparison result, and the output end of the adjustment signal acts on the conductive heating plate;

[0009] The conductive heating plates are arranged in the space to be heated according to the path of the Hilbert curve.

[0010] Furthermore, the control circuit includes a main control circuit and a regulating circuit;

[0011] The main control circuit includes a main control chip U4, a capacitor C1, a resistor R1, a resistor R2, a light emitting diode D1 and a light emitting diode D2;

[0012] Pin 1 of the main control chip U4 is the ground terminal, which is used to connect the ground wire;

[0013] Pin 2 of the main control chip U4 is the serial data debugging input interface, which is used to write the temperature curve;

[0014] Pin 3 of the main control chip U4 is the clock signal debugging input interface, which is used to write the clock signal;

[0015] Pin 4 of the main control chip U4 is the RS485 communication command output interface, which is used to output RS485 communication commands;

[0016] Pin 5 of the main control chip U4 is the bootstrap boost signal input terminal, which is used to input the bootstrap boost signal;

[0017] Pin 8 of the main control chip U4 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the light-emitting diode D1, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply;

[0018] Pin 9 of the main control chip U4 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the anode of the light-emitting diode D2, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply;

[0019] Pin 10 of the main control chip U4 is the reset signal input terminal, which is used to input the reset signal;

[0020] Pin 11 of the main control chip U4 is the first communication signal output terminal, which is used to output RS485 communication signals;

[0021] Pin 12 of the main control chip U4 is the first communication signal input terminal, which is used to input RS485 communication signals;

[0022] Pin 13 of the main control chip U4 is the second communication signal output terminal, which is used to output the debugging communication signal;

[0023] Pin 14 of the main control chip U4 is the second communication signal input terminal, which is used to input the debugging communication signal;

[0024] Pin 15 of the main control chip U4 is a first temperature sensing signal input terminal, used to input a first temperature sensing signal;

[0025] Pin 16 of the main control chip U4 is a second temperature sensing signal input terminal, used to input a second temperature sensing signal;

[0026] Pin 17 of the main control chip U4 is a low-voltage logic signal output terminal, which is used to output a low-voltage logic signal;

[0027] Pin 18 of the main control chip U4 is a shutdown logic signal output terminal, which is used to output a shutdown logic signal;

[0028] Pin 19 of the main control chip U4 is a high-voltage logic signal output terminal, which is used to output a high-voltage logic signal;

[0029] The low-voltage logic signal, the shutdown logic signal and the high-voltage logic signal output by the main control chip U4 all act on the regulating circuit, so that the regulating circuit controls the conductive heating plate 3 to heat;

[0030] Pin 20 of the main control chip U4 is connected to the 3.3V power input terminal, while pin 20 of the main control chip U2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded.

[0031] Further, the regulating circuit includes a gate isolation driver U1, a MOS tube M1, a MOS tube M2, capacitors C2 to C7, resistors R3 to R7, a diode D3, a diode D4 and a diode D5;

[0032] Pin 1 of the gate isolation driver U1 is connected to one end of the resistor R6; the other end of the resistor R6 is simultaneously connected to the gate of the MOS tube M2 and one end of the resistor R7; the other end of the resistor R7 is simultaneously connected to the source of the MOS tube M2, the anode of the diode D4 and one end of the capacitor C7, and is grounded; the drain of the MOS tube M2 is connected to one end of the conductive heating plate 3;

[0033] Pin 2 of the gate isolation driver U1 is grounded;

[0034] Pin 3 of the gate isolation driver U1 is connected to one end of the capacitor C5 and one end of the capacitor C6 at the same time, and pin 3 of the gate isolation driver U1 is connected to a 12V power supply; the other end of the capacitor C5 is connected to the other end of the capacitor C6 and is grounded;

[0035] Pin 6 of the gate isolation driver U1 is simultaneously connected to one end of the capacitor C3, one end of the capacitor C4 and one end of the resistor R5; the other end of the resistor R5 is simultaneously connected to the source of the MOS tube M1, the anode of the diode D3 and the other end of the conductive heating plate 3;

[0036] Pin 7 of the gate isolation driver U1 is simultaneously connected to the other end of the capacitor C3, the other end of the capacitor C4, and the cathode of the diode D5; the anode of the diode D5 is connected to the 12V power supply;

[0037] Pin 8 of the gate isolation driver U1 is connected to one end of the resistor R3; the other end of the resistor R3 is simultaneously connected to one end of the resistor R4 and the gate of the MOS tube M1; the other end of the resistor R4 is simultaneously connected to the drain of the MOS tube M1, the cathode of the diode D3 and the other end of the capacitor C7, and is connected to a 12V power supply;

[0038] Pin 11 of the gate isolation driver U1 is connected to one end of the capacitor C2 and connected to a 3.3V power supply; the other end of the capacitor C2 is grounded;

[0039] Pin 12 of the gate isolation driver U1 is a high voltage logic signal input terminal, and pin 12 of the gate isolation driver U1 is connected to pin 19 of the main control chip U4;

[0040] Pin 13 of the gate isolation driver U1 is a shutdown logic signal input terminal, and pin 13 of the gate isolation driver U1 is connected to pin 18 of the main control chip U4;

[0041] Pin 14 of the gate isolation driver U1 is a low-voltage logic signal input terminal, and pin 14 of the gate isolation driver U1 is connected to pin 17 of the main control chip U4;

[0042] Pin 14 of the gate isolation driver U1 is connected to ground.

[0043] Furthermore, the heating unit also includes a fixed voltage output circuit and a switching voltage stabilizing circuit;

[0044] The switching voltage regulator circuit is used to convert 24V DC power into 12V DC power; the 12V DC power supplies power to the gate isolation driver U1;

[0045] The fixed voltage output circuit is used to convert 12V DC power into 3.3V DC power; the 3.3V DC power is used to power the main control chip U4.

[0046] Furthermore, the fixed voltage output circuit includes capacitors C8 to C12 and a power chip U2;

[0047] Pin 3 of the power chip U2 is connected to one end of the capacitor C8 and one end of the capacitor C9 at the same time, and is connected to a 12V power supply; the other end of the capacitor C8 is grounded; the other end of the capacitor C9 is grounded;

[0048] Pin 1 of the power chip U2 is grounded;

[0049] Pin 2 of the power chip U2 is simultaneously connected to one end of the capacitor C10 , one end of the capacitor C11 , and one end of the capacitor C12 , and pin 2 of the power chip U2 is a 3.3V power output terminal.

[0050] Further, the switching voltage stabilization circuit includes a switching voltage stabilizer U3, capacitors C13 to C21, a resistor R8, a resistor R9, a diode D6 and an inductor L1;

[0051] Pin 3 of the switching regulator U3 is simultaneously connected to one end of the capacitor C15, one end of the capacitor C14, one end of the capacitor C13 and the cathode of the diode D6; the anode of the diode D6 is connected to the 24V power supply; the other end of the capacitor C15 is grounded; the other end of the capacitor C14 is grounded; the other end of the capacitor C13 is grounded;

[0052] Pin 4 of the switching regulator U3 is grounded;

[0053] Pin 5 of the switching regulator U3 is simultaneously connected to one end of the capacitor C16 and one end of the inductor L1; the other end of the inductor L1 is simultaneously connected to one end of the capacitor C18, one end of the resistor R9, one end of the capacitor C19, one end of the capacitor C20 and one end of the capacitor C21; and the other end of the inductor L1 is the 12V power supply output end;

[0054] Pin 6 of the switching regulator U3 is connected to the other end of the capacitor C16;

[0055] Pin 7 of the switching regulator U3 is connected to one end of the capacitor C17; the other end of the capacitor C17 is grounded;

[0056] Pin 8 of the switching regulator U3 is simultaneously connected to the other end of the capacitor C18, the other end of the resistor R9, and one end of the resistor R8; the other end of the resistor R8 is grounded.

[0057] Furthermore, the heating unit also includes an interface circuit;

[0058] The interface circuit includes a debugging chip U5 and a resistor R20;

[0059] Pin 1 of the debug chip U5 is a reset signal input terminal, which is used to input a reset signal;

[0060] Pin 2 of the debug chip U5 is connected to pin 4 of the debug chip U5 and pin 6 of the debug chip U5 at the same time, and is connected to a 3.3V power supply;

[0061] Pin 3 of the debug chip U5 is a clock signal debug output interface, and pin 3 of the debug chip U5 is connected to pin 3 of the main control chip U4;

[0062] Pin 5 of the debug chip U5 is a serial data debug output interface, and pin 3 of the debug chip U5 is connected to pin 2 of the main control chip U4;

[0063] Pin 7 of the debug chip U5 is the second communication signal output terminal, and pin 7 of the debug chip U5 is connected to pin 14 of the main control chip U4;

[0064] Pin 8 of the debugging chip U5 is connected to one end of the resistor R20; the other end of the resistor R20 is a data terminal ready signal output end, which is used to output the data terminal ready signal;

[0065] Pin 9 of the debug chip U5 is the second communication signal input terminal, and pin 9 of the debug chip U5 is connected to pin 13 of the main control chip U4;

[0066] Pin 10 of the debug chip U5 is a request data receiving terminal, used to receive request data;

[0067] Pin No. 12 of the debug chip U5 is connected to pin No. 14 of the debug chip U5 and is grounded.

[0068] Furthermore, the heating unit also includes a bootstrap voltage boost circuit;

[0069] The bootstrap boost circuit includes resistors R15 to R19, transistors Q1, Q2 and Q3;

[0070] The collector of transistor Q1 is a reset signal input terminal, which is used to input a reset signal;

[0071] The emitter of transistor Q1 is connected to one end of resistor R15 and pin 10 of debug chip U5 at the same time;

[0072] The base of transistor Q1 is connected to one end of resistor R17;

[0073] The base of transistor Q2 is connected to one end of resistor R16; the other end of resistor R16 is connected to the other end of resistor R15;

[0074] The collector of transistor Q2 is connected to one end of resistor R18;

[0075] The emitter of transistor Q2 is connected to the other end of resistor R17 and the other end of resistor R20 at the same time;

[0076] The base of transistor Q3 is connected to the other end of resistor R18;

[0077] The collector of transistor Q3 is connected to a 3.3V power supply;

[0078] The emitter of the transistor Q3 is connected to one end of the resistor R19; the other end of the resistor R19 is the output end of the bootstrap boost signal.

[0079] Further, the heating unit includes two temperature sensors 4;

[0080] A temperature sensor includes a first sensor body, a resistor R10, a resistor R11 and an inductor C22;

[0081] The negative input terminal of the first sensor body is grounded;

[0082] The positive input terminal of the first sensor body is simultaneously connected to one end of the resistor R11, one end of the inductor C22 and one end of the resistor R10; the other end of the resistor R11 is connected to the other end of the inductor C22 and connected to a 3.3V power supply;

[0083] The other end of the resistor R10 is the first sensing signal output end, and the other end of the resistor R10 is connected to the pin 15 of the main control chip U4;

[0084] Another temperature sensor includes a second sensor body, resistors R12 to R14 and an inductor C23;

[0085] The negative input terminal of the second sensor body is grounded;

[0086] The positive input terminal of the second sensor body is simultaneously connected to one end of the resistor R14, one end of the inductor C23 and one end of the resistor R13; the other end of the resistor R14 is connected to the other end of the inductor C23 and connected to a 3.3V power supply;

[0087] The other end of the resistor R13 is connected to one end of the resistor R12;

[0088] The other end of the resistor R12 is the second sensing signal output end, and the other end of the resistor R12 is connected to pin No. 16 of the main control chip U4.

[0089] Furthermore, the heating unit also includes a PCB board;

[0090] The PCB board is provided with a heating area and a circuit area; wherein the conductive heating sheet is printed in the heating area according to the path of the Hilbert curve; and the control circuit is arranged in the circuit area;

[0091] The length of the heating zone is 100 mm; the width of the heating zone is 100 mm;

[0092] The resistance calculation formula of the conductive heating plate is:

[0093]

[0094] Wherein, R is the resistance of the conductive heating sheet; ρ is the resistivity of the conductive heating sheet; L is the length of the conductive heating sheet; W is the width of the conductive heating sheet; and D is the thickness of the conductive heating sheet.

[0095] Compared with the prior art, the present invention has the following beneficial effects:

[0096] 1: Significantly improved heating uniformity: By using the Hilbert curve to design the heating path of the conductive heating plate, the conductive heating plate can cover a wider range and be more evenly distributed within a limited space, effectively reducing the hot and cold spot problems common in existing serpentine circuit designs. The heat distribution uniformity test shows that the temperature uniformity has been improved by about 30%.

[0097] 2: Improved space utilization: The Hilbert curve-shaped conductive heating sheet is a compact design, which allows a longer heating path to be arranged on the same PCB board area, thereby improving space utilization. Experimental data shows that compared with the existing design, the space utilization is improved by about 20%.

[0098] 3: Enhanced temperature control accuracy: Due to the heating uniformity and path optimization, the conductive heating plate of the present invention has significantly improved the accuracy of the control circuit, and the temperature fluctuation is controlled within ±0.5°C, which is of great significance for electronic equipment requiring high-precision temperature control.

[0099] 4. Reduced energy consumption: The optimized heating path of the conductive heating plate reduces energy loss, thereby improving the energy efficiency of the entire heating system. After comparative testing, the energy consumption of the present invention is reduced by about 15%, which improves the heating efficiency while reducing energy consumption.

[0100] 5. Increased design flexibility: Since the Hilbert curve-shaped conductive heating plate is adjustable, the density of the heating circuit can be flexibly designed according to the needs of different devices, adapting to the design requirements of PCB boards of various complex shapes, thereby enhancing the flexibility and applicability of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Figure 1 This is a physical diagram of a self-constant temperature heating unit based on the Hilbert curve described in the first specific implementation mode;

[0102] Figure 2 is a circuit diagram of the main control circuit in the second specific implementation mode;

[0103] Figure 3 is a circuit diagram of the regulating circuit in the third specific implementation mode;

[0104] Figure 4 is a circuit diagram of a fixed voltage output circuit in a fifth specific implementation mode;

[0105] Figure 5 is a circuit diagram of a switching voltage regulator circuit in a sixth specific implementation mode;

[0106] Figure 6 is a circuit diagram of the interface circuit in the seventh specific implementation mode;

[0107] Figure 7is a circuit diagram of a bootstrap boost circuit in a specific implementation manner eight;

[0108] Figure 8 is a circuit diagram of a reset circuit in specific implementation mode eight;

[0109] Fig. 9 It is a circuit schematic diagram of the temperature sensor in the ninth embodiment. DETAILED DESCRIPTION

[0110] Specific implementation method 1. Combination Figure 1 This embodiment is described as a self-constant temperature heating unit based on the Hilbert curve, wherein the heating unit comprises a control circuit 2, a conductive heating sheet 3 and a temperature sensor 4;

[0111] The temperature sensor 4 is used to monitor the temperature change of the conductive heating plate 3 in real time and output a temperature sensing signal; the temperature sensing signal output end of the temperature sensor 4 is connected to the temperature sensing signal input end of the control circuit 2;

[0112] The control circuit 2 compares the temperature sensing signal with the preset temperature curve, generates an adjustment signal according to the comparison result, and the output end of the adjustment signal acts on the conductive heating plate 3;

[0113] The conductive heating plates 3 are arranged in the space to be heated according to the path of the Hilbert curve.

[0114] In this embodiment, the heating unit utilizes the space filling characteristics of the Hilbert curve to achieve uniform and efficient heat distribution within the limited area of ​​the space to be heated; the conductive heating plate 3 can be designed as a single layer or multiple layers; when the conductive heating plate 3 is designed as a multiple layer, the upper and lower adjacent layers are connected by conductive columns; the conductive heating plate 3 is made of conductive material and is arranged in the space to be heated according to the path of the Hilbert curve; the Hilbert curve is a recursive fractal curve with the characteristics of a high space filling rate, so it can maximize the length and uniformity of the heating path within the limited area of ​​the space to be heated. At the same time, the conductive heating sheet 3 is responsible for converting electrical energy into thermal energy, and realizing uniform heat distribution by forming a Hilbert curve-shaped path in the space to be heated; the conductive heating sheet 3 can be made of copper foil or other highly conductive materials, and after a multi-layer setting, the heating path can be interconnected between multiple levels, further improving the heating uniformity; the thickness and width of the conductive heating sheet 3 can be adjusted according to actual needs to control the heating power and uniformity; the control circuit 2 is used to manage the flow of current to ensure that the entire conductive heating sheet 3 can work according to the preset temperature curve; the control circuit 2 is designed as an embedded system and can communicate with an external host computer to realize remote or automatic temperature adjustment. Experimental data show that the heating unit performs well in maintaining a constant temperature inside the device, with a temperature uniformity of more than 95%, effectively reducing the temperature control accuracy problem caused by local overheating or cooling.

[0115] Working principle:

[0116] When the control circuit 2 is powered on, the current passes through the Hilbert curve-shaped conductive heating plate 3 according to a preset temperature curve. The Hilbert curve-shaped conductive heating plate 3 converts electrical energy into thermal energy, and the conductive heating plate 3 is evenly distributed in the space to be heated. Due to the high space filling rate of the Hilbert curve-shaped conductive heating plate 3, the heat distribution of the entire space to be heated is more uniform, avoiding the hot spot and cold spot problems common in the existing serpentine path design.

[0117] The temperature sensor 4 is embedded in the conductive heating plate 3 of the space to be heated, and is used to monitor the temperature of the conductive heating plate 3 in real time, and feed back the temperature sensing signal to the control circuit 2. The control circuit 2 adjusts the current passing through the conductive heating plate 3 to ensure that the temperature of the space to be heated is stable within the range of ±0.5°C and follows the preset temperature curve.

[0118] Specific implementation method 2: Combination Figure 2 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the specific embodiment 1. In this embodiment, the control circuit 2 includes a main control circuit and a regulating circuit;

[0119] The main control circuit includes a main control chip U4, a capacitor C1, a resistor R1, a resistor R2, a light emitting diode D1 and a light emitting diode D2;

[0120] Pin 1 of the main control chip U4 is the ground terminal, which is used to connect the ground wire;

[0121] Pin 2 of the main control chip U4 is the serial data debugging input interface, which is used to write the temperature curve;

[0122] Pin 3 of the main control chip U4 is the clock signal debugging input interface, which is used to write the clock signal;

[0123] Pin 4 of the main control chip U4 is the RS485 communication command output interface, which is used to output RS485 communication commands;

[0124] Pin 5 of the main control chip U4 is the bootstrap boost signal input terminal, which is used to input the bootstrap boost signal;

[0125] Pin 8 of the main control chip U4 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the light-emitting diode D1, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply;

[0126] Pin 9 of the main control chip U4 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the anode of the light-emitting diode D2, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply;

[0127] Pin 10 of the main control chip U4 is the reset signal input terminal, which is used to input the reset signal;

[0128] Pin 11 of the main control chip U4 is the first communication signal output terminal, which is used to output RS485 communication signals;

[0129] Pin 12 of the main control chip U4 is the first communication signal input terminal, which is used to input RS485 communication signals;

[0130] Pin 13 of the main control chip U4 is the second communication signal output terminal, which is used to output the debugging communication signal;

[0131] Pin 14 of the main control chip U4 is the second communication signal input terminal, which is used to input the debugging communication signal;

[0132] Pin 15 of the main control chip U4 is a first temperature sensing signal input terminal, used to input a first temperature sensing signal;

[0133] Pin 16 of the main control chip U4 is a second temperature sensing signal input terminal, used to input a second temperature sensing signal;

[0134] Pin 17 of the main control chip U4 is a low-voltage logic signal output terminal, which is used to output a low-voltage logic signal;

[0135] Pin 18 of the main control chip U4 is a shutdown logic signal output terminal, which is used to output a shutdown logic signal;

[0136] Pin 19 of the main control chip U4 is a high-voltage logic signal output terminal, which is used to output a high-voltage logic signal;

[0137] The low-voltage logic signal, the shutdown logic signal and the high-voltage logic signal output by the main control chip U4 all act on the regulating circuit, so that the regulating circuit controls the conductive heating plate 3 to heat;

[0138] Pin 20 of the main control chip U4 is connected to the 3.3V power input terminal, while pin 20 of the main control chip U2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded.

[0139] In this embodiment, the model of the main control chip U4 is AIR001, and a reset circuit is provided on the main control circuit; the light-emitting diode D1 and the light-emitting diode D2 are two indicator lights; the capacitance value of the capacitor C1 is 100nF; the resistance value of the resistor R1 and the resistance value of the resistor R2 are both 10KΩ; the main control chip U4 is equipped with an RS485 communication command output interface, a first communication signal output terminal and a first communication signal input terminal, which is convenient for external connection to the RS485 communication interface.

[0140] Specific implementation method 3: Combination Figure 3 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the second embodiment. In this embodiment, the regulating circuit includes a gate isolation driver U1, a MOS tube M1, a MOS tube M2, capacitors C2 to C7, resistors R3 to R7, a diode D3, a diode D4 and a diode D5;

[0141] Pin 1 of the gate isolation driver U1 is connected to one end of the resistor R6; the other end of the resistor R6 is simultaneously connected to the gate of the MOS tube M2 and one end of the resistor R7; the other end of the resistor R7 is simultaneously connected to the source of the MOS tube M2, the anode of the diode D4 and one end of the capacitor C7, and is grounded; the drain of the MOS tube M2 is connected to one end of the conductive heating plate 3;

[0142] Pin 2 of the gate isolation driver U1 is grounded;

[0143] Pin 3 of the gate isolation driver U1 is connected to one end of the capacitor C5 and one end of the capacitor C6 at the same time, and pin 3 of the gate isolation driver U1 is connected to a 12V power supply; the other end of the capacitor C5 is connected to the other end of the capacitor C6 and is grounded;

[0144] Pin 6 of the gate isolation driver U1 is simultaneously connected to one end of the capacitor C3, one end of the capacitor C4 and one end of the resistor R5; the other end of the resistor R5 is simultaneously connected to the source of the MOS tube M1, the anode of the diode D3 and the other end of the conductive heating plate 3;

[0145] Pin 7 of the gate isolation driver U1 is simultaneously connected to the other end of the capacitor C3, the other end of the capacitor C4, and the cathode of the diode D5; the anode of the diode D5 is connected to the 12V power supply;

[0146] Pin 8 of the gate isolation driver U1 is connected to one end of the resistor R3; the other end of the resistor R3 is simultaneously connected to one end of the resistor R4 and the gate of the MOS tube M1; the other end of the resistor R4 is simultaneously connected to the drain of the MOS tube M1, the cathode of the diode D3 and the other end of the capacitor C7, and is connected to a 12V power supply;

[0147] Pin 11 of the gate isolation driver U1 is connected to one end of the capacitor C2 and connected to a 3.3V power supply; the other end of the capacitor C2 is grounded;

[0148] Pin 12 of the gate isolation driver U1 is a high voltage logic signal input terminal, and pin 12 of the gate isolation driver U1 is connected to pin 19 of the main control chip U4;

[0149] Pin 13 of the gate isolation driver U1 is a shutdown logic signal input terminal, and pin 13 of the gate isolation driver U1 is connected to pin 18 of the main control chip U4;

[0150] Pin 14 of the gate isolation driver U1 is a low-voltage logic signal input terminal, and pin 14 of the gate isolation driver U1 is connected to pin 17 of the main control chip U4;

[0151] Pin 14 of the gate isolation driver U1 is connected to ground.

[0152] In this embodiment, the model of the gate isolation driver U1 is IR2113STRPBF; by adjusting the setting of the circuit, the actual adjustment of the heating power of the conductive heating plate 3 is achieved.

[0153] Specific implementation method 4: This implementation method further limits the self-constant temperature heating unit based on the Hilbert curve described in specific implementation method 3. In this implementation method, the heating unit further includes a fixed voltage output circuit and a switching voltage stabilizing circuit;

[0154] The switching voltage regulator circuit is used to convert 24V DC power into 12V DC power; the 12V DC power supplies power to the gate isolation driver U1;

[0155] The fixed voltage output circuit is used to convert 12V DC power into 3.3V DC power; the 3.3V DC power is used to power the main control chip U4.

[0156] In this embodiment, a switching voltage regulator circuit is used to convert 24V DC power into 12V DC power; 12V DC power supplies power to the gate isolation driver U1; a fixed voltage output circuit is used to convert 12V DC power into 3.3V DC power; 3.3V DC power supplies power to the main control chip U4, and 3.3V DC power also supplies power to the temperature sensor 4. By designing the fixed voltage output circuit and the switching voltage regulator circuit, all power supply requirements of the heating unit are met.

[0157] Specific implementation method V. Combination Figure 4 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the fourth embodiment. In this embodiment, the fixed voltage output circuit includes capacitors C8 to C12 and a power chip U2;

[0158] Pin 3 of the power chip U2 is connected to one end of the capacitor C8 and one end of the capacitor C9 at the same time, and is connected to a 12V power supply; the other end of the capacitor C8 is grounded; the other end of the capacitor C9 is grounded;

[0159] Pin 1 of the power chip U2 is grounded;

[0160] Pin 2 of the power chip U2 is simultaneously connected to one end of the capacitor C10 , one end of the capacitor C11 , and one end of the capacitor C12 , and pin 2 of the power chip U2 is a 3.3V power output terminal.

[0161] In this embodiment, the model of the power chip U2 is AMS1117-3.3; the power chip U2 is a forward low-dropout voltage regulator with an output voltage of 3.3V, which is suitable for the heating unit described in this embodiment.

[0162] Specific implementation method 6. Combination Figure 5 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the specific embodiment 4. In this embodiment, the switching voltage regulator circuit includes a switching voltage regulator U3, capacitors C13 to C21, resistors R8, R9, a diode D6 and an inductor L1;

[0163] Pin 3 of the switching regulator U3 is simultaneously connected to one end of the capacitor C15, one end of the capacitor C14, one end of the capacitor C13 and the cathode of the diode D6; the anode of the diode D6 is connected to the 24V power supply; the other end of the capacitor C15 is grounded; the other end of the capacitor C14 is grounded; the other end of the capacitor C13 is grounded;

[0164] Pin 4 of the switching regulator U3 is grounded;

[0165] Pin 5 of the switching regulator U3 is simultaneously connected to one end of the capacitor C16 and one end of the inductor L1; the other end of the inductor L1 is simultaneously connected to one end of the capacitor C18, one end of the resistor R9, one end of the capacitor C19, one end of the capacitor C20 and one end of the capacitor C21; and the other end of the inductor L1 is the 12V power supply output end;

[0166] Pin 6 of the switching regulator U3 is connected to the other end of the capacitor C16;

[0167] Pin 7 of the switching regulator U3 is connected to one end of the capacitor C17; the other end of the capacitor C17 is grounded;

[0168] Pin 8 of the switching regulator U3 is simultaneously connected to the other end of the capacitor C18, the other end of the resistor R9, and one end of the resistor R8; the other end of the resistor R8 is grounded.

[0169] In this embodiment, the model of the switching regulator U3 is: TPS62932DRLR; the switching frequency fluctuation of the resistor at pin 1 of the switching regulator U3 is greater than 280KΩ500KHz; and the switching frequency fluctuation of the resistor at pin 1 of the switching regulator U3 is less than 1KΩ1200KHz.

[0170] Specific implementation method VII. Combination Figure 6 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the second embodiment. In this embodiment, the heating unit further includes an interface circuit;

[0171] The interface circuit includes a debugging chip U5 and a resistor R20;

[0172] Pin 1 of the debug chip U5 is a reset signal input terminal, which is used to input a reset signal;

[0173] Pin 2 of the debug chip U5 is connected to pin 4 of the debug chip U5 and pin 6 of the debug chip U5 at the same time, and is connected to a 3.3V power supply;

[0174] Pin 3 of the debug chip U5 is a clock signal debug output interface, and pin 3 of the debug chip U5 is connected to pin 3 of the main control chip U4;

[0175] Pin 5 of the debug chip U5 is a serial data debug output interface, and pin 3 of the debug chip U5 is connected to pin 2 of the main control chip U4;

[0176] Pin 7 of the debug chip U5 is the second communication signal output terminal, and pin 7 of the debug chip U5 is connected to pin 14 of the main control chip U4;

[0177] Pin 8 of the debugging chip U5 is connected to one end of the resistor R20; the other end of the resistor R20 is a data terminal ready signal output end, which is used to output the data terminal ready signal;

[0178] Pin 9 of the debug chip U5 is the second communication signal input terminal, and pin 9 of the debug chip U5 is connected to pin 13 of the main control chip U4;

[0179] Pin 10 of the debug chip U5 is a request data receiving terminal, used to receive request data;

[0180] Pin No. 12 of the debug chip U5 is connected to pin No. 14 of the debug chip U5 and is grounded.

[0181] In this embodiment, the model of the debugging chip U5 is DP-LINK; the temperature curve and the clock signal are written to the main control chip U4 through the interface circuit; the temperature curve can be easily preset and modified.

[0182] Specific implementation method 8. Combination Figure 7 and Figure 8 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the seventh embodiment. In this embodiment, the heating unit further includes a bootstrap voltage boost circuit;

[0183] The bootstrap boost circuit includes resistors R15 to R19, transistors Q1, Q2 and Q3;

[0184] The collector of transistor Q1 is a reset signal input terminal, which is used to input a reset signal;

[0185] The emitter of transistor Q1 is connected to one end of resistor R15 and pin 10 of debug chip U5 at the same time;

[0186] The base of transistor Q1 is connected to one end of resistor R17;

[0187] The base of transistor Q2 is connected to one end of resistor R16; the other end of resistor R16 is connected to the other end of resistor R15; the collector of transistor Q2 is connected to one end of resistor R18;

[0188] The emitter of transistor Q2 is connected to the other end of resistor R17 and the other end of resistor R20 at the same time;

[0189] The base of transistor Q3 is connected to the other end of resistor R18;

[0190] The collector of transistor Q3 is connected to a 3.3V power supply;

[0191] The emitter of the transistor Q3 is connected to one end of the resistor R19; the other end of the resistor R19 is the output end of the bootstrap boost signal.

[0192] In this embodiment, the model of transistor Q1 and the model of transistor Q2 are both LMBT3904DW1T1G, and the model of transistor Q3 is KS8550LCD; and the transistor Q1 and the transistor Q2 can be packaged together, and the bootstrap boost circuit is used to improve the duty cycle and conduction time of the main control chip U4.

[0193] At the same time, in this embodiment, a reset circuit is added, and the reset circuit includes a reset switch SW1, a capacitor C24 and a resistor R21; one end of the reset switch SW1 is grounded, and the other end of the reset switch SW1 is connected to one end of the capacitor C24 and one end of the resistor R21 at the same time; the other end of the capacitor C24 is grounded; the other end of the resistor R21 is connected to a 3.3V power supply; the other end of the reset switch SW1 is a reset signal output end; through the setting of the reset circuit, each time the reset switch SW1 is pressed, a reset signal will be output, and the reset signal acts on the collector of the transistor Q1; at the same time, the reset signal can also act on the main control chip U4.

[0194] Specific implementation method IX. Combination Figure 7 and Figure 8 This embodiment is described. This embodiment further limits the self-constant temperature heating unit based on the Hilbert curve described in the second embodiment. In this embodiment, the heating unit includes two temperature sensors 4;

[0195] A temperature sensor 4 includes a first sensor body 4-1, a resistor R10, a resistor R11 and an inductor C22;

[0196] The negative input terminal of the first sensor body 4 - 1 is grounded;

[0197] The positive input terminal of the first sensor body 4-1 is simultaneously connected to one end of the resistor R11, one end of the inductor C22 and one end of the resistor R10; the other end of the resistor R11 is connected to the other end of the inductor C22 and connected to a 3.3V power supply;

[0198] The other end of the resistor R10 is the first sensing signal output end, and the other end of the resistor R10 is connected to the pin 15 of the main control chip U4;

[0199] Another temperature sensor 4 includes a second sensor body 4-2, resistors R12 to R14 and an inductor C23;

[0200] The negative input terminal of the second sensor body 4 - 2 is grounded;

[0201] The positive input terminal of the second sensor body 4-2 is simultaneously connected to one end of the resistor R14, one end of the inductor C23 and one end of the resistor R13; the other end of the resistor R14 is connected to the other end of the inductor C23 and connected to a 3.3V power supply;

[0202] The other end of the resistor R13 is connected to one end of the resistor R12;

[0203] The other end of the resistor R12 is the second sensing signal output end, and the other end of the resistor R12 is connected to pin No. 16 of the main control chip U4.

[0204] In this embodiment, two temperature sensors 4 are provided, and the two temperature sensors 4 are respectively arranged at different positions of the heating zone 1 - 1 on the PCB board 1 to avoid the problem of uneven temperature in the heating zone 1 - 1 .

[0205] Specific implementation method 10. This implementation method further limits the self-constant temperature heating unit based on the Hilbert curve described in specific implementation method 2. In this implementation method, the heating unit further includes a PCB board 1;

[0206] The PCB board 1 is provided with a heating area 1-1 and a circuit area 1-2; wherein the conductive heating sheet 3 is printed in the heating area 1-1 according to the path of the Hilbert curve; and the control circuit 2 is arranged in the circuit area 1-2;

[0207] The length of the heating zone 1-1 is 100 mm; the width of the heating zone 1-1 is 100 mm;

[0208] The resistance calculation formula of the conductive heating plate (3) is:

[0209]

[0210] Wherein, R is the resistance of the conductive heating sheet 3; ρ is the resistivity of the conductive heating sheet 3; L is the length of the conductive heating sheet 3; W is the width of the conductive heating sheet 3; and D is the thickness of the conductive heating sheet 3.

[0211] In this embodiment, the Hilbert curve is a curve. As long as the function is properly selected, a continuous parameter curve is drawn. When the parameter t takes a value in the interval of 0 and 1, the curve will traverse all points in the unit square and obtain a curve that fills the space. The thickness of the conductive heating sheet 3 is set to 0.035. The conductive heating sheet 3 is made of copper, so the resistivity of the conductive heating sheet 3 is 0.0175Ω ohm·mm. 2 / meter; the width of the conductive heating sheet 3 is set to 0.035mm; the length of the conductive heating sheet 3 is equal to 2 (2n)-1; wherein n is the order of the Hilbert curve, which is also the number of unit squares set in the heating zone 1-1; the spacing between adjacent portions of the conductive heating plate 3 is 0.5 mm; such a design can ensure uniform heat distribution over the entire surface of the heating zone 1-1; according to experimental calculations, the length of the heating zone 1-1 is 100 mm; when the width of the heating zone 1-1 is 100 mm, the resistance of the conductive heating plate 3 is 6.6 Ω.

[0212] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A self-constant temperature heating unit based on Hilbert curve, characterized in that: The heating unit comprises a control circuit (2), a conductive heating sheet (3) and a temperature sensor (4); The temperature sensor (4) is used to monitor the temperature change of the conductive heating plate (3) in real time and output a temperature sensing signal; the temperature sensing signal output end of the temperature sensor (4) is connected to the temperature sensing signal input end of the control circuit (2); The control circuit (2) compares the temperature sensing signal with the preset temperature curve, generates an adjustment signal according to the comparison result, and the output end of the adjustment signal acts on the conductive heating plate (3); The conductive heating plates (3) are arranged in the space to be heated according to the path of the Hilbert curve.

2. The self-constant temperature heating unit based on the Hilbert curve according to claim 1, characterized in that: The control circuit (2) comprises a main control circuit and a regulating circuit; The main control circuit includes a main control chip U4, a capacitor C1, a resistor R1, a resistor R2, a light emitting diode D1 and a light emitting diode D2; Pin 1 of the main control chip U4 is the ground terminal, which is used to connect the ground wire; Pin 2 of the main control chip U4 is the serial data debugging input interface, which is used to write the temperature curve; Pin 3 of the main control chip U4 is the clock signal debugging input interface, which is used to write the clock signal; Pin 4 of the main control chip U4 is the RS485 communication command output interface, which is used to output RS485 communication commands; Pin 5 of the main control chip U4 is the bootstrap boost signal input terminal, which is used to input the bootstrap boost signal; Pin 8 of the main control chip U4 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the light-emitting diode D1, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply; Pin 9 of the main control chip U4 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the anode of the light-emitting diode D2, and the cathode of the light-emitting diode D2 is connected to the 3.3V power supply; Pin 10 of the main control chip U4 is the reset signal input terminal, which is used to input the reset signal; Pin 11 of the main control chip U4 is the first communication signal output terminal, which is used to output RS485 communication signals; Pin 12 of the main control chip U4 is the first communication signal input terminal, which is used to input RS485 communication signals; Pin 13 of the main control chip U4 is the second communication signal output terminal, which is used to output the debugging communication signal; Pin 14 of the main control chip U4 is the second communication signal input terminal, which is used to input the debugging communication signal; Pin 15 of the main control chip U4 is a first temperature sensing signal input terminal, used to input a first temperature sensing signal; Pin 16 of the main control chip U4 is a second temperature sensing signal input terminal, used to input a second temperature sensing signal; Pin 17 of the main control chip U4 is a low-voltage logic signal output terminal, which is used to output a low-voltage logic signal; Pin 18 of the main control chip U4 is a shutdown logic signal output terminal, which is used to output a shutdown logic signal; Pin 19 of the main control chip U4 is a high-voltage logic signal output terminal, which is used to output a high-voltage logic signal; The low-voltage logic signal, the shutdown logic signal and the high-voltage logic signal output by the main control chip U4 all act on the regulating circuit, so that the regulating circuit controls the conductive heating plate (3) to heat; Pin 20 of the main control chip U4 is connected to the 3.3V power input terminal, while pin 20 of the main control chip U2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded.

3. The self-constant temperature heating unit based on the Hilbert curve according to claim 2, characterized in that: The regulating circuit includes a gate isolation driver U1, a MOS tube M1, a MOS tube M2, capacitors C2 to C7, resistors R3 to R7, a diode D3, a diode D4 and a diode D5; Pin No. 1 of the gate isolation driver U1 is connected to one end of the resistor R6; the other end of the resistor R6 is simultaneously connected to the gate of the MOS tube M2 and one end of the resistor R7; the other end of the resistor R7 is simultaneously connected to the source of the MOS tube M2, the anode of the diode D4 and one end of the capacitor C7, and is grounded; the drain of the MOS tube M2 is connected to one end of the conductive heating plate (3); Pin 2 of the gate isolation driver U1 is grounded; Pin 3 of the gate isolation driver U1 is connected to one end of the capacitor C5 and one end of the capacitor C6 at the same time, and pin 3 of the gate isolation driver U1 is connected to a 12V power supply; the other end of the capacitor C5 is connected to the other end of the capacitor C6 and is grounded; Pin 6 of the gate isolation driver U1 is simultaneously connected to one end of the capacitor C3, one end of the capacitor C4 and one end of the resistor R5; the other end of the resistor R5 is simultaneously connected to the source of the MOS tube M1, the anode of the diode D3 and the other end of the conductive heating plate (3); Pin 7 of the gate isolation driver U1 is simultaneously connected to the other end of the capacitor C3, the other end of the capacitor C4, and the cathode of the diode D5; the anode of the diode D5 is connected to the 12V power supply; Pin 8 of the gate isolation driver U1 is connected to one end of the resistor R3; the other end of the resistor R3 is simultaneously connected to one end of the resistor R4 and the gate of the MOS tube M1; the other end of the resistor R4 is simultaneously connected to the drain of the MOS tube M1, the cathode of the diode D3 and the other end of the capacitor C7, and is connected to a 12V power supply; Pin 11 of the gate isolation driver U1 is connected to one end of the capacitor C2 and connected to a 3.3V power supply; the other end of the capacitor C2 is grounded; Pin 12 of the gate isolation driver U1 is a high voltage logic signal input terminal, and pin 12 of the gate isolation driver U1 is connected to pin 19 of the main control chip U4; Pin 13 of the gate isolation driver U1 is a shutdown logic signal input terminal, and pin 13 of the gate isolation driver U1 is connected to pin 18 of the main control chip U4; Pin 14 of the gate isolation driver U1 is a low-voltage logic signal input terminal, and pin 14 of the gate isolation driver U1 is connected to pin 17 of the main control chip U4; Pin 14 of the gate isolation driver U1 is connected to ground.

4. The self-constant temperature heating unit based on the Hilbert curve according to claim 3, characterized in that: The heating unit also includes a fixed voltage output circuit and a switching voltage stabilizing circuit; The switching voltage regulator circuit is used to convert 24V DC power into 12V DC power; the 12V DC power supplies power to the gate isolation driver U1; The fixed voltage output circuit is used to convert 12V DC power into 3.3V DC power; the 3.3V DC power is used to power the main control chip U4.

5. The self-constant temperature heating unit based on the Hilbert curve according to claim 4, characterized in that: The fixed voltage output circuit includes capacitors C8 to C12 and a power chip U2; Pin 3 of the power chip U2 is connected to one end of the capacitor C8 and one end of the capacitor C9 at the same time, and is connected to a 12V power supply; the other end of the capacitor C8 is grounded; the other end of the capacitor C9 is grounded; Pin 1 of the power chip U2 is grounded; Pin 2 of the power chip U2 is simultaneously connected to one end of the capacitor C10 , one end of the capacitor C11 , and one end of the capacitor C12 , and pin 2 of the power chip U2 is a 3.3V power output terminal.

6. The self-constant temperature heating unit based on the Hilbert curve according to claim 4, characterized in that: The switching voltage stabilization circuit includes a switching voltage stabilizer U3, capacitors C13 to C21, a resistor R8, a resistor R9, a diode D6 and an inductor L1; Pin 3 of the switching regulator U3 is simultaneously connected to one end of the capacitor C15, one end of the capacitor C14, one end of the capacitor C13 and the cathode of the diode D6; the anode of the diode D6 is connected to the 24V power supply; the other end of the capacitor C15 is grounded; the other end of the capacitor C14 is grounded; the other end of the capacitor C13 is grounded; Pin 4 of the switching regulator U3 is grounded; Pin 5 of the switching regulator U3 is simultaneously connected to one end of the capacitor C16 and one end of the inductor L1; the other end of the inductor L1 is simultaneously connected to one end of the capacitor C18, one end of the resistor R9, one end of the capacitor C19, one end of the capacitor C20 and one end of the capacitor C21; and the other end of the inductor L1 is the 12V power supply output end; Pin 6 of the switching regulator U3 is connected to the other end of the capacitor C16; Pin 7 of the switching regulator U3 is connected to one end of the capacitor C17; the other end of the capacitor C17 is grounded; Pin 8 of the switching regulator U3 is simultaneously connected to the other end of the capacitor C18, the other end of the resistor R9, and one end of the resistor R8; the other end of the resistor R8 is grounded.

7. The self-constant temperature heating unit based on the Hilbert curve according to claim 2, characterized in that: The heating unit also includes an interface circuit; The interface circuit includes a debugging chip U5 and a resistor R20; Pin 1 of the debug chip U5 is a reset signal input terminal, which is used to input a reset signal; Pin 2 of the debug chip U5 is connected to pin 4 of the debug chip U5 and pin 6 of the debug chip U5 at the same time, and is connected to a 3.3V power supply; Pin 3 of the debug chip U5 is a clock signal debug output interface, and pin 3 of the debug chip U5 is connected to pin 3 of the main control chip U4; Pin 5 of the debug chip U5 is a serial data debug output interface, and pin 3 of the debug chip U5 is connected to pin 2 of the main control chip U4; Pin 7 of the debug chip U5 is the second communication signal output terminal, and pin 7 of the debug chip U5 is connected to pin 14 of the main control chip U4; Pin 8 of the debugging chip U5 is connected to one end of the resistor R20; the other end of the resistor R20 is a data terminal ready signal output end, which is used to output the data terminal ready signal; Pin 9 of the debug chip U5 is the second communication signal input terminal, and pin 9 of the debug chip U5 is connected to pin 13 of the main control chip U4; Pin 10 of the debug chip U5 is a request data receiving terminal, used to receive request data; Pin No. 12 of the debug chip U5 is connected to pin No. 14 of the debug chip U5 and is grounded.

8. The self-constant temperature heating unit based on the Hilbert curve according to claim 7, characterized in that: The heating unit also includes a bootstrap voltage boost circuit; The bootstrap boost circuit includes resistors R15 to R19, transistors Q1, Q2 and Q3; The collector of transistor Q1 is a reset signal input terminal, which is used to input a reset signal; The emitter of transistor Q1 is connected to one end of resistor R15 and pin 10 of debugging chip U5 at the same time; The base of transistor Q1 is connected to one end of resistor R17; The base of transistor Q2 is connected to one end of resistor R16; the other end of resistor R16 is connected to the other end of resistor R15; The collector of transistor Q2 is connected to one end of resistor R18; The emitter of transistor Q2 is connected to the other end of resistor R17 and the other end of resistor R20 at the same time; The base of transistor Q3 is connected to the other end of resistor R18; The collector of transistor Q3 is connected to a 3.3V power supply; The emitter of the transistor Q3 is connected to one end of the resistor R19; the other end of the resistor R19 is the output end of the bootstrap boost signal.

9. The self-constant temperature heating unit based on the Hilbert curve according to claim 2, characterized in that: The heating unit comprises two temperature sensors (4); A temperature sensor (4) includes a first sensor body (4-1), a resistor R10, a resistor R11 and an inductor C22; The negative input terminal of the first sensor body (4-1) is grounded; The positive input terminal of the first sensor body (4-1) is simultaneously connected to one end of the resistor R11, one end of the inductor C22 and one end of the resistor R10; the other end of the resistor R11 is connected to the other end of the inductor C22 and is connected to a 3.3V power supply; The other end of the resistor R10 is the first sensing signal output end, and the other end of the resistor R10 is connected to the pin 15 of the main control chip U4; Another temperature sensor (4) includes a second sensor body (4-2), resistors R12 to R14 and an inductor C23; The negative input terminal of the second sensor body (4-2) is grounded; The positive input terminal of the second sensor body (4-2) is simultaneously connected to one end of the resistor R14, one end of the inductor C23 and one end of the resistor R13; the other end of the resistor R14 is connected to the other end of the inductor C23 and is connected to a 3.3V power supply; The other end of the resistor R13 is connected to one end of the resistor R12; The other end of the resistor R12 is the second sensing signal output end, and the other end of the resistor R12 is connected to pin No. 16 of the main control chip U4.

10. The self-constant temperature heating unit based on the Hilbert curve according to claim 1, characterized in that: The heating unit further comprises a PCB board (1); The PCB board (1) is provided with a heating area (1-1) and a circuit area (1-2); wherein the conductive heating sheet (3) is printed in the heating area (1-1) according to the path of the Hilbert curve; and the control circuit (2) is arranged in the circuit area (1-2); The length of the heating zone (1-1) is 100 mm; the width of the heating zone (1-1) is 100 mm; The resistance calculation formula of the conductive heating plate (3) is: Wherein, R is the resistance of the conductive heating sheet (3); ρ is the resistivity of the conductive heating sheet (3); L is the length of the conductive heating sheet (3); W is the width of the conductive heating sheet (3); and D is the thickness of the conductive heating sheet (3).

Images