Fiber laser constant-current driving circuit and fiber laser

Abstract

According to the optical fiber laser constant-current driving circuit and the optical fiber laser, through the combined design of the front-stage BUCK voltage reduction module and the rear-stage linear constant-current control module, the working efficiency of a driving power supply can be effectively improved, and ripples in output current can be remarkably reduced. The preceding stage BUCK voltage reduction module realizes efficient voltage reduction through switch control, ensures voltage stability, and reduces energy loss at the same time. And the backward-stage linear constant-current control module keeps the constancy of the current by accurately adjusting the output current, so that the current ripple is further reduced, and the high requirement of the fiber laser on constant-current driving is met. The design ensures that the circuit outputs stable and low-ripple constant current while efficiently converting voltage, and the performance and reliability of the fiber laser driving power supply are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber laser driving power supply, and in particular to a fiber laser constant current driving circuit and a fiber laser. Background Art

[0002] In the prior art, the fiber laser driving power supply adopts a BUCK topology or linear mode control. The BUCK topology improves the power efficiency through switch control, but introduces a large current ripple; while the linear mode can effectively suppress the current ripple, the voltage difference between the two ends of the MOS tube is too large, resulting in increased power loss and reduced efficiency. Therefore, the technical problem of the prior art is how to suppress the output current ripple while maintaining efficient power conversion to meet the requirements of high-precision constant current for fiber laser driving. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and provide a fiber laser constant current drive circuit and a fiber laser to solve the technical problem in the related art of how to suppress output current ripple while maintaining efficient power conversion and meet the requirements of fiber laser drive for high-precision constant current.

[0004] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a fiber laser constant current drive circuit, the circuit comprising:

[0006] A front-stage BUCK step-down module, wherein the front-stage BUCK step-down module is configured to receive an input voltage and step down the input voltage into a stable voltage suitable for driving a fiber laser through switch control;

[0007] The rear-stage linear constant current control module is configured to be connected to the front-stage BUCK buck module, and is used to receive the output voltage of the front-stage BUCK buck module, and adjust the output current to maintain the constancy of the output current, reduce the ripple in the output current, and ensure that a low-ripple constant current output is provided when driving the fiber laser.

[0008] Furthermore, the front-stage BUCK step-down module at least includes:

[0009] A first switch tube, wherein the first switch tube is used to achieve a voltage step-down output by controlling a switching frequency and a duty cycle;

[0010] an energy storage inductor, the energy storage inductor being connected in series with the first switch tube and being used for storing energy when the first switch tube is turned on and releasing the energy to the load when the first switch tube is turned off;

[0011] A freewheeling diode, which is used to provide freewheeling current for the load when the first switch tube is turned off, thereby ensuring continuous output current.

[0012] Furthermore, the front-stage BUCK step-down module further includes:

[0013] An input protection module is configured to provide overcurrent or overvoltage protection at the input end of the circuit to prevent the circuit from being damaged when the input voltage or current is abnormal.

[0014] Furthermore, the front-stage BUCK step-down module further includes:

[0015] An input filter module is configured between the input protection module and the first switch tube, and is used to filter out high-frequency noise in the input voltage to ensure the stability of the input voltage.

[0016] Furthermore, the post-stage linear constant current control module at least includes:

[0017] The second switch tube is configured to work in a linear region, and is used to achieve a constant output current by adjusting the gate voltage, thereby reducing the ripple in the output current.

[0018] Furthermore, the post-stage linear constant current control module also includes:

[0019] A feedback sampling circuit is configured to detect the output current and generate a feedback signal, wherein the feedback signal is connected to the gate of the second switch tube, and by adjusting its gate voltage, the second switch tube is controlled to operate in a linear region, thereby adjusting the magnitude of the output current.

[0020] Furthermore, the post-stage linear constant current control module also includes:

[0021] The feedback filter capacitor module is configured to filter out high-frequency noise in the feedback signal to ensure the stability of the feedback signal.

[0022] Furthermore, the post-stage linear constant current control module also includes:

[0023] A first resistor is configured to be used for current collection, and the first resistor is connected in series between the second switch tube and the load.

[0024] Furthermore, the post-stage linear constant current control module also includes:

[0025] A protection diode is configured to be connected in parallel across the load.

[0026] In a second aspect, the present invention provides a fiber laser, which includes the above-mentioned fiber laser constant current drive circuit.

[0027] Beneficial effects:

[0028] The present invention can effectively improve the working efficiency of the driving power supply and significantly reduce the ripple in the output current through the combined design of the front-stage BUCK buck module and the rear-stage linear constant current control module. The front-stage BUCK buck module achieves efficient voltage reduction through switch control, ensuring voltage stability while reducing energy loss; the rear-stage linear constant current control module maintains the constancy of the current by accurately adjusting the output current, further reducing the current ripple, and meeting the high requirements of the fiber laser for constant current drive. This design ensures that the circuit outputs a stable, low-ripple constant current while efficiently converting the voltage, greatly improving the performance and reliability of the fiber laser driving power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a circuit structure diagram of a laser driving power supply provided in the related art;

[0030] Figure 2 It is a circuit structure diagram of a laser driving power supply provided in the related art;

[0031] Figure 3 is a block diagram of a fiber laser constant current drive circuit used in an embodiment of the present invention;

[0032] Figure 4 The diagram is a circuit structure diagram of a fiber laser constant current drive circuit used in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0034] In related technologies, such as Figure 1 As shown, in the laser driving power supply, a switching BUCK topology circuit structure is adopted with a series sampling resistor. By using the voltage difference across the sampling resistor R4 for loop control, the operating frequency of the switching MOS tube Q1 is increased, thereby achieving the purpose of improving the working efficiency of the driving power supply.

[0035] like Figure 2As shown, in the laser driving power supply, a non-switching circuit structure is adopted to limit the output current through the linear mode of the MOS tube Q3, thereby reducing the output current ripple of the power supply.

[0036] exist Figure 1 In the circuit structure, due to its BUCK topology, the switch MOS tube Q1 adjusts the switching frequency and duty cycle of Q1 by detecting the current in the circuit, thereby improving the conversion efficiency of the circuit. However, due to its own switching characteristics, the switching frequency will be introduced into the switching characteristics of the output current ripple, resulting in an increase in the current ripple. Figure 2 In the circuit structure, because the MOS tube Q3 works in the linear region, the current passing through the MOS is fixed, and the voltage difference between the two ends of the MOS is large, which increases the dissipated power of the MOS tube Q3 and reduces the circuit conversion efficiency. In the above two circuit structures, the conversion efficiency of the first circuit structure is high but the output current ripple is large, and the current ripple of the second circuit structure is small but the conversion efficiency is low. Therefore, the technical problem existing in the prior art is how to suppress the output current ripple while maintaining efficient power conversion to meet the requirements of the fiber laser drive for high-precision constant current. In response to this technical problem, the embodiment of the present application provides a fiber laser constant current drive circuit, which can effectively improve the working efficiency of the driving power supply and significantly reduce the ripple in the output current through the combined design of the front-stage BUCK buck module and the rear-stage linear constant current control module. The front-stage BUCK buck module realizes efficient voltage step-down through switch control, ensures voltage stability, and reduces energy loss at the same time; the rear-stage linear constant current control module maintains the constancy of the current by accurately adjusting the output current, further reduces the current ripple, and meets the high requirements of the fiber laser for constant current drive. This design ensures that the circuit can efficiently convert voltage while outputting stable, low-ripple constant current, greatly improving the performance and reliability of the fiber laser driver power supply.

[0037] Example 1

[0038] like Figure 3 The present embodiment provides a fiber laser constant current driving circuit, and the fiber laser constant current driving circuit comprises:

[0039] The front-stage BUCK buck module 100 is configured to receive an input voltage and buck the input voltage into a stable voltage suitable for driving a fiber laser through switch control.

[0040] The rear-stage linear constant current control module 200 is configured to be connected to the front-stage BUCK buck module 100, and is used to receive the output voltage of the front-stage BUCK buck module 100, and adjust the output current to maintain the constancy of the output current, reduce the ripple in the output current, and ensure that a low-ripple constant current output is provided when driving the fiber laser.

[0041] In this embodiment, the combined design of the front-stage BUCK buck module and the rear-stage linear constant current control module can effectively improve the working efficiency of the driving power supply and significantly reduce the ripple in the output current. The front-stage BUCK buck module achieves efficient voltage reduction through switch control, ensuring voltage stability while reducing energy loss; the rear-stage linear constant current control module maintains the constancy of the current by accurately adjusting the output current, further reducing the current ripple and meeting the high requirements of the fiber laser for constant current drive. This design ensures that the circuit outputs a stable, low-ripple constant current while efficiently converting the voltage, greatly improving the performance and reliability of the fiber laser driving power supply.

[0042] like Figure 4 In some embodiments, the front-stage BUCK step-down module 100 at least includes:

[0043] A first switch tube, wherein the first switch tube is used to achieve voltage step-down output by controlling a switching frequency and a duty cycle.

[0044] In this embodiment, the first switch tube can be an insulated gate bipolar transistor (IGBT), a bipolar junction transistor (BJT) or a metal oxide semiconductor field effect transistor (MOSFET). It is understandable that the first switch tube can be controlled by a driving signal of a controller to achieve on and off. The controller can be a PWM controller. When the first switch tube adopts MOSFET, the controller outputs a PWM signal and controls the on time of the MOSFET by adjusting the width (duty cycle) of the PWM signal on the gate. When the gate voltage is higher than the threshold voltage, the MOSFET is turned on; when the gate voltage is lower than the threshold, the MOSFET is turned off.

[0045] In a specific embodiment, the first switch tube may be Figure 4 The MOS tube Q2 shown in the figure has a drain connected to the positive input voltage terminal VI N+2 for receiving the input voltage. The source of the MOS tube Q2 is connected to the energy storage inductor, and then connected to the subsequent linear constant current control module 200. The gate of the MOS tube Q2 is connected to Q2G, and SW2 is the negative terminal of Q2G, which is connected to the source of the MOS tube Q2. When the MOS tube Q2 is turned on, the current flows from the drain through the source to the energy storage inductor, and then connected to the subsequent circuit.

[0046] The switching state of the MOS tube Q2 can be controlled by the voltage difference between the gate (Q2G) and the source (SW2), and the gate voltage is adjusted by the feedback control signal.

[0047] Specifically, by collecting the Vsense signal, the circuit can detect the difference between the output voltage and the target voltage, and then adjust the frequency and duty cycle between Q2G and SW2. The Vsense voltage is used to reflect the changes in the output voltage of the circuit in real time. When the Vsense voltage is higher than the target voltage, it means that the output voltage is too high. At this time, the control circuit will reduce the switching frequency between Q2G and SW2 or reduce the duty cycle, thereby reducing the on-time of the MOS tube Q2 and reducing the output voltage. When the Vsense voltage is lower than the target voltage, it means that the output voltage is insufficient. The control circuit will increase the switching frequency between Q2G and SW2 or increase the duty cycle, and increase the on-time of the MOS tube Q2 to increase the output voltage.

[0048] More specifically, the working state of the MOS transistor Q2 is controlled by the gate Q2G voltage, and the voltage difference between the gate voltage and the source (SW2) determines the on and off of the MOS transistor Q2. When the gate voltage exceeds the threshold voltage, the MOS transistor Q2 is turned on and the voltage is transferred to the energy storage inductor; when the gate voltage is lower than the threshold, the MOS transistor Q2 is turned off, and the energy storage inductor provides current to the load through the freewheeling diode.

[0049] An energy storage inductor is connected in series with the first switch tube, and is used to store energy when the first switch tube is turned on, and release the energy to the load when the first switch tube is turned off.

[0050] In a specific embodiment, the energy storage inductor may be Figure 4 The energy storage inductor L4 shown in the figure serves as an energy storage element. When the MOS tube Q2 is turned on, the energy storage inductor L4 stores energy; when the MOS tube Q2 is turned off, the energy storage inductor L4 releases the stored energy to the load.

[0051] Specifically, in this embodiment, one end of the energy storage inductor L4 is directly connected to the source of the MOS tube Q2. When the MOS tube Q2 is turned on, the current flows from the positive input voltage terminal VI N+2 through the MOS tube Q2 into the energy storage inductor L4, and the energy storage inductor L4 starts to store energy. When the MOS tube Q2 is turned on, the current passes through the energy storage inductor L4, and the magnetic field in the energy storage inductor L4 gradually increases to store energy; when the MOS tube Q2 is turned off, the energy storage inductor L4 will release the stored energy and continue to supply power to the load.

[0052] A freewheeling diode, which is used to provide freewheeling current for the load when the first switch tube is turned off, thereby ensuring continuous output current.

[0053] In this embodiment, the freewheeling diode may be Figure 4 The freewheeling diode D3 is shown in FIG. The positive electrode of the freewheeling diode D3 is connected to the ground (PGND) of the circuit, and the negative electrode of the freewheeling diode D3 is connected to one end of the energy storage inductor L4 and the source of the MOS tube Q2.

[0054] Specifically, when the MOS tube Q2 is turned on, the positive input voltage terminal VI N+2 flows through the MOS tube Q2 and the energy storage inductor L4, the energy storage inductor L4 stores energy, and the freewheeling diode D3 is in a reverse bias state and is not turned on.

[0055] When the MOS tube Q2 is turned off, the energy storage inductor L4 begins to release its stored energy. At this time, since the current cannot be suddenly interrupted, the energy storage inductor L4 will provide a freewheeling path through the freewheeling diode D3. The current flows from one end of the energy storage inductor L4 through the subsequent linear constant current control module 200 and the load, and finally returns to the energy storage inductor L4 through the ground (PGND) of the circuit and the positive electrode of the freewheeling diode D3. Therefore, the freewheeling diode D3 provides a current discharge path for the energy storage inductor L4, ensuring the continuity of the load current and reducing the current ripple. This design avoids the sudden interruption of the load current during the switching process and improves the stability of the power supply.

[0056] In the above implementation, efficient voltage reduction and stable output current are effectively achieved through the design of the front-stage BUCK buck module. The first switch tube accurately adjusts the output voltage by controlling the switching frequency and duty cycle to ensure efficient voltage conversion; the energy storage inductor stores energy when the switch tube is turned on, and releases the energy to the load when the switch tube is turned off, ensuring the continuity and stability of the current; the freewheeling diode provides a freewheeling path for the load to avoid current interruption during the switch tube shutdown period, further smoothing the output current and reducing current ripple. This combined design improves the efficiency and stability of the power supply and is suitable for application scenarios with high requirements for current smoothness.

[0057] In some implementations, the front-stage BUCK step-down module 100 further includes:

[0058] An input protection module is configured to provide overcurrent or overvoltage protection at the input end of the circuit to prevent the circuit from being damaged when the input voltage or current is abnormal.

[0059] In this embodiment, the input protection module may be a resettable fuse, an electronic fuse, a transient voltage suppressor diode, or the like.

[0060] In a specific embodiment, the input protection module can be as follows Figure 4The fuse F2 shown in FIG. One end of the circuit breaker F2 can be connected to the positive input voltage terminal VI N+2. The other end of the circuit breaker F2 can be connected to the energy storage inductor, that is, connected to the energy storage inductor L4. When the current in the circuit is too large, the fuse F2 will melt to prevent further circuit damage.

[0061] In this embodiment, the front-stage BUCK step-down module 100 implements the overcurrent or overvoltage protection function for the circuit input terminal by introducing an input protection module. When the input voltage or current is abnormal, the input protection module can respond in time and limit the abnormal voltage or current from entering the circuit, preventing the key components in the circuit from being damaged due to overload, thereby improving the reliability and stability of the entire driving power supply. This design effectively avoids circuit failures caused by sudden abnormalities at the input terminal and ensures the safe operation of the system under harsh working conditions.

[0062] In some implementations, the front-stage BUCK step-down module further includes:

[0063] An input filter module is configured between the input protection module and the first switch tube, and is used to filter out high-frequency noise in the input voltage to ensure the stability of the input voltage.

[0064] In this implementation, the input filter module may be an electrolytic capacitor, a ceramic capacitor, an RC filter, an LC filter, or the like.

[0065] In a specific embodiment, the input filter module may include an input filter inductor and an input filter capacitor. Specifically, in this embodiment, the input filter inductor may be as follows: Figure 4 The input filter inductor L2 shown in the figure is used to filter out the high-frequency noise in the input power supply and ensure the stability of the input voltage. The input filter capacitor can be an input filter capacitor C3 and an input filter capacitor C4. The input filter capacitor C3 and the input filter capacitor C4 form an input filter circuit with the input filter inductor L2 to further suppress the high-frequency noise in the input voltage. The input filter capacitors C3 and C4 are responsible for bypassing the high-frequency components in the input voltage and reducing the input ripple. Specifically, one end of the input filter inductor L2 is connected to the circuit breaker F2. The other end of the input filter inductor L2 is connected to one end of the input filter capacitor C3 and the input filter capacitor C4, respectively, and the drain of the MOS tube Q2. Correspondingly, the other ends of the input filter capacitor C3 and the input filter capacitor C4 are respectively connected to the negative input voltage terminal VIN-2, PGND and the positive electrode of the freewheeling diode D3.

[0066] In this embodiment, the input filter module in the front-stage BUCK step-down module can effectively filter out high-frequency noise in the input voltage by being configured between the input protection module and the first switch tube. This design significantly improves the stability of the input voltage and prevents the influence of high-frequency interference on the subsequent circuit, thereby ensuring that the first switch tube works under stable voltage conditions and improving the overall performance and reliability of the circuit. In addition, a stable input voltage helps to reduce the switching loss of the switch tube, improve the efficiency of the system, and extend the service life of the equipment.

[0067] In some embodiments, the post-stage linear constant current control module at least includes:

[0068] The second switch tube is configured to work in a linear region, and is used to achieve a constant output current by adjusting the gate voltage, thereby reducing the ripple in the output current.

[0069] In this embodiment, the second switch tube can be an insulated gate bipolar transistor (IGBT), a bipolar junction transistor (BJT) or a metal oxide semiconductor field effect transistor (MOSFET). It is understandable that the second switch tube can also be controlled by a driving signal of a controller to achieve on and off.

[0070] In a specific embodiment, the second switch tube can be Figure 4 The MOS tube Q5 shown in FIG. The gate of the MOS tube Q5 is connected to Q5G, and SW5 is the negative terminal of Q5G, which is connected to the source of the MOS tube Q5. The drain of the MOS tube Q5 can be connected to the energy storage inductor L4. The source of the MOS tube Q5 is connected to the positive electrode Vout+ of the output voltage terminal. More specifically, the gate (Q5G) of the MOS tube Q5 is connected to the drive signal output by the controller. This connection enables the controller to control the on and off state of the MOS tube Q5 by adjusting the gate voltage. Changes in the gate voltage directly affect the degree of conduction of the MOS tube Q5, thereby adjusting the current flowing through the load. The MOS tube Q5 is controlled in its linear operating area, so it has a relatively stable on-resistance in the on state. At this time, the difference between the gate voltage and the source voltage determines the degree of conduction of the MOS tube Q5. By accurately controlling the gate voltage, the controller can achieve a stable output current to meet the load requirements.

[0071] In this embodiment, the post-stage linear constant current control module can achieve a stable constant output current by introducing a second switch tube to operate in the linear region. This design effectively reduces the ripple in the output current and improves the accuracy and stability of the driving power supply. By adjusting the gate voltage, the second switch tube can respond to changes in the output current in real time to ensure that the current output always remains near the set value, thereby meeting the fiber laser's requirements for high-precision constant current. This approach not only improves the performance of the system, but also extends the service life of the fiber laser, ensuring its reliability under different working conditions.

[0072] In some implementations, the post-stage linear constant current control module further includes:

[0073] A feedback sampling circuit is configured to detect the output current and generate a feedback signal, wherein the feedback signal is connected to the gate of the second switch tube, and by adjusting its gate voltage, the second switch tube is controlled to operate in a linear region, thereby adjusting the magnitude of the output current.

[0074] In a specific embodiment, Figure 4 As shown, the feedback sampling circuit may include input ports Vsense+ and Vsense-. The Vsense+ is arranged between the energy storage inductor L4 and the MOS tube Q5, and the Vsense- is arranged between the MOS tube Q5 and the positive electrode Vout+ of the output voltage terminal. The feedback sampling circuit may also include a voltage difference measurement module, a voltage regulation unit and a feedback signal processing module. Specifically, the voltage difference measurement module is used to compare the voltage difference (Vsense) between Vsense+ and Vsense-. For example, an operational amplifier (Op-Amp) can be configured as a differential amplifier to accurately measure the voltage difference between the two and convert the result into a feedback signal. The voltage regulation unit can be based on Figure 4 The value of the target voltage value (VO+) described in the circuit is used to adjust the voltage of Vsense by controlling the logic or adjusting the resistor, so that the voltage difference rate between Vsense+ and Vsense- remains greater than the turn-on voltage of the MOS tube Q5. The feedback signal processing module can send the signal from the voltage difference measurement module to the controller or comparator, compare it according to the preset target voltage value, and generate a control signal. The control signal is used to adjust the gate voltage of the second switch tube Q5 to ensure that it remains in the linear working area. Therefore, in order to improve the efficiency of the power supply output in this circuit, by detecting the voltage difference between Vsense+ and Vsense-, the voltage of Vsense is adjusted according to the voltage value of VO+ so that the voltage difference rate between Vsense+ and Vsense- is greater than the turn-on voltage of the MOS tube Q5. Thereby improving the working efficiency of the MOS tube Q5 working in the linear area.

[0075] In this embodiment, the feedback sampling circuit in the post-stage linear constant current control module can effectively monitor current changes and adjust the gate voltage of the second switch tube in time by detecting the output current in real time and generating a feedback signal. This design ensures that the second switch tube always operates in the linear region to achieve precise regulation of the output current. By dynamically adjusting the gate voltage, the system can quickly respond to load changes, maintain the constancy of the output current, significantly reduce the ripple in the output current, and improve the stability and reliability of the power supply. This closed-loop control strategy not only improves system performance, but also enhances the working efficiency and life of loads such as fiber lasers.

[0076] In some implementations, the post-stage linear constant current control module further includes:

[0077] The feedback filter capacitor module is configured to filter out high-frequency noise in the feedback signal to ensure the stability of the feedback signal.

[0078] In a specific embodiment, the feedback filter capacitor module may include a feedback filter capacitor C12 and a feedback filter capacitor C13. One end of the feedback filter capacitor C12 and the feedback filter capacitor C13 may be connected to the energy storage inductor L4 and the Vsense+, respectively. The other end of the feedback filter capacitor C12 and the feedback filter capacitor C13 is connected to PGND.

[0079] In this embodiment, the feedback filter capacitor module effectively improves the stability and accuracy of the feedback signal by filtering out high-frequency noise in the feedback signal. This design can prevent the influence of high-frequency interference on the control system, thereby ensuring that the second switch tube responds more smoothly when adjusting the output current and reducing the fluctuation and ripple of the output current. By providing a more stable feedback signal, the module significantly improves the overall performance and reliability of the system, ensuring that loads such as fiber lasers can always obtain accurate and constant current output under different working conditions.

[0080] In some implementations, the post-stage linear constant current control module further includes:

[0081] A first resistor is configured to be used for current collection, and the first resistor is connected in series between the second switch tube and the load.

[0082] In a specific embodiment, the first resistor may be a resistor R5, one end of which is connected to the Vsense-. The resistor R5 is connected to the target voltage value (VO+). It is understood that the target voltage value (VO+) is configured between the resistor R5 and the positive electrode Vout+ of the output voltage terminal.

[0083] In this embodiment, the first resistor R5 is used as a current collection element, which is connected in series between the second switch tube and the load to effectively monitor the output current. One end of R5 is connected to Vsense-, and the other end is connected to the target voltage value (VO+). This configuration allows the voltage drop generated when the current passes through R5 to be accurately measured. Through this design, the system can obtain the changes in load current in real time, and use this information for feedback adjustment to ensure the constancy and stability of the output current. This method improves the control accuracy, reduces the fluctuation of the output current, and thus improves the performance and reliability of the entire system, especially in applications such as driving fiber lasers that require high current stability.

[0084] In some implementations, the post-stage linear constant current control module further includes:

[0085] A protection diode is configured to be connected in parallel across the load.

[0086] In a specific embodiment, the protection diode may be a protection diode D7. The cathode of the protection diode D7 may be connected to Vout+3 (the positive electrode of the output voltage terminal) and VO+ (the target voltage), and the anode of the protection diode D7 may be connected to Vout-3 (the negative electrode of the output voltage terminal) and VO- (the negative electrode of the target voltage), respectively.

[0087] In this embodiment, the protection diode D7 is connected in parallel across the load to effectively prevent reverse current from damaging the circuit. By connecting the cathode of D7 to the positive electrode Vout+ of the output voltage terminal and the target voltage VO+, and the anode to the negative electrode Vout- of the output voltage terminal and the negative electrode VO- of the target voltage, this configuration ensures that when the load is over-voltage or reverse current occurs, the protection diode can be quickly turned on, providing a safe path, thereby protecting the subsequent circuit and load from damage. This design improves the reliability and safety of the system, which is particularly important in applications such as fiber lasers that require high current and voltage stability.

[0088] In summary, this application proposes a high-efficiency, low-current-ripple driving power supply circuit based on a BUCK power supply and a linear constant current method. The present invention uses a BUCK topology to control the voltage to improve the working efficiency of the power supply, and a MOS linear constant current method to control the power supply output current and reduce the power supply output current ripple. Thus, the circuit achieves the purpose of improving both the power supply output efficiency and the power supply output current ripple. The constant current control of this method can be used for the drive required by most fiber lasers on the market.

[0089] This embodiment provides a fiber laser, and the fiber laser includes the above-mentioned fiber laser constant current driving circuit.

[0090] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0091] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0092] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0093] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0094] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A fiber laser constant current drive circuit, characterized in that: The circuit comprises: A front-stage BUCK step-down module, wherein the front-stage BUCK step-down module is configured to receive an input voltage and step down the input voltage into a stable voltage suitable for driving a fiber laser through switch control; The rear-stage linear constant current control module is configured to be connected to the front-stage BUCK buck module, and is used to receive the output voltage of the front-stage BUCK buck module, and adjust the output current to maintain the constancy of the output current, reduce the ripple in the output current, and ensure that a low-ripple constant current output is provided when driving the fiber laser.

2. A fiber laser constant current drive circuit according to claim 1, characterized in that: The front-stage BUCK step-down module at least includes: A first switch tube, wherein the first switch tube is used to achieve a voltage step-down output by controlling a switching frequency and a duty cycle; an energy storage inductor, which is connected in series with the first switch tube and is used to store energy when the first switch tube is turned on and release the energy to the load when the first switch tube is turned off; A freewheeling diode, which is used to provide freewheeling current for the load when the first switch tube is turned off, thereby ensuring continuous output current.

3. A fiber laser constant current drive circuit according to claim 2, characterized in that: The front-stage BUCK step-down module also includes: An input protection module is configured to provide overcurrent or overvoltage protection at the input end of the circuit to prevent the circuit from being damaged when the input voltage or current is abnormal.

4. A fiber laser constant current drive circuit according to claim 3, characterized in that: The front-stage BUCK step-down module also includes: An input filter module is configured between the input protection module and the first switch tube, and is used to filter out high-frequency noise in the input voltage to ensure the stability of the input voltage.

5. A fiber laser constant current drive circuit according to claim 4, characterized in that: The post-stage linear constant current control module at least includes: The second switch tube is configured to work in a linear region, and is used to achieve a constant output current by adjusting the gate voltage, thereby reducing the ripple in the output current.

6. A fiber laser constant current driving circuit according to claim 5, characterized in that: The post-stage linear constant current control module also includes: A feedback sampling circuit is configured to detect the output current and generate a feedback signal, wherein the feedback signal is connected to the gate of the second switch tube, and by adjusting its gate voltage, the second switch tube is controlled to operate in a linear region, thereby adjusting the magnitude of the output current.

7. A fiber laser constant current driving circuit according to claim 6, characterized in that: The post-stage linear constant current control module also includes: The feedback filter capacitor module is configured to filter out high-frequency noise in the feedback signal to ensure the stability of the feedback signal.

8. The fiber laser constant current drive circuit according to claim 5, characterized in that: The post-stage linear constant current control module also includes: A first resistor is configured to be used for current collection, and the first resistor is connected in series between the second switch tube and the load.

9. The fiber laser constant current driving circuit according to claim 5, characterized in that: The post-stage linear constant current control module also includes: A protection diode is configured to be connected in parallel across the load.

10. A fiber laser, characterized in that: The fiber laser comprises a fiber laser constant current drive circuit as claimed in any one of claims 1 to 9.

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