A laser therapeutic apparatus

Abstract

The utility model discloses a kind of laser therapeutic apparatus, its circuit board is provided with laser driver circuit, including main controller, constant-current source drive circuit and TEC drive circuit.The main controller is connected with the constant-current source drive circuit, and the constant-current source drive circuit is connected with the semiconductor laser.The main controller is connected with the TEC drive circuit, and the TEC drive circuit is connected with the TEC of the semiconductor laser.The laser driver circuit is configured, and the temperature of the semiconductor laser is collected by the NTC thermistor of semiconductor laser of its main controller, and instructs the TEC drive circuit to work.

Description

Technical Field

[0001] This utility model relates to the field of laser therapy instruments and equipment technology, and in particular to a laser therapy instrument. Background Technology

[0002] Laser therapy is non-invasive and convenient, making it an important adjunct to rhinitis treatment. Laser therapy for rhinitis is a technique based on photothermal and biostimulation effects. It primarily utilizes the energy characteristics of lasers to promote local blood circulation, reduce nasal turbinate swelling, suppress inflammatory responses, and enhance the immune function of the nasal mucosa.

[0003] Currently, laser therapy devices used for rhinitis treatment mainly employ semiconductor lasers. Semiconductor lasers are sensitive devices that rely on precise operating conditions, requiring specific current and temperature controls. Because the output characteristics of semiconductor lasers are extremely sensitive to driving current and operating temperature, even minute changes in temperature and current can lead to significant alterations in the laser's output wavelength and power, thus affecting the stability of the laser therapy device.

[0004] Currently, existing laser therapy devices neglect temperature control of semiconductor lasers, and further optimization of the circuit design of laser therapy devices is still needed. Utility Model Content

[0005] To address the technical problems existing in the prior art, the purpose of this utility model is to provide a laser therapy device. This laser drive circuit, by controlling the operating temperature and drive current of the semiconductor laser, solves the problem of unstable laser output caused by temperature and current variations in existing laser therapy devices. Precise temperature control can avoid significant changes in the laser output wavelength and power, thereby improving the stability of the laser therapy device. Simultaneously, a stable current supply further ensures the operational reliability of the semiconductor laser and extends its service life.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] This utility model provides a laser therapy device, including a control host and a nasal plug connected to each other. The nasal plug is equipped with a semiconductor laser, and the control host is equipped with a circuit board. The characteristic of this invention is that the circuit board is equipped with a laser driving circuit connected to the semiconductor laser.

[0008] The laser driving circuit includes a main controller, a constant current source driving circuit, and a TEC driving circuit;

[0009] The main controller is connected to the constant current source drive circuit, and the constant current source drive circuit is connected to the semiconductor laser;

[0010] The main controller is connected to the TEC drive circuit, and the TEC drive circuit is connected to the TEC of the semiconductor laser; the main controller collects the temperature of the semiconductor laser through the NTC thermistor of the semiconductor laser, and the main controller instructs the TEC drive circuit to work.

[0011] In one specific implementation, the constant current source driving circuit is connected to the laser diode LD of the semiconductor laser, and the constant current source driving circuit includes:

[0012] Operational amplifier U1 has its positive power supply pin connected to power supply VCC and its negative power supply pin grounded. The non-inverting input of operational amplifier U1 is connected to the input voltage Uset, and the inverting input of operational amplifier U1 is connected to one end of resistor R5. Resistor R5 is connected in series with resistor R4, and one end of resistor R4 is grounded.

[0013] Operational amplifier U2, the output terminal of which is connected to the inverting input terminal of operational amplifier U1, and the inverting input terminal of operational amplifier U1 is connected to resistor R4;

[0014] The NMOS transistor has its gate connected to a resistor R1, the other end of which is connected to the output of the operational amplifier U1. The source of the NMOS transistor is connected to the non-inverting input of the operational amplifier U2, and the source of the NMOS transistor is also connected to a resistor Rs, the other end of which is grounded. The drain of the NMOS transistor is connected to the negative terminal of the laser diode LD.

[0015] Resistor R2, one end of which is connected to power supply VCC1, and the other end of which is connected to the positive terminal of laser diode LD.

[0016] In one specific implementation, the TEC driving circuit includes a TEC driving chip with an H-bridge circuit, the TEC driving chip being connected to the TEC of the semiconductor laser, and the TEC driving chip being configured in pulse width modulation mode.

[0017] In one specific implementation, the main controller uses an STM32 chip, and the two output pins of the advanced timer of the STM32 chip are respectively connected to the TEC driver chip.

[0018] In one specific implementation, the laser driving circuit further includes:

[0019] A protection circuit is connected to the laser diode LD of the semiconductor laser. The protection circuit includes a current surge protection circuit, an overcurrent protection circuit, and an electrostatic discharge protection circuit.

[0020] In one specific implementation, the current surge protection circuit includes capacitor C4, capacitor C5, and diode D3. Capacitor C4, capacitor C5, and diode D3 are all connected in parallel with the laser diode LD. The negative terminal of diode D3 is connected to the positive terminal of the laser diode LD, and the positive terminal of diode D3 is connected to the negative terminal of the laser diode LD.

[0021] In one specific implementation, the electrostatic discharge protection circuit includes a normally closed relay K1, a diode D4, a transistor Q5, and a resistor R6; one end of the coil of the normally closed relay K1 is connected to the positive terminal of the laser diode LD, and the other end of the coil of the normally closed relay K1 is grounded; the switching terminal of the normally closed relay K1 is connected to the negative terminal of the laser diode LD and the collector of the transistor Q5; the base of the transistor Q5 is connected to the resistor R6, and the emitter of the transistor Q5 is grounded; the negative terminal of the diode D4 is connected to the positive terminal of the laser diode LD, and the positive terminal of the diode D4 is grounded.

[0022] In one specific implementation, the overcurrent protection circuit includes operational amplifier A1, operational amplifier A2, MOSFET Q3, MOSFET Q4, resistor R7, resistor R8, resistor RS1, resistor RS2 and resistor RS3;

[0023] The non-inverting input terminal of the operational amplifier A1 is connected to a voltage U. set The output terminal of the operational amplifier A1 is connected to the gate of the MOS transistor Q3 through a resistor R7, and the drain of the MOS transistor Q3 is connected to the negative terminal of the laser diode LD.

[0024] The non-inverting input terminal of the operational amplifier A2 is connected to a voltage U. set The inverting input terminal of the operational amplifier A2 is connected to the inverting input terminal of the operational amplifier A1, and the output terminal of the operational amplifier A2 is connected to the gate of the MOS transistor Q4 through the resistor R8. The drain of the MOS transistor Q4 is connected to the positive terminal of the laser diode LD.

[0025] The resistors RS1, RS2 and RS3 are connected in parallel. One end of the resistor RS1 is connected to the inverting input of the operational amplifier A1, one end of the resistor RS2 is connected to the source of the MOS transistor Q3, and the other end of the resistor RS2 is grounded.

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

[0027] 1. This utility model provides a laser driving circuit for a laser therapy device, wherein the laser driving circuit is connected to the semiconductor laser. The laser driving circuit includes a main controller, a constant current source driving circuit, and a TEC driving circuit. The main controller is connected to the constant current source driving circuit, which is connected to the semiconductor laser. The main controller is also connected to the TEC driving circuit, which is connected to the TEC of the semiconductor laser. The laser driving circuit is configured such that the main controller acquires the temperature of the semiconductor laser through the NTC thermistor of the semiconductor laser and instructs the TEC driving circuit to operate.

[0028] The laser driving circuit of this invention acquires the temperature of the semiconductor laser through a main controller and instructs the TEC driving circuit to operate. The TEC driving circuit then controls the TEC of the semiconductor laser, thereby controlling the laser's operating temperature. Simultaneously, the main controller is also connected to a constant current source driving circuit to provide a stable driving current to the semiconductor laser, ensuring its operation under specified conditions.

[0029] This laser driver circuit solves the problem of unstable laser output caused by temperature and current variations in existing laser therapy devices by controlling the operating temperature and drive current of the semiconductor laser. Precise temperature control avoids significant changes in the laser output wavelength and power, thereby improving the stability of the laser therapy device. Simultaneously, a stable current supply further ensures the operational reliability of the semiconductor laser and extends its service life. Attached Figure Description

[0030] Figure 1 This is a block diagram illustrating the driving principle of the laser driving circuit of this utility model.

[0031] Figure 2 This is a circuit diagram of the constant current source drive circuit of this utility model;

[0032] Figure 3 This is the circuit schematic diagram of the TEC drive circuit of this utility model.

[0033] Figure 4 This is a circuit diagram of the protection circuit of this utility model;

[0034] Figure 5 This is a schematic diagram of the composition of the laser therapy device of this utility model;

[0035] Figure 6 This is an assembly diagram of the control host of this utility model.

[0036] In the picture:

[0037] 100 - Control host; 110 - Circuit board;

[0038] 200-Nose plug. Detailed Implementation

[0039] To facilitate understanding of this utility model, the technical solutions and advantages of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Any mechanisms or methods not elaborated in this utility model can be referred to in the prior art. The specific structure and features of this utility model are illustrated below by way of example and should not constitute any limitation on this utility model. Furthermore, any technical feature mentioned below (including implicit or disclosed features), as well as any technical feature directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form more other embodiments that may not be directly or indirectly mentioned in this utility model. The accompanying drawings show preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0040] like Figure 5 and Figure 6 As shown, this embodiment utilizes a laser therapy device, which is a medical laser instrument and belongs to the category of low-power laser external medical devices. The laser therapy device comprises a control unit, a wristband, a nasal plug, and a protective sleeve. It employs semiconductor laser technology to provide auxiliary treatment to the patient using specific laser wavelengths and power.

[0041] In one specific implementation, the main components of the laser therapy device are a control unit and a nasal prong. The control unit includes a housing, with a wristband attached to the back of the housing. The housing houses a circuit board and a rechargeable lithium battery, and is equipped with an LCD screen that clearly displays information such as treatment time, mode, and power. Both the rechargeable lithium battery and the LCD screen are connected to the circuit board. The circuit board has multiple physical buttons for user operation.

[0042] In one specific implementation, the nasal plug laser head is one of the key components of the laser therapy device. Through precise laser output, it achieves non-invasive treatment of nasal cavity tissues while ensuring safety and comfort during use. Specifically, the nasal plug laser head of the laser therapy device is an existing device in the art and will not be described in detail here. The nasal plug head is used to mount a semiconductor laser.

[0043] It should be noted that the semiconductor laser of this invention uses gallium arsenide semiconductor (GaAIAs) as its laser working material, with a laser wavelength of 650nm±10nm, which conforms to the standard wavelength range for medical laser therapy and is suitable for low-intensity phototherapy of biological tissues. The maximum output power of the semiconductor laser does not exceed 5mW. The nasal conduit laser head has a spot diameter of 2mm during operation, with a tolerance of ±20%. This size ensures concentrated laser energy while avoiding localized damage caused by over-focusing. The laser therapy device can be set to continuous or pulsed operation.

[0044] In this field, semiconductor lasers are widely used in medical devices and other areas due to their advantages such as small size, light weight, high efficiency, low energy consumption, and long lifespan. However, semiconductor lasers are very sensitive to temperature during actual use. The mechanism by which temperature affects semiconductor lasers is relatively complex. First, starting from the material itself, due to the special properties of semiconductor materials, an increase in temperature will lead to a sharp decrease in the concentration of charge carriers, thereby affecting the output power. Temperature changes not only affect the output power and output wavelength of the laser.

[0045] As 1 to Figure 4 As shown, the circuit board of the laser therapy device houses the laser driver circuit. This laser driver circuit is connected to the semiconductor laser. The laser driver circuit includes a main controller, a constant current source driver circuit, and a TEC driver circuit. The laser output wavelength is one of the key physical quantities that the semiconductor laser driver circuit needs to control stably. Adjusting the operating temperature of the semiconductor laser allows for effective control of the output wavelength. By setting the temperature of the semiconductor laser and stabilizing it at the set temperature, the stability of the output wavelength is ensured.

[0046] Specifically, the main controller is connected to the constant current source drive circuit, which in turn is connected to the semiconductor laser. The main controller is also connected to the TEC drive circuit, which is connected to the TEC of the semiconductor laser. The laser drive circuit is configured such that the main controller acquires the actual operating temperature of the semiconductor laser via its NTC thermistor and instructs the TEC drive circuit to operate based on this real-time operating temperature.

[0047] In this invention, the main controller, as the core of the entire laser drive circuit, is responsible for coordinating the work of each part and processing various signals and commands. It controls the operating temperature of the semiconductor laser, ensuring its operation within a stable temperature range. The constant current source drive circuit provides a stable current to the semiconductor laser, ensuring the stability and consistency of its output power. The TEC drive circuit regulates the temperature of the semiconductor laser by controlling the operating state of the TEC. The NTC thermistor is used to monitor the actual operating temperature of the semiconductor laser in real time.

[0048] It's important to note that in semiconductor lasers, TEC stands for Thermoelectric Cooler, a device that utilizes the Peltier effect to achieve temperature control. A TEC is composed of P-type and N-type semiconductor materials. When current flows through it, one end absorbs heat (cooling end) and the other releases heat (heating end). By changing the direction of the current, the TEC can switch between cooling and heating. This characteristic allows the TEC to precisely control the operating temperature of the semiconductor laser. TECs offer advantages such as being noiseless, vibration-free, requiring no refrigerant, small in size, lightweight, fast in cooling and heating, and highly precise in temperature control. They can achieve temperature control stability better than 0.1°C, making them ideal for temperature-sensitive semiconductor lasers.

[0049] In the circuit configuration of this technology, the main controller is connected to the constant current source drive circuit, and controls the output current of the constant current source drive circuit through commands, thereby adjusting the power of the semiconductor laser. The main controller is also connected to the TEC drive circuit, and adjusts the operating state of the TEC according to the temperature feedback signal to achieve temperature control. The TEC drive circuit is connected to the TEC of the semiconductor laser, providing current to the TEC to achieve cooling or heating functions.

[0050] In a specific implementation, such as Figure 2 As shown, the constant current source driving circuit is connected to the laser diode LD of the semiconductor laser. The constant current source driving circuit includes:

[0051] Operational amplifier U1 has its positive power supply pin connected to power supply VCC and its negative power supply pin grounded. The non-inverting input of operational amplifier U1 is connected to the input voltage Uset, and the inverting input is connected to one end of resistor R5. Resistor R5 is connected in series with resistor R4, and one end of resistor R4 is grounded.

[0052] Operational amplifier U2 is connected to the output terminal of operational amplifier U1, and the inverting input terminal of operational amplifier U1 is connected to resistor R4.

[0053] The NMOS transistor's gate is connected to resistor R1, and the other end of resistor R1 is connected to the output terminal of operational amplifier U1. The source of the NMOS transistor is connected to the non-inverting input terminal of operational amplifier U2. The source of the NMOS transistor is also connected to resistor Rs, and the other end of resistor Rs is grounded. The drain of the NMOS transistor is connected to the negative terminal of laser diode LD.

[0054] Resistor R2, one end of resistor R2 is connected to power supply VCC1, and the other end of resistor R2 is connected to the positive terminal of laser diode LD.

[0055] Based on the above description, the constant current source drive circuit design uses the main controller as the core controller, employs a closed-loop negative feedback operational amplifier circuit to control the output current, and uses an NMOS transistor to achieve voltage-to-current conversion. It should be noted that when the main controller detects a real-time current value in the constant current source drive circuit that is greater than the set value, the negative feedback automatically reduces the gain of operational amplifier U1, decreasing the output voltage of U1 and reducing the conduction level of the NMOS transistor, thus making the current value of the constant current source drive circuit equal to the set value. Conversely, when the current in the constant current source branch decreases, the negative feedback increases the gain of operational amplifier U1, increasing the output voltage of U1 and increasing the conduction level of the NMOS transistor, restoring the current value to the set value.

[0056] Specifically, the feedback loop formed by operational amplifiers U1 and U2 can precisely control the current flowing through the laser diode LD, ensuring the stability and consistency of the laser output. This feedback control mechanism can effectively address the impact of power supply voltage fluctuations and load changes on the current. The reference voltage value Uset is output from the main controller's internal DAC module and amplified to control the conduction of the NMOS transistor, achieving voltage-to-current conversion. Combined with closed-loop negative feedback characteristics, the real-time current value is adjusted to achieve constant current output. Precise current control reduces the impact of temperature changes on laser output power, improving the stability and reliability of the laser therapy device.

[0057] Understandably, the constant current source drive circuit achieves constant current output and control by controlling the conduction level of the NMOS transistor through the gate voltage. When the gate voltage is greater than the threshold voltage, the internal channel conducts under the influence of the electric field, allowing current to flow; when the gate voltage is less than the threshold voltage, the internal channel is cut off, and no current flows. The current value in the constant current source branch is controlled by the conduction level of the NMOS transistor.

[0058] On the other hand, through a precision sampling resistor Rs, one end of the non-inverting input of operational amplifier U2 is connected to the sampling resistor Rs. The sampled voltage value is amplified and transmitted to the inverting input of operational amplifier U1, forming a closed-loop negative feedback circuit. By introducing negative feedback, that is, introducing part of the voltage from the output of operational amplifier U2 to the input of operational amplifier U1, the constant current source system is stabilized and its performance is improved.

[0059] like Figure 3 As shown, the TEC driver circuit includes a TEC driver chip with an H-bridge circuit. The TEC driver chip is connected to the TEC of the semiconductor laser and is configured in pulse width modulation (PWM) mode. The TEC driver chip receives a PWM signal from the main controller, which determines the TEC's operating state (cooling or heating) and power level.

[0060] In one specific implementation, the TEC driver chip uses the DRV8212P chip. The current direction determines whether the TEC is cooling or heating, and this function is achieved using the four N-channel MOSFETs in the H-bridge circuit of the DRV8212P chip. The main controller primarily drives and controls the TEC driver chip. Through the logic input pins of the DRV8212P (such as IN1 and IN2), the switching state of the MOSFETs can be controlled, thereby switching between cooling and heating modes. For example: Cooling mode: IN1 = high level, IN2 = low level. Heating mode: IN1 = low level, IN2 = high level.

[0061] In one specific implementation, the main controller uses an STM32 chip, and the two output pins of the STM32 chip's advanced timer are connected to the TEC driver chip. The main controller's control output value is set by the TIM_SetCompare function to set the output state of the advanced timer pins to generate the corresponding PWM wave; the output state is either high or low.

[0062] Understandably, when the STM32 receives the input temperature signal, it calculates the value against the set temperature. The resulting value then uses the TIM_SetCompare function to determine whether the output state of the advanced timer pin is high or low, and finally generates the corresponding PWM wave. The two output pins of the advanced timer are connected to the two input pins IN1 and IN2 of the DRV8212P. After the pin connected to nSLEEP in the STM32 is enabled, the DRV8212P starts working. At this time, the two output pins OUT1 and OUT2 will generate current. The TEC receives the current and starts cooling or heating, ultimately achieving temperature control of the laser.

[0063] The main controller's output value sets the comparison register value of the advanced timer via the TIM_SetCompare function, thus determining the duty cycle of the PWM signal. A higher duty cycle results in a larger TEC current and a stronger cooling or heating effect. The PID controller dynamically adjusts the PWM signal's duty cycle based on temperature deviation, thereby controlling the TEC's output current in real time.

[0064] In specific implementation, such as Figure 4 As shown, the laser driving circuit also includes a protection circuit, which is connected to the laser diode LD of the semiconductor laser. The protection circuit includes a current surge protection circuit, an overcurrent protection circuit, and an electrostatic discharge protection circuit.

[0065] In specific implementation, the current surge protection circuit includes capacitor C4, capacitor C5 and diode D3. Capacitor C4, capacitor C5 and diode D3 are all connected in parallel with laser diode LD. The negative terminal of diode D3 is connected to the positive terminal of laser diode LD, and the positive terminal of diode D3 is connected to the negative terminal of laser diode LD.

[0066] In practical implementation, the electrostatic discharge protection circuit includes a normally closed relay K1, a diode D4, a transistor Q5, and a resistor R6. One end of the coil of the normally closed relay K1 is connected to the positive terminal of the laser diode LD, and the other end of the coil of the normally closed relay K1 is grounded. The switching terminal of the normally closed relay K1 is connected to the negative terminal of the laser diode LD and the collector of the transistor Q5. The base of the transistor Q5 is connected to the resistor R6, and the emitter of the transistor Q5 is grounded. The negative terminal of the diode D4 is connected to the positive terminal of the laser diode LD, and the positive terminal of the diode D4 is grounded.

[0067] In specific implementation, the overcurrent protection circuit includes operational amplifier A1, operational amplifier A2, MOSFET Q3, MOSFET Q4, resistor R7, resistor R8, resistor RS1, resistor RS2 and resistor RS3;

[0068] The non-inverting input of operational amplifier A1 is connected to voltage U. set The output of operational amplifier A1 is connected to the gate of MOSFET Q3 through resistor R7, and the drain of MOSFET Q3 is connected to the negative terminal of laser diode LD.

[0069] The non-inverting input of operational amplifier A2 is connected to voltage U. set The inverting input of operational amplifier A2 is connected to the inverting input of operational amplifier A1. The output of operational amplifier A2 is connected to the gate of MOSFET Q4 through resistor R8. The drain of MOSFET Q4 is connected to the positive terminal of laser diode LD.

[0070] Resistors RS1, RS2, and RS3 are connected in parallel. One end of resistor RS1 is connected to the inverting input of operational amplifier A1, one end of resistor RS2 is connected to the source of MOSFET Q3, and the other end of resistor RS2 is grounded.

[0071] Depend on Figure 4 As can be seen, a current surge protection circuit is formed by connecting diode D3 and a small capacitor C4 in parallel across the laser diode LD, together with a large capacitor C5. This circuit prevents damage to the laser diode LD from reverse surges and sudden voltage changes, and also reduces high-frequency current spikes. The small capacitor C4 works with diode D3 to help absorb sudden voltage changes, reducing the impact on the laser diode. The large capacitor C5, together with the small capacitor C4, further smooths voltage changes, reduces high-frequency current spikes, and protects the laser diode.

[0072] An overcurrent protection circuit is constructed using a single operational amplifier (op-amp) and a MOSFET to prevent damage from excessive injection current. Operational amplifiers A1 and A2 monitor the input current. When the current exceeds a set threshold, the operational amplifiers output a signal. MOSFETs Q3 and Q4 control the current based on the operational amplifier's output signal, preventing excessive injection current from damaging the laser diode.

[0073] An electrostatic discharge (ESD) protection circuit is constructed using normally closed relay K1, transistor Q5, and other components to prevent ESD from damaging the laser diode (LD). Furthermore, the relay is short-circuited during power-on and power-off to prevent surge damage to the LD.

[0074] The above embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. For those skilled in the art, it will be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A laser therapy device, comprising a control unit and a nasal prong connected to each other, wherein the nasal prong is equipped with a semiconductor laser, and the control unit contains a circuit board, characterized in that, The circuit board is equipped with a laser driver circuit that is connected to the semiconductor laser. The laser driving circuit includes a main controller, a constant current source driving circuit, and a TEC driving circuit; The main controller is connected to the constant current source drive circuit, and the constant current source drive circuit is connected to the semiconductor laser; The main controller is connected to the TEC drive circuit, and the TEC drive circuit is connected to the TEC of the semiconductor laser; the main controller collects the temperature of the semiconductor laser through the NTC thermistor of the semiconductor laser, and the main controller instructs the TEC drive circuit to work.

2. The laser therapy device as described in claim 1, characterized in that, The constant current source driving circuit is connected to the laser diode LD of the semiconductor laser, and the constant current source driving circuit includes: Operational amplifier U1 has its positive power supply pin connected to power supply VCC and its negative power supply pin grounded. The non-inverting input of operational amplifier U1 is connected to the input voltage Uset, and the inverting input of operational amplifier U1 is connected to one end of resistor R5. Resistor R5 is connected in series with resistor R4, and one end of resistor R4 is grounded. Operational amplifier U2, the output terminal of which is connected to the inverting input terminal of operational amplifier U1, and the inverting input terminal of operational amplifier U1 is connected to resistor R4; The NMOS transistor has its gate connected to a resistor R1, the other end of which is connected to the output of the operational amplifier U1. The source of the NMOS transistor is connected to the non-inverting input of the operational amplifier U2, and the source of the NMOS transistor is also connected to a resistor Rs, the other end of which is grounded. The drain of the NMOS transistor is connected to the negative terminal of the laser diode LD. Resistor R2, one end of which is connected to power supply VCC1, and the other end of which is connected to the positive terminal of laser diode LD.

3. The laser therapy device as described in claim 1, characterized in that: The TEC driving circuit includes a TEC driving chip with an H-bridge circuit, the TEC driving chip being connected to the TEC of the semiconductor laser, and the TEC driving chip being configured in pulse width modulation mode.

4. The laser therapy device as described in claim 3, characterized in that: The main controller uses an STM32 chip, and the two output pins of the advanced timer of the STM32 chip are connected to the TEC driver chip respectively.

5. The laser therapy device as described in claim 1, characterized in that... The laser driving circuit further includes: A protection circuit is connected to the laser diode LD of the semiconductor laser. The protection circuit includes a current surge protection circuit, an overcurrent protection circuit, and an electrostatic discharge protection circuit.

6. The laser therapy device as described in claim 5, characterized in that: The current surge protection circuit includes capacitor C4, capacitor C5, and diode D3. Capacitor C4, capacitor C5, and diode D3 are all connected in parallel with the laser diode LD. The negative terminal of diode D3 is connected to the positive terminal of the laser diode LD, and the positive terminal of diode D3 is connected to the negative terminal of the laser diode LD.

7. The laser therapy device as described in claim 5, characterized in that: The electrostatic discharge protection circuit includes a normally closed relay K1, a diode D4, a transistor Q5, and a resistor R6. One end of the coil of the normally closed relay K1 is connected to the positive terminal of the laser diode LD, and the other end of the coil of the normally closed relay K1 is grounded. The switching terminal of the normally closed relay K1 is connected to the negative terminal of the laser diode LD and the collector of the transistor Q5. The base of the transistor Q5 is connected to the resistor R6, and the emitter of the transistor Q5 is grounded. The negative terminal of the diode D4 is connected to the positive terminal of the laser diode LD, and the positive terminal of the diode D4 is grounded.

8. The laser therapy device as described in claim 5, characterized in that: The overcurrent protection circuit includes operational amplifier A1, operational amplifier A2, MOSFET Q3, MOSFET Q4, resistor R7, resistor R8, resistor RS1, resistor RS2 and resistor RS3; The non-inverting input terminal of the operational amplifier A1 is connected to a voltage U. set The output terminal of the operational amplifier A1 is connected to the gate of the MOS transistor Q3 through a resistor R7, and the drain of the MOS transistor Q3 is connected to the negative terminal of the laser diode LD. The non-inverting input terminal of the operational amplifier A2 is connected to a voltage U. set The inverting input terminal of the operational amplifier A2 is connected to the inverting input terminal of the operational amplifier A1, and the output terminal of the operational amplifier A2 is connected to the gate of the MOS transistor Q4 through the resistor R8. The drain of the MOS transistor Q4 is connected to the positive terminal of the laser diode LD. The resistors RS1, RS2 and RS3 are connected in parallel. One end of the resistor RS1 is connected to the inverting input of the operational amplifier A1, one end of the resistor RS2 is connected to the source of the MOS transistor Q3, and the other end of the resistor RS2 is grounded.

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