Power supply circuit for a laser pump source, laser pump source and laser device

Abstract

The application provides a power supply circuit of a laser pump source, the laser pump source and a laser device. The circuit comprises an input power supply module, a DC-DC step-down module, a constant current driving module, a voltage detection module and a control module. The input end of the DC-DC step-down module is connected with the input power supply module, and the control end receives an adjusting signal to adjust the output voltage. The constant current driving module comprises a switch tube group, the input end of which is connected with the output end of the DC-DC step-down module, and the output end is used for providing constant current to the pump source. The voltage detection module collects a voltage signal reflecting the voltage drop between the switch tube group and converts it into a digital signal. The control module generates an adjusting signal according to the digital signal, so that the voltage drop between the switch tube group is maintained within a preset safety range. The output voltage of the DC-DC step-down module changes with the adjusting signal to share the voltage drop of the switch tube group, so that the voltage drop of the switch tube group is limited within a safety range when driving pump sources with different rated voltages, and the circuit reliability is improved.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a power supply circuit for a laser pump source, a laser pump source, and a laser device. Background Technology

[0002] The laser pump source is the core driving component of a laser. Different types and power pump sources, such as semiconductor laser diode pumps or lamp pumps, have vastly different rated operating voltages. Existing driving circuits typically employ a constant current driving architecture, where a fixed voltage provides a constant current to the pump source through a switching transistor. When a pump source with a low rated voltage is connected, the switching transistor must withstand the difference between the supply voltage and the pump source's operating voltage. Under high current, this voltage drop generates enormous power consumption, leading to severe overheating of the switching transistor, low circuit conversion efficiency, and a high risk of overheating and damage to the switching transistor, seriously affecting the reliability and safety of the circuit. Summary of the Invention

[0003] This application provides a power supply circuit for a laser pump source, a laser pump source, and a laser device, which limits the voltage drop of the switching transistor group within a safe range when driving pump sources with different rated voltages, reduces the heat loss of the switching transistor group, and improves the reliability of the circuit.

[0004] In a first aspect, embodiments of this application provide a power supply circuit for a laser pump source, comprising: Input power supply module, used to provide input voltage; A DC-DC step-down module, with its input terminal connected to the input power supply module, and its control terminal used to receive analog adjustment signals and adjust its output voltage according to the analog adjustment signals; The constant current drive module includes a group of switching transistors. The input terminal is connected to the output terminal of the DC-DC buck module. The output terminal is used to connect to the laser pump source and provide a constant current to the pump source. The group of switching transistors generates a voltage drop when driving the pump source. The voltage detection module has its input terminals connected to both ends of the switching transistor group, and is used to collect voltage signals reflecting the voltage drop across the switching transistor group and convert the voltage signals into digital voltage signals. The control module, with its input terminal connected to the output terminal of the voltage detection module, is used to receive the digital voltage signal and generate an adjustment signal based on the digital voltage signal to maintain the voltage drop across the switching transistor group within a preset safety range. The output voltage of the DC-DC buck module varies with the adjustment signal to share the voltage drop of the switching transistor group, so that when the switching transistor group drives pump sources with different rated voltages, the voltage drop across the switching transistor group is limited to the preset safety range.

[0005] In some embodiments, the power supply circuit further includes: a through-bypass module; The direct bypass module is connected in parallel with the DC-DC buck module. The input terminal of the direct bypass module is connected to the output terminal of the input power supply module, and the output terminal is connected to the input terminal of the constant current drive module. It is used to allow the input voltage to bypass the DC-DC buck module and directly conduct to the constant current drive module when the working voltage of the pump source is higher than a preset threshold.

[0006] In some embodiments, the DC-DC buck module is a synchronous buck DC-DC converter, comprising: an upper bridge arm switch and a lower bridge arm switch; The drain of the upper bridge arm switch is connected to the output terminal of the input power supply module, the source of the upper bridge arm switch is connected to the drain of the lower bridge arm switch, and is connected to the input terminal of the constant current drive module through an inductor, and the source of the lower bridge arm switch is grounded; the gates of the upper bridge arm switch and the lower bridge arm switch serve as the control terminals of the DC-DC buck module.

[0007] In some embodiments, the voltage detection module includes: a voltage follower and an analog-to-digital converter; The input terminals of the voltage follower are respectively connected to the first and second terminals of the switching transistor group, and are used to isolate and collect the voltage signal reflecting the voltage drop across the switching transistor group; The input terminal of the analog-to-digital converter is connected to the output terminal of the voltage follower, and is used to convert the voltage signal into the digital voltage signal.

[0008] In some embodiments, the power supply circuit further includes: a temperature detection module; The temperature detection module includes a thermistor disposed at the switching transistor group, used to collect the temperature signal of the switching transistor group and transmit it to the control module; When the temperature signal exceeds a preset temperature threshold, the control module adjusts the output voltage of the DC-DC buck module to reduce the voltage drop of the switching transistor group, or cuts off the circuit output when the temperature continues to rise, thereby achieving overheat protection.

[0009] In some embodiments, the control module is configured to: During the operation of the pump source, the digital voltage signal is continuously received and the actual voltage drop of the switching transistor group is calculated. The actual voltage drop is then compared with the preset safety range. If the actual voltage drop is greater than the upper limit of the preset safety range, then the adjustment signal is increased to raise the output voltage of the DC-DC buck module and reduce the voltage drop of the switching transistor group; If the actual voltage drop is less than the lower limit of the preset safety range, then the adjustment signal is reduced to lower the output voltage of the DC-DC buck module.

[0010] In some embodiments, the control module includes: a storage unit, the storage unit pre-stores the rated voltage and rated current parameters of various specifications of laser pump sources; After the pump source is connected, the control module retrieves the corresponding preset parameters from the storage unit according to the identified pump source specifications in order to quickly generate the adjustment signal.

[0011] In some embodiments, a current sampling resistor is provided between the output terminal of the constant current drive module and the pump source. The current sampling resistor is used to collect the working current signal flowing to the pump source and feed the working current signal back to the control module.

[0012] Secondly, embodiments of this application provide a laser pump source, including a pump source light-emitting component and a power supply circuit for the laser pump source as described in any one of the embodiments of this application; the output terminal of the power supply circuit is electrically connected to the pump source light-emitting component, and is used to adaptively provide a matching driving voltage and constant current to the pump source light-emitting component according to its rated voltage requirements.

[0013] Thirdly, embodiments of this application provide a laser device, including an optical resonant cavity and a laser pump source as described in embodiments of this application, wherein the laser pump source is used to emit a pump beam into the optical resonant cavity to excite the optical resonant cavity to output laser light.

[0014] This application provides a power supply circuit for a laser pump source, comprising: an input power supply module, a DC-DC buck converter module, a constant current drive module, a voltage detection module, and a control module; the input power supply module provides an input voltage; the DC-DC buck converter module has its input terminal connected to the input power supply module, and its control terminal receives an analog adjustment signal and adjusts its output voltage according to the analog adjustment signal; the constant current drive module includes a group of switching transistors, with its input terminal connected to the output terminal of the DC-DC buck converter module, and its output terminal connected to the laser pump source and providing a constant current to the pump source, wherein the switching transistors generate a voltage drop when driving the pump source; the voltage detection module... The input terminals are connected to both ends of the switching transistor group to acquire voltage signals reflecting the voltage drop across the switching transistor group and convert the voltage signals into digital voltage signals. The control module has its input terminal connected to the output terminal of the voltage detection module to receive the digital voltage signals and generate adjustment signals based on the digital voltage signals to maintain the voltage drop across the switching transistor group within a preset safety range. The output voltage of the DC-DC buck module changes with the adjustment signal to share the voltage drop of the switching transistor group, so that when the switching transistor group drives pump sources with different rated voltages, the voltage drop across the switching transistor group is limited to the preset safety range. In the circuit described above, the voltage detection module collects the voltage drop signal across the switching transistor in real time and converts it into a digital voltage signal. The control module generates an adjustment signal based on this signal to control the DC-DC buck module to dynamically adjust its output voltage. This actively shares the voltage drop generated by the switching transistor when driving the pump source, ensuring that the voltage drop across the switching transistor is always maintained within a preset safe range. This effectively avoids excessive power dissipation caused by a fixed supply voltage, significantly reduces the heat loss and thermal failure risk of the switching transistor, and improves the adaptability and operational reliability of the drive circuit to pump sources with different rated voltages. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic block diagram of a power supply circuit for a laser pump source provided in an embodiment of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described below with reference to the accompanying drawings.

[0018] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0019] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] It should be understood that in this application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0021] The laser pump source is the core driving component of a laser. Different types and power pump sources, such as semiconductor laser diode pumps or lamp pumps, have vastly different rated operating voltages. Existing driving circuits typically employ a constant current driving architecture, where a fixed voltage provides a constant current to the pump source through a switching transistor. When a pump source with a low rated voltage is connected, the switching transistor must withstand the difference between the supply voltage and the pump source's operating voltage. Under high current, this voltage drop generates enormous power consumption, leading to severe overheating of the switching transistor, low circuit conversion efficiency, and a high risk of overheating and damage to the switching transistor, seriously affecting the reliability and safety of the circuit.

[0022] Specifically, the laser pump source is the core driving component of a laser. Different types and powers of pump sources, such as semiconductor laser diode pumps and lamp pumps, have vastly different rated operating voltages, ranging from approximately 1.7V for low-power single-tube pumps to hundreds of volts for high-power lamp pumps. Existing driving circuits generally employ a constant current driving architecture, where a fixed voltage bus (e.g., 48V) supplies power to the switching transistor group in the constant current driving module, and a constant current is provided to the pump source by controlling the conduction level of the switching transistor group. However, this architecture has a fundamental contradiction: the input supply voltage is fixed, while the rated operating voltage of the pump source varies significantly depending on its specifications. When a pump source with a low rated voltage is connected, the switching transistor group must withstand the entire difference between the supply voltage and the pump source's operating voltage; this difference is the ineffective voltage drop of the switching transistor group.

[0023] When the switching transistor array operates in the linear region, its power consumption equals the product of the voltage drop and the operating current. In high-current (e.g., several amperes to tens of amperes) driving scenarios, even an additional voltage drop of a few volts can generate tens of watts of dissipated power. This energy is entirely converted into Joule heat, causing a sharp rise in the junction temperature of the switching transistor array. From a performance hazard analysis perspective, continuous high-temperature operation accelerates electromigration and oxide layer degradation in the switching transistor array, leading to increased on-resistance and threshold voltage drift, further exacerbating heat generation and creating a vicious cycle. This can cause the switching transistor array to overheat and be damaged, or trigger over-temperature protection, resulting in unexpected laser shutdown, reducing circuit reliability and pump source safety.

[0024] To solve the compatibility problem of multiple pump sources, existing solutions can only configure different fixed output voltage power supplies for pump sources with different voltage specifications, resulting in high equipment costs and high usage complexity. Moreover, if the wrong power supply is selected, the pump source is easily burned out due to overvoltage or cannot be driven normally due to undervoltage.

[0025] The root cause of the above problem is that, under a fixed voltage power supply architecture, the voltage drop of the switching transistor bank is entirely passively determined by the rated voltage of the pump source, and there is a lack of an active adjustment mechanism to control the voltage drop of the switching transistor bank within a preset safe range.

[0026] To address the aforementioned issues, embodiments of this application provide a power supply circuit for a laser pump source, a laser pump source, and a laser device, which limit the voltage drop of the switching transistor group within a safe range when driving pump sources with different rated voltages, thereby reducing the heat loss of the switching transistor group and improving circuit reliability.

[0027] Please see Figure 1 , Figure 1 This is a schematic block diagram of a power supply circuit for a laser pump source provided in an embodiment of this application. Figure 1As shown, the power supply circuit 100 of the laser pump source includes: an input power supply module 11, a DC-DC step-down module 12, a constant current drive module 13, a voltage detection module 14, and a control module 15.

[0028] Input power module 11 is used to provide input voltage.

[0029] For example, the input port of the input power supply module 11 can be adapted to the 48V DC power supply specifications commonly used in industrial and scientific research fields, and has a built-in input filter circuit and bypass capacitor network to filter out high-frequency ripple and transient noise in the input power supply, ensuring that the subsequent DC-DC buck module 12 and constant current drive module 13 obtain low-noise operating power. The input power supply module 11 may also include an overvoltage protection circuit and an overcurrent protection circuit. The overvoltage protection circuit is composed of, for example, a transient voltage suppression diode and a self-resetting fuse. When the input voltage exceeds a preset safety threshold, the overvoltage protection circuit clamps the input voltage within a safe range or disconnects the input circuit to prevent abnormal high voltage from damaging subsequent circuit devices. The overcurrent protection circuit is composed of, for example, a sampling resistor and a comparator. When the input current exceeds the rated value, it automatically cuts off the input path. In addition, the output terminal of the input power supply module 11 may also be equipped with an energy storage capacitor bank to provide instantaneous energy replenishment when the load current changes transiently, reducing the voltage drop of the input bus.

[0030] Based on the above-mentioned input power supply module 11, the external input power supply, after being filtered, bypassed, and protected against overvoltage and overcurrent, provides a stable and low-noise DC bus voltage to the DC-DC step-down module 12.

[0031] The DC-DC step-down module 12 has its input terminal connected to the input power supply module, and its control terminal is used to receive analog adjustment signals and adjust its output voltage according to the analog adjustment signals.

[0032] For example, the DC-DC buck module 12 adopts a synchronous buck topology, including an upper bridge arm switch, a lower bridge arm switch, an output inductor, and an output capacitor. The drain of the upper bridge arm switch is connected to the output terminal of the input power supply module 11, and the source of the upper bridge arm switch is connected to the drain of the lower bridge arm switch and connected to the input terminal of the constant current drive module 13 through the output inductor. The source of the lower bridge arm switch is grounded. The gates of the upper and lower bridge arm switches serve as the control terminals of the DC-DC buck module 12, receiving pulse width modulation signals or analog adjustment signals from the control module 15. Compared with the asynchronous buck topology, the synchronous buck topology uses the lower bridge arm switch instead of the freewheeling diode, which effectively reduces the conduction loss in the freewheeling stage and improves the conversion efficiency. Both the upper and lower bridge arm switches can be N-channel enhancement-mode power MOSFETs, and their selection must meet the requirements of input voltage margin and output current margin.

[0033] The output voltage regulation range of the DC-DC buck module 12 can cover a wide range from several volts to close to the input voltage. The voltage regulation resolution depends on the accuracy of the control signal. For example, when using a 12-bit resolution digital-to-analog converter, millivolt-level voltage regulation steps can be achieved.

[0034] The DC-DC buck module 12 may also include an output voltage feedback compensation network for frequency compensation of the control loop, ensuring the stability and transient response speed of the loop during wide-range output voltage regulation.

[0035] Based on the aforementioned DC-DC buck module 12, after the input voltage is synchronously buck-converted, the output voltage amplitude is dynamically adjusted according to the analog adjustment signal. This allows the input voltage of the switching transistor group in the subsequent constant current drive module 13 to adaptively adjust with the change of the pump source's rated voltage, thereby reducing the ineffective voltage drop that the switching transistor group needs to withstand from the source. At the same time, the high conversion efficiency of the synchronous buck topology ensures that energy transfer loss is always kept at a low level within a wide voltage regulation range.

[0036] The constant current drive module 13 includes a switching transistor group. Its input terminal is connected to the output terminal of the DC-DC buck module, and its output terminal is used to connect to the laser pump source and provide a constant current to the pump source. The switching transistor group generates a voltage drop when driving the pump source.

[0037] For example, the constant current drive module 13 is used to obtain electrical energy from the output of the DC-DC buck module 12 and provide a constant drive current to the connected laser pump source through a switching transistor group. This module includes a switching transistor group, a current sampling element, and a current control loop. The switching transistor group may consist of one or more power MOSFETs, with its input connected to the output of the DC-DC buck module 12 and its output connected to the positive terminal of the pump source. The negative terminal of the pump source is connected to ground through a current sampling resistor whose resistance value is precisely known. When the operating current flows through it, a voltage signal proportional to the current magnitude is generated across it. The current control loop feeds back the voltage signal across the sampling resistor to an error amplifier, comparing it with a reference voltage representing a preset current value. The error amplifier outputs a control voltage, which is applied to the control terminal of the switching transistor group (such as the gate of a MOSFET) to adjust the channel conduction level of the switching transistor group. When the actual current deviates from the preset value due to load or power supply changes, the feedback loop adjusts the on-resistance of the switching transistor group accordingly, restoring the current to the set value, thus forming a closed-loop constant current control. During this process, the switching transistor group operates in the linear region, and a voltage drop will be generated across its terminals. The value of this voltage drop is equal to the output voltage of the DC-DC buck module 12 minus the positive operating voltage of the pump source and the small voltage drop across the sampling resistor.

[0038] Based on the configuration of the constant current drive module 13, the switching transistor group naturally generates a voltage drop reflecting the current operating state while providing a constant current. This voltage drop becomes the controlled variable of the entire adaptive regulation system. The voltage detection module 14 can obtain information to determine whether the preceding voltage needs to be adjusted by directly measuring this voltage drop across the switching transistor group. Thus, the constant current drive module 13 not only realizes the current drive function but also integrates the voltage drop sensing function.

[0039] The voltage detection module 14 has its input terminals connected to both ends of the switching transistor group. It is used to collect voltage signals that reflect the voltage drop across the switching transistor group and convert the voltage signals into digital voltage signals.

[0040] For example, the voltage detection module 14 is used to acquire the voltage drop across the switching transistor group and convert the analog voltage information into a digital signal for processing by the control module 15. The input terminals of this module are connected to the first and second terminals of the switching transistor group, i.e., the drain and source of the switching transistor group. To accurately obtain the true voltage drop across the switching transistor group and avoid interference from the detection circuit to the high-voltage main circuit, the voltage detection module 14 first incorporates a signal conditioning circuit, which may include a resistor divider network, a filter circuit, and a buffer amplifier. The voltage divider network attenuates potentially high common-mode voltages proportionally to a level suitable for subsequent circuit processing; the filter circuit suppresses switching noise and spike interference; and the buffer amplifier provides high input impedance and low output impedance to ensure that the voltage signal is not distorted during transmission. The conditioned analog voltage signal is sent to an analog-to-digital converter (ADC), which quantizes and encodes the signal according to a predetermined sampling rate, outputting a digital voltage signal proportional to the voltage drop. This digital signal is transmitted to the control module 15 via a parallel or serial interface.

[0041] Based on the voltage detection module 14, the instantaneous voltage drop across the switching transistor group is converted into a digital quantity in real time and accurately, enabling the control module 15 to grasp the instantaneous operating stress state of the switching transistor group. Through the digital processing of the analog-to-digital converter, the voltage drop information can be accurately compared and calculated in the digital domain, unaffected by drift and noise accumulation in analog signal transmission, ensuring the accuracy and reliability of subsequent control decisions. Simultaneously, the high input impedance conditioning circuit effectively isolates the detection circuit from the main power circuit, ensuring that the voltage acquisition process draws almost no current from the switching transistor group, thus not interfering with the control accuracy of the constant current drive or the normal operation of the pump source.

[0042] The control module 15 has its input terminal connected to the output terminal of the voltage detection module. It is used to receive digital voltage signals and generate adjustment signals based on the digital voltage signals to keep the voltage drop across the switching transistor group within a preset safe range.

[0043] For example, the control module 15 is the control core of the entire adaptive voltage supply circuit. It is responsible for generating adjustment signals based on the digital voltage drop information provided by the voltage detection module 14 to actively manage the voltage drop of the switching transistor group. This module includes a digital processing unit, such as a microcontroller or digital signal processor, whose input receives the digital voltage signal from the voltage detection module 14.

[0044] The digital processing unit internally stores a preset safety range, including an upper threshold and a lower threshold. These thresholds are determined based on the safe operating area and heat dissipation design of the switching transistor group. During operation, the digital processing unit continuously reads the voltage drop value of the switching transistor group and compares it with the preset safety range. If the current voltage drop is higher than the upper threshold, the digital processing unit calculates the output voltage value of the DC-DC buck module 12 that needs to be increased and outputs an increased digital adjustment amount; if the current voltage drop is lower than the lower threshold, it outputs a decreased digital adjustment amount to reduce the output voltage; if the voltage drop is within the range, the output remains unchanged. The digital adjustment amount is then sent to a digital-to-analog converter to be converted into an analog adjustment signal, which is directly connected to the control terminal of the DC-DC buck module 12 to realize continuous adjustment of the output voltage.

[0045] Based on the settings of the control module 15, the voltage drop across the switching transistor bank is no longer a randomly changing quantity with the pump source replacement, but is monitored in real time and actively limited to a preset safe range. This closed-loop regulation mechanism enables the output voltage of the DC-DC buck module 12 to automatically adapt to changes when driving pump sources with different rated voltages, always distributing the voltage drop of the switching transistor bank to a safe level. This fundamentally solves the problem of overheating damage caused by uncontrollable voltage drop of the switching transistor bank under a fixed voltage power supply architecture, and achieves adaptive and compatible driving of multiple pump sources.

[0046] The output voltage of the DC-DC step-down module 12 varies with the adjustment signal to share the voltage drop of the switching transistor group, so that when the switching transistor group drives pump sources with different rated voltages, the voltage drop across the switching transistor group is limited to a preset safe range.

[0047] This application provides a power supply circuit for a laser pump source, comprising: an input power supply module, a DC-DC buck converter module, a constant current drive module, a voltage detection module, and a control module; the input power supply module provides an input voltage; the DC-DC buck converter module has its input terminal connected to the input power supply module, and its control terminal receives an analog adjustment signal and adjusts its output voltage according to the analog adjustment signal; the constant current drive module includes a group of switching transistors, with its input terminal connected to the output terminal of the DC-DC buck converter module, and its output terminal connected to the laser pump source and providing a constant current to the pump source, wherein the switching transistors generate a voltage drop when driving the pump source; the voltage detection module... The input terminals are connected to both ends of the switching transistor group to acquire voltage signals reflecting the voltage drop across the switching transistor group and convert the voltage signals into digital voltage signals. The control module has its input terminal connected to the output terminal of the voltage detection module to receive the digital voltage signals and generate adjustment signals based on the digital voltage signals to maintain the voltage drop across the switching transistor group within a preset safety range. The output voltage of the DC-DC buck module changes with the adjustment signal to share the voltage drop of the switching transistor group, so that when the switching transistor group drives pump sources with different rated voltages, the voltage drop across the switching transistor group is limited to the preset safety range. In the circuit described above, the voltage detection module collects the voltage drop signal across the switching transistor in real time and converts it into a digital voltage signal. The control module generates an adjustment signal based on this signal to control the DC-DC buck module to dynamically adjust its output voltage. This actively shares the voltage drop generated by the switching transistor when driving the pump source, ensuring that the voltage drop across the switching transistor is always maintained within a preset safe range. This effectively avoids excessive power dissipation caused by a fixed supply voltage, significantly reduces the heat loss and thermal failure risk of the switching transistor, and improves the adaptability and operational reliability of the drive circuit to pump sources with different rated voltages.

[0048] To more clearly illustrate the technical solution of this application, the technical solution of this application will be described below through specific embodiments. It should be noted that the specific embodiments are used to expand the description of the technical solution of this application, and are not intended to limit this application.

[0049] In some embodiments, the power supply circuit further includes a through-bypass module.

[0050] The direct bypass module is connected in parallel with the DC-DC buck module. The input terminal of the direct bypass module is connected to the output terminal of the input power supply module, and the output terminal is connected to the input terminal of the constant current drive module. This allows the input voltage to bypass the DC-DC buck module and directly conduct to the constant current drive module when the working voltage of the pump source is higher than a preset threshold.

[0051] In some embodiments, the DC-DC buck module is a synchronous buck DC-DC converter, including: an upper bridge arm switch and a lower bridge arm switch.

[0052] The drain of the upper bridge arm switch is connected to the output of the input power supply module, and the source of the upper bridge arm switch is connected to the drain of the lower bridge arm switch, and then connected to the input of the constant current drive module through an inductor. The source of the lower bridge arm switch is grounded. The gates of the upper and lower bridge arm switches serve as the control terminals of the DC-DC buck converter module.

[0053] For example, the direct bypass module 16 provides a direct transmission path for the input voltage, bypassing the DC-DC buck module 12. This module is connected in parallel with the DC-DC buck module 12, with its input connected to the output of the input power supply module 11 and its output connected to the input of the constant current drive module 13. The direct bypass module 16 contains a controllable switch, such as an electronic switch composed of an electromagnetic relay or a power MOSFET. The switching on and off is controlled by a bypass enable signal generated by the control module 15. When the control module 15 determines that the rated operating voltage of the pump source is higher than a preset threshold, for example, if the pump source is a high-voltage lamp pump type and its normal operating voltage is close to or slightly lower than the input voltage, if the input voltage is still stepped down through the DC-DC buck module 12, it will not only cause unnecessary power conversion losses but may also result in the output voltage failing to meet the pump source's drive requirements due to the minimum voltage difference limitation of the DC-DC buck module 12. In this case, the control module 15 sends a control signal to close the controllable switch in the through-bypass module 16, and the input voltage is directly transmitted to the input terminal of the constant current drive module 13 via the switch.

[0054] For example, for a flash pump source with a rated operating voltage of 220V, the input power supply module 11 provides a DC bus voltage of 240V. The preset threshold is 180V. After the system detects that the rated voltage of the pump source, 220V, is greater than the 180V threshold, the control module 15 puts the DC-DC buck module 12 into standby or high-impedance output state, and at the same time activates the pass-through bypass module 16, so that the 240V bus voltage directly supplies power to the constant current drive module 13. At this time, the switching transistor group only needs to withstand a small voltage difference between 240V and 220V.

[0055] Based on the above-mentioned direct-through bypass module 16, the compatible voltage range of the power supply circuit is expanded. When driving a pump source with a high rated voltage, the input voltage can directly power the subsequent stage without going through the step-down conversion stage, eliminating the power conversion loss and potential minimum voltage difference limitation problem of the DC-DC step-down module 12 under high voltage output conditions. This allows the entire power supply circuit to adapt to low-voltage pump sources through step-down mode and directly drive high-voltage pump sources through bypass mode, thereby maintaining high operating efficiency and driving capability over a wide voltage range.

[0056] In some embodiments, the voltage detection module includes a voltage follower and an analog-to-digital converter.

[0057] The input terminals of the voltage follower are connected to the first and second terminals of the switching transistor group, respectively, to isolate and acquire the voltage signal reflecting the voltage drop across the switching transistor group. The switching transistor group includes the third switching transistor Q3 and the third switching transistor Q4.

[0058] The input of the analog-to-digital converter is connected to the output of the voltage follower to convert the voltage signal into a digital voltage signal.

[0059] For example, a synchronous buck DC-DC converter achieves voltage conversion through a pair of complementary driven switches. The drain of the upper arm switch Q1 serves as the input terminal of the DC-DC buck module 12, connected to the output terminal of the input power supply module 11; the source of Q1 is connected to the drain of the lower arm switch Q2, and this common node is connected to the input terminal of the constant current drive module 13 through a power inductor L, forming a switching node; the source of the lower arm switch Q2 is connected to ground. The gates of the upper arm switch Q1 and the lower arm switch Q2 together serve as the control terminal of the DC-DC buck module 12, receiving the pulse width modulation drive signal generated by the control module 15. During one switching cycle, when Q1 is on and Q2 is off, the input current flows to the output terminal through Q1 and inductor L, inductor L stores energy, and the inductor current rises linearly; when Q1 is off and Q2 is on, the current in inductor L freewheels through Q2, and inductor L releases energy to the output terminal. The output voltage is determined by the proportion of Q1's conduction time to the entire switching cycle. Control module 15 continuously adjusts the output voltage by regulating the level of the analog adjustment signal and changing the duty cycle of the pulse width modulation signal. In the synchronous rectification structure, the lower bridge arm switch Q2 replaces the traditional Schottky freewheeling diode with a low on-resistance diode during the freewheeling phase, significantly reducing the freewheeling on-state voltage drop and power consumption.

[0060] For example, with an input voltage of 48V, a 24V output is required to power the constant current drive module 13. In this case, the duty cycle of the pulse width modulation signal is approximately 50%. The upper bridge arm switch Q1 can be an N-channel MOSFET with a withstand voltage of 75V and an on-resistance of 10mΩ. The lower bridge arm switch Q2 is the same type of device. The inductance value L is selected as 47μH. The output capacitor is a 100μF low-ESR ceramic capacitor connected in parallel with a 470μF electrolytic capacitor.

[0061] Based on the aforementioned synchronous buck topology, the power conversion efficiency of the DC-DC buck module 12 is improved, and the conduction loss in the freewheeling stage is significantly reduced. The adjustment accuracy and response speed of the output voltage are directly determined by the duty cycle resolution of the pulse width modulation signal, ensuring the control bandwidth and steady-state accuracy of the entire adaptive voltage regulation loop. This provides a controllable front-stage voltage source for the fine management of the voltage drop of the switching transistor group in the subsequent constant current drive module 13.

[0062] In some embodiments, the power supply circuit further includes a temperature detection module.

[0063] The temperature detection module includes a thermistor located at the switching transistor group, which is used to collect the temperature signal of the switching transistor group and transmit it to the control module.

[0064] When the temperature signal exceeds the preset temperature threshold, the control module adjusts the output voltage of the DC-DC buck module to reduce the voltage drop of the switching transistor group, or cuts off the circuit output when the temperature continues to rise, thus achieving overheat protection.

[0065] For example, the input terminals of voltage follower U1 are connected to the first and second terminals of the switching transistor group, i.e., the drain and the source, respectively, directly acquiring the differential voltage drop across the switching transistor group. Voltage follower U1 uses an operational amplifier to form a unity-gain buffer. Its non-inverting input is connected to the drain of the switching transistor group, and its inverting input is shorted to the output, thus forming a voltage follower structure. This structure has high input impedance and low output impedance characteristics. The input impedance can reach tens of megohms or even higher, ensuring that the current drawn from the high-voltage node under test is extremely small and does not affect the normal operation of the switching transistor group and the constant current drive module 13. The low output impedance ensures that it can drive the input capacitor and sample-and-hold circuit of the subsequent analog-to-digital converter (ADC), so that the signal settling time meets the sampling rate requirements. The input terminal of the ADC is connected to the output terminal of voltage follower U1, receiving the buffered voltage drop signal. Driven by the sampling clock, the signal is discretized and quantized, outputting a digital voltage signal proportional to the voltage drop, which is then transmitted to the control module 15.

[0066] For example, the voltage follower U1 uses a low offset voltage, rail-to-rail input / output operational amplifier, and the analog-to-digital converter (ADC) uses a 12-bit resolution, 1MSPS sampling rate successive approximation ADC. When the voltage drop across the switching transistor group varies from 0V to 5V, the minimum resolution voltage of the 12-bit ADC is approximately 1.22mV, which meets the accuracy requirements for voltage drop detection.

[0067] Based on the aforementioned voltage follower U1 and analog-to-digital converter (ADC) configuration, the voltage detection module 14 accurately acquires the voltage drop signal of the switching transistor group while simultaneously achieving electrical isolation buffering between the detection circuit and the main power circuit, thus avoiding interference from the detection circuit on the constant current control accuracy. The quantization accuracy of the ADC directly determines the minimum voltage drop change that the control module 15 can sense, thereby affecting the steady-state ripple and regulation resolution of the adaptive voltage regulation, enabling the closed-loop control system to accurately maintain the voltage drop of the switching transistor group within a preset safety range.

[0068] In some embodiments, the control module is configured to: During pump source operation, digital voltage signals are continuously received and the actual voltage drop of the switching transistor group is calculated. The actual voltage drop is then compared with the preset safety range.

[0069] If the actual voltage drop exceeds the upper limit of the preset safety range, the adjustment signal is increased to raise the output voltage of the DC-DC buck module and reduce the voltage drop of the switching transistor group.

[0070] If the actual voltage drop is less than the lower limit of the preset safety range, the adjustment signal is reduced to lower the output voltage of the DC-DC buck converter.

[0071] For example, the temperature detection module 17 includes a negative temperature coefficient thermistor (NTC). This thermistor is positioned on the heatsink or package surface of the switching transistor assembly, and is tightly bonded to the heat dissipation surface of the switching transistor assembly using thermal grease or other thermally conductive medium to accurately sense changes in the junction temperature of the switching transistor assembly. The NTC is connected in series with a fixed resistor to form a voltage divider circuit, and the voltage divider node is connected to the analog input port of the control module 15. When the temperature of the switching transistor assembly rises, the resistance of the NTC decreases exponentially, and the voltage at the voltage divider node changes accordingly. The control module 15 reads this voltage value through an analog-to-digital converter channel and calculates the current temperature value based on the NTC's resistance-temperature characteristic curve and the voltage divider relationship. The control module 15 compares the current temperature value with a preset temperature threshold, which can be set to multiple levels: the first level threshold is used to trigger a power reduction strategy, and the control module 15 further reduces the voltage drop of the switching transistor group by adjusting the output voltage of the DC-DC buck module 12, thereby reducing its power dissipation; the second level threshold is used to trigger shutdown protection, and when the voltage drop adjustment still cannot effectively suppress the temperature rise, the control module 15 shuts off the output of the constant current drive module 13, cuts off the pump source current, and realizes overheat protection.

[0072] For example, an NTC thermistor with a resistance of 10kΩ and a B constant of 3950 at room temperature (25℃) is selected. The pull-up resistor of the voltage divider circuit is 10kΩ and connected to a 3.3V reference voltage. The first-stage temperature threshold is set to 85℃, corresponding to an NTC resistance of approximately 1.2kΩ and a voltage divider value of approximately 0.35V; the second-stage temperature threshold is set to 110℃, corresponding to a voltage divider value of approximately 0.18V. The control module 15 periodically reads the voltage divider values ​​to complete temperature conversion and threshold comparison.

[0073] Based on the aforementioned temperature detection module 17, the control module 15 obtains a second-dimensional feedback quantity in addition to the voltage drop information, namely the thermal state of the switching transistor group. Even when the voltage drop of the switching transistor group is within a preset safe range, if the junction temperature rises abnormally due to excessively high ambient temperature or deteriorated heat dissipation conditions, the temperature detection module 17 provides an independent thermal protection path. This allows the control module 15 to promptly take power reduction or shutdown measures to prevent damage to the switching transistor group due to overheating, forming a supplementary protection mechanism for voltage closed-loop regulation.

[0074] In some embodiments, the control module includes a storage unit that pre-stores rated voltage and rated current parameters of various laser pump sources.

[0075] After the pump source is connected, the control module retrieves the corresponding preset parameters from the storage unit according to the identified pump source specifications in order to quickly generate an adjustment signal.

[0076] For example, during pump source operation, control module 15 continuously reads a digital voltage signal, denoted as Vds, from voltage detection module 14 at fixed intervals, reflecting the voltage drop across the switching transistor group. Control module 15 internally defines a preset safety range, defined by an upper threshold Vref_high and a lower threshold Vref_low, both of which are pre-calibrated constants. Within each control cycle, control module 15 compares Vds with the preset thresholds. If Vds is greater than Vref_high, it indicates that the voltage drop across the switching transistor group is too high, and its power dissipation and heat generation exceed expectations. Control module 15 performs positive adjustment: increasing the adjustment signal value output to DC-DC buck module 12, thereby raising the output voltage of DC-DC buck module 12. After the voltage output to constant current drive module 13 increases, the actual voltage drop across the switching transistor group decreases accordingly. If Vds is less than Vref_low, it indicates that the output voltage of DC-DC buck module 12 is too high. Although the voltage drop and heat loss of the switching transistor group are small, the conversion loss of DC-DC buck module 12 is relatively increased, and the dynamic margin of constant current adjustment of the switching transistor group is limited. Control module 15 performs reverse adjustment: decreasing the adjustment signal value, reducing the output voltage of DC-DC buck module 12, and causing Vds to rise back to a safe range. If Vds is between the upper and lower thresholds, i.e., satisfying Vref_low≤Vds≤Vref_high, it indicates that the voltage drop of the switching transistor group is in the optimal operating range, and control module 15 maintains the current adjustment signal unchanged.

[0077] For example, the upper limit threshold Vref_high of the preset safety range is set to 2.5V, and the lower limit threshold Vref_low is set to 1.5V. At a certain moment, the control module 15 reads a Vds value of 3.2V, which is greater than the 2.5V upper limit. The control module 15 calculates the adjustment signal increment through a proportional-integral control algorithm and increases the adjustment signal from the current value of 1.8V to 2.0V. The corresponding output voltage of the DC-DC buck converter 12 increases from 20V to 22V, and the voltage drop of the switching transistor group decreases to 1.8V, falling within the safety range.

[0078] Based on the aforementioned closed-loop voltage drop regulation logic, the control module 15 continuously maintains the voltage drop of the switching transistor group within a preset safe range throughout the entire operation of the pump source, eliminating the problem of excessively high or low voltage drop of the switching transistor group caused by different pump source voltage specifications. When the voltage drop is too high, it actively increases the output voltage of the preceding stage to share the voltage drop; when the voltage drop is too low, it appropriately reduces the output voltage of the preceding stage to optimize overall efficiency. This achieves closed-loop control with adaptive voltage drop management, ensuring that the switching transistor group always operates within a safe and efficient operating range.

[0079] In some embodiments, a current sampling resistor is provided between the output terminal of the constant current drive module and the pump source. The current sampling resistor is used to collect the working current signal flowing to the pump source and feed the working current signal back to the control module.

[0080] For example, storage unit 18 is a non-volatile memory, such as Flash memory or EEPROM, which pre-stores the rated voltage and rated current parameters of various specifications of laser pump sources. The parameters for each specification are organized in the form of a data table, including fields such as pump source model identifier, rated operating voltage Vnom, and rated operating current Inom. When the pump source is connected to the power supply circuit through the pump source interface, the control module 15 first reads the initial voltage across the pump source through the voltage detection module 14, or detects the voltage response of the pump source after applying a small current test excitation through the constant current drive module 13, thereby identifying the specification type of the connected pump source. After identification, the control module 15 retrieves and calls the rated voltage parameter Vnom corresponding to the pump source from storage unit 18, and calculates the initial target output voltage of DC-DC buck module 12, i.e., Vout_init = Vnom + Vds_target, where Vds_target is the intermediate value of the preset safety range. The control module 15 generates a corresponding adjustment signal to quickly establish the output voltage of the DC-DC buck module 12 to close to the target value, thus completing the initial voltage preset, and then finely adjusting it by the closed-loop voltage drop regulation logic.

[0081] For example, storage unit 18 pre-stores three pump source parameters: pump source A, rated voltage 2.0V, rated current 500mA; pump source B, rated voltage 12V, rated current 2A; and pump source C, rated voltage 36V, rated current 5A. When pump source B is connected, control module 15 detects that its initial voltage response characteristics match those of pump source B, calls the parameter Vnom=12V, sets Vds_target=2.0V, calculates Vout_init=14V, and quickly outputs an adjustment signal to make the DC-DC buck module 12 output 14V voltage. The entire initial setup process is completed within tens of milliseconds.

[0082] Based on the configuration of the aforementioned storage unit 18, when a pump source of known specifications is connected, the control module 15 can skip the process of repeatedly searching for the target voltage and directly call the preset parameters for initial voltage setting, significantly shortening the convergence time of adaptive adjustment. Subsequently, closed-loop adjustment only needs to correct for minor voltage drop deviations, which not only speeds up the circuit startup speed but also avoids the risk of instantaneous overvoltage or undervoltage of the switching transistor group due to unsuitable output voltage in the early stage of adjustment, thus improving the response speed and operational safety of adaptive adjustment.

[0083] This application also provides a laser pump source, including a pump source light-emitting component and a power supply circuit for the laser pump source as described in any of the embodiments of this application. The output terminal of the power supply circuit is electrically connected to the pump source light-emitting component and is used to adaptively provide a matching driving voltage and constant current to the pump source light-emitting component according to its rated voltage requirements.

[0084] This application also provides a laser device, including an optical resonant cavity and a laser pump source as described in this application embodiment. The laser pump source is used to emit a pump beam into the optical resonant cavity to excite the optical resonant cavity to output laser light.

[0085] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power supply circuit for a laser pump source, characterized in that, include: Input power supply module, used to provide input voltage; A DC-DC step-down module, with its input terminal connected to the input power supply module, and its control terminal used to receive analog adjustment signals and adjust its output voltage according to the analog adjustment signals; The constant current drive module includes a group of switching transistors. The input terminal is connected to the output terminal of the DC-DC buck module. The output terminal is used to connect to the laser pump source and provide a constant current to the pump source. The group of switching transistors generates a voltage drop when driving the pump source. The voltage detection module has its input terminals connected to both ends of the switching transistor group, and is used to collect voltage signals reflecting the voltage drop across the switching transistor group and convert the voltage signals into digital voltage signals. The control module, with its input terminal connected to the output terminal of the voltage detection module, is used to receive the digital voltage signal and generate an adjustment signal based on the digital voltage signal to maintain the voltage drop across the switching transistor group within a preset safety range. The output voltage of the DC-DC buck module varies with the adjustment signal to share the voltage drop of the switching transistor group, so that when the switching transistor group drives pump sources with different rated voltages, the voltage drop across the switching transistor group is limited to the preset safety range.

2. The power supply circuit for the laser pump source according to claim 1, characterized in that, Also includes: Straight-through bypass module; The direct bypass module is connected in parallel with the DC-DC buck module. The input terminal of the direct bypass module is connected to the output terminal of the input power supply module, and the output terminal is connected to the input terminal of the constant current drive module. It is used to allow the input voltage to bypass the DC-DC buck module and directly conduct to the constant current drive module when the working voltage of the pump source is higher than a preset threshold.

3. The power supply circuit for the laser pump source according to claim 1, characterized in that, The DC-DC buck module is a synchronous buck DC-DC converter, including: an upper bridge arm switch and a lower bridge arm switch; The drain of the upper bridge arm switch is connected to the output terminal of the input power supply module, the source of the upper bridge arm switch is connected to the drain of the lower bridge arm switch, and is connected to the input terminal of the constant current drive module through an inductor, and the source of the lower bridge arm switch is grounded; the gates of the upper bridge arm switch and the lower bridge arm switch serve as the control terminals of the DC-DC buck module.

4. The power supply circuit for the laser pump source according to claim 1, characterized in that, The voltage detection module includes: a voltage follower and an analog-to-digital converter; The input terminals of the voltage follower are respectively connected to the first and second terminals of the switching transistor group, and are used to isolate and collect the voltage signal reflecting the voltage drop across the switching transistor group; The input terminal of the analog-to-digital converter is connected to the output terminal of the voltage follower, and is used to convert the voltage signal into the digital voltage signal.

5. The power supply circuit for the laser pump source according to claim 1, characterized in that, Also includes: Temperature detection module; The temperature detection module includes a thermistor disposed at the switching transistor group, used to collect the temperature signal of the switching transistor group and transmit it to the control module; When the temperature signal exceeds a preset temperature threshold, the control module adjusts the output voltage of the DC-DC buck module to reduce the voltage drop of the switching transistor group, or cuts off the circuit output when the temperature continues to rise, thereby achieving overheat protection.

6. The power supply circuit for the laser pump source according to claim 1, characterized in that, The control module is configured as follows: During the operation of the pump source, the digital voltage signal is continuously received and the actual voltage drop of the switching transistor group is calculated. The actual voltage drop is then compared with the preset safety range. If the actual voltage drop is greater than the upper limit of the preset safety range, the adjustment signal is increased to raise the output voltage of the DC-DC buck module and reduce the voltage drop of the switching transistor group. If the actual voltage drop is less than the lower limit of the preset safety range, the adjustment signal is reduced to decrease the output voltage of the DC-DC buck module and improve the circuit conversion efficiency.

7. The power supply circuit for the laser pump source according to claim 1, characterized in that, The control module includes a storage unit, which pre-stores the rated voltage and rated current parameters of various laser pump sources. After the pump source is connected, the control module retrieves the corresponding preset parameters from the storage unit according to the identified pump source specifications in order to quickly generate the adjustment signal.

8. The power supply circuit for the laser pump source according to claim 1, characterized in that, A current sampling resistor is provided between the output terminal of the constant current drive module and the pump source. The current sampling resistor is used to collect the working current signal flowing to the pump source and feed the working current signal back to the control module.

9. A laser pump source, characterized in that, It includes a pump source light-emitting component and a laser pump source adaptive power supply circuit as described in any one of claims 1 to 8; the output terminal of the power supply circuit is electrically connected to the pump source light-emitting component and is used to adaptively provide a matching driving voltage and constant current to the pump source light-emitting component according to its rated voltage requirements.

10. A laser device, characterized in that, It includes an optical resonant cavity and a laser pump source as described in claim 9, wherein the laser pump source is used to emit a pump beam into the optical resonant cavity to excite the optical resonant cavity to output laser light.

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