Protection circuit and laser
By designing a protection circuit for pulsed lasers, measuring and responding to the pulse width of the pulse width control signal, the current uncontrollable problem caused by software out of control is solved, ensuring the safety and stability of the laser.
Patent Information
- Application Number
- CN202421933097.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-08-09
AI Technical Summary
When existing pulsed lasers are out of control, the pulse width and amplitude of the current output from the constant current source are uncontrollable, which may cause the laser to be damaged or the laser output energy to be out of control.
A protection circuit is designed to measure the pulse width of the pulse width control signal through the pulse width acquisition circuit. When the pulse width is greater than the preset value, the path between the laser power supply and the laser emission component is disconnected through the timer and switching circuit.
It effectively avoids excessive current through the laser emission component due to out-of-control pulse width control signal, preventing laser damage and laser output energy from being out of control.
Smart Images
Figure CN222953725U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lasers, in particular to a protection circuit and a laser. Background Art
[0002] Pulse lasers are widely used in industrial processing, biomedicine, radar sensing, space exploration, military research and other fields. At present, common pulsed constant current sources are driven by software to generate corresponding pulses, that is, the amplitude and pulse width of the current output by the constant current source depend on the amplitude of the pulse, and the amplitude of the pulse depends on the pulse width of the pulse width control signal. If the software program runs out of control, the pulse width control signal will be out of control, and the pulse width and amplitude of the current output by the constant current source will also be uncontrollable, which may cause damage to the laser or out of control of the laser output energy, and cause harm. Utility Model Content
[0003] The main purpose of the utility model is to propose a protection circuit and a laser, which aims to measure the pulse width of a pulse width control signal and disconnect the path between the laser power supply and the laser emitting component when the pulse width is greater than a preset value, thereby avoiding the problem of excessive current passing through the laser emitting component causing damage to the laser or loss of control of the laser output energy.
[0004] In order to achieve the above object, the utility model provides a protection circuit, which includes:
[0005] Main control circuit;
[0006] A timer, electrically connected to the main control circuit;
[0007] A switch circuit, wherein the switch circuit is arranged in series in the path between the laser power supply and the laser emitting component, and the controlled end of the switch circuit is electrically connected to the control end of the main control circuit;
[0008] A pulse width acquisition circuit, wherein the input end of the pulse width acquisition circuit is connected to the pulse width control signal, and the output end of the pulse width acquisition circuit is electrically connected to the timer; when the pulse width acquisition circuit detects that the pulse width control signal is at a high level, the timer is triggered to start timing; when the pulse width acquisition circuit detects that the pulse width control signal is at a low level, the timer is triggered to stop timing.
[0009] In one implementation, the pulse width acquisition circuit includes:
[0010] A trigger circuit, wherein the input end of the trigger circuit is connected to a pulse width control signal, and the output end of the trigger circuit is electrically connected to the main control circuit; when the pulse width control signal is a rising edge, the trigger circuit outputs a high level, and when the pulse width control signal is a falling edge, the trigger circuit outputs a low level.
[0011] In one embodiment, the input end of the timer is electrically connected to the output end of the trigger circuit, and the output end of the timer is electrically connected to the controlled end of the switch circuit; the timer starts timing when it receives a high level, and if it does not receive a low level within a preset time, it outputs a corresponding control signal to control the switch circuit to shut down.
[0012] In one embodiment, the protection circuit further includes:
[0013] An overcurrent protection circuit, wherein the detection end of the overcurrent protection circuit is electrically connected to the second end of the laser emitting component, and the output end of the overcurrent protection circuit is electrically connected to the controlled end of the switch circuit.
[0014] In one embodiment, the protection circuit further includes:
[0015] An OR gate circuit, wherein the first input end of the OR gate circuit is electrically connected to the output end of the main control circuit, the second input end of the OR gate circuit is electrically connected to the output end of the overcurrent protection circuit, and the output end of the OR gate circuit is electrically connected to the controlled end of the switch circuit.
[0016] In one embodiment, the protection circuit further includes:
[0017] A NOT gate circuit, wherein the output end of the OR gate circuit is electrically connected to the input end of the NOT gate circuit, and the output end of the NOT gate circuit is electrically connected to the controlled end of the switch circuit.
[0018] In one embodiment, the overcurrent protection circuit includes:
[0019] A current sampling circuit, wherein a detection end of the current sampling circuit is electrically connected to the second end of the laser emitting component, and the current sampling circuit is used to detect the current passing through the laser emitting component and output a corresponding current detection signal;
[0020] A comparator circuit, wherein the in-phase end of the comparator circuit is electrically connected to the output end of the current sampling circuit, the inverting end of the comparator circuit is connected to a preset voltage, and the output end of the comparator circuit is electrically connected to the controlled end of the switch circuit; the comparator circuit is used to control the switch circuit to shut down when the voltage of the current detection signal is greater than the preset voltage.
[0021] In one embodiment, the switch circuit comprises:
[0022] A first switch component is arranged in series in the path between the laser power supply and the laser emitting component, and a controlled end of the first switch component is electrically connected to a control end of the main control circuit.
[0023] In one embodiment, the protection circuit further includes:
[0024] An operational amplifier and a first resistor, wherein a first end of the first resistor is electrically connected to a source of the N-channel MOSFET, and a second end of the first resistor is grounded;
[0025] The non-inverting terminal of the operational amplifier is connected to the current amplitude signal, the inverting terminal of the operational amplifier is electrically connected to the first end of the first resistor, and the output terminal of the operational amplifier is electrically connected to the gate of the N-channel MOSFET.
[0026] The utility model also provides a laser, comprising a laser emitting component and any one of the protection circuits described above.
[0027] The technical solution of the utility model uses a pulse width acquisition circuit to collect the pulse width of the pulse width control signal. When the pulse width control signal is at a high level, the timer starts timing, and when the pulse width control signal is at a low level, the timer stops timing. The main control circuit determines the pulse width of the pulse width control signal according to the timing duration of the timer, and controls the switch circuit to shut down when the determined pulse width is greater than the preset pulse width. With such a setting, in actual applications, when the controller responsible for outputting the pulse width control signal loses control and causes the pulse width of the pulse width control signal to be too large, the protection circuit of the utility model can disconnect the path between the laser power supply and the laser emission component to avoid long-term output of excessively long pulse width laser. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0029] Figure 1 This is a schematic diagram of a module of an embodiment of the utility model;
[0030] Figure 2 This is a schematic diagram of a module of an embodiment of the utility model;
[0031] Figure 3 This is a schematic diagram of a module of another embodiment of the utility model;
[0032] Figure 4 This is a module schematic diagram of another embodiment of the utility model;
[0033] Figure 5 This is a module schematic diagram of yet another embodiment of the utility model;
[0034] Figure 6 This is a schematic diagram of the circuit structure of another embodiment of the utility model;
[0035] Figure 7 This is a schematic diagram of the circuit structure of another embodiment of the utility model;
[0036] Figure 8 It is a circuit structure schematic diagram of an existing constant current source circuit.
[0037] Description of Figure Numbers:
[0038] 10. Main control circuit; 11. Timer; 20. Switch circuit; 21. First switch component; 30. Pulse width acquisition circuit; 31. Trigger circuit; 40. Overcurrent protection circuit; 41. Current sampling circuit; 42. Comparator circuit; 50. OR gate circuit; 60. NOT gate circuit.
[0039] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0040] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0041] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0042] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.
[0043] Pulse lasers are widely used in industrial processing, biomedicine, radar sensing, space exploration, military research and other fields. At present, common pulsed constant current sources are driven by software to generate corresponding pulses, that is, the amplitude and pulse width of the current output by the constant current source are controlled by the software. If the software program runs out of control, the pulse width and amplitude of the current output by the constant current source will be uncontrollable, which may cause damage to the laser or out-of-control of the laser output energy, causing harm.
[0044] refer to Figure 8 In the existing constant current source circuit shown, the luminescence degree of the laser emission component Laser depends on the magnitude of the current passing through the laser emission component. The DAC signal (current amplitude signal) and the EN signal (pulse width control signal) are generated by the controller. The DAC signal is output to the gate of the N-channel MOSFET. The conduction degree of the N-channel MOSFET depends on the amplitude of the DAC signal, that is, the current passing through the laser emission component depends on the amplitude of the DAC signal. The amplitude of the DAC signal is determined by the pulse width of the EN signal. The wider the pulse width of the EN signal, the longer the conduction time of the analog switch, and the larger the amplitude of the DAC signal; on the contrary, the narrower the pulse width of the EN signal, the shorter the conduction time of the analog switch, and the smaller the amplitude of the DAC signal.
[0045] When the current amplitude signal DAC or the pulse width control signal EN output by the controller is out of control, the amplitude and pulse width of the current passing through the laser are out of control, which may cause irreversible harm (laser damage) or bring unacceptable risks (energy output out of control).
[0046] To this end, the utility model proposes a protection circuit and a laser, aiming to solve the problem that if the software responsible for driving the existing constant current source circuit is out of control, the amplitude and pulse width of the current output by the constant current source will be uncontrollable, thereby causing damage to the laser or loss of control of the laser output energy.
[0047] refer to Figure 1-7 , a protection circuit comprising:
[0048] Main control circuit 10;
[0049] A timer 11, electrically connected to the main control circuit 10;
[0050] A switch circuit 20, wherein the switch circuit 20 is arranged in series in the path between the laser power supply and the laser emitting component, and the controlled end of the switch circuit 20 is electrically connected to the control end of the main control circuit 10;
[0051] A pulse width acquisition circuit 30, wherein the input end of the pulse width acquisition circuit 30 is connected to the pulse width control signal, and the output end of the pulse width acquisition circuit 30 is electrically connected to the timer 11; when the pulse width acquisition circuit 30 detects that the pulse width control signal is at a high level, the timer 11 of the main control circuit 10 is triggered to start timing; when the pulse width acquisition circuit 30 detects that the pulse width control signal is at a low level, the timer 11 of the main control circuit 10 is triggered to stop timing.
[0052] In this embodiment, the main control circuit 10 can be implemented by a main controller, such as MCU (Microcontroller Unit), DSP (Digital Signal Process), FPGA (Field Programmable Gate Array), SOC (System On Chip), etc.
[0053] In this embodiment, the switching circuit 20 can be implemented by using at least one switching component or analog switch, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc., and / or by using at least one switching device, such as a contactor, a circuit breaker and a relay.
[0054] In this embodiment, the pulse width acquisition circuit 30 can be implemented by a microcontroller, using the GPIO (general purpose input output) pin of the microcontroller to directly read the level change of the pulse width control signal, and calculate the pulse width by the duration of the high level; it can also be implemented by a digital circuit, for example, a trigger can be used to detect and respond to the edge of the pulse width control signal, thereby realizing the measurement of the signal pulse width.
[0055] Specifically, the technical solution of the utility model uses a pulse width acquisition circuit 30 to acquire the pulse width of the pulse width control signal. When the pulse width control signal is at a high level, the pulse width acquisition circuit 30 controls the timer 11 to start timing. When the pulse width control signal is at a low level, the pulse width acquisition circuit 30 controls the timer 11 to stop timing. The main control circuit 10 determines the pulse width of the pulse width control signal according to the timing duration of the timer, and controls the switch circuit 20 to turn off when the determined pulse width is greater than the preset pulse width. With such a setting, in actual applications, when the controller responsible for outputting the pulse width control signal loses control and causes the pulse width of the pulse width control signal to be too large, the protection circuit of the utility model can disconnect the path between the laser power supply and the laser emission component to prevent excessive current from passing through the laser emission component.
[0056] refer to Figure 2 In one embodiment of the present utility model, the pulse width acquisition circuit 30 includes:
[0057] A trigger circuit 31, wherein the input end of the trigger circuit 31 is connected to the pulse width control signal, and the output end of the trigger circuit 31 is electrically connected to the main control circuit 10; when the pulse width control signal is a rising edge, the trigger circuit 31 outputs a falling edge, and when the pulse width control signal is a low level, the trigger circuit 31 outputs a low level.
[0058] In this embodiment, the trigger circuit 31 uses a single trigger, and the input end of the trigger is connected to the pulse width control signal. When the pulse width control signal is at a rising edge, the output end of the trigger will send a high level to the main control circuit 10, and when the pulse width control signal is at a falling edge, the trigger will send a low level to the main control circuit 10. In this way, if the frequency of the clock signal connected to the clock end of the trigger is small enough, when the pulse width control signal is at a rising edge, the trigger can output a high level signal in time, and similarly, when the pulse width control signal is at a falling edge, the trigger can output a low level signal in time. Compared with the pulse width of the pulse width control signal measured by software, the pulse width measurement by software requires sampling, processing and calculation, and these processes all take time, so the response speed is relatively slow, so that the software can only recognize when the pulse width control signal is already at a high level or a low level, and the software cannot recognize in time when the pulse width control signal is at a rising edge or a falling edge, resulting in a certain error in the measured pulse width.
[0059] Furthermore, in this embodiment, the input end of the timer 11 is electrically connected to the output end of the trigger circuit 31, and the output end of the timer 11 is electrically connected to the controlled end of the switch circuit 20; the timer 11 starts timing when it receives a high level, and if it does not receive a low level within a preset time, it outputs a corresponding control signal to control the switch circuit 20 to shut down.
[0060] In this embodiment, the main control circuit 10 is a timer 11. The timer 11 starts timing after receiving the high level output by the trigger. If the low level output by the trigger is not received within the preset time, it means that the pulse width control signal is still at a high level, that is, the pulse width of the pulse width control signal is too large, and the timer 11 outputs a high level to the switch circuit 20 to turn off the switch circuit 20; if the timer 11 receives the low level output by the trigger within the preset time, it means that the pulse width control signal has been flipped to a low level, that is, the pulse width of the pulse width control signal does not exceed the preset value, and the timer 11 is reset and waits for the next high level again. With such a setting, compared with the method of determining the pulse width control signal by software calculation, the protection circuit of the utility model only needs one trigger and one timer 11 to complete the detection of the pulse width of the pulse width control signal, and the cost is relatively low. Moreover, since the trigger and the timer 11 are both based on hardware implementation, they are more stable than software and will not be out of control.
[0061] refer to Figure 3In one embodiment of the present utility model, the protection circuit further includes:
[0062] An overcurrent protection circuit 40, wherein a detection end of the overcurrent protection circuit 40 is electrically connected to the second end of the laser emitting assembly, and an output end of the overcurrent protection circuit 40 is electrically connected to a controlled end of the switch circuit 20;
[0063] When the current passing through the laser emitting component is greater than a preset current value, the overcurrent protection circuit 40 controls the switch circuit 20 to be turned off.
[0064] In this embodiment, when the current passing through the laser emitting component is too large, the overcurrent protection circuit 40 controls the switch circuit 20 to shut down, so as to disconnect the path between the laser power supply and the laser emitting component, thereby preventing excessive current from passing through the laser emitting component, thereby outputting high-power laser to cause harm to the human body, or causing severe heat generation of the circuit and causing circuit damage.
[0065] For further reference, Figure 5 , the overcurrent protection circuit 40 comprises:
[0066] A current sampling circuit 41, wherein the detection end of the current sampling circuit 41 is electrically connected to the second end of the laser emitting component, and the current sampling circuit 41 is used to detect the current passing through the laser emitting component and output a corresponding current detection signal;
[0067] A comparator circuit 42, wherein the in-phase end of the comparator circuit 42 is electrically connected to the output end of the current sampling circuit 41, the inverting end of the comparator circuit 42 is connected to a preset voltage, and the output end of the comparator circuit 42 is electrically connected to the controlled end of the switch circuit 20; the comparator circuit 42 is used to control the switch circuit 20 to shut down when the voltage of the current detection signal is greater than the preset voltage.
[0068] In this embodiment, the current sampling circuit 41 may be a resistor shunt, a current transformer or a Hall sensor, and the comparator circuit 42 may be at least one comparator.
[0069] Furthermore, the current sampling circuit 41 may further include a sampling resistor, and the comparator circuit 42 may use a single comparator. Figure 7 The in-phase terminal of the comparator circuit 42 collects the voltage of the sampling resistor RS and compares the voltage of the sampling resistor RS with a preset voltage. When the voltage of the sampling resistor RS is greater than the preset voltage, a high level signal is output to turn off the switch circuit 20.
[0070] refer to Figure 4 In one embodiment of the present utility model, the protection circuit further includes:
[0071] An OR gate circuit 50, wherein the first input end of the OR gate circuit 50 is electrically connected to the output end of the main control circuit 10, the second input end of the OR gate circuit 50 is electrically connected to the output end of the overcurrent protection circuit 40, and the output end of the OR gate circuit 50 is electrically connected to the controlled end of the switch circuit 20.
[0072] In this embodiment, the OR gate circuit 50 uses at least one OR gate. When the current passing through the laser emitting component is too large or the pulse width of the pulse width control signal is too large, the main control circuit 10 or the comparator circuit 42 outputs a high level to the OR gate circuit 50. After receiving at least one high level, the OR gate circuit 50 will output a high level to the switch circuit 20 to turn off the switch circuit 20.
[0073] Furthermore, when the switch circuit 20 adopts a switch tube that is turned off at a low level, such as an NMOS tube or an NPN transistor, a NOT gate circuit 60 can be set between the output end of the OR gate circuit 50 and the controlled end of the switch circuit 20. When the OR gate circuit 50 outputs a high level, the NOT gate circuit 60 converts the high level into a low level to turn off the switch circuit 20; when the switch circuit 20 adopts a switch tube that is turned off at a high level, such as a PMOS tube or a PNP transistor, there is no need to set the NOT gate circuit 60.
[0074] refer to Figure 7 In one embodiment of the present utility model, the switch circuit 20 includes:
[0075] The first switch component 21 is arranged in series in the path between the laser power supply and the laser emitting component, and the controlled end of the first switch component 21 is electrically connected to the control end of the main control circuit 10.
[0076] In this embodiment, the first switch component 21 can be one of a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc.
[0077] refer to Figure 6 In one embodiment of the present utility model, the protection circuit further includes:
[0078] An operational amplifier and a first resistor, wherein a first end of the first resistor is electrically connected to a source of the N-channel MOSFET, and a second end of the first resistor is grounded;
[0079] The non-inverting terminal of the operational amplifier is connected to the current amplitude signal, the inverting terminal of the operational amplifier is electrically connected to the first end of the first resistor, and the output terminal of the operational amplifier is electrically connected to the gate of the N-channel MOSFET.
[0080] In this embodiment, due to the virtual short characteristic of the operational amplifier, the voltage of its inverting terminal is equal to the voltage of its non-inverting terminal, and the non-inverting terminal of the operational amplifier is used to receive the DAC signal, and the inverting terminal is electrically connected to the first resistor, so the current I passing through the first resistor is equal to the voltage V of the current amplitude signal DAC and the resistance value of the first resistor R1, that is, I = V DAC / R1, since the laser emitting component, N-channel MOSFET and the first resistor are in series, the current passing through the first resistor is equal to the current passing through the laser emitting component, which can be adjusted by adjusting V DAC The value of is used to adjust the current passing through the laser emission component. In this configuration, the operational amplifier usually contains a negative feedback mechanism, which helps to reduce the nonlinear distortion and noise of the current amplitude signal and ensure that the current I (i.e., I = V DAC / R1) is strictly proportional to the voltage value VDAC of the DAC signal, thereby improving the accuracy of controlling the current through the laser emission component. However, the existing constant current source circuit may not be accurate enough in current control due to factors such as the nonlinear relationship between the gate voltage and the source voltage, the gate capacitance effect, and the threshold voltage of the MOSFET itself, because the current amplitude signal is connected to the gate of the N-channel MOSFET.
[0081] It can be understood that the first resistor and the above-mentioned sampling resistor RS can be the same resistor.
[0082] refer to Figure 7 In summary, in combination with the above circuit, the utility model collects the pulse width of the pulse width control signal through the trigger circuit 31. When the pulse width control signal is a rising edge, the trigger circuit 31 outputs a high level to the timer 11, and the timer 11 starts timing. If the low level output by the trigger is not received within the preset time, it means that the pulse width control signal is still at a high level at this time, that is, the pulse width of the pulse width control signal is too large, then the timer 11 outputs a high level to the switch circuit 20 through the OR gate circuit 50 and the NOT gate circuit 60 to turn off the switch circuit 20; if the timer 11 receives the low level output by the trigger within the preset time, it means that the pulse width control signal has been flipped to a low level at this time, that is, the pulse width of the pulse width control signal does not exceed the preset value, and at this time the timer 11 is reset and waits for the next high level again. When the amplitude and pulse width of the current amplitude signal are too large, resulting in an excessive current passing through the laser emitting component, the voltage of the sampling resistor RS is greater than the preset voltage, the comparator circuit 42 outputs a high level, and is output to the switch circuit 20 through the OR gate circuit 50 and the NOT gate circuit 60, so that the switch circuit 20 is turned off. With this arrangement, when the controller responsible for outputting the pulse width control signal loses control and causes the pulse width of the pulse width control signal to be too large, the protection circuit of the utility model can disconnect the path between the laser power supply and the laser emitting component to prevent excessive current from passing through the laser emitting component.
[0083] The utility model also provides a laser, comprising a laser emitting component and the protection circuit as described above.
[0084] It is worth noting that, since the laser of the present invention is based on the above-mentioned protection circuit, the embodiments of the laser of the present invention include all technical solutions of all embodiments of the above-mentioned protection circuit, and the technical effects achieved are also exactly the same, which will not be repeated here.
[0085] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A protection circuit, characterized in that: The protection circuit comprises: Main control circuit; A timer, electrically connected to the main control circuit; A switch circuit, wherein the switch circuit is arranged in series in the path between the laser power supply and the laser emitting component, and the controlled end of the switch circuit is electrically connected to the control end of the main control circuit; A pulse width acquisition circuit, wherein the input end of the pulse width acquisition circuit is connected to the pulse width control signal, and the output end of the pulse width acquisition circuit is electrically connected to the timer; when the pulse width acquisition circuit detects that the pulse width control signal is at a high level, the timer is triggered to start timing; when the pulse width acquisition circuit detects that the pulse width control signal is at a low level, the timer is triggered to stop timing.
2. The protection circuit according to claim 1, characterized in that: The pulse width acquisition circuit comprises: A trigger circuit, wherein the input end of the trigger circuit is connected to a pulse width control signal, and the output end of the trigger circuit is electrically connected to the main control circuit; when the pulse width control signal is a rising edge, the trigger circuit outputs a high level, and when the pulse width control signal is a falling edge, the trigger circuit outputs a low level.
3. The protection circuit according to claim 2, characterized in that: The input end of the timer is electrically connected to the output end of the trigger circuit, and the output end of the timer is electrically connected to the controlled end of the switch circuit; the timer starts timing when it receives a high level, and if it does not receive a low level within a preset time, it outputs a corresponding control signal to control the switch circuit to shut down.
4. The protection circuit according to claim 1, characterized in that: The protection circuit further comprises: An overcurrent protection circuit, wherein the detection end of the overcurrent protection circuit is electrically connected to the second end of the laser emitting component, and the output end of the overcurrent protection circuit is electrically connected to the controlled end of the switch circuit.
5. The protection circuit according to claim 4, characterized in that: The protection circuit further comprises: An OR gate circuit, wherein the first input end of the OR gate circuit is electrically connected to the output end of the main control circuit, the second input end of the OR gate circuit is electrically connected to the output end of the overcurrent protection circuit, and the output end of the OR gate circuit is electrically connected to the controlled end of the switch circuit.
6. The protection circuit according to claim 5, characterized in that: The protection circuit further comprises: A NOT gate circuit, wherein the output end of the OR gate circuit is electrically connected to the input end of the NOT gate circuit, and the output end of the NOT gate circuit is electrically connected to the controlled end of the switch circuit.
7. The protection circuit according to claim 4, characterized in that: The overcurrent protection circuit comprises: A current sampling circuit, wherein a detection end of the current sampling circuit is electrically connected to the second end of the laser emitting component, and the current sampling circuit is used to detect the current passing through the laser emitting component and output a corresponding current detection signal; A comparator circuit, wherein the in-phase end of the comparator circuit is electrically connected to the output end of the current sampling circuit, the inverting end of the comparator circuit is connected to a preset voltage, and the output end of the comparator circuit is electrically connected to the controlled end of the switch circuit; the comparator circuit is used to control the switch circuit to shut down when the voltage of the current detection signal is greater than the preset voltage.
8. The protection circuit according to claim 1, characterized in that: The switch circuit comprises: A first switch component is arranged in series in the path between the laser power supply and the laser emitting component, and a controlled end of the first switch component is electrically connected to a control end of the main control circuit.
9. The protection circuit according to claim 1, characterized in that: The protection circuit further comprises: An operational amplifier and a first resistor, wherein a first end of the first resistor is electrically connected to a source of the N-channel MOSFET, and a second end of the first resistor is grounded; The non-inverting terminal of the operational amplifier is connected to the current amplitude signal, the inverting terminal of the operational amplifier is electrically connected to the first end of the first resistor, and the output terminal of the operational amplifier is electrically connected to the gate of the N-channel MOSFET.
10. A laser, characterized in that: It comprises a laser emitting component and a protection circuit as claimed in any one of claims 1 to 9.