Temperature control circuit

Abstract

The utility model discloses a temperature control circuit, which relates to the field of temperature control and comprises a triangular wave generation module, a temperature control trigger module and a temperature control module, the temperature control trigger module is used for obtaining a temperature signal based on the thermistor, obtaining a PWM signal based on the temperature signal and the triangular wave, and outputting the PWM signal to the heating work module; the lower the temperature is, the larger the duty ratio of the PWM signal is, and the higher the temperature is, the smaller the duty ratio of the PWM signal is until the duty ratio is 0; the heating working module is used for electrifying an electric heater to work for heating when the PWM signal is received; the beneficial effects of the utility model are that the temperature control trigger module controls the power of the electric heater of the heating work module based on the triangular wave and the voltage on the thermistor, so that the power is high at a low temperature and low at a high temperature, thereby ensuring the temperature rise speed, and solving the problem that the power of the electric heater is relatively low at a set temperature; and the temperature rise accuracy is ensured.

Description

Technical Field

[0001] The utility model relates to the field of temperature control, in particular to a temperature control circuit. Background Art

[0002] During the manufacturing process, temperature is one of the key factors affecting product quality. Proper temperature conditions can optimize the operating efficiency of production equipment, reducing energy consumption and downtime.

[0003] Existing temperature control technologies often use the same power heating, which results in slow temperature rise and is not conducive to quickly creating the required suitable temperature, and needs to be improved. Utility Model Content

[0004] The purpose of the present invention is to provide a temperature control circuit to solve the problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] A temperature control circuit comprising:

[0007] The triangle wave generation module is used to generate a triangle wave and output it to the temperature control trigger module;

[0008] The temperature control trigger module is used to obtain a temperature signal based on the thermistor, and obtain a PWM signal based on the temperature signal and the triangular wave, and output it to the heating working module. The lower the temperature, the larger the duty cycle of the PWM signal, and the higher the temperature, the smaller the duty cycle of the PWM signal, until the duty cycle is 0;

[0009] The heating working module is used to power the electric heater and perform heating when receiving the PWM signal;

[0010] The delay protection module is used to detect the PWM signal output by the temperature control trigger module. When the accumulated voltage of the output PWM signal reaches the threshold, the temperature control trigger module is controlled to stop outputting the PWM signal to the heating working module and emits a light indication;

[0011] The triangle wave generating module is connected to the temperature control triggering module, and the temperature control triggering module is connected to the heating working module and the time delay protection module.

[0012] As a further solution of the present invention: the triangle wave generation module includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an amplifier U1, and a capacitor C1. One end of the resistor R1 is connected to the voltage VCC, the other end of the resistor R1 is connected to one end of the resistor R2, one end of the resistor R3, and the non-inverting end of the amplifier U1, the other end of the resistor R2 is grounded, the output end of the amplifier U1 is connected to the other end of the resistor R3, one end of the resistor R4, and one end of the resistor R5, the other end of the resistor R4 is connected to the voltage VCC, the other end of the resistor R5 is connected to the inverting end of the amplifier U1, one end of the capacitor C1, and the temperature control trigger module, and the other end of the capacitor C1 is grounded.

[0013] As a further solution of the present invention: the temperature control trigger module includes a capacitor C2, a resistor R6, a thermistor RW, an amplifier U2, and a resistor R7. One end of the resistor R6 is connected to one end of the capacitor C2 and the voltage VCC, and the other end of the capacitor C2 is grounded. The other end of the resistor R6 is connected to the inverting end of the amplifier U2 and one end of the thermistor RW, and the other end of the thermistor RW is grounded. The non-inverting end of the amplifier U2 is connected to the triangle wave generation module, the output end of the amplifier U2 is connected to one end of the resistor R7 and the delay protection module, and the other end of the resistor R7 is connected to the heating working module and the delay protection module.

[0014] As a further solution of the present utility model: the heating working module includes a transistor V2, a resistor R8, a transistor V1, and an electric heater X. The base of the transistor V2 is connected to the temperature control trigger module, the emitter of the transistor V2 is grounded, the collector of the transistor V2 is connected to the base of the transistor V1 and one end of the resistor R8, the other end of the resistor R8 is connected to the voltage VCC and the emitter of the transistor V1, the collector of the transistor V1 is connected to one end of the electric heater X, and the other end of the electric heater X is grounded.

[0015] As a further solution of the present utility model: the delay protection module includes a potentiometer RP1, a resistor R9, a capacitor C3, a diode D2, a diode D1, and a MOS tube V3. One end of the potentiometer RP1 is connected to a common point A, the other end of the potentiometer RP1 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to one end of the capacitor C3 and the positive electrode of the diode D2, the other end of the capacitor C3 is grounded, the negative electrode of the diode D2 is connected to the negative electrode of the diode D1, the positive electrode of the diode D1 is connected to the G electrode of the MOS tube V3, the S electrode of the MOS tube V3 is grounded, and the D electrode of the MOS tube V3 is connected to the common point B.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the temperature control trigger module of the present invention controls the power of the electric heater of the heating working module based on the triangular wave and the voltage on the thermistor, so that the power is high at low temperatures and low at high temperatures, which ensures the speed of heating and ensures the accuracy of heating based on the solution of the low power of the electric heater when the set temperature is set. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a temperature control circuit.

[0018] Figure 2 This is the circuit diagram of the triangle wave generation module, temperature control trigger module and heating working module.

[0019] Figure 3 This is the circuit diagram of the delay protection module. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 , a temperature control circuit comprising:

[0022] The triangle wave generation module is used to generate a triangle wave and output it to the temperature control trigger module;

[0023] The temperature control trigger module is used to obtain a temperature signal based on the thermistor, and obtain a PWM signal based on the temperature signal and the triangular wave, and output it to the heating working module. The lower the temperature, the larger the duty cycle of the PWM signal, and the higher the temperature, the smaller the duty cycle of the PWM signal, until the duty cycle is 0;

[0024] The heating working module is used to power the electric heater and perform heating when receiving the PWM signal;

[0025] The delay protection module is used to detect the PWM signal output by the temperature control trigger module. When the accumulated voltage of the output PWM signal reaches the threshold, the temperature control trigger module is controlled to stop outputting the PWM signal to the heating working module and emits a light indication;

[0026] The triangle wave generating module is connected to the temperature control triggering module, and the temperature control triggering module is connected to the heating working module and the time delay protection module.

[0027] In this example: See Figure 2The triangle wave generation module includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an amplifier U1, and a capacitor C1. One end of the resistor R1 is connected to the voltage VCC, the other end of the resistor R1 is connected to one end of the resistor R2, one end of the resistor R3, and the non-inverting end of the amplifier U1, the other end of the resistor R2 is grounded, the output end of the amplifier U1 is connected to the other end of the resistor R3, one end of the resistor R4, and one end of the resistor R5, the other end of the resistor R4 is connected to the voltage VCC, the other end of the resistor R5 is connected to the inverting end of the amplifier U1, one end of the capacitor C1, and the temperature control trigger module, and the other end of the capacitor C1 is grounded.

[0028] When the voltage at the non-inverting terminal of the amplifier U1 is higher than the voltage at the inverting terminal, the amplifier U1 outputs a high level. At this time, the capacitor C1 is charged and the voltage at the inverting terminal of the amplifier U1 rises. When the voltage at the inverting terminal of the amplifier U1 is higher than the voltage at the non-inverting terminal, the amplifier U1 outputs a low level and the capacitor C1 discharges, making the voltage at the non-inverting terminal of the amplifier U1 higher than the voltage at the inverting terminal again. Finally, the capacitor C1 is charged again, and this cycle repeats, forming a triangular wave signal at the capacitor C1.

[0029] In this example: See Figure 2 The temperature control trigger module includes a capacitor C2, a resistor R6, a thermistor RW, an amplifier U2, and a resistor R7. One end of the resistor R6 is connected to one end of the capacitor C2 and the voltage VCC, and the other end of the capacitor C2 is grounded. The other end of the resistor R6 is connected to the inverting end of the amplifier U2 and one end of the thermistor RW. The other end of the thermistor RW is grounded. The non-inverting end of the amplifier U2 is connected to the triangle wave generation module. The output end of the amplifier U2 is connected to one end of the resistor R7 and the delay protection module. The other end of the resistor R7 is connected to the heating working module and the delay protection module.

[0030] The resistance of the thermistor RW increases as the temperature rises. Therefore, when the ambient temperature is low, the duty cycle of the PWM signal output by the amplifier U2 in one triangle wave cycle is relatively large. When the ambient temperature is high, the duty cycle of the PWM signal output by the amplifier U2 in one triangle wave cycle is relatively small. When the ambient temperature reaches the threshold, the amplifier U2 outputs a low level.

[0031] In this example: See Figure 2 The heating working module includes a transistor V2, a resistor R8, a transistor V1, and an electric heater X. The base of the transistor V2 is connected to the temperature control trigger module, the emitter of the transistor V2 is grounded, the collector of the transistor V2 is connected to the base of the transistor V1 and one end of the resistor R8, the other end of the resistor R8 is connected to the voltage VCC and the emitter of the transistor V1, the collector of the transistor V1 is connected to one end of the electric heater X, and the other end of the electric heater X is grounded.

[0032] When a high-level PWM signal is input to the base of transistor V2 (NPN), transistor V2 turns on, pulling down the base voltage of transistor V1 (PNP). This turns on transistor V1, energizing Heater X and enabling heating. A higher PWM signal duty cycle results in a longer unit on-time of transistor V1 and a higher power output from Heater X. Conversely, a lower PWM signal duty cycle results in a lower power output. This results in higher power output and faster heating at low temperatures, while lower power output and more precise heating at high temperatures.

[0033] In this example: See Figure 3 The delay protection module includes a potentiometer RP1, a resistor R9, a capacitor C3, a diode D2, a diode D1, and a MOS tube V3. One end of the potentiometer RP1 is connected to a common point A, the other end of the potentiometer RP1 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to one end of the capacitor C3 and the positive electrode of the diode D2, the other end of the capacitor C3 is grounded, the cathode of the diode D2 is connected to the cathode of the diode D1, the positive electrode of the diode D1 is connected to the G electrode of the MOS tube V3, the S electrode of the MOS tube V3 is grounded, and the D electrode of the MOS tube V3 is connected to the common point B.

[0034] Considering the possibility of a temperature control trigger module failure, such as thermistor RW position offset, resulting in abnormal temperature detection, when the temperature reaches the required value, the thermistor RW voltage is small due to the position offset, and the amplifier U2 still outputs a PWM signal; at this time, the capacitor C3 is continuously charged based on the PWM signal, so that the voltage on the capacitor C3 is sufficient to turn on the voltage regulator diode D1 through the diode D2, triggering the MOS tube V3 to turn on, pulling down the voltage of the common point B, and no longer triggering the transistor V2 to turn on, avoiding continuous heating and damage to the device.

[0035] The working principle of the utility model is as follows: the triangle wave generation module is used to generate a triangle wave and output it to the temperature control trigger module; the temperature control trigger module is used to obtain a temperature signal based on a thermistor, and obtain a PWM signal based on the temperature signal and the triangle wave, and output it to the heating working module; the lower the temperature, the greater the duty cycle of the PWM signal, and the higher the temperature, the smaller the duty cycle of the PWM signal, until the duty cycle is 0; the heating working module is used to power the electric heater to work and heat when it receives the PWM signal; the delay protection module is used to detect the PWM signal output by the temperature control trigger module, and when the accumulated voltage of the output PWM signal reaches a threshold, the temperature control trigger module is controlled to stop outputting the PWM signal to the heating working module and emit a light indication.

[0036] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive.

[0037] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A temperature control circuit, characterized in that: The temperature control circuit includes: The triangle wave generation module is used to generate a triangle wave and output it to the temperature control trigger module; The temperature control trigger module is used to obtain a temperature signal based on the thermistor, and obtain a PWM signal based on the temperature signal and the triangular wave, and output it to the heating working module. The lower the temperature, the larger the duty cycle of the PWM signal, and the higher the temperature, the smaller the duty cycle of the PWM signal, until the duty cycle is 0; The heating working module is used to power the electric heater and perform heating when receiving the PWM signal; The delay protection module is used to detect the PWM signal output by the temperature control trigger module. When the accumulated voltage of the output PWM signal reaches the threshold, the temperature control trigger module is controlled to stop outputting the PWM signal to the heating working module and emits a light indication; The triangle wave generating module is connected to the temperature control triggering module, and the temperature control triggering module is connected to the heating working module and the time delay protection module.

2. The temperature control circuit according to claim 1, characterized in that: The triangle wave generation module includes resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, amplifier U1, and capacitor C1. One end of resistor R1 is connected to voltage VCC, the other end of resistor R1 is connected to one end of resistor R2, one end of resistor R3, and the non-inverting end of amplifier U1, the other end of resistor R2 is grounded, the output end of amplifier U1 is connected to the other end of resistor R3, one end of resistor R4, and one end of resistor R5, the other end of resistor R4 is connected to voltage VCC, the other end of resistor R5 is connected to the inverting end of amplifier U1, one end of capacitor C1, and temperature control trigger module, and the other end of capacitor C1 is grounded.

3. The temperature control circuit according to claim 1, wherein: The temperature control trigger module includes capacitor C2, resistor R6, thermistor RW, amplifier U2, and resistor R7. One end of resistor R6 is connected to one end of capacitor C2 and voltage VCC, and the other end of capacitor C2 is grounded. The other end of resistor R6 is connected to the inverting end of amplifier U2 and one end of the thermistor RW. The other end of the thermistor RW is grounded. The non-inverting end of amplifier U2 is connected to the triangle wave generation module. The output end of amplifier U2 is connected to one end of resistor R7 and the delay protection module. The other end of resistor R7 is connected to the heating working module and the delay protection module.

4. The temperature control circuit according to claim 1, wherein: The heating working module includes a transistor V2, a resistor R8, a transistor V1, and an electric heater X. The base of the transistor V2 is connected to the temperature control trigger module, the emitter of the transistor V2 is grounded, the collector of the transistor V2 is connected to the base of the transistor V1 and one end of the resistor R8, the other end of the resistor R8 is connected to the voltage VCC and the emitter of the transistor V1, the collector of the transistor V1 is connected to one end of the electric heater X, and the other end of the electric heater X is grounded.

5. The temperature control circuit according to claim 3, characterized in that: The delay protection module includes a potentiometer RP1, a resistor R9, a capacitor C3, a diode D2, a diode D1, and a MOS transistor V3. One end of the potentiometer RP1 is connected to a common point A, the other end of the potentiometer RP1 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to one end of the capacitor C3 and the positive electrode of the diode D2, the other end of the capacitor C3 is grounded, the cathode of the diode D2 is connected to the cathode of the diode D1, the positive electrode of the diode D1 is connected to the G electrode of the MOS transistor V3, the S electrode of the MOS transistor V3 is grounded, and the D electrode of the MOS transistor V3 is connected to the common point B.

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