A temperature control circuit and laser

Abstract

The application discloses a temperature control circuit and a laser. In the temperature control circuit, a first input end of a hardware PID module is connected with a temperature setting voltage, a second input end of the hardware PID module is connected with a temperature feedback voltage, an output end of the hardware PID module is connected with a control end of a first power module and a first input end of an inverting amplification module, a second input end of the inverting amplification module is connected with a reference voltage, an output end of the inverting amplification module is connected with a control end of a second power module, an input end of the first power module is connected with an input voltage, an output end of the first power module serves as a first output end of the temperature control circuit and is grounded through a first switching device, an input end of the second power module is connected with the input voltage, and an output end of the second power module serves as a second output end of the temperature control circuit and is grounded through a second switching device. The scheme provided by the application can adapt to different loads, reduce cost and shorten development period.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a temperature control circuit and a laser. Background Technology

[0002] A temperature control circuit is an electronic circuit system used to detect, compare, and regulate the temperature of a target object or environment. It acquires a temperature signal through a temperature detection element, compares the signal with a preset reference temperature value, and controls the working state of the heating device and / or cooling device based on the comparison result, thereby maintaining the target temperature within a set range or at a specific temperature point.

[0003] In related technologies, different voltage loads require different temperature control circuits, which increases costs and extends the development cycle. Summary of the Invention

[0004] In view of this, this application provides a temperature control circuit and a laser. The temperature control circuit can be adapted to different loads, reducing costs and shortening the development cycle.

[0005] To solve the above problems, the technical solution provided in this application is as follows: In a first aspect of this application, a temperature control circuit is provided, comprising: a hardware PID module, an inverting amplifier module, a first power supply module, a second power supply module, a first switching device, and a second switching device; The first input terminal of the hardware PID module is used to connect to the temperature setting voltage, the second input terminal of the hardware PID module is used to connect to the temperature feedback voltage, and the output terminal of the hardware PID module is connected to the control terminal of the first power supply module and the first input terminal of the inverting amplifier module. The second input terminal of the inverting amplifier module is used to connect to the reference voltage, and the output terminal of the inverting amplifier module is connected to the control terminal of the second power supply module. The input terminal of the first power module is used to connect to the input voltage, and the output terminal of the first power module serves as the first output terminal of the temperature control circuit and is grounded through the first switching device; the input terminal of the second power module is used to connect to the input voltage, and the output terminal of the second power module serves as the second output terminal of the temperature control circuit and is grounded through the second switching device. A first switching device is configured to turn on when current flows to a first power module; a second switching device is configured to turn on when current flows to a second power module.

[0006] In one possible implementation, the temperature control circuit further includes: a first current-limiting resistor and a second current-limiting resistor; The first end of the first current-limiting resistor is connected to the output end of the hardware PID module, and the second end of the first current-limiting resistor is connected to the control end of the first power supply module. The first end of the second current-limiting resistor is connected to the output terminal of the inverting amplifier module, and the second end of the second current-limiting resistor is connected to the control terminal of the second power supply module.

[0007] In one possible implementation, the first switching device includes a first transistor, and the second switching device includes a second transistor; The first terminal of the first transistor is connected to the output terminal of the first power module, the second terminal of the first transistor is grounded, and the control terminal of the first transistor is connected to the output terminal of the first control circuit; the first terminal of the second transistor is connected to the output terminal of the second power module, the second terminal of the second transistor is grounded, and the control terminal of the second transistor is connected to the output terminal of the second control circuit. The first control circuit includes a first comparator, the first input terminal of the first comparator is connected to the output terminal of the hardware PID module, the second input terminal of the first comparator is used to connect to the reference voltage, and the output terminal of the first comparator is connected to the control terminal of the first transistor. The second control circuit includes a second comparator. The first input terminal of the second comparator is connected to the output terminal of the inverting amplifier module, the second input terminal of the second comparator is used to connect to the reference voltage, and the output terminal of the second comparator is connected to the control terminal of the second transistor.

[0008] In one possible implementation, the first control circuit further includes a first hysteresis resistor, and the second control circuit further includes a second hysteresis resistor. The first end of the first hysteresis resistor is connected to the first input terminal of the first comparator, and the second end of the first hysteresis resistor is connected to the output terminal of the first comparator. The first end of the second hysteresis resistor is connected to the first input terminal of the second comparator, and the second end of the second hysteresis resistor is connected to the output terminal of the second comparator.

[0009] In one possible implementation, the output voltage of the first power module is negatively correlated with the corresponding control voltage, and the output voltage of the second power module is negatively correlated with the corresponding control voltage.

[0010] In one possible implementation, the temperature control circuit also includes a temperature feedback module; The temperature feedback module includes an operational amplifier, a first half-bridge, a second half-bridge, and a thermistor; The first terminal of the first half-bridge and the first terminal of the second half-bridge are connected together to the reference voltage. The second terminals of the first half-bridge and the second terminals of the second half-bridge are connected together through a thermistor and grounded. The midpoint of the first half-bridge and the midpoint of the second half-bridge are respectively connected to the first input terminal and the second input terminal of the operational amplifier. The output of the operational amplifier is the temperature feedback voltage.

[0011] In one possible implementation, the hardware PID module includes: an operational amplifier; The first input terminal of the operational amplifier is connected to the temperature setting voltage, the second input terminal of the operational amplifier is used to connect to the temperature feedback voltage, and the output terminal of the operational amplifier is connected to the control terminal of the first power supply module and the first input terminal of the inverting amplifier module.

[0012] Secondly, embodiments of this application provide a laser, including: a semiconductor cooler and a temperature control circuit as described in any embodiment of the first aspect; The positive terminal of the power supply of the semiconductor cooler is connected to the first output terminal of the temperature control circuit, and the negative terminal of the power supply of the semiconductor cooler is connected to the second output terminal of the temperature control circuit.

[0013] In one possible implementation, the laser is configured to operate in a heating mode when the temperature set voltage is greater than the temperature feedback voltage, and in a cooling mode when the temperature set voltage is less than the temperature feedback voltage.

[0014] In one possible implementation, in heating mode, current flows to ground through the second power module, the negative power terminal of the semiconductor cooler, the positive power terminal of the semiconductor cooler, and the first switching device; in cooling mode, current flows to ground through the first power module, the positive power terminal of the semiconductor cooler, the negative power terminal of the semiconductor cooler, and the second switching device.

[0015] To reduce costs and shorten development cycles, this application provides a temperature control circuit, including: a hardware PID module, an inverting amplifier module, a first power supply module, a second power supply module, a first switching device, and a second switching device. The first input terminal of the hardware PID module is connected to a temperature setting voltage, and the second input terminal is connected to a temperature feedback voltage. The output terminal of the hardware PID module is connected to the control terminal of the first power supply module and the first input terminal of the inverting amplifier module. The second input terminal of the inverting amplifier module is connected to a reference voltage, and the output terminal is connected to the control terminal of the second power supply module. The input terminal of the first power supply module is connected to an input voltage, and its output terminal serves as the first output terminal of the temperature control circuit and is grounded through the first switching device. The input terminal of the second power supply module is connected to an input voltage, and its output terminal serves as the second output terminal of the temperature control circuit and is grounded through the second switching device. The first switching device is configured to conduct when current flows to the first power supply module; the second switching device is configured to conduct when current flows to the second power supply module. In this embodiment, a switching device is configured at the output end of the power module (a first switching device is configured at the output end of the first power module, and a second switching device is configured at the output end of the second power module). This solves the engineering application problem that the power module does not have synchronous rectification function to block the current loop, or that the power module blocks the circuit loop by configuring an anti-backflow protection circuit. Furthermore, by configuring the power module (first power module and second power module) in the temperature control circuit, the power module can be replaced according to different loads to adapt the temperature control circuit to different loads, thereby reducing costs and shortening the development cycle.

[0016] In addition, in this embodiment of the application, a temperature control circuit is constructed by hardware modules (hardware PID module, inverting amplifier module, first power supply module, second power supply module, first switching device and second switching device). Since the temperature control circuit does not have the sampling period, AD / DA conversion and algorithm calculation delay of the software PID, it can achieve fast response for loads with extremely small thermal time constants and meet their requirements for control period.

[0017] In addition, the temperature control circuit in this embodiment can achieve smooth, stepless control of voltage / current, and eliminates minor temperature fluctuations caused by quantization; it does not have problems such as code bugs, watchdog resets, or uncertain power-on transients; it is composed of discrete components, and different power supply modules can be selected to adapt to temperature control systems of different power according to project application requirements. Attached Figure Description

[0018] Figure 1 A schematic diagram of a temperature control circuit provided in an embodiment of this application; Figure 2A circuit diagram of a temperature setting module provided in an embodiment of this application; Figure 3 A circuit diagram of a temperature feedback module provided in an embodiment of this application; Figure 4 A circuit diagram of a hardware PID module provided in an embodiment of this application; Figure 5 A circuit diagram of a feedback amplification module provided in an embodiment of this application; Figure 6 A schematic diagram of a first control circuit provided in an embodiment of this application; Figure 7 A schematic diagram of a second control circuit provided in an embodiment of this application; Figure 8 A schematic diagram of the temperature control circuit provided for the implementation of this application; Figure 9 This is a schematic diagram of a laser provided in an embodiment of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] The terms "first" and "second," etc., used in the specification of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first operation instruction" and "second operation instruction," etc., are used to distinguish different operation instructions, not to describe a specific order of operation instructions.

[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0024] See Figure 1 The figure is a schematic diagram of a temperature control circuit provided in an embodiment of this application.

[0025] like Figure 1 As shown, the temperature control circuit includes: a hardware PID module 1000, an inverting amplifier module 2000, a first power supply module 3000, a second power supply module 4000, a first switching device 5000, and a second switching device 6000.

[0026] The first input terminal of the hardware PID module 1000 is used to connect to the temperature setting voltage T_VSet, the second input terminal of the hardware PID module 1000 is used to connect to the temperature feedback voltage T_VFB, and the output terminal of the hardware PID module 1000 is connected to the control terminal of the first power supply module 3000 and the first input terminal of the inverting amplifier module 2000. The second input terminal of the inverting amplifier module 2000 is used to connect to the reference voltage REF, and the output terminal of the inverting amplifier module is connected to the control terminal of the second power supply module 4000. The input terminal of the first power module 3000 is used to connect to the input voltage Vin, and the output terminal of the first power module 3000 serves as the first output terminal (+) of the temperature control circuit and is grounded through the first switching device 5000; the input terminal of the second power module 4000 is used to connect to the input voltage Vin, and the output terminal of the second power module 4000 serves as the second output terminal (-) of the temperature control circuit and is grounded through the second switching device 6000. The first switching device 5000 is configured to be turned on when current flows to the first power module 3000; the second switching device 6000 is configured to be turned on when current flows to the second power module 4000.

[0027] In this embodiment, a switching device is configured at the output end of the power module (a first switching device is configured at the output end of the first power module, and a second switching device is configured at the output end of the second power module). This solves the engineering application problem that the power module does not have synchronous rectification function to block the current loop, or that the power module blocks the circuit loop by configuring an anti-backflow protection circuit. Furthermore, by configuring a power module (first power module and second power module) in the temperature control circuit, the power module can be replaced according to different loads to adapt the temperature control circuit to different loads, thereby reducing costs and shortening the development cycle.

[0028] In addition, in this embodiment of the application, a temperature control circuit is constructed by hardware modules (hardware PID module, inverting amplifier module, first power supply module, second power supply module, first switching device and second switching device). Since the temperature control circuit does not have the sampling period, AD / DA conversion and algorithm calculation delay of the software PID, it can achieve fast response for loads with extremely small thermal time constants and meet their requirements for control period.

[0029] In addition, the temperature control circuit in this embodiment can achieve smooth, stepless control of voltage / current, and eliminates minor temperature fluctuations caused by quantization; it does not have problems such as code bugs, watchdog resets, or uncertain power-on transients; it is composed of discrete components, and different power supply modules can be selected to adapt to temperature control systems of different power according to project application requirements.

[0030] To facilitate understanding of the technical solution of this application, the various modules involved in the temperature control circuit will be described below. It should be noted that the temperature setting voltage T_VSet is output by the temperature setting module, and the temperature feedback voltage T_VFB is output by the temperature feedback module.

[0031] like Figure 2 As shown, the temperature setting module includes: a first operational amplifier U1A, a third resistor R3, a fourth resistor R4, a seventh resistor R7, and an eighth resistor R8.

[0032] The first input terminal of the first operational amplifier U1A is connected to T_VSet_IN through the third resistor R3 and grounded through the seventh resistor R7; the second input terminal of the first operational amplifier U1A is grounded through the fourth resistor R4 and connected to the output terminal of the first operational amplifier U1A through the eighth resistor R8; the output terminal of the first operational amplifier U1A outputs the temperature setting voltage T_VSet.

[0033] In this embodiment of the application, the temperature setting module is configured to output a temperature setting voltage T_VSet corresponding to the target temperature through differential amplification.

[0034] like Figure 3 As shown, the temperature feedback module includes: a second operational amplifier U1B, a first resistor R1, a second resistor R2, a fifth resistor R5, a sixth resistor R6, a thermistor RT1, a ninth resistor R9, and a first capacitor C1. The first resistor R1 and the second resistor R2 form the first half-bridge, and the fifth resistor R5 and the sixth resistor R6 form the second half-bridge.

[0035] The first input terminal of the second operational amplifier U1B is connected to the midpoint of the first half-bridge (the connection point of the first resistor R1 and the second resistor R2), and the second input terminal of the second operational amplifier U1B is connected to the midpoint of the second half-bridge (the connection point of the fifth resistor R5 and the sixth resistor R6). The first terminals of the first and second half-bridges are connected together to the reference voltage REF, and the second terminals of the first and second half-bridges are connected together through thermistor RT1 and grounded. The first terminal of the ninth resistor R9 is connected to the second input terminal of the second operational amplifier U1B, and the second terminal of the ninth resistor R9 is connected to the output terminal of the second operational amplifier U1B. The first capacitor C1 is connected in parallel across the ninth resistor R9.

[0036] In this embodiment, the temperature feedback module is configured to convert the resistance change of the thermistor RT1 into a linearly amplified temperature feedback voltage T_VFB.

[0037] like Figure 4 As shown, the hardware PID module includes: the third operational amplifier U2B, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4.

[0038] The first input terminal of the third operational amplifier U2B is connected to the temperature setting voltage T_VSet through the eleventh resistor R11, and the second input terminal of the third operational amplifier U2B is connected to the temperature feedback voltage T_VFB through the twelfth resistor R12. The two ends of the twelfth resistor R12 are connected to the first RC circuit (the first RC circuit is composed of the tenth resistor R10 and the second capacitor C2 connected in series). The second input terminal and the output terminal of the third operational amplifier U2B are connected to the second RC circuit (the second RC circuit is composed of the thirteenth resistor R13 and the fourth capacitor C4 connected in series). The third capacitor C3 is connected in parallel across the two ends of the second RC circuit.

[0039] In this embodiment, the hardware PID module is configured to perform proportional-integral-derivative (PID) calculations on the deviation between the temperature setting voltage T_VSet and the temperature feedback voltage T_VFB, and output a first control voltage T_Cold that gradually decreases or increases. The first control voltage T_Cold is used to control the cooling voltage amplitude, i.e., it serves as the control terminal voltage of the first power supply module, controlling the output voltage of the first power supply module.

[0040] like Figure 5 As shown, the inverting amplifier module includes: the fourth operational amplifier U2A, the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16, the seventeenth resistor R17, and the fifth capacitor C5.

[0041] The second input terminal of the fourth operational amplifier U2A is connected to the reference voltage REF through the fourteenth resistor R14 and grounded through the fifteenth resistor. The first input terminal of the fourth operational amplifier U2A is connected to the first control voltage T_Cold through the sixteenth resistor R16. The output terminal of the fourth operational amplifier U2A outputs the second control voltage T_Heat. The seventeenth resistor R17 is connected between the first input terminal and the output terminal of the fourth operational amplifier U2A. The fifth capacitor C5 is connected between the first input terminal and the output terminal of the fourth operational amplifier U2A.

[0042] In this embodiment, the inverting amplifier module is configured to proportionally invert the first control voltage T_Cold and output a second control voltage T_Heat (the second control voltage T_Heat gradually increases as the first control voltage T_Cold gradually decreases, and gradually decreases as the first control voltage T_Cold gradually increases). The second control voltage T_Heat is used to control the heating voltage amplitude, i.e., it serves as the control terminal voltage of the second power supply module, controlling the output voltage of the second power supply module.

[0043] It should be noted that in the embodiments of this application, the output voltage of the first power module is negatively correlated with the corresponding control voltage, and the output voltage of the second power module is negatively correlated with the corresponding control voltage.

[0044] In this application embodiment, the types of the first switching device and the second switching device are not specifically limited. When the first switching device includes a first transistor, the first end of the first transistor is connected to the output end of the first power module, the second end of the first transistor is grounded, and the control end of the first transistor is connected to the output end of the first control circuit. When the second switching device includes a second transistor, the first end of the second transistor is connected to the output end of the second power module, the second end of the second transistor is grounded, and the control end of the second transistor is connected to the output end of the second control circuit.

[0045] The first control circuit includes a first comparator, the first input terminal of which is connected to the output terminal of the hardware PID module, the second input terminal of which is connected to a reference voltage, and the output terminal of which is connected to the control terminal of the first transistor; the second control circuit includes a second comparator, the first input terminal of which is connected to the output terminal of the inverting amplifier module, the second input terminal of which is connected to a reference voltage, and the output terminal of which is connected to the control terminal of the second transistor.

[0046] like Figure 6As shown, the first control circuit includes: a first comparator U3B, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fifth resistor R25, a twenty-seventh resistor R27, a twenty-ninth resistor R29, and a thirty-first resistor R31.

[0047] The first input terminal of the first comparator U3B is connected to the first control voltage T_Cold through the twenty-second resistor R22, and is connected to the output terminal of the first comparator U3B through the twenty-seventh resistor R27. The second input terminal of the first comparator U3B is connected to the reference voltage REF through the twenty-third resistor R23, and is grounded through the twenty-fifth resistor R25. The output terminal of the first comparator U3B is connected to the control terminal (e.g., the gate of the first transistor Q1) through the twenty-ninth resistor R29, and is connected to VCC through the thirty-first resistor R31.

[0048] The first control circuit in this embodiment is configured to control the first switching device to turn on or off. Furthermore, by introducing a 27th resistor R27 as a positive feedback hysteresis resistor in the first control circuit, even if the first control voltage T_Cold fluctuates slowly near a set threshold, the presence of the first hysteresis resistor can prevent radiated interference and power spikes caused by high-speed switching. The first comparator U3B will not jitter, and the first switching device Q1 will remain in a stable state, thus improving the long-term reliability of the temperature control circuit.

[0049] like Figure 7 As shown, the second control circuit includes: a second comparator U3A, a twentieth resistor R20, a twenty-first resistor R21, a twenty-fourth resistor R24, a twenty-sixth resistor R26, a twenty-eighth resistor R28, and a thirtieth resistor R30.

[0050] The first input terminal of the second comparator U3A is connected to the second control voltage T_Heat through the twentieth resistor R20, and is connected to the output terminal of the second comparator U3A through the twenty-sixth resistor R26. The second input terminal of the second comparator U3A is connected to the reference voltage REF through the twenty-first resistor R21, and is grounded through the twenty-fourth resistor R24. The output terminal of the second comparator U3A is connected to the control terminal (e.g., the gate of the second transistor Q2) through the twenty-eighth resistor R28, and is connected to VCC through the thirtieth resistor R30.

[0051] The second control circuit in this embodiment is configured to control the second switching device to turn on or off. Furthermore, by introducing a 26th resistor R26 as a positive feedback hysteresis resistor in the second control circuit, even if the second control voltage T_Heat fluctuates slowly near a set threshold, the presence of the second hysteresis resistor can prevent radiated interference and power spikes caused by high-speed switching. The second comparator U3A will not jitter its output, and the second switching device Q2 will remain stable, thus improving the long-term reliability of the temperature control circuit.

[0052] In addition, embodiments of this application may also introduce a first current-limiting resistor and a second current-limiting resistor in the temperature control circuit; the first end of the first current-limiting resistor is connected to the output end of the hardware PID module, and the second end of the first current-limiting resistor is connected to the control end of the first power supply module; the first end of the second current-limiting resistor is connected to the output end of the inverting amplifier module, and the second end of the second current-limiting resistor is connected to the control end of the second power supply module.

[0053] By adding a first current-limiting resistor, the minimum control terminal voltage of the first power module can be limited, thereby controlling the maximum output terminal voltage of the first power module and thus limiting the maximum current; by adding a second current-limiting resistor, the minimum control terminal voltage of the second power module can be limited, thereby controlling the maximum output terminal voltage of the second power module and thus limiting the maximum current.

[0054] Based on the modules described above, the specific implementation of the temperature control circuit is as follows: Figure 8 As shown, the first current-limiting resistor is the nineteenth resistor R19, and the second current-limiting resistor is the eighteenth resistor R18.

[0055] The following will address... Figure 8 The temperature control circuit shown here will be used to introduce the circuit principle related to this application.

[0056] The temperature setting voltage T_VSet_IN is adjusted by the first operational amplifier U1A to output the temperature setting voltage T_Vset, which is then sent to the non-inverting input of the third operational amplifier U2B. The resistance of the thermistor RT1 is corrected and amplified by the second operational amplifier U1B to output the temperature feedback voltage T_VFB, which is then sent to the inverting input of the third operational amplifier U2B. The third operational amplifier U2B performs PID calculation on the deviation between the temperature setting voltage T_Vset and the temperature feedback voltage T_VFB, and outputs the first control voltage T_Cold. The second control voltage T_Heat is output proportionally and inverted by the fourth operational amplifier U2A.

[0057] According to the comparison result of the temperature-setting voltage T_Vset and the temperature-feedback voltage T_VFB, the temperature control circuit can automatically switch between the heating or cooling modes. The principles of the temperature control circuit for the heating and cooling modes will be introduced as follows: In the heating mode, that is, when the temperature-setting voltage T_Vset is greater than the temperature-feedback voltage T_VFB (T_Vset > T_VFB), the hardware PID module outputs a first control voltage T_Cold that gradually increases according to the adjustment rule, and the second control voltage T_Heat output by the inverting amplifier module gradually decreases.

[0058] The first control voltage T_Cold gradually increases and is sent to the control terminal (Trim terminal) of the first power supply module M1 through the nineteenth resistor R19. Since the higher the voltage at the control terminal of the first power supply module M1, the lower the voltage at its output terminal, when the first control voltage T_Cold gradually increases, the output (TEC+) of the first power supply module M1 linearly decreases to nearly 0V.

[0059] The second control voltage T_Heat gradually decreases and is sent to the control terminal (Trim terminal) of the second power supply module M2 through the eighteenth resistor R18. Since the lower the voltage at the control terminal of the second power supply module M2, the higher the voltage at its output terminal, when the second control voltage T_Heat gradually decreases, the output (TEC-) of the second power supply module M2 linearly increases to the set maximum voltage.

[0060] In the heating mode, the second control voltage T_Heat is connected to the non-inverting input terminal of the second comparator U3A through the twentieth resistor R20. The voltage at its inverting input terminal (divided by R21 / R24) is higher than the voltage at the non-inverting input terminal, causing the second comparator U3A to output a low level and the second switching device Q2 to turn off; the first control voltage T_Cold is connected to the non-inverting input terminal of the first comparator U3B through the twenty-second resistor R22. The voltage at its inverting input terminal (divided by R23 / R25) is lower than the voltage at the non-inverting input terminal, causing the first comparator U3B to output a high level and the first switching device Q1 to turn on.

[0061] In the heating mode, the current path is successively the second power supply module M2, TEC-, TEC+, the first switching device Q1, and GND, achieving heating.

[0062] In the cooling mode, that is, when the temperature-setting voltage T_Vset is less than the temperature-feedback voltage T_VFB (T_Vset < T_VFB), the hardware PID module outputs a first control voltage T_Cold that gradually decreases according to the adjustment rule, and the second control voltage T_Heat output by the inverting amplifier module gradually increases.

[0063] The first control voltage T_Cold gradually decreases and is sent to the control terminal (Trim terminal) of the first power module M1 via the nineteenth resistor R19. Since the lower the control terminal voltage of the first power module M1, the higher its output voltage, as the first control voltage T_Cold gradually decreases, the output (TEC+) of the first power module M1 linearly rises to the set maximum voltage.

[0064] The second control voltage T_Heat gradually increases and is sent to the control terminal (Trim terminal) of the second power module M2 via the eighteenth resistor R18. Since the higher the control terminal voltage of the second power module M2, the lower its output voltage, as the second control voltage T_Heat gradually increases, the output (TEC-) of the second power module M2 linearly decreases to close to 0V.

[0065] In cooling mode, the second control voltage T_Heat is connected to the non-inverting input of the second comparator U3A via the twentieth resistor R20. The voltage at its inverting input (voltage divider R21 / R24) is lower than the voltage at the non-inverting input, causing the second comparator U3A to output a high level and the second switching device Q2 to turn on. The first control voltage T_Cold is connected to the non-inverting input of the first comparator U3B via the twenty-second resistor R22. The voltage at its inverting input (voltage divider R23 / R25) is higher than the voltage at the non-inverting input, causing the first comparator U3B to output a low level and the first switching device Q1 to turn off.

[0066] In cooling mode, the current path is sequentially through the first power module M1, TEC+, TEC-, the second switching device Q2, and GND to achieve cooling.

[0067] In this embodiment, the above process can adapt to the temperature difference by linearly adjusting the output voltage of the two power modules and coordinating the switching of the first switching device Q1 and the second switching device Q2 to achieve bidirectional temperature control.

[0068] It should be understood that, for ease of description, Figure 8 In the embodiments described above, the first and second output terminals of the temperature control circuit are connected to the positive and negative power supply terminals of the thermoelectric cooler (TEC), respectively. In this application embodiment, the connection of the output terminal of the temperature control circuit to the thermoelectric cooler (TEC) is not specifically limited; the connection is merely exemplary.

[0069] The temperature control circuit described in this embodiment achieves continuous, linear, and low-noise temperature heating and cooling regulation by adjusting the control ports of the two power modules using an analog PID controller and an inverting error amplifier. It also limits the maximum voltage output of the power module by limiting the minimum voltage value of the control terminal pin through the selection of the current-limiting resistor. This eliminates the need for an additional current monitoring sampling feedback circuit, which simplifies the circuit, improves reliability, and limits the maximum current.

[0070] In addition, a hysteresis resistor is added to the control circuit so that the output will only flip when the input signal changes beyond the hysteresis width. This avoids radiation interference and power spikes caused by high-speed switching, prevents the comparator from jittering, keeps the switching devices in a stable state, and improves the long-term reliability of the temperature control system.

[0071] Based on the temperature control circuit described in the preceding embodiments, this application also provides a laser, the schematic diagram of which is shown below. Figure 9 .

[0072] like Figure 9 As shown, the laser includes a semiconductor cooler 20000 of the temperature control circuit 10000 described in the foregoing embodiments; the positive power supply of the semiconductor cooler 20000 is connected to the first output terminal of the temperature control circuit 10000, and the negative power supply of the semiconductor cooler 20000 is connected to the second output terminal of the temperature control circuit 10000.

[0073] In this embodiment, a switching device is configured at the output end of the power module (a first switching device is configured at the output end of the first power module, and a second switching device is configured at the output end of the second power module). This solves the engineering application problem that the power module does not have synchronous rectification function to block the current loop, or that the power module blocks the circuit loop by configuring an anti-backflow protection circuit. Furthermore, by configuring a power module (first power module and second power module) in the temperature control circuit, the power module can be replaced according to different loads to adapt the temperature control circuit to different loads, thereby reducing costs and shortening the development cycle.

[0074] In addition, in this embodiment of the application, a temperature control circuit is constructed by hardware modules (hardware PID module, inverting amplifier module, first power supply module, second power supply module, first switching device and second switching device). Since the temperature control circuit does not have the sampling period, AD / DA conversion and algorithm calculation delay of the software PID, it can achieve fast response for loads with extremely small thermal time constants and meet their requirements for control period.

[0075] In addition, the temperature control circuit in this embodiment can achieve smooth, stepless control of voltage / current, and eliminates minor temperature fluctuations caused by quantization; it does not have problems such as code bugs, watchdog resets, or uncertain power-on transients; it is composed of discrete components, and different power supply modules can be selected to adapt to temperature control systems of different power according to project application requirements.

[0076] In one possible implementation, the laser is configured to operate in a heating mode when the temperature set voltage is greater than the temperature feedback voltage, and in a cooling mode when the temperature set voltage is less than the temperature feedback voltage.

[0077] In one possible implementation, in heating mode, current flows to ground through the second power module, the negative power terminal of the semiconductor cooler, the positive power terminal of the semiconductor cooler, and the first switching device; in cooling mode, current flows to ground through the first power module, the positive power terminal of the semiconductor cooler, the negative power terminal of the semiconductor cooler, and the second switching device.

[0078] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0079] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature control circuit, characterized by, include: Hardware PID module, inverting amplifier module, first power supply module, second power supply module, first switching device and second switching device; The first input terminal of the hardware PID module is used to connect to the temperature setting voltage, the second input terminal of the hardware PID module is used to connect to the temperature feedback voltage, and the output terminal of the hardware PID module is connected to the control terminal of the first power supply module and the first input terminal of the inverting amplifier module. The second input terminal of the inverting amplifier module is used to connect to the reference voltage, and the output terminal of the inverting amplifier module is connected to the control terminal of the second power supply module. The input terminal of the first power module is used to connect to the input voltage, and the output terminal of the first power module serves as the first output terminal of the temperature control circuit and is grounded through the first switching device; the input terminal of the second power module is used to connect to the input voltage, and the output terminal of the second power module serves as the second output terminal of the temperature control circuit and is grounded through the second switching device. The first switching device is configured to turn on when current flows to the first power module; the second switching device is configured to turn on when current flows to the second power module.

2. The circuit according to claim 1, characterized in that, The temperature control circuit further includes: a first current-limiting resistor and a second current-limiting resistor; The first end of the first current-limiting resistor is connected to the output end of the hardware PID module, and the second end of the first current-limiting resistor is connected to the control end of the first power module. The first end of the second current-limiting resistor is connected to the output terminal of the inverting amplifier module, and the second end of the second current-limiting resistor is connected to the control terminal of the second power supply module.

3. The circuit according to claim 2, characterized in that, The first switching device includes a first transistor, and the second switching device includes a second transistor; The first terminal of the first transistor is connected to the output terminal of the first power module, the second terminal of the first transistor is grounded, and the control terminal of the first transistor is connected to the output terminal of the first control circuit; the first terminal of the second transistor is connected to the output terminal of the second power module, the second terminal of the second transistor is grounded, and the control terminal of the second transistor is connected to the output terminal of the second control circuit. The first control circuit includes a first comparator, the first input terminal of the first comparator is connected to the output terminal of the hardware PID module, the second input terminal of the first comparator is used to connect to the reference voltage, and the output terminal of the first comparator is connected to the control terminal of the first transistor. The second control circuit includes a second comparator. The first input terminal of the second comparator is connected to the output terminal of the inverting amplifier module, the second input terminal of the second comparator is used to connect to the reference voltage, and the output terminal of the second comparator is connected to the control terminal of the second transistor.

4. The circuit according to claim 3, characterized in that, The first control circuit further includes a first hysteresis resistor, and the second control circuit further includes a second hysteresis resistor; The first end of the first hysteresis resistor is connected to the first input terminal of the first comparator, and the second end of the first hysteresis resistor is connected to the output terminal of the first comparator. The first end of the second hysteresis resistor is connected to the first input terminal of the second comparator, and the second end of the second hysteresis resistor is connected to the output terminal of the second comparator.

5. The circuit according to claim 1, characterized in that, The output voltage of the first power module is negatively correlated with the corresponding control voltage, and the output voltage of the second power module is negatively correlated with the corresponding control voltage.

6. The circuit according to any one of claims 1-5, characterized in that, The temperature control circuit further includes: a temperature feedback module; The temperature feedback module includes an operational amplifier, a first half-bridge, a second half-bridge, and a thermistor; The first terminal of the first half-bridge and the first terminal of the second half-bridge are connected together to the reference voltage. The second terminals of the first half-bridge and the second half-bridge are connected together through the thermistor and grounded. The midpoint of the first half-bridge and the midpoint of the second half-bridge are respectively connected to the first input terminal and the second input terminal of the operational amplifier. The operational amplifier outputs the temperature feedback voltage.

7. The circuit according to any one of claims 1-5, characterized in that, The hardware PID module includes: an operational amplifier; The first input terminal of the operational amplifier is connected to the temperature setting voltage, the second input terminal of the operational amplifier is connected to the temperature feedback voltage, and the output terminal of the operational amplifier is connected to the control terminal of the first power supply module and the first input terminal of the inverting amplifier module.

8. A laser, characterized in that, include: A semiconductor cooler and a temperature control circuit as described in any one of claims 1-7; The positive terminal of the power supply of the semiconductor cooler is connected to the first output terminal of the temperature control circuit, and the negative terminal of the power supply of the semiconductor cooler is connected to the second output terminal of the temperature control circuit.

9. The laser according to claim 8, characterized in that, The laser is configured to operate in a heating mode when the temperature setting voltage is greater than the temperature feedback voltage, and in a cooling mode when the temperature setting voltage is less than the temperature feedback voltage.

10. The laser according to claim 9, characterized in that, In the heating mode, the current flows to ground through the second power module, the negative power terminal of the semiconductor cooler, the positive power terminal of the semiconductor cooler, and the first switching device; in the cooling mode, the current flows to ground through the first power module, the positive power terminal of the semiconductor cooler, the negative power terminal of the semiconductor cooler, and the second switching device.

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