TEC control unit, control method and laser control system

Abstract

The invention belongs to the technical field of circuit design, and discloses a TEC control unit, a control method and a laser control system. The TEC control unit is used for controlling a TEC to heat or refrigerate equipment and comprises an MCU main control circuit, a communication control circuit, a slave control circuit, a power supply circuit, a TEC driving control circuit and an analog signal acquisition circuit, the communication control circuit is connected with the MCU main control circuit, the slave control circuit is connected with the MCU main control circuit, and the power supply circuit is connected with the TEC driving control circuit. The power supply circuit is used for converting an input voltage into a reference voltage required by a circuit board where the TEC control unit is located and supplying power to the circuit board, and the analog signal acquisition circuit acquires a temperature analog signal of equipment from an external temperature sensor in real time, generates a voltage signal and transmits the voltage signal to the MCU main control circuit; the MCU main control circuit generates a PWM signal and sends the PWM signal to the TEC driving control circuit, and the TEC driving control circuit converts the PWM signal into a control voltage and transmits the control voltage to the TEC so as to control the TEC to heat or refrigerate equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit design, and in particular to a TEC control unit, a control method and a laser control system. Background Art

[0002] Thermoelectric coolers (TECs) are widely used for temperature control in various devices. The basic principle of TEC systems is the Peltier effect, also known as the thermoelectric effect, which refers to the phenomenon in which metal contacts absorb and release heat simultaneously. The use of semiconductor materials can amplify the thermoelectric effect of pure metals. The hot and cold sides of a TEC switch when the current flows in different directions. Simply put, under the influence of an applied electric field, electron flow can transfer internal energy from one location to another.

[0003] The existing TEC control system has too few IO controls and lacks functions such as analog signal acquisition, ambient temperature acquisition, and bidirectional TEC control. The original Ethernet communication function needs to be converted through an RS485 to Ethernet network server. There are many problems with the circuit layout and component prototypes, which cannot meet the needs of various industrial air-cooled laser products.

[0004] Therefore, it is urgent to design a control system that can meet all the above functions and has a reasonable layout and component selection that meets the requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a TEC control unit, a control method and a laser control system to solve the problems existing in the existing TEC control system, such as too few IO controls, lack of analog signal acquisition, ambient temperature acquisition, bidirectional control of TEC, lack of network server conversion, as well as problems in circuit layout and component prototype selection and performance improvement.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a TEC control unit for controlling TEC to heat or cool a device, comprising: an MCU main control circuit, a communication control circuit, a slave control circuit, a power supply circuit, a TEC drive control circuit, and an analog signal acquisition circuit;

[0008] The communication control circuit is connected to the MCU main control circuit, allowing the TEC control unit to exchange information with external devices through the communication control circuit; the slave control circuit is connected to the MCU main control circuit to send power and control signals to the slave control unit, and at the same time collect the working status information of the slave control unit and send it to the MCU main control circuit; the power supply circuit is used to convert the input voltage into the reference voltage required by the circuit board where the TEC control unit is located and supply power to the circuit board;

[0009] The analog signal acquisition circuit obtains the device's temperature analog signal from the external temperature sensor in real time, and generates a voltage signal based on the temperature analog signal and transmits it to the MCU main control circuit. The MCU main control circuit calculates the difference between the device temperature and the preset temperature based on the voltage signal, and generates a PWM signal based on the difference and sends it to the TEC drive control circuit. The TEC drive control circuit converts the PWM signal into a control voltage and transmits it to the TEC to control the TEC to heat or cool the device.

[0010] As a possible implementation method, the interface between the communication control circuit and the MCU main control circuit is a serial port, and the interface with the external device is a network port; the interface between the slave control circuit and the MCU main control circuit is a serial port, and the interface with the slave control unit is an RS485 interface.

[0011] As a possible implementation method, when the difference is positive, the control voltage is positive and the TEC cools the device; when the difference is negative, the control voltage is negative and the TEC heats the device; when the difference is 0, no control voltage is output.

[0012] As a possible implementation method, the TEC drive control circuit uses a 4-way TEC control interface to connect to the MCU main control circuit.

[0013] As a possible implementation manner, the range of the control voltage is 0% to 95% of the input voltage.

[0014] As a possible implementation, the TEC control unit also includes a fan drive circuit, which is connected to the MCU main control circuit and an external fan; the fan drive circuit is used to control the fan to turn on to dissipate heat from the TEC.

[0015] As a possible implementation method, the fan drive circuit obtains the temperature of the hot end of the TEC in real time and feeds it back to the MCU main control circuit. The MCU main control circuit compares the temperature of the hot end with the ambient temperature. When the temperature of the hot end is higher than the ambient temperature, the MCU main control circuit transmits the PWM signal and I / O signal to the fan drive circuit to control the external fan to turn on and dissipate heat from the TEC.

[0016] In a second aspect, the present invention provides a TEC control method, which uses the TEC control unit provided in the first aspect, comprising:

[0017] Collect device temperature, generate a temperature analog signal, and generate a voltage signal based on the temperature analog signal;

[0018] Calculate the difference between the device temperature and a preset temperature value of the device based on the voltage signal and generate a PWM signal;

[0019] The PWM signal is converted into a control voltage, and the TEC heats or cools the device based on the control voltage.

[0020] As a possible implementation manner, the control voltage includes a positive voltage and a negative voltage. When the control voltage is a positive voltage, the TEC cools the device; when the control voltage is a negative voltage, the TEC heats the device.

[0021] In a third aspect, the present invention provides a laser control system, comprising: a temperature sensor, a TEC control unit, a TEC, a slave control unit, a drive unit, a pump source, and a power supply, wherein the TEC control unit is the TEC control unit provided in the first aspect;

[0022] The temperature sensor is connected to the analog signal acquisition circuit included in the TEC control unit. The temperature sensor collects the temperature of the pump source in real time, generates a temperature analog signal, and transmits it to the analog signal acquisition circuit.

[0023] The drive unit is connected to the TEC drive control circuit included in the TEC control unit to receive the PWM signal sent by the TEC control unit and convert the PWM signal into a control voltage and transmit it to the TEC to control the TEC to heat or cool the pump source;

[0024] The slave control unit is connected to the slave control circuit included in the TEC control unit to realize the operation control of the slave control unit by the MCU main control circuit in the TEC control unit;

[0025] The power supply is connected to a power supply circuit included in the TEC control unit to supply power to a circuit board where the TEC control unit is located.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The TEC control unit proposed in the present invention can heat and cool the device using a single control circuit and generate a control voltage based on the real-time collected device temperature, enabling precise control of the device temperature.

[0028] 2. The TEC control unit proposed in this invention not only precisely controls the device temperature but also monitors the TEC's own operating temperature. When the operating temperature rises above the ambient temperature, it activates a fan to cool the TEC, eliminating the need for additional cooling devices. Compared to existing technologies, this invention achieves temperature control of the TEC itself within a single control circuit, enabling long-term, stable TEC operation.

[0029] 3. The TEC control unit proposed in the present invention integrates temperature acquisition function, TEC bidirectional control function, fan control function and external communication function, and can realize Ethernet communication function without an additional network server. The circuit layout is reasonable and efficient, and can meet the application requirements of various different scenarios.

[0030] 4. The TEC control unit proposed in the present invention achieves a large control voltage generation range through the setting of three circuits, namely the MCU main control circuit, the TEC drive control circuit and the analog signal acquisition circuit, which can meet the temperature control requirements of a variety of different devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 A schematic diagram of the structure of a TEC control unit provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the pin connection relationship between the circuits included in the TEC control unit provided in an embodiment of the present invention;

[0034] Figure 3 This is the temperature change curve of TEC control in the heating mode experiment in the embodiment of the present invention;

[0035] Figure 4 This is the temperature change curve of TEC control in the cooling mode experiment in the embodiment of the present invention.

[0036] Reference numerals

[0037] 10-TEC, 11-device, 12-MCU main control circuit, 13-communication control circuit, 14-slave control circuit, 15-power supply circuit, 16-TEC drive control circuit, 17-analog signal acquisition circuit, 18-temperature sensor, 19-circuit board, 20-fan drive circuit, 21-fan. DETAILED DESCRIPTION

[0038] To facilitate a clear description of the technical solutions of the embodiments of the present invention, the words "first" and "second" are used in the embodiments of the present invention to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are merely used to distinguish between different thresholds and do not limit their order. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0039] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0040] In the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. The following at least one item (item) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (item) of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0041] The present invention aims to provide a TEC control unit, control method, and laser control system to address existing TEC control systems, including insufficient I / O control, lack of analog signal acquisition, ambient temperature acquisition, bidirectional TEC control, and network server conversion, as well as circuit layout, component prototype selection, and performance improvement issues. Specific implementations are as follows:

[0042] In a first aspect, an embodiment of the present invention provides a TEC control unit, see Figure 1 , used to control the TEC 10 to heat or cool the device 11, the TEC control unit includes: an MCU main control circuit 12, a communication control circuit 13, a slave control circuit 14, a power supply circuit 15, a TEC drive control circuit 16 and an analog signal acquisition circuit 17;

[0043] The MCU main control circuit 12 is the core circuit of the TEC control unit, which is used to implement the operation, detection, control and communication functions of the entire TEC control unit. As an example, the MCU main control circuit 12 uses an STM32F103RET6 chip.

[0044] See also Figure 1The communication control circuit 13 is connected to the MCU main control circuit 12, allowing the TEC control unit to exchange information with external devices through the communication control circuit 13. As a possible implementation, the interface between the communication control circuit 13 and the MCU main control circuit 12 is a serial port, and the interface with the external device is a network port. For example, the external device can be a PC or a host computer. The communication control circuit 13 has a serial port as its internal interface and a network port as its external interface. It can convert external input into TTL signals recognizable by the MCU, enabling the control unit to communicate with the external device through the network port.

[0045] See also Figure 1 The slave control circuit 14 is connected to the MCU main control circuit 12 and is used to send power and control signals to the slave control unit. At the same time, it collects the operating status information of the slave control unit and sends it to the MCU main control circuit 12. As a possible implementation, the interface between the slave control circuit 14 and the MCU main control circuit 12 is a serial port, and the interface between the slave control circuit 14 and the slave control unit is an RS485 interface. This configuration can realize communication between the control unit and the slave control unit, as well as control the operation of the slave control unit.

[0046] See also Figure 1 The power supply circuit 15 is used to convert the input voltage into the reference voltage required by the circuit board 19 where the TEC control unit is located, and supply power to the circuit board 19. For example, the power supply circuit 15 can implement multi-channel voltage conversion, for example, converting the external input 24V voltage into the 12V, 5V, 3.3V, and 2.5V reference voltages required by the circuit board.

[0047] See also Figure 1 The external temperature sensor 18 collects the temperature of the device 11 in real time, generates a temperature analog signal and transmits it to the analog signal acquisition circuit 17.

[0048] As an example, temperature sensor 18 employs an NTC10K temperature sensor. Analog signal acquisition circuit 17 generates a voltage signal based on the temperature analog signal and transmits it to MCU main control circuit 12. MCU main control circuit 12 calculates the difference between the temperature of device 11 and a preset temperature based on the voltage signal and generates a PWM signal based on this difference, which is then transmitted to TEC drive control circuit 16.

[0049] As an example, the MCU control circuit 12 first performs analog-to-digital conversion on the voltage signal to obtain a temperature value. It then calculates the difference between this value and a preset temperature, which is the desired temperature for the device. After obtaining this difference, the MCU control circuit 12 uses a PID algorithm to calculate a voltage value. This voltage value is then used to generate a PWM signal, which is then transmitted to the TEC drive control circuit 16.

[0050] See also Figure 2As a possible implementation, the TEC drive control circuit 16 uses four TEC control interfaces to connect to the MCU main control circuit 12, and each TEC control interface includes four pins. Specifically, the four pins of the first TEC control interface are MODE, on / off1, PWM1, and VOL1, which are respectively connected to the pins PD2, PA15, PB6, and ADC_IN10 of the MCU main control circuit 12. The four pins of the second TEC control interface are MODE, on / off2, PWM2, and VOL2, which are respectively connected to the pins PD2, PC10, PB7, and ADC_IN11 of the MCU main control circuit 12. The four pins of the third TEC control interface are MODE, on / off3, PWM3, and VOL3, which are respectively connected to the pins PD2, PC11, PB8, and ADC_IN12 of the MCU main control circuit 12. The four pins of the fourth TEC control interface are MODE, on / off4, PWM4, and VOL4, which are respectively connected to the pins PD2, PC12, PB9, and ADC_IN13 of the MCU main control circuit 12. The TEC drive control circuit 16 converts the PWM signal into a control voltage and transmits it to the TEC 10 to control the TEC 10 to heat or cool the device 11 .

[0051] As a possible implementation method, when the difference is positive, the control voltage is positive and the TEC cools the device; when the difference is negative, the control voltage is negative and the TEC heats the device; when the difference is 0, no control voltage is output.

[0052] Since the basic principle of TEC is the Peltier effect, that is, the thermoelectric effect, different current directions will cause the hot and cold sides of TEC to switch. The TEC control unit provided in the embodiment of the present invention collects the temperature of the device in real time, and then the MCU main control circuit determines whether the device needs to be heated or cooled by calculating the difference between the temperature and the preset temperature. When the actual collected temperature is higher than the preset temperature, it means that the device needs to be cooled. At this time, the calculated temperature difference is a positive value, and the TEC drive control circuit outputs a positive control voltage to the TEC. Under the action of the current direction generated by the positive voltage, the TEC brings the heat from one side to the other side to achieve cooling of the device. The same principle applies when the device needs to be heated, and it will not be repeated here.

[0053] Existing TEC control systems can only heat or cool the device, making it difficult to achieve precise control of the device temperature. Compared with the existing technology, the present invention uses a set of TEC control units to heat and cool the device, and generates a control voltage based on the real-time collected device temperature, which can achieve precise control of the device temperature.

[0054] As an example, the range of the control voltage is 0% to 95% of the input voltage.

[0055] The embodiment of the present invention achieves a large control voltage generation range by setting up three circuits, namely the MCU main control circuit, the TEC drive control circuit and the analog signal acquisition circuit, and can meet the temperature control requirements of various different devices.

[0056] See also Figures 1 to 2 As a possible implementation, the TEC control unit also includes a fan drive circuit 20, which is connected to the MCU main control circuit 12 and an external fan 21. The fan drive circuit 20 is used to control the activation of the fan 21 to dissipate heat from the TEC 10. Specifically, the fan drive circuit 20 obtains the temperature of the hot end of the TEC 10 in real time and feeds it back to the MCU main control circuit 12. The MCU main control circuit 12 compares the hot end temperature with the ambient temperature. When the hot end temperature is higher than the ambient temperature, the MCU main control circuit 12 transmits a PWM signal and an I / O signal to the fan drive circuit 20 to activate the external fan 21, dissipating heat from the TEC.

[0057] The TEC control unit provided by the present invention not only precisely controls the device's temperature but also monitors the TEC's own operating temperature. When the operating temperature rises above the ambient temperature, it activates a fan to cool the TEC, eliminating the need for additional cooling devices. Compared to existing technologies, the present invention achieves temperature control of the TEC itself within a single control circuit, enabling long-term, stable TEC operation.

[0058] See also Figure 2, which shows the pin connections between the communication control circuit 13, slave control circuit 14, TEC drive control circuit 16, analog signal acquisition circuit 17, and fan drive circuit 20 and the MCU main control circuit 12 in an embodiment of the present invention. The analog signal acquisition circuit 17 includes eight TEMP pins, with pins TEMP1-TEMP8 respectively connected to pins ADC_IN9, ADC_IN8, ADC_IN15, ADC_IN14, ADC_IN7, ADC_IN6, ADC_IN5, and ADC_IN4 of the MCU main control circuit 12. The slave control circuit 14 includes three pins: RS485_RX, RS485_TX, and RX_TX, which are respectively connected to pins USART1_RX, USART1_TX, and PA11 of the MCU main control circuit 12. The communication control circuit 13 includes six pins: ETH_RX, ETH_TX, ETH_RESET, SD_E, E-stop_Safety, and Interlock_Safety, which are respectively connected to the pins USART2_RX, USART2_TX, PA1, PA12, PB10, and PB11 included in the MCU main control circuit 12. The fan drive circuit 20 includes eight pins: FAN_PWM1, FAN_ON / OFF1, FAN_PWM2, FAN_ON / OFF2, FAN_PWM3, FAN_ON / OFF3, FAN_PWM4, and FAN_ON / OFF4, which are respectively connected to the pins PB12, PB13, PB14, PB15, PC6, PC7, PC8, and PC9 included in the MCU main control circuit 12.

[0059] The TEC control unit provided in the embodiment of the present invention integrates temperature acquisition function, TEC bidirectional control function, fan control function and external communication function, and can realize Ethernet communication function without an additional network server. The circuit layout is reasonable and efficient, and can meet the application requirements of various different scenarios.

[0060] In a second aspect, the present invention provides a TEC control method, which uses the TEC control unit provided in the first aspect, comprising:

[0061] Collect device temperature, generate a temperature analog signal, and generate a voltage signal based on the temperature analog signal;

[0062] Calculate the difference between the device temperature and a preset temperature value of the device based on the voltage signal and generate a PWM signal;

[0063] The PWM signal is converted into a control voltage, and the TEC heats or cools the device based on the control voltage.

[0064] As a possible implementation manner, the control voltage includes a positive voltage and a negative voltage. When the control voltage is a positive voltage, the TEC cools the device; when the control voltage is a negative voltage, the TEC heats the device.

[0065] Next, we will illustrate the TEC control unit and control method provided in this embodiment with reference to specific experimental data. Two experiments were conducted in this embodiment. The first experiment set the target temperature to 35°C, and the second experiment set the target temperature to 25°C. The ambient temperature during both experiments was 25.4°C. The TEC control unit was used to control the target temperature in both experiments. TEC control temperature data was collected every minute, for a total of 31 sets of data. The collected temperature data is shown in Table 1, where Actual Temperature 1 to Actual Temperature 4 represent the temperature data for each of the four TEC control interfaces.

[0066] The temperature data collected in the first experiment are shown in Table 1:

[0067] Table 1 Temperature data of TEC control in the first experiment (35℃)

[0068]

[0069] The temperature data collected in the second experiment are shown in Table 2:

[0070] Table 2 Temperature data of TEC control in the second experiment (25℃)

[0071]

[0072] The temperature change curve of TEC control in the first experiment is shown in Figure 3 , the temperature change curve of TEC control in the second experiment is shown in Figure 4 As can be seen from the figure, the temperature change range of TEC control in the first experiment is 34.7℃~35.3℃, and the temperature change range of TEC control in the second experiment is 24.8℃~25.3℃. The temperature changes in both experiments did not exceed ±0.3℃ of the set temperature value, indicating that the TEC control unit and control method provided in this application can achieve ±0.3℃ precise temperature control.

[0073] In a third aspect, the present invention provides a laser control system, comprising: a temperature sensor, a TEC control unit, a TEC, a slave control unit, a drive unit, a pump source, and a power supply, wherein the TEC control unit is the TEC control unit provided in the first aspect;

[0074] The temperature sensor is connected to the analog signal acquisition circuit included in the TEC control unit. The temperature sensor collects the temperature of the pump source in real time, generates a temperature analog signal, and transmits it to the analog signal acquisition circuit.

[0075] The drive unit is connected to the TEC drive control circuit included in the TEC control unit to receive the PWM signal sent by the TEC control unit and convert the PWM signal into a control voltage and transmit it to the TEC to control the TEC to heat or cool the pump source;

[0076] The slave control unit is connected to the slave control circuit included in the TEC control unit to realize the operation control of the slave control unit by the MCU main control circuit in the TEC control unit;

[0077] The power supply is connected to a power supply circuit included in the TEC control unit to supply power to a circuit board where the TEC control unit is located.

[0078] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the accompanying drawings. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0079] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations thereof may be made without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations of the present invention may be made by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the invention and its equivalents.

Claims

1. A TEC control unit for controlling TEC to heat or cool a device, characterized in that: include: MCU main control circuit, communication control circuit, slave control circuit, power supply circuit, TEC drive control circuit and analog signal acquisition circuit; The communication control circuit is connected to the MCU main control circuit, so that the TEC control unit exchanges information with external devices through the communication control circuit; the slave control circuit is connected to the MCU main control circuit, and is used to send power and control signals to the slave control unit, and at the same time collect the working status information of the slave control unit and send it to the MCU main control circuit; the power supply circuit is used to convert the input voltage into the reference voltage required by the circuit board where the TEC control unit is located, and supply power to the circuit board; The analog signal acquisition circuit obtains the device's temperature analog signal from an external temperature sensor in real time, and generates a voltage signal based on the temperature analog signal and transmits it to the MCU main control circuit. The MCU main control circuit calculates the difference between the device temperature and the preset temperature based on the voltage signal, generates a PWM signal based on the difference and sends it to the TEC drive control circuit. The TEC drive control circuit converts the PWM signal into a control voltage and transmits it to the TEC to control the TEC to heat or cool the device.

2. The TEC control unit according to claim 1, characterized in that: The interface between the communication control circuit and the MCU main control circuit is a serial port, and the interface between the communication control circuit and the external device is a network port; the interface between the slave control circuit and the MCU main control circuit is a serial port, and the interface between the slave control circuit and the slave control unit is an RS485 interface.

3. The TEC control unit according to claim 1, characterized in that: When the difference is positive, the control voltage is positive and the TEC cools the device; when the difference is negative, the control voltage is negative and the TEC heats the device; when the difference is 0, no control voltage is output.

4. The TEC control unit according to claim 1, characterized in that: The TEC drive control circuit is connected to the MCU main control circuit using a 4-way TEC control interface.

5. The TEC control unit according to claim 1, characterized in that: The control voltage ranges from 0% to 95% of the input voltage.

6. The TEC control unit according to claim 1, characterized in that: The TEC control unit further includes a fan drive circuit, which is connected to the MCU main control circuit and an external fan; the fan drive circuit is used to control the fan to turn on so that the TEC dissipates heat.

7. The TEC control unit according to claim 6, characterized in that: The fan drive circuit obtains the temperature of the hot end of the TEC in real time and feeds it back to the MCU main control circuit. The MCU main control circuit compares the temperature of the hot end with the ambient temperature. When the temperature of the hot end is higher than the ambient temperature, the MCU main control circuit transmits a PWM signal and an I / O signal to the fan drive circuit to control the external fan to turn on and dissipate heat from the TEC.

8. A TEC control method, using the TEC control unit according to any one of claims 1 to 7, characterized in that: include: Collecting device temperature, generating a temperature analog signal, and generating a voltage signal based on the temperature analog signal; Calculate the difference between the device temperature and a preset device temperature value based on the voltage signal, and generate a PWM signal; The PWM signal is converted into a control voltage, and the TEC heats or cools the device based on the control voltage.

9. The TEC control method according to claim 8, wherein: The control voltage includes a positive voltage and a negative voltage. When the control voltage is a positive voltage, the TEC cools the device; when the control voltage is a negative voltage, the TEC heats the device.

10. A laser control system, characterized in that: include: A temperature sensor, a TEC control unit, a TEC, a slave control unit, a drive unit, a pump source, and a power supply, wherein the TEC control unit is the TEC control unit according to any one of claims 1 to 7; The temperature sensor is connected to the analog signal acquisition circuit included in the TEC control unit, and the temperature sensor collects the temperature of the pump source in real time, generates a temperature analog signal, and transmits it to the analog signal acquisition circuit; The driving unit is connected to the TEC driving control circuit included in the TEC control unit to receive the PWM signal sent by the TEC control unit and convert the PWM signal into a control voltage and transmit it to the TEC to control the TEC to heat or cool the pump source; The slave control unit is connected to the slave control circuit included in the TEC control unit to enable the MCU main control circuit in the TEC control unit to control the operation of the slave control unit; The power supply is connected to a power supply circuit included in the TEC control unit to supply power to a circuit board where the TEC control unit is located.

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