An open loop adaptive driver circuit and method

Abstract

The application discloses an open-loop self-adaptive driving circuit and method, and belongs to the technical field of laser driving circuits, and comprises: a direct-current power supply, which is used for providing energy input to a power loop; a laser pump tube, which is used for providing energy to a working medium and generating stimulated radiation; an energy storage inductor, which is arranged in the power loop and is used for storing or releasing energy; a constant current source, which is arranged in the power loop and is used for setting the size of the power loop current; a bypass switch, which is used for bypassing the laser pump tube or the laser pump tube and the constant current source; and a controller, which is used for outputting a control signal to the control end of the bypass switch; the whole circuit adopts a pure open-loop architecture, and a global feedback regulation loop for the voltage of the laser pump tube and the load current is not arranged; the local negative feedback in the constant current source is only used for stabilizing the working current of the loop, does not participate in the adaptive matching process of the load voltage, and the adaptive load voltage is completely passively and instantaneously realized by the electromagnetic induction characteristics of the inductor.

Description

Technical Field

[0001] This invention relates to the field of laser driving circuit technology, and in particular to an open-loop adaptive driving circuit and method. Background Technology

[0002] Laser diodes, as the core light source, exhibit significant individual variability and temperature drift characteristics in their forward voltage drop (Vf), typically ranging from 1.5V to over 100V. Customizing a drive power supply for laser diodes with a specific forward voltage drop (Vf) leads to high production costs and complex material management. To address the issue of universality, existing technologies mainly follow two paths, but both have fundamental drawbacks:

[0003] 1. Closed-loop feedback regulation path: such as the Chinese invention patent with patent number CN112582876B, the load voltage is sampled in real time by a microcontroller and the output voltage of the switching power supply is dynamically adjusted. In essence, it is an active control mode of detection-calculation-regulation. This method is complex and has a millisecond-level lag in response, making it difficult to achieve nanosecond-level ultra-high-speed pulse drive. 2. Inductor energy storage switching path: As shown in Chinese invention patent application with publication number CN119542909A, this path uses the principle of inductor current continuity to improve the driving speed, but the control is complicated, and it also uses capacitors for slow adaptive charging and discharging, and it cannot adapt to load changes at high speed.

[0004] Therefore, it is essential to provide an open-loop adaptive drive circuit and method that, through a unique circuit topology and preset timing actions, allows the drive voltage to passively and instantaneously match the load's operating requirements, thereby improving the technical problems of slow response and complex system structure in traditional methods. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an open-loop adaptive driving circuit and method. It abandons the traditional closed-loop feedback structure and capacitor energy storage architecture, and relies on the electromagnetic induction characteristics of inductors to achieve passive adaptation of load voltage. While simplifying the circuit, it achieves nanosecond-level high-speed response and wide voltage load adaptation.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an open-loop adaptive drive circuit, comprising: a DC power supply, an energy storage inductor, a laser pump tube branch, and a bypass switch; wherein, The energy storage inductor is electrically connected to the laser pump tube branch to form a power circuit; the bypass switch is connected in parallel to the laser pump tube branch for selectively bypassing the laser pump tube branch. The bypass switch is controlled to periodically switch on and off: when the bypass switch is on, the laser pump tube branch is bypassed, and the DC power supply stores energy in the energy storage inductor; when the bypass switch is off, the energy storage inductor is connected to the power circuit of the laser pump tube branch, and passively and instantaneously matches the real-time positive voltage drop of the laser pump tube branch by relying on the inductor-induced voltage combined with Kirchhoff's voltage law. The power circuit is a pure open-loop structure and does not have a global feedback regulation circuit for the voltage and load current of the laser pump tube branch.

[0007] Based on the above technical solutions, preferably, the bypass switch includes a first switching device, the two ends of which are respectively connected to the two ends of the laser pump tube branch, for bypassing the current of the laser pump tube branch, and the maximum charging current of the energy storage inductor is limited by controlling the conduction time of the bypass switch.

[0008] Preferably, the laser pump tube branch includes a laser pump tube and a circuit matching device, and a bypass switch is connected across both ends of the laser pump tube and the circuit matching device to achieve overall bypass of the laser pump tube and the matching device, or a bypass switch; the circuit matching device includes a constant current source, which is used to clamp the charging current of the energy storage inductor at a preset target value.

[0009] Preferably, the laser pump tube branch includes a laser pump tube, and a bypass switch is connected across both ends of the laser pump tube.

[0010] Preferably, the constant current source includes an operational amplifier and a second switching device, which, together with the sampling resistor, form a local negative feedback loop; the local negative feedback is only used to maintain the constant loop current and does not participate in the adaptive voltage adjustment of the laser pump tube.

[0011] Preferably, it also includes a timing controller, the output of which is connected to the control terminal of the bypass switch, and is used to output a timing control signal to drive the bypass switch to periodically switch on and off.

[0012] Preferably, the control terminal of the bypass switch is connected to a self-excited oscillation circuit, and the self-excited oscillation circuit generates periodic switching signals to drive the bypass switch to open and close, without the need for an external timing controller.

[0013] Based on the above technical solutions, preferably, the power circuit further includes an auxiliary protection circuit, which consists of a first diode and a second diode, used to suppress the reverse electromotive force of the inductor and prevent reverse current from damaging the DC power supply.

[0014] On the other hand, the present invention also provides an open-loop adaptive driving method applied to the above-mentioned open-loop adaptive circuit; in the open-loop adaptive circuit, the DC power supply, the laser pump tube branch, and the energy storage inductor together constitute a power loop, and the energy storage inductor is disposed in the power loop between the DC power supply and the anode side of the laser pump tube branch, or in the power loop between the cathode side of the laser pump tube branch and the ground wire; the laser pump tube branch includes a laser pump tube, and the laser pump tube branch is also selectively and independently configured with a constant current source to clamp the energy storage current; a bypass switch enables the laser pump tube branch circuit to be bypassed, and the driving method includes the following steps: S1: Control bypass switch is turned on, current on laser pump tube is reduced. I pump =0; When a constant current source is configured, the DC power supply charges the energy storage inductor, and the constant current source clamps the energy storage current to the target current. I cons When no constant current source is configured, the DC power supply freely charges the energy storage inductor. By controlling the conduction time, the inductor's energy storage current is increased. I stor Achieve target current I cons ; S2: Control bypass switch is turned off, laser pump tube branch is connected to power circuit, power circuit satisfies voltage relationship , V in This is the DC power supply voltage. V pump This represents the real-time forward voltage drop of the laser pump tube. V cs The voltage drop automatically adjusted by the constant current source; the inductor-induced voltage, on the one hand, matches the DC power supply voltage and the automatically adjusted voltage drop of the constant current source to adapt to the real-time forward voltage drop of the laser pump tube, and on the other hand, provides additional voltage for the rapid rise of the power circuit current, causing the power circuit current to climb to... I stor = I cons The current is kept stable by a constant current source; S3: Repeat steps S1 and S2 to continuously output pulse drive current.

[0015] Preferably, when no independent constant current source is configured, the charging time during the energy storage phase satisfies the following formula: In the formula t For charging time, L This is the value of the energy storage inductance. R For the power circuit resistance, V in This is the DC power supply voltage. I 0 The initial current for charging the inductor, Istor The target current for inductor energy storage.

[0016] Compared with the prior art, the open-loop adaptive driving circuit and method provided by the present invention have the following beneficial effects: 1) The constant current source can be connected in series in the power circuit as an independent device, or it can be directly integrated into the DC power supply to clamp the inductor charging current. When no constant current source is configured, the maximum charging current of the inductor can be limited by precisely controlling the conduction time of the bypass switch. The constant current source can be internally configured with a local negative feedback loop consisting of an operational amplifier, switching devices, and sampling resistors. This local negative feedback is only used to stabilize the circuit current and does not participate in the load voltage adaptation process. The power circuit as a whole adopts a pure open-loop architecture, without a global feedback adjustment loop for the load voltage and load current. It relies on the inductor-induced voltage combined with Kirchhoff's voltage law to compensate for the circuit voltage difference and provide the voltage required for current rise, while simultaneously instantaneously and passively matching the real-time forward voltage drop of the laser pump tube. This invention breaks the inherent thinking that load adaptation must rely on a feedback loop. It adopts a pure open-loop architecture with no global voltage or current feedback loop, eliminating the oscillation risk of the closed-loop circuit from the root. The circuit is robust and insensitive to component parameter drift and environmental interference.

[0017] 2) Simplified Topology, Reduced Costs and Increased Efficiency: The core circuit consists of only a DC power supply, an energy storage inductor, a bypass switch, and a laser pump tube. Compared to existing technologies, this reduces the number of core components, resulting in a smaller circuit size, lower material costs, and fewer potential failure points, facilitating mass production and engineering integration. Additionally, an optional signal generation module is available: an external timing controller can output switching signals, or a self-excited oscillation circuit can generate periodic signals to drive the bypass switch, eliminating the need for an additional controller.

[0018] 3) An auxiliary protection circuit consisting of two diodes can be added to the power circuit to suppress the reverse electromotive force generated when the inductor is disconnected, and to prevent reverse current from damaging the DC power supply.

[0019] 4) This invention also provides an open-loop adaptive driving method. Based on the above-mentioned driving circuit, the core consists of two cyclic stages: energy storage and discharge. In the energy storage stage, a bypass switch is used to cut off the laser pump tube circuit, completing inductor energy storage. In the discharge stage, the laser pump tube is connected to the circuit, and the inductor-induced voltage adapts to the load voltage and outputs a pulse current. Depending on the circuit configuration, a constant current clamping mode or a timed current control mode can be selected to limit the inductor charging current. The switch drive signal can be provided by a timing controller or a self-excited oscillation circuit.

[0020] 5) The load voltage matching of the present invention is achieved by relying on the physical law of electromagnetic induction of inductance, and the response speed reaches the nanosecond level, completely eliminating the millisecond-level delay of traditional feedback circuits, and the current establishment speed is more than twice that of traditional solutions.

[0021] 6) This invention achieves wide-range adaptability and strong versatility. It eliminates the need for customized drive circuits for different load specifications, automatically adapting to various laser pump tubes with forward voltage drops from 1.5V to 100V, enabling plug-and-play operation and compatibility with multiple laser equipment models. It supports various combinations, including those with and without constant current sources, external controllers / self-excited oscillation circuits, and can generate eight different circuit topologies, adapting to various operating conditions such as lidar, laser processing, medical lasers, and high-speed solenoid valve drives. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a circuit schematic diagram of an open-loop adaptive driving circuit and method according to the present invention. Figure 2 This is a schematic diagram of eight extended circuit structures for an open-loop adaptive driving circuit and method according to the present invention. Figure 3 This is a schematic diagram of the current waveform during the two-stage operation of an open-loop adaptive driving circuit and method according to the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] When customizing a drive power supply for a laser pump tube with a specific forward voltage drop Vf, the existing technologies mainly employ certain approaches, but all have fundamental drawbacks: 1. Closed-loop feedback regulation path: This path uses a microcontroller to sample the load voltage in real time and dynamically adjust the output voltage of the switching power supply. Essentially, it is an active control mode of detection-calculation-regulation. This method results in a complex system with millisecond-level lag in response, making it difficult to achieve nanosecond-level ultra-high-speed pulse drive; 2. Inductor energy storage switching path: This path utilizes the principle of continuous inductor current to improve the drive speed, but the control is complex. It also uses capacitors for charging and discharging and cannot adapt to changes in the load.

[0026] In view of this, such as Figure 1As shown, in one aspect, the present invention provides an open-loop adaptive driving circuit and method, comprising: A DC power supply is used to provide energy input to a power circuit. A laser pump tube is used to provide energy to the working medium and generate stimulated emission; that is, marked D3 in the figure. An energy storage inductor, disposed in the power circuit, is used to store or release energy; corresponding to the markings in the figure. L ; A constant current source is installed in the power circuit to set the current magnitude of the power circuit. Bypass switch, used to bypass the laser pump tube, or the laser pump tube and constant current source current; The controller is used to output control signals to the control terminal of the bypass switch, so as to control the bypass switch to be turned on or off. When the controller turns on the bypass switch, the energy storage inductor is charged, and the maximum charging current of the energy storage inductor is clamped by the constant current source. When the controller turns off the bypass switch, both the energy storage inductor and the laser pump tube are connected to the power circuit, so that the induced voltage of the energy storage inductor follows the voltage change of the laser pump tube until the current on the laser pump tube reaches the target current.

[0027] The specific working principle is as follows: Figure 1 Taking the circuit structure as an example, the bypass switch receives the timing control signal from the controller. When the bypass switch is on, the current of the laser pump tube D3 is bypassed, and the energy storage inductor stores energy through the bypass switch. The charging current of the energy storage inductor is limited by the constant current source. When the bypass switch is off, the energy storage inductor, the constant current source, and the laser pump tube D3 are connected in series in the power circuit, and the induced voltage of the energy storage inductor is... , I pump The current on the laser pump tube, L The inductance value of the energy storage inductor is given. The term on the right-hand side of the formula represents the voltage required for the energy storage inductor to generate the current driving the laser pump tube to rise, thereby enabling the laser pump tube to reach the expected operating current. I pump ; Induced voltage V L Kirchhoff's voltage law forces the following relationship to be satisfied. , V in The DC power supply voltage remains constant. V pump This represents the real-time forward voltage drop of the laser pump tube. V cs The voltage drop is automatically adjusted by the constant current source to achieve the induced voltage. V L For laser pump tubes V pumpThe instantaneous, passive adaptive matching of the voltage.

[0028] The above Figure 1 This is a special case with both a constant current source and a controller. In practice, the branch containing the laser pump tube and the constant current source is considered the laser pump tube branch. This branch can contain only the laser pump tube, or it can contain both. When a constant current source is included, during the charging process of the energy storage inductor by the DC power supply, the constant current source clamps the stored current to the target current. I cons When no constant current source is configured, the DC power supply freely charges the energy storage inductor. By controlling the conduction time, the energy storage current of the inductor can reach the target value. Both can achieve the purpose of enabling the laser pump tube to reach the expected operating current.

[0029] like Figure 1 As shown, in one embodiment, the bypass switch includes a first switching device Q1, the gate of the first switching device Q1 is electrically connected to the controller, the drain of the first switching device Q1 is electrically connected to the power circuit on the anode side of the laser pump tube, and the source of the first switching device Q1 is electrically connected to the power circuit on the cathode side of the laser pump tube.

[0030] Without a constant current source, a timing controller can be configured to precisely control the conduction duration and accurately turn off the bypass switch, thus meeting the requirements for precise control of the conduction duration. Alternatively, other delay devices can be configured, such as connecting a self-excited oscillation circuit to the control terminal of the bypass switch, which generates periodic switching signals to drive the bypass switch on and off.

[0031] refer to Figure 2 As shown in the figure, in a laser pump tube branch, if both a laser pump tube and a constant current source are configured, then the laser pump tube and the constant current source are arranged adjacent to each other, and their positions in the power circuit can be interchanged.

[0032] like Figure 1 Combination Figure 2 As shown in the diagram, illustrating a circuit structure where the laser pump tube and constant current source are arranged adjacently and their positions are interchangeable, in one embodiment, the constant current source is located in the power circuit between the DC power supply and the anode side of the laser pump tube, or in the power circuit between the cathode side of the laser pump tube and the ground line. The constant current source includes an operational amplifier and a second switching device. The non-inverting input of the operational amplifier is electrically connected to the analog output of the controller, the output of the operational amplifier is electrically connected to the gate of the second switching device, and the drain of the second switching device is electrically connected to the DC power supply or the cathode side of the laser pump tube. The controller also acquires a current sampling signal from the power circuit, and the current sampling signal is also sent to the inverting input of the operational amplifier. The source of the second switching device is electrically connected to the anode side of the laser pump tube or the ground line. Figure 2In the eight examples (a), (b), ..., (h), the constant current source can be located between the anode side of the laser pump tube D3 and the DC power supply, or between the cathode side of the laser pump tube D3 and the ground wire. The bypass switch can bypass the power supply of the laser pump tube D3 alone, or it can bypass the current of both the laser pump tube D3 and the constant current source simultaneously.

[0033] Also from Figure 2 As can be seen in the various examples, energy storage inductors L It can be set in the power circuit between the DC power supply and the anode side of the laser pump tube D3, or it can be set in the power circuit between the cathode side of the laser pump tube D3 and the ground wire.

[0034] An auxiliary protection circuit is also configured in the power circuit. This circuit includes diodes D1 and D2. The anode of diode D1 is electrically connected to the DC power supply, and the cathode of diode D1 is electrically connected to both the cathode of diode D2 and the anode of the pump tube. The anode of diode D2 is grounded. Both diodes D1 and D2 have unidirectional conductivity, allowing current from the DC power supply to flow into the energy storage inductor. They also prevent reverse electromotive force from flowing back into the DC power supply from the energy storage inductor, thus providing isolation and protection.

[0035] like Figure 2 As shown, without the controller and auxiliary protection circuit, Figure 2 (a) shows a structure in which an energy storage inductor is located on the anode side of a laser pump tube D3, a constant current source is located on the cathode side of a laser pump tube D3, and a bypass switch is used to bypass the laser pump tube current. Figure 2 (b) shows a structure in which both the energy storage inductor and the constant current source are located on the anode side of the laser pump tube D3, and a bypass switch is used to bypass the laser pump tube current. Figure 2 (c) shows a structure in which the energy storage inductor is located on the anode side of the laser pump tube D3, the constant current source is located on the cathode side of the laser pump tube D3, and the bypass switch is used to bypass the current of both the laser pump tube and the constant current source simultaneously. Figure 2 (d) shows a structure in which both the energy storage inductor and the constant current source are located on the anode side of the laser pump tube D3, and a bypass switch is used to simultaneously bypass the current of the laser pump tube and the constant current source. Figure 2 (e) shows a structure in which the constant current source and the energy storage inductor are both located on the cathode side of the laser pump tube D3, and a bypass switch is used to simultaneously bypass the current of the laser pump tube and the constant current source. Figure 2(f) shows a structure in which a constant current source is located on the anode side of the laser pump tube D3, an energy storage inductor is located on the cathode side of the laser pump tube D3, and a bypass switch is used to bypass the laser pump tube and the constant current source simultaneously. Figure 2 (g) shows a structure in which the constant current source and the energy storage inductor are both located on the cathode side of the laser pump tube D3, and the bypass switch is used to bypass the laser pump tube current. Figure 2 Figure (h) shows a structure in which a constant current source is located on the anode side of the laser pump tube D3, an energy storage inductor is located on the cathode side of the laser pump tube D3, and a bypass switch is used to bypass the laser pump tube current.

[0036] On the other hand, the present invention provides an open-loop adaptive driving method, comprising the following steps: S1: Configure the above-mentioned open-loop adaptive drive circuit to form a power loop consisting of a DC power supply, a laser pump tube, a constant current source, and an energy storage inductor. The energy storage inductor is placed in the power loop between the DC power supply and the anode side of the laser pump tube, or in the power loop between the cathode side of the laser pump tube and the ground line. The constant current source is placed in the power loop between the DC power supply and the anode side of the laser pump tube, or in the power loop between the cathode side of the laser pump tube and the ground line. The constant current source includes an operational amplifier and a second switching device. The non-inverting input of the operational amplifier is electrically connected to the analog output of the controller, and the output of the operational amplifier is electrically connected to the gate of the second switching device. The drain of the second switching device is electrically connected to the DC power supply or the cathode side of the laser pump tube. The controller also configures a sampling resistor from the power loop. R The current sampling signal is obtained and then fed into the inverting input of the operational amplifier; the bypass switch is used to bypass the laser pump tube's current individually, or to bypass the combined current of the laser pump tube and the constant current source. Although a sampling resistor is used here... R However, it is part of a constant current source, and the entire power circuit does not form a closed-loop voltage / current feedback loop structure with the controller, which simplifies the circuit structure.

[0037] S2: When the bypass switch is turned on, bypassing the laser pump tube's current alone, the DC power supply first charges the energy storage inductor, and the current on the laser pump tube... I pump =0, at which point the maximum charging current flowing through the energy storage inductor is 0. I stor Under the control of a constant current source, the maximum charging current of the energy storage inductor is reached through a period of charging. I stor Achieve target current I consThe energy storage phase is complete; then the bypass switch is turned off, the laser pump tube is connected to the power circuit, the energy storage inductor releases energy, and the induced voltage on the energy storage inductor... V L Through DC power supply voltage V in The voltage of the laser pump tube V pump and constant current voltage drop V cs Together, the operational amplifier is combined with the sampling resistor. R A negative feedback amplifier circuit is formed to make the constant current voltage drop V cs To maintain stability for varying laser pump tube voltage V pump The induced voltage on the energy storage inductor V L Automatically match the voltage of the laser pump tube V pump Changes in the current on the laser pump tube I pump Rise to the maximum charging current of the energy storage inductor I stor ,satisfy I pump = I stor = I cons The current on the laser pump tube is then controlled by a constant current source. I pump The current on the laser pump tube I pump Maintain at the target current I cons Repeat the above charging and releasing process to obtain the pulsed current driving the laser pump tube.

[0038] This situation is equivalent to Figure 2 (a), (b), (g), (h); with Figure 2 (a) combination Figure 1 Explanation: To drive a 24V laser pump tube and generate a 30A pulse current with a width of 500ns and a frequency of 10kHz, a 50V DC power supply is used. When the 24V laser pump tube starts up, the driving voltage here is much higher than 24V, satisfying the condition that the induced voltage equals the pump tube's rated voltage plus the voltage required for current rise, but the current will not exceed the rated value, so the laser pump tube will not be damaged. Energy storage inductor LThe laser pump tube D3 and the constant current source are connected in series. A bypass switch is used to bypass the current of the laser pump tube D3. A 200μH, 50A power inductor is selected for energy storage. Both the first switching device Q1 and the second switching device Q2 are BMW60N026UC1 MOSFETs. The operational amplifier U1 is an AD8028, and the sampling resistor... R The resistance is 5mΩ. During the energy storage phase, this is equivalent to... Figure 3 In stage T1, when the circuit first starts working, the energy storage inductor... L The current on the circuit is 0, and the first charging time is slightly longer. After the controller drives the bypass switch to turn on, the controller sends an analog voltage signal to the operational amplifier U1, causing the constant current source to operate at a target of 30A. At this time, the energy storage inductor... L Energy storage begins; this charging process takes approximately 20μs. Due to the limitation of the constant current source, the current of the energy storage inductor will not exceed 30A, so the energy storage phase is completed after 25μs. During the energy release phase, it is equivalent to... Figure 3 In phase T2, the controller turns off the bypass switch and connects the laser pump tube to the power circuit, which then uses the energy storage inductor... L Drive the laser pump tube under the induced voltage V pump Under the influence of this, the pump current of the laser pump tube rises rapidly until it reaches the target current of 30A. I cons After the first switching device Q1 is turned off, the timer starts for 500ns to enter the next stage.

[0039] The second energy storage phase is equivalent to Figure 3 In the T3 stage, due to the energy storage inductor L The current has reached 30A. No energy storage time is needed at this stage. During this stage, the controller drives the bypass switch to turn on again, simply to shut off the pump current of the laser pump tube. The pump current shutdown time meets the requirements, such as 9.5μs, before resuming operation. Figure 3 During the T2 phase, the process of charging and releasing energy is repeated in subsequent processes, thereby continuously generating pulse current.

[0040] Figure 2 (b), (g), (h) and Figure 2 (a) has a basically the same working process.

[0041] S3: When the bypass switch is turned on, bypassing the overall current of the laser pump tube and the constant current source, the DC power supply first charges the energy storage inductor, and the current on the laser pump tube... I pump =0, at which point the maximum charging current flowing through the energy storage inductor is 0. I storUnaffected by a constant current source, the controller sets the turn-off time of the bypass switch to meet the charging time constraint, thereby maximizing the charging current of the energy storage inductor. I stor Achieve target current I cons The energy storage phase is complete; then the bypass switch is turned off, and the laser pump tube and constant current source are connected to the power circuit. The energy storage inductor releases energy, and the induced voltage on the energy storage inductor... V L Through DC power supply voltage V in The voltage of the laser pump tube V pump and constant current voltage drop V cs Together, the operational amplifier is combined with the sampling resistor. R A negative feedback amplifier circuit is formed to make the constant current voltage drop V cs To maintain stability for varying laser pump tube voltage V pump The induced voltage on the energy storage inductor V L Automatically match the voltage of the laser pump tube V pump Changes in the current on the laser pump tube I pump Rise to the maximum charging current of the energy storage inductor I stor ,satisfy I pump = I stor = I cons The current on the laser pump tube is then controlled by a constant current source. I pump The current on the laser pump tube I pump Maintain at the target current I cons Repeat the above charging and releasing process to obtain the pulsed current driving the laser pump tube.

[0042] This situation is equivalent to Figure 2 (c), (d), (e), and (f) in the text. Figure 2 Let's take (c) as an example for explanation. In the energy storage stage, it's also equivalent to... Figure 3 In the T1 phase, the controller drives the bypass switch to turn on, and the current in the laser pump tube... I pump The current is 0, which is the maximum charging current flowing through the energy storage inductor. I storIt is not controlled by a constant current source. The charging time constraint here is calculated by dividing the inductance value of the energy storage inductor by the sampling resistor. R The result is obtained by multiplying the logarithmic term, where the logarithmic term is the power circuit steady-state current minus the initial current at the start of charging of the energy storage inductor. I The first result of 0 is calculated by dividing the steady-state current of the power circuit by the maximum charging current of the energy storage inductor. I stor The second result is obtained by taking the logarithm of the result obtained by division, with the base of the logarithmic term being the natural logarithm. e : The steady-state current of the power circuit is V in / R This formula allows us to calculate the charging time constraint, and through precise timing, determine the maximum charging current of the inductor. I stor =Target current I cons The energy storage phase is complete; while the energy release phase and the re-energy storage phase are equivalent to... Figure 3 The T2 and T3 stages are the same as those described in step S2.

[0043] The overall process can be summarized as follows: In the first stage (T1), the first switching device Q1 is turned on, the second switching device Q2 is turned on, and the DC power supply is an energy storage inductor. L Charging; in the second stage T2, the first switching device Q1 is turned off, and the second switching device Q2 is turned on to maintain a constant current, and the energy storage inductor... L The laser pump tube D3 is directly discharged until the target current is reached. In the third stage T3, the first switching device Q1 is briefly turned on, briefly turning off the pump current of the laser pump tube, thus forming an alternating waveform pulse current. During this process, when the first switching device Q1 is turned on, it is in a saturated state and fully conducting so that the current bypasses the laser pump tube; while the second switching device Q2 operates in the linear region and is not fully turned on, used to control the current on the energy storage inductor.

[0044] Figure 2 The working processes of (d), (e), and (f) in the text are similar to... Figure 2 The working process of (c) is basically the same.

[0045] In one embodiment, to better drive the bypass switch and set the target current of the constant current source, the controller is equipped with several digital-to-analog converters (DACs). One DAC is used to generate the control signal for the bypass switch; another DAC is used to generate the current control signal, which is sent to the non-inverting input of the operational amplifier to establish the target current. I cons .

[0046] Compared to conventional boost converters, the method of this invention offers advantages such as faster switching speed, smaller size, lower cost, and full process controllability, and it can adapt to the load, i.e., the requirements of the laser pump tube. Due to the minimal number of components used, it enables plug-and-play driving of a wide range of unknown loads, such as 1.5V-100V, i.e., the laser pump tube, significantly reducing system design complexity. Furthermore, it meets the requirement of nanosecond-level current build-up speed and maintains high stability and robustness even when the power circuit operates in open loop.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An open-loop adaptive driving circuit, characterized in that, include: DC power supply, energy storage inductor, laser pump tube branch, and bypass switch; among which, The energy storage inductor is electrically connected to the laser pump tube branch to form a power circuit; the bypass switch is connected in parallel to the laser pump tube branch for selectively bypassing the laser pump tube branch. The bypass switch is controlled to periodically switch on and off: when the bypass switch is on, the laser pump tube branch is bypassed, and the DC power supply stores energy in the energy storage inductor; when the bypass switch is off, the energy storage inductor is connected to the power circuit of the laser pump tube branch, and passively and instantaneously matches the real-time positive voltage drop of the laser pump tube branch by relying on the inductor-induced voltage combined with Kirchhoff's voltage law. The power circuit is a pure open-loop structure and does not have a global feedback regulation circuit for the voltage and load current of the laser pump tube branch.

2. The open-loop adaptive driving circuit according to claim 1, characterized in that, The bypass switch includes a first switching device, the two ends of which are respectively connected to the two ends of the laser pump tube branch, for bypassing the current of the laser pump tube branch. By controlling the conduction time of the bypass switch, the maximum charging current of the energy storage inductor is limited.

3. The open-loop adaptive driving circuit according to claim 2, characterized in that, The laser pump tube branch includes a laser pump tube and a circuit matching device. A bypass switch is connected across both ends of the laser pump tube and the circuit matching device to achieve overall bypass of the laser pump tube and the matching device, or a bypass switch. The circuit matching device includes a constant current source, which is used to clamp the charging current of the energy storage inductor at a preset target value.

4. The open-loop adaptive driving circuit according to claim 2, characterized in that, The laser pump tube branch includes a laser pump tube, and a bypass switch is connected across both ends of the laser pump tube.

5. The open-loop adaptive driving circuit according to claim 3, characterized in that, The constant current source includes an operational amplifier and a second switching device, which, together with a sampling resistor, form a local negative feedback loop; the local negative feedback is only used to maintain the constant loop current and does not participate in the adaptive voltage adjustment of the laser pump tube.

6. The open-loop adaptive driving circuit according to claim 2, characterized in that, It also includes a timing controller, the output of which is connected to the control terminal of the bypass switch, and is used to output a timing control signal to drive the bypass switch to periodically switch on and off.

7. The open-loop adaptive driving circuit according to claim 2, characterized in that, The control terminal of the bypass switch is connected to a self-excited oscillation circuit. The self-excited oscillation circuit generates periodic switching signals to drive the bypass switch to open and close, eliminating the need for an external timing controller.

8. The open-loop adaptive driving circuit according to claim 1, characterized in that, The power circuit also includes an auxiliary protection circuit, which consists of a first diode and a second diode, used to suppress the reverse electromotive force of the inductor and prevent reverse current from damaging the DC power supply.

9. An open-loop adaptive driving method, characterized in that, The circuit is applied to the open-loop adaptive circuit according to any one of claims 3 to 8; in the circuit, the DC power supply, the laser pump tube branch, and the energy storage inductor together constitute a power loop, the energy storage inductor is disposed in the power loop between the DC power supply and the anode side of the laser pump tube branch, or in the power loop between the cathode side of the laser pump tube branch and the ground wire; the laser pump tube branch includes a laser pump tube, and the laser pump tube branch is also selectively and independently configured with a constant current source to clamp the energy storage current; the bypass switch enables the laser pump tube branch circuit to be bypassed, and the driving method includes the following steps: S1: Control bypass switch is turned on, current on laser pump tube is reduced. I pump =0; When a constant current source is configured, the DC power supply charges the energy storage inductor, and the constant current source clamps the energy storage current to the target current. I cons When no constant current source is configured, the DC power supply freely charges the energy storage inductor. By controlling the conduction time, the inductor's energy storage current is controlled. I stor Achieve target current I cons ; S2: Control bypass switch is turned off, laser pump tube branch is connected to power circuit, power circuit satisfies voltage relationship , V in This is the DC power supply voltage. V pump This represents the real-time forward voltage drop of the laser pump tube. V cs The voltage drop automatically adjusted by the constant current source; the inductor-induced voltage, on the one hand, matches the DC power supply voltage and the automatically adjusted voltage drop of the constant current source to adapt to the real-time forward voltage drop of the laser pump tube, and on the other hand, provides additional voltage for the rapid rise of the power circuit current, causing the power circuit current to climb to... I stor = I cons The current is kept stable by a constant current source; S3: Repeat steps S1 and S2 to continuously output pulse drive current.

10. The open-loop adaptive driving method according to claim 9, characterized in that, When no independent constant current source is configured, the charging time during the energy storage phase is calculated according to the following formula: , In the formula t For charging time, L This is the value of the energy storage inductance. R For the power circuit resistance, V in This is the DC power supply voltage. I 0 The initial current for charging the inductor, I stor The target current for inductor energy storage.

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