Temperature control system of semiconductor refrigerator

Abstract

The application aims to provide a semiconductor refrigerator temperature control system with small interference and low noise. The application comprises four temperature measurement modules, four signal amplification modules, an MCU module, two H-bridge driving modules, a DAC module, two constant current source modules and two semiconductor refrigerators. The four temperature measurement modules are connected to the input ends of the four signal amplification modules, the output ends of the four signal amplification modules are connected to the MCU module, the output end of the MCU module is divided into three paths, two of which are connected to the H-bridge driving modules and the semiconductor refrigerators respectively, and the other path is connected to the two constant current source modules through the DAC module. The application is applied to the technical field of temperature control systems.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of temperature control systems, and particularly relates to a semiconductor refrigerator temperature control system. BACKGROUND

[0002] With the development of VCSEL technology and the popularity of VCSEL in the electronic consumer field, VCSEL is widely used in various industries, and the IC designed based on VCSEL technology is also increasingly popular. In the testing field of such ICs, TEC is used to control the temperature of such ICs so as to measure the related properties of the ICs at different temperature states. The driving board of the TEC on the market is driven by a PWM mode and a PID algorithm to realize accurate temperature control of the TEC. For ICs with low signal sensitivity requirements, this method can meet the requirements, but for ICs with high signal sensitivity requirements, the PWM mode driving will bring a lot of noise to signal acquisition, so that the collected signal cannot be used. Therefore, it is necessary to provide a semiconductor refrigerator temperature control system with small interference and low noise. SUMMARY

[0003] The technical problem to be solved by the application is to overcome the shortcomings of the prior art and provide a semiconductor refrigerator temperature control system with small interference and low noise.

[0004] The technical scheme adopted by the application is: the application comprises four temperature measurement modules, four signal amplification modules, an MCU module, two H-bridge driving modules, a DAC module, two constant current source modules and two semiconductor refrigerators. The four temperature measurement modules are connected to the input ends of the four signal amplification modules, the output ends of the four signal amplification modules are connected to the MCU module, the output end of the MCU module is divided into three paths, two of which are connected to the H-bridge driving module and the semiconductor refrigerator respectively, and the other path is connected to the two constant current source modules through the DAC module.

[0005] As can be seen from the above scheme, the semiconductor refrigerator temperature control system mainly converts the change of temperature into the change of resistance value through the semiconductor refrigerator, so as to cause the change of the voltage across the two ends. The signal amplification module behind amplifies the signal and transmits it to the DAC module behind. The DAC module transforms the input analog signal and transmits the value of the analog signal to the MCU module through the serial port. The MCU module adjusts the working state of the semiconductor refrigerator by controlling the current direction and size of the control board of the semiconductor refrigerator through the PID algorithm according to the input value, controls the heating or refrigeration of the semiconductor refrigerator, and thus achieves the purpose of temperature control.

[0006] The MCU module controls the on / off state of the corresponding MOSFETs in the H-bridge driver module to control the current flow, such as... Figure 7 ;

[0007] Test conditions: Ambient temperature 26℃, target temperatures 50℃ and 53℃ respectively. The heating curve of the semiconductor cooler is shown below. Figure 8 ; Figure 8 The two curves above represent the changes in the temperature of two different targets.

[0008] Test conditions: Ambient temperature 26℃, target temperatures 13℃ and 12℃ respectively. The cooling curve of the semiconductor cooler is shown below. Figure 9 ; Figure 9 The two curves above represent the changes in the temperature of two different targets.

[0009] Depend on Figure 11 and Figure 12 It was learned that the noise current of temperature control using constant current is below -45dBuA, while the noise of temperature control using PWM is below -40dB and has more sawtooth waveforms, which is not conducive to passing the EMC test results.

[0010] Compared with traditional compressor refrigeration methods, the semiconductor cooler temperature control system has the following advantages:

[0011] 1. The temperature control method of the semiconductor cooler can be selected as constant current drive, which can reduce EMI interference to the tested material;

[0012] 2. The entire refrigeration system is small in size and does not produce noise when the equipment is working;

[0013] 3. No refrigerant is required for refrigeration, making it suitable for applications requiring flammable gas, and eliminating concerns about the environmental and personal safety impacts of refrigerant leaks;

[0014] 4. The absence of a compressor greatly reduces electromagnetic interference to external devices;

[0015] 5. Wide voltage input, suitable for various rated voltage semiconductor cooler elements;

[0016] 6. Use PID algorithm for temperature control to make the temperature control curve smoother.

[0017] The temperature control method of the semiconductor cooler can be selected as constant current drive, which can reduce EMI interference to the tested material;

[0018] The entire refrigeration system is small in size and does not produce noise when the equipment is working;

[0019] No need to use refrigerant refrigeration, can be applied to the flammable gas requirements, no need to consider the impact of refrigerant leakage on the environment and personal safety;

[0020] The presence of the compressor is greatly reduced, so that the electromagnetic interference of external equipment is greatly reduced;

[0021] Wide voltage input, suitable for a variety of rated voltage of the semiconductor refrigerator element;

[0022] Using PID algorithm temperature control, the temperature control curve is gentle.

[0023] R1 resistance (Ω) Amplifier gain 49.9k 1.990 12.4 k 4.984 5.49 k 9.998 2.61 k 19.93 1.00 k 50.40 499 100.0 249 199.4 100 495.0 49.9 991.0

[0024] One preferred scheme is that the signal amplification module includes a first operational amplifier and a fifth resistor, a first pin of the first operational amplifier is connected to a first signal port, a second pin and a third pin of the first operational amplifier are connected in series to the fifth resistor, a fourth pin of the first operational amplifier is connected to a second signal port, and a sixth pin of the first operational amplifier is connected to ground.

[0025] From the above scheme, it can be seen that the chip model of the first operational amplifier is AD8221ARZ-R7.

[0026] One preferred scheme is that the H-bridge driving module includes a first field effect transistor, a second field effect transistor, a third field effect transistor, and a fourth field effect transistor, a drain of the first field effect transistor is connected to a drain of the second field effect transistor, and a node of the two is connected to a voltage, a source of the first field effect transistor is connected to a drain of the third field effect transistor, and a node of the two is connected to a first port of the semiconductor refrigerator, a source of the second field effect transistor is connected to a drain of the fourth field effect transistor, and a node of the two is connected to a second port of the semiconductor refrigerator.

[0027] From the above scheme, it can be seen that the H-bridge driving module drives the current direction and size of the semiconductor refrigerator, and the current direction through the H-bridge is controlled by a special H-bridge control chip, and the H-bridge driving module is connected to the MCU module through an IO port.

[0028] A preferred solution is that the constant current source module comprises a second operational amplifier, a third operational amplifier, a fifth field effect transistor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor, a third pin of the second operational amplifier is connected to a port of the DAC module through the sixth resistor, one end of the seventh resistor is connected to a second pin of the second operational amplifier through the eighth resistor and to a source of the fifth field effect transistor, the other end of the seventh resistor is grounded, a source of the third field effect transistor is connected to a source of the fourth field effect transistor and to a drain of the fifth field effect transistor, a first pin of the second operational amplifier is connected to a fifth pin of the third operational amplifier, a sixth pin of the third operational amplifier is connected to a seventh pin of the third operational amplifier and to a gate of the fifth field effect transistor through the ninth resistor.

[0029] A preferred solution is that the semiconductor refrigerator temperature control system further comprises an Ethernet module, the Ethernet module is connected to the MCU module through an RMII interface and connected to a host computer through a network cable.

[0030] As can be seen from the above solution, the Ethernet module is mainly responsible for communication between an electric control board of the semiconductor refrigerator temperature control system and the host computer, receives commands sent by the host computer, and sends information such as temperature to the host computer when needed. The Ethernet module is connected to the host computer through a network cable, and the Ethernet module is connected to the MCU module through an RMII interface.

[0031] A preferred solution is that the semiconductor refrigerator temperature control system further comprises a USB module, the USB module is connected to the MCU module through a serial port and connected to the host computer through a USB data line.

[0032] As can be seen from the above solution, the USB module is used as a backup communication interface to communicate with the host computer, responsible for receiving commands sent by the host computer, and can also send running information of the hardware board to the host computer. The USB module is connected to the host computer using the USB data line, and the USB module is connected to the MCU module through a serial port.

[0033] A preferred solution is that the semiconductor refrigerator temperature control system further comprises a DC-DC module, the DC-DC module is connected to the MCU module through an I2C.

[0034] From the above scheme, it can be seen that the DC-DC module is used to power the H-bridge driving module and the semiconductor refrigerator, the input voltage range is wide, the output voltage can be controlled by the MCU module, and 5A current can be output to the lower-level power consumer. The DC-DC module is installed on the bottom plate of the semiconductor refrigerator temperature control system through a board-to-board connector, and the MCU module controls the output of the DC-DC module through I2C.

[0035] One preferred scheme is that the chip model of the MCU module is STM32H743, and the chip models of the first field effect tube, the second field effect tube, the third field effect tube, the fourth field effect tube and the fifth field effect tube are BUZ11_NR4941. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a system block diagram of the application;

[0037] Figure 2 is a program flowchart of the application;

[0038] Figure 3 is a circuit schematic diagram of the temperature measurement module 1;

[0039] Figure 4 is a circuit schematic diagram of the signal amplification module 2;

[0040] Figure 5 is a circuit schematic diagram of the H-bridge driving module 4;

[0041] Figure 6 is a circuit schematic diagram of the constant current source module 6;

[0042] Figure 7 is a structure schematic diagram of the current flow direction of the H-bridge driving module when the MCU module controls the conduction and closing of the corresponding field effect tubes of the H-bridge driving module;

[0043] Figure 8 is a semiconductor refrigerator heating curve diagram when the test conditions are at an ambient temperature of 26℃ and the target temperatures are 50 and 53℃ respectively;

[0044] Figure 9 is a semiconductor refrigerator cooling curve diagram when the test conditions are at an ambient temperature of 26℃ and the target temperatures are 13 and 12℃ respectively;

[0045] Figure 10 is a test connection block diagram of the semiconductor refrigerator temperature control system;

[0046] Figure 11 is a test waveform diagram of PWM temperature control;

[0047] Figure 12 The waveform diagram shows the temperature control using the constant current source module. Detailed Implementation

[0048] like Figures 1 to 12 As shown, in this embodiment, the present invention includes four sets of temperature measurement modules 1, four sets of signal amplification modules 2, an MCU module 3, two sets of H-bridge driver modules 4, a DAC module 5, two sets of constant current source modules 6, and two sets of semiconductor coolers 7. The four sets of temperature measurement modules 1 are connected to the input terminals of the four sets of signal amplification modules 2, and the output terminals of the four sets of signal amplification modules 2 are connected to the MCU module 3. The output terminal of the MCU module 3 is divided into three paths, two of which are connected to the H-bridge driver module 4 and the semiconductor cooler 7 respectively, and the other path is connected to the two sets of constant current source modules 6 through the DAC module 5.

[0049] In this embodiment, the temperature measurement module 1 includes a thermistor NTC, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. One end of the thermistor NTC is split into two paths: one path is connected to the second resistor R2, and the other path is connected to the voltage VCC through the first resistor R1. The other end of the second resistor R2 is split into two paths: one path is connected to the first signal port SIGNAL N, and the other path is grounded through the fourth resistor R4. The other end of the thermistor NTC is split into two paths: one path is connected to the second signal port SIGNAL P, and the other path is grounded through the third resistor R3.

[0050] In this embodiment, the signal amplification module 2 includes a first operational amplifier U1 and a fifth resistor R5. The first pin of the first operational amplifier U1 is connected to the first signal port SIGNAL N. The second and third pins of the first operational amplifier U1 are connected in series with the fifth resistor R5. The fourth pin of the first operational amplifier U1 is connected to the second signal port SIGNAL P. The sixth pin of the first operational amplifier U1 is grounded.

[0051] In this embodiment, the H-bridge driving module 4 includes a first field-effect transistor Q1, a second field-effect transistor Q2, a third field-effect transistor Q3, and a fourth field-effect transistor Q4. The drain D of the first field-effect transistor Q1 is connected to the drain D of the second field-effect transistor Q2, and their node is connected to the voltage TEC VCC. The source S of the first field-effect transistor Q1 is connected to the drain D of the third field-effect transistor Q3, and their node is connected to the first port TEC 1 of the thermoelectric cooler 7. The source S of the second field-effect transistor Q2 is connected to the drain D of the fourth field-effect transistor Q4, and their node is connected to the second port TEC 2 of the thermoelectric cooler 7.

[0052] In the embodiment, the constant current source module 6 comprises a second operational amplifier U2, a third operational amplifier U3, a fifth field effect transistor Q5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9, a third pin of the second operational amplifier U2 is connected to the port of the DAC module 5 through the sixth resistor R6, one end of the seventh resistor R7 is branched into two paths, one path is connected to the second pin of the second operational amplifier U2 through the eighth resistor R8, and the other path is connected to the source S of the fifth field effect transistor Q5, the other end of the seventh resistor R7 is connected to the ground, the source S of the third field effect transistor Q3 and the source S of the fourth field effect transistor Q4 are commonly connected to the drain D of the fifth field effect transistor Q5, the first pin of the second operational amplifier U2 is connected to the fifth pin of the third operational amplifier U3, the sixth pin of the third operational amplifier U3 is branched into two paths, one path is connected to the seventh pin of the third operational amplifier U3, and the other path is connected to the gate G of the fifth field effect transistor Q5 through the ninth resistor R9.

[0053] In the embodiment, the semiconductor refrigerator temperature control system further comprises an Ethernet module 8, the Ethernet module 8 is connected with the MCU module 3 through an RMII interface and is connected with the upper computer through a network cable.

[0054] In the embodiment, the semiconductor refrigerator temperature control system further comprises a USB module 9, the USB module 9 is connected with the MCU module 3 through a serial port and is connected with the upper computer through a USB data line.

[0055] In the embodiment, the semiconductor refrigerator temperature control system further comprises a DC-DC module 10, the DC-DC module 10 is connected with the MCU module 3 through an I2C.

[0056] In the embodiment, the chip model of the MCU module 3 is STM32H743, and the chip models of the first field effect transistor Q1, the second field effect transistor Q2, the third field effect transistor Q3, the fourth field effect transistor Q4 and the fifth field effect transistor Q5 are BUZ11_NR4941.

[0057] Working principle of the application:

[0058] The semiconductor refrigerator temperature control system mainly converts the change of temperature into the change of resistance value through the semiconductor refrigerator, thereby causing the change of two end voltage, the signal amplification module amplifies the signal and transmits to the DAC module at the back end, the DAC module transforms the input analog signal, and the value of the analog signal is transmitted into the MCU module through the serial port. The MCU module adjusts the working state of the semiconductor refrigerator by controlling the current direction and size of the control panel of the semiconductor refrigerator according to the input value through the PID algorithm, controls the heating or refrigeration, and thus achieves the purpose of temperature control.

Claims

1. A temperature control system for a semiconductor cooler, characterized in that: It includes four temperature measurement modules (1), four signal amplification modules (2), an MCU module (3), two H-bridge drive modules (4), a DAC module (5), two constant current source modules (6), and two semiconductor coolers (7). The four temperature measurement modules (1) are connected to the input terminals of the four signal amplification modules (2), and the output terminals of the four signal amplification modules (2) are connected to the MCU module (3). The output terminal of the MCU module (3) is divided into three paths, two of which are connected to the H-bridge drive module (4) and the semiconductor cooler (7) respectively, and the other path is connected to the two constant current source modules (6) through the DAC module (5). The H-bridge driver module (4) includes a first field-effect transistor (Q1), a second field-effect transistor (Q2), a third field-effect transistor (Q3), and a fourth field-effect transistor (Q4). The drain (D) of the first field-effect transistor (Q1) is connected to the drain (D) of the second field-effect transistor (Q2), and their node is connected to a voltage (TEC VCC). The source (S) of the first field-effect transistor (Q1) is connected to the drain (D) of the third field-effect transistor (Q3), and their node is connected to the first port (TEC 1) of the thermoelectric cooler (7). The source (S) of the second field-effect transistor (Q2) is connected to the drain (D) of the fourth field-effect transistor (Q4), and their node is connected to the second port (TEC 2) of the thermoelectric cooler (7). The constant current source module (6) includes a second operational amplifier (U2), a third operational amplifier (U3), a fifth field-effect transistor (Q5), a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8), and a ninth resistor (R9). The third pin of the second operational amplifier (U2) is connected to the port of the DAC module (5) via the sixth resistor (R6). One end of the seventh resistor (R7) is split into two paths: one path is connected to the second pin of the second operational amplifier (U2) via the eighth resistor (R8), and the other path is connected to the source of the fifth field-effect transistor (Q5). The other end of the seventh resistor (R7) is grounded. The source (S) of the third field-effect transistor (Q3) and the source (S) of the fourth field-effect transistor (Q4) are connected to the drain (D) of the fifth field-effect transistor (Q5). The first pin of the second operational amplifier (U2) is connected to the fifth pin of the third operational amplifier (U3). The sixth pin of the third operational amplifier (U3) is divided into two paths: one path is connected to the seventh pin of the third operational amplifier (U3), and the other path is connected to the gate (G) of the fifth field-effect transistor (Q5) through the ninth resistor (R9).

2. The temperature control system for a semiconductor cooler according to claim 1, characterized in that: The temperature measurement module (1) includes a thermistor (NTC), a first resistor (R1), a second resistor (R2), a third resistor (R3), and a fourth resistor (R4). One end of the thermistor (NTC) is divided into two paths: one path is connected to the second resistor (R2), and the other path is connected to the voltage VCC through the first resistor (R1). The other end of the second resistor (R2) is divided into two paths: one path is connected to the first signal port (SIGNAL N), and the other path is grounded through the fourth resistor (R4). The other end of the thermistor (NTC) is divided into two paths: one path is connected to the second signal port (SIGNAL P), and the other path is grounded through the third resistor (R3).

3. The temperature control system for a semiconductor cooler according to claim 2, characterized in that: The signal amplification module (2) includes a first operational amplifier (U1) and a fifth resistor (R5). The first pin of the first operational amplifier (U1) is connected to the first signal port (SIGNAL N). The second and third pins of the first operational amplifier (U1) are connected in series with the fifth resistor (R5). The fourth pin of the first operational amplifier (U1) is connected to the second signal port (SIGNAL P). The sixth pin of the first operational amplifier (U1) is grounded.

4. The temperature control system for a semiconductor cooler according to claim 1, characterized in that: The semiconductor cooler temperature control system also includes an Ethernet module (8), which is connected to the MCU module (3) via an RMII interface and to the host computer via a network cable.

5. The temperature control system for a semiconductor cooler according to claim 1, characterized in that: The semiconductor cooler temperature control system also includes a USB module (9), which is connected to the MCU module (3) via a serial port and to the host computer via a USB data cable.

6. The temperature control system for a semiconductor cooler according to claim 1, characterized in that: The semiconductor cooler temperature control system also includes a DC-DC module (10), which is connected to the MCU module (3) via I2C.

7. The temperature control system for a semiconductor cooler according to claim 1, characterized in that: The chip model of the MCU module (3) is STM32H743, and the chip model of the first field-effect transistor (Q1), the second field-effect transistor (Q2), the third field-effect transistor (Q3), the fourth field-effect transistor (Q4) and the fifth field-effect transistor (Q5) is BUZ11_NR4941.

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