Laser and electrostatic protection circuit, electrostatic protection method and instrument thereof

Abstract

The application discloses a laser and an electrostatic protection circuit, an electrostatic protection method and an instrument thereof, and belongs to the technical field of laser instruments. The laser electrostatic protection circuit comprises a laser signal input interface circuit, a constant current circuit, a signal detection circuit, a power supply circuit, a power supply electrostatic protection circuit and a signal electrostatic protection circuit. The signal detection circuit is connected with the laser signal input interface circuit and is used for detecting a laser signal received by the laser signal input interface circuit. The power supply circuit is connected with the laser signal input interface circuit and is used for providing a power supply for the laser. The power supply electrostatic protection circuit is connected with the power supply circuit and is used for performing electrostatic protection on the power supply output by the power supply circuit. The signal electrostatic protection circuit is connected with the signal detection circuit and is used for performing electrostatic protection on the signal output by the signal detection circuit. The application can eliminate static electricity generated in the process of using the laser and improve the beam quality of the laser.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of laser equipment, and relates to a laser, in particular to a laser and an electrostatic protection circuit thereof. BACKGROUND

[0002] A laser is a device capable of emitting laser. There are many types of lasers, which can be classified into gas lasers, solid-state lasers, semiconductor lasers, dye lasers, etc. according to the working medium, among which the semiconductor laser is one of the most commonly used lasers at present.

[0003] The semiconductor laser has the characteristics of small size, long service life, and can be pumped by a simple injection current. Its working current and voltage are compatible with integrated circuits, so it can be monolithically integrated and widely used in laser communication, optical storage, optical gyroscopes, laser printing, ranging, and radar. However, during use, external factors such as static electricity can cause partial discharge inside the laser, thereby weakening the beam quality of the laser and affecting the use effect of the laser.

[0004] Therefore, there is an urgent need to design a new laser to overcome at least some of the above-mentioned deficiencies of the existing laser. SUMMARY

[0005] The present application provides a laser and an electrostatic protection circuit, an electrostatic protection method, and an instrument, which can eliminate static electricity generated during use of the laser and improve the beam quality of the laser.

[0006] To solve the above technical problems, according to one aspect of the present application, the following technical solution is adopted:

[0007] A laser electrostatic protection circuit, comprising: a laser signal input interface circuit, a constant current circuit, a signal detection circuit, a power supply circuit, a power supply electrostatic protection circuit, and a signal electrostatic protection circuit;

[0008] The constant current circuit is connected to the signal detection circuit, the power supply protection circuit, and the signal protection circuit, respectively, and provides a constant current power supply for the signal detection circuit, the power supply protection circuit, and the signal protection circuit;

[0009] The signal detection circuit is connected to the laser signal input interface circuit, and is used to detect the laser signal received by the laser signal input interface circuit;

[0010] The power supply circuit is connected to the laser signal input interface circuit, and is used to provide a power supply for the laser;

[0011] The power supply electrostatic protection circuit is connected to the power supply circuit, and is used to perform electrostatic protection on the power supply output by the power supply circuit;

[0012] The signal electrostatic protection circuit is connected to the signal detection circuit, and is used for electrostatic protection of a signal output by the signal detection circuit.

[0013] As an embodiment of the present application, the power electrostatic protection circuit comprises a first diode D16, a second diode D17, a third diode D18, a fourth diode D19, a fifth diode D20, a sixth diode D21, a second inductor L2, a ninth resistor R29, and a third resistor R32, and a second connection terminal P2.

[0014] A negative electrode of the second diode D17 is connected to a power supply voltage and a first end of the ninth resistor R29, and a positive electrode of the second diode D17 is grounded.

[0015] A second end of the ninth resistor R29 is connected to a positive electrode of the first diode D16, and a negative electrode of the first diode D16 is connected to a first end of the second inductor L2.

[0016] A second end of the second inductor L2 is connected to a first pin of the second connection terminal P2, a negative electrode of the third diode D18, a negative electrode of the fourth diode D19, and a negative electrode of the fifth diode D20.

[0017] A positive electrode of the third diode D18 is grounded, and a second pin of the second connection terminal P2 is connected to a positive electrode of the fourth diode D19, a positive electrode of the fifth diode D20, and a negative electrode of the sixth diode D21.

[0018] A positive electrode of the sixth diode D21 is grounded, a third pin of the second connection terminal P2 is connected to a first end of the third resistor R32, and a second end of the third resistor R32 is grounded.

[0019] As an embodiment of the present application, when the semiconductor laser works, a semiconductor substance emits light by interband transition, two parallel reflecting surfaces formed by cleavage planes of a semiconductor crystal are used as reflecting mirrors to form a resonant cavity, light oscillation and feedback are realized, light radiation amplification is generated, and laser is emitted; the second resistor R29, the first diode D16, and the second inductor L2 are added to a power supply of the laser to limit current, and laser damage caused by sudden change of current is prevented.

[0020] When static electricity is applied to the laser power supply: the first eight diode D18, the first nine diode D19, and the second one diode D21 are reverse-conducted, one end of the protection device is connected to the power signal, and the other end is connected to the ground, forming an equipotential body, thereby preventing the accumulation and discharge of static electricity; although the COM and LD signals inside the laser can be equivalent to a forward diode, the impedance of the first nine diode D19 when reverse-conducting is relatively small compared to the impedance inside the laser. Therefore, when static electricity is generated at the power supply, most of it will be released to the ground, and only a small part will flow into the laser, thereby protecting the laser;

[0021] When -4KV static electricity is applied at AGND: the forward conductivity of the second zero diode D20 will absorb the spike generated by the static electricity and then lead it to the ground; the photodiode PD and the laser diode LD inside the laser can be equivalent to a forward diode. Due to the current limiting effect of the third resistor R32 and the impedance of the wire between the second connection terminal P2 and the laser, the static electricity interference will be suppressed, and even if negative static electricity is generated, it will play a good protective role.

[0022] As an embodiment of the present invention, the signal electrostatic protection circuit includes a third operational amplifier U3, a first eight diode D18, a second zero diode D20, a second first diode D21, a second third diode D23, a second fourth diode D24, a third second resistor R32 and a third third resistor R33;

[0023] The first pin of the second connection terminal P2 is respectively connected to the cathode of the first eight diodes D18, the cathode of the second zero diode D20, the cathode of the second second diode D22, and the cathode of the second fourth diode D24; the anode of the first eight diodes D18 is grounded;

[0024] The second pin of the second connection terminal P2 is connected to the anode of the second zero diode D20 and the cathode of the second first diode D21 respectively, and the anode of the second first diode D21 is grounded;

[0025] The third pin of the second connection terminal P2 is connected to the anode of the second-second diode D22, the anode of the second-fourth diode D24, the first end of the second-third diode D23, the first end of the third-second resistor R32, the first end of the third-third resistor R33, and the fourth pin of the third operational amplifier U3; the second end of the third-second resistor R32 is grounded, and the second end of the second-third diode D23 is grounded;

[0026] The fourth pin of the third operational amplifier U3 serves as a non-inverting input terminal, the third pin of the third operational amplifier U3 serves as an inverting input terminal, and the first pin of the third operational amplifier U3 is connected to the second end of the third resistor R33.

[0027] As an embodiment of the present invention, when static electricity is applied to the signal end LD, since the first eight diodes D18, the second zero diodes D20, and the second one diodes D21 are close to the laser terminal and are in a reverse conduction state, the electrostatic charge will be released to the ground, thereby protecting the laser; when static electricity is applied to the signal end PD, the second two diodes D22 are forward-conducted, and the second four diodes D24, the first eight diodes D18, and the second three diodes D23 are close to the laser terminal and are in a reverse conduction state, the electrostatic charge will be released to the ground, thereby protecting the laser; after the two signal ends have undergone electrostatic testing, the laser light intensity has not changed.

[0028] As an embodiment of the present invention, the constant current circuit includes a first operational amplifier U1, a second transistor Q2, a second sixth diode D26, a second seventh diode D27, a third fifth resistor R35, a third sixth resistor R36, a third seventh resistor R37, a third eighth resistor R38 and a first connection terminal P1;

[0029] The non-inverting input terminal of the first operational amplifier U1 is connected to the second end of the third sixth resistor R36; the inverting input terminal of the first operational amplifier U1 is respectively connected to the emitter of the second transistor Q2, the first end of the second sixth diode D26, and the first end of the third eighth resistor R38, and the second end of the second sixth diode D26 and the second end of the third fifth resistor R35 are respectively grounded;

[0030] The collector of the second transistor Q2 is connected to the second pin of the first connection terminal P1 and the cathode of the second seventh diode D27 respectively; the anode of the second seventh diode D27 is grounded;

[0031] The third pin of the first connection terminal P1 is connected to a first end of the third fifth resistor R35 , and a second end of the third fifth resistor R35 is grounded.

[0032] As an embodiment of the present invention, the DAC signal is a controllable voltage output by the single-chip microcomputer, which can change according to the change of the laser feedback signal PD; the DAC signal is connected to the positive input terminal of the first operational amplifier U1. Since the voltages of the positive input terminal and the reverse input terminal are always equal and there is no current input, the voltage of the reverse input terminal of the first operational amplifier U1 is constant. According to I=U / R, the current flowing through the second transistor Q2 is constant, thereby realizing the laser constant current source driving mode.

[0033] According to another aspect of the present invention, the following technical solution is adopted: a laser, comprising the above-mentioned laser electrostatic protection circuit.

[0034] According to another aspect of the present invention, the following technical solution is adopted: an instrument, wherein the instrument includes the above-mentioned laser electrostatic protection circuit.

[0035] According to still another aspect of the present application, the technical solution is as follows: an electrostatic protection method of the above laser electrostatic protection circuit, the electrostatic protection method comprising:

[0036] When no static electricity is generated: the power supply circuit provides voltage for the laser; the same direction input end of the first operational amplifier U1 in the constant current source circuit receives the controllable voltage signal DAC of the MCU, and since the voltage at the forward input end and the reverse input end is always equal and no current is input, the voltage at the reverse input end of the first operational amplifier U1 is constant, and according to I=U / R, the current flowing through the second triode Q2 is constant, thus realizing the mode of constant current source driving of the laser; the PD signal is transmitted to the single-chip microcomputer as a feedback signal, and the single-chip microcomputer adjusts the controllable voltage signal DAC through the signal;

[0037] When static electricity is generated: the semiconductor laser works by using the band-to-band transition of a semiconductor substance to emit light, using the cleavage surface of a semiconductor crystal to form two parallel reflecting mirrors as reflecting mirrors, to form a resonant cavity, so that light oscillates and feeds back, to produce optical radiation amplification and emit laser; the second nine resistor R29, the first six diode D16 and the second inductor L2 are added to the laser power supply to limit the current, to prevent the laser from being damaged due to sudden current change;

[0038] When static electricity is applied at the laser power supply: the first eight diode D18, the first nine diode D19 and the second twelve diode D21 are reversely conducted, the protection device one end is connected to the power supply signal, and the other end is connected to the ground, to form an equipotential body, thus preventing the accumulation and discharge of static electricity charges; although the COM and LD signals inside the laser can be equivalent to a forward diode, the impedance of the first nine diode D19 when reversely conducted is relatively small compared with the impedance inside the laser, and thus when static electricity charges are generated at the power supply, most of them will be released to the ground, and only a small part will flow into the laser, thus protecting the laser;

[0039] When -4KV static electricity is applied at the AGND: the second zero diode D20 will absorb the spike generated by the static electricity and then lead it to the ground; the photodiode PD and the laser diode LD inside the laser can be equivalent to a forward diode, and due to the current limiting effect of the third two resistor R32 and the impedance effect of the wire between the second connection terminal P2 and the laser, the static electricity interference will be suppressed, and even when negative static electricity is generated, the laser will also be well protected.

[0040] When static electricity is applied to the signal end LD, the static charge is released to the ground due to the first eight diode D18, the second zero diode D20, and the second one diode D21 close to the laser terminal and in the reverse conduction state, thereby protecting the laser; when static electricity is applied to the signal end PD, the second two diode D22 is forward conducting, and the second four diode D24, the first eight diode D18, and the second three diode D23 are close to the laser terminal and in the reverse conduction state, and the static charge is released to the ground, thereby protecting the laser; after the static electricity test, the light intensity of the laser is not changed.

[0041] The laser and the static electricity protection circuit, the static electricity protection method, and the instrument and meter provided by the application can eliminate static electricity generated during the use of the laser and improve the beam quality of the laser. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a composition schematic diagram of the laser static electricity protection circuit in an embodiment of the application.

[0043] Figure 2 It is an internal equivalent diagram of the semiconductor laser.

[0044] Figure 3 It is a circuit schematic diagram of the power protection circuit in an embodiment of the application.

[0045] Figure 4 It is a circuit schematic diagram of the power protection circuit in an embodiment of the application.

[0046] Figure 5 It is a circuit schematic diagram of the constant current source circuit in an embodiment of the application. DETAILED DESCRIPTION

[0047] The preferred embodiments of the application are described in detail below with reference to the drawings.

[0048] In order to further understand the application, the preferred embodiments of the application are described below with reference to the embodiments, but it should be understood that the description is only for further illustrating the features and advantages of the application, and is not a limitation on the claims of the application.

[0049] The description in this part is only for several typical embodiments, and the application is not limited to the scope described in the embodiments. The same or similar prior art means and some technical features in the embodiments can be replaced with each other, which is within the description and protection scope of the application.

[0050] The description of the steps in each embodiment in the specification is only for convenience, and the implementation mode of the application is not limited by the order of the step implementation.

[0051] "Connected" in the specification includes both direct connection and indirect connection, such as connection through some active devices, passive devices or electrically conductive media; it can also include connection through other active devices or passive devices on the basis of achieving the same or similar functional purposes known to those skilled in the art, such as connection through circuits or components such as switches, follower circuits, etc.

[0052] The application discloses a laser static protection circuit, Figure 1 For the composition schematic diagram of the laser static protection circuit in an embodiment of the application; please refer to Figure 1 The laser static protection circuit comprises a laser signal input interface circuit 1, a constant current circuit 2, a signal detection circuit 3, a power supply circuit 4, a power supply static protection circuit 5 and a signal static protection circuit 6.

[0053] The constant current circuit 2 is connected with the signal detection circuit 3, the power supply protection circuit 5 and the signal protection circuit 6 respectively, and provides constant current power supply for the signal detection circuit 3, the power supply protection circuit 5 and the signal protection circuit 6.

[0054] The signal detection circuit 3 is connected with the laser signal input interface circuit 1, and is used for detecting the laser signal received by the laser signal input interface circuit 1. The power supply circuit 4 is connected with the laser signal input interface circuit 1, and is used for providing power supply for the laser. The power supply static protection circuit 5 is connected with the power supply circuit 4, and is used for performing static protection on the power supply output by the power supply circuit 4. The signal static protection circuit 6 is connected with the signal detection circuit 3, and is used for performing static protection on the signal output by the signal detection circuit 3.

[0055] Figure 3 For the circuit schematic diagram of the power supply protection circuit in an embodiment of the application; please refer to Figure 3 In an embodiment of the application, the power supply static protection circuit comprises a first 62 diode D16, a first 72 diode D17, a first 82 diode D18, a first 92 diode D19, a second 02 diode D20, a second 12 diode D21, a second inductor L2, a second 9 resistor R29, a third 2 resistor R32 and a second connection terminal P2.

[0056] The cathode of the first-seventh diode D17 is connected to the power supply voltage and the first end of the second-nineth resistor R29, and the anode of the first-seventh diode D17 is grounded; the second end of the second-nineth resistor R29 is connected to the anode of the first-sixth diode D16, and the cathode of the first-sixth diode D16 is connected to the first end of the second inductor L2; the second end of the second inductor L2 is respectively connected to the first pin of the second connection terminal P2, the cathode of the first-eighth diode D18, the cathode of the first-nineth diode D19, and the cathode of the second-zero diode D20; the anode of the first-eighth diode D18 is grounded, and the second pin of the second connection terminal P2 is respectively connected to the anode of the first-nineth diode D19, the anode of the second-zero diode D20, and the cathode of the second-first diode D21; the anode of the second-first diode D21 is grounded, the third pin of the second connection terminal P2 is connected to the first end of the third-second resistor R32, and the second end of the third-second resistor R32 is grounded.

[0057] When a semiconductor laser is working, it uses semiconductor materials (i.e., electrons) to emit light by transitioning between energy bands. The cleavage planes of the semiconductor crystal form two parallel reflection surfaces as reflectors to form a resonant cavity, causing light oscillation and feedback, generating light radiation amplification and emitting laser light. A second resistor R29, a first diode D16, and a second inductor L2 are added to the laser power supply to limit the current and prevent current mutations from causing damage to the laser.

[0058] When static electricity is applied to the laser power supply (A5V): the ESD protection device's first eight diodes D18, first nine diodes D19, and second one diodes D21 conduct in reverse, one end of the protection device is connected to the power signal, and the other end is connected to the ground, forming an equipotential body, thereby preventing the accumulation and discharge of static electricity charges; Figure 2 As shown, although the COM and LD signals inside the laser are equivalent to a forward diode, the impedance of the first nine diodes D19 of the ESD protection device when reverse conducting is relatively small compared to the impedance inside the laser. Therefore, when electrostatic charge is generated at the power supply, most of it will be released to the ground, and only a small part will flow into the laser, thereby protecting the laser.

[0059] When -4KV static electricity is applied at AGND: the forward conductivity of the second zero diode D20 will absorb the spike generated by the static electricity and then lead it to the ground; the photodiode PD and the laser diode LD inside the laser can be equivalent to a forward diode. Due to the current limiting effect of the third resistor R32 and the impedance of the wire between the second connection terminal P2 and the laser, the static electricity interference will be suppressed, and even if negative static electricity is generated, it will play a good protective role.

[0060] Figure 4 This is a circuit diagram of a power protection circuit according to an embodiment of the present invention;Figure 4 In one embodiment of the present invention, the signal electrostatic protection circuit includes a third operational amplifier U3, a first eight-diode D18, a second zero diode D20, a second first diode D21, a second third diode D23, a second fourth diode D24, a third second resistor R32 and a third third resistor R33.

[0061] The first pin of the second connection terminal P2 is respectively connected to the cathode of the first eight-diode D18, the cathode of the second zero diode D20, the cathode of the second second diode D22, and the cathode of the second fourth diode D24; the anode of the first eight-diode D18 is grounded; the second pin of the second connection terminal P2 is respectively connected to the anode of the second zero diode D20 and the cathode of the second first diode D21, and the anode of the second first diode D21 is grounded.

[0062] The third pin of the second connection terminal P2 is connected to the anode of the second-second diode D22, the anode of the second-fourth diode D24, the first end of the second-third diode D23, the first end of the third-second resistor R32, the first end of the third-third resistor R33, and the fourth pin of the third operational amplifier U3; the second end of the third-second resistor R32 is grounded, and the second end of the second-third diode D23 is grounded; the fourth pin of the third operational amplifier U3 serves as the non-inverting input terminal, the third pin of the third operational amplifier U3 serves as the inverting input terminal, and the first pin of the third operational amplifier U3 is connected to the second end of the third-third resistor R33.

[0063] When static electricity is applied to the signal end LD, since the first eight diodes D18, the second zero diodes D20, and the second first diodes D21 are close to the laser terminal and are in the reverse conduction state, the electrostatic charge will be released to the ground by the ESD protection device, thereby protecting the laser; when static electricity is applied to the signal end PD, the second second diode D22 is forward-conducted, and the second fourth diode D24, the first eight diodes D18, and the second third diodes D23 are close to the laser terminal and are in the reverse conduction state, the electrostatic charge will be released to the ground by the ESD protection device, thereby protecting the laser; after the two signal ends have undergone electrostatic testing, the laser light intensity has not changed.

[0064] Figure 5 is a circuit diagram of a constant current source circuit in one embodiment of the present invention; please refer to Figure 5 In one embodiment of the present invention, the constant current circuit includes a first operational amplifier U1, a second transistor Q2, a second sixth diode D26, a second seventh diode D27, a third fifth resistor R35, a third sixth resistor R36, a third seventh resistor R37, a third eighth resistor R38 and a first connecting terminal P1.

[0065] The noninverting input end of the first operational amplifier U1 is connected with the second end of the third sixth resistor R36; the inverting input end of the first operational amplifier U1 is connected with the emitter of the second third transistor Q2, the first end of the second sixth diode D26 and the first end of the third eighth resistor R38 respectively, and the second end of the second sixth diode D26 and the second end of the third fifth resistor R35 are grounded respectively. The collector of the second third transistor Q2 is connected with the second pin of the first connecting terminal P1 and the negative electrode of the second seventh diode D27 respectively; the positive electrode of the second seventh diode D27 is grounded; the third pin of the first connecting terminal P1 is connected with the first end of the third fifth resistor R35, and the second end of the third fifth resistor R35 is grounded.

[0066] The DAC signal is a controllable voltage output by the single-chip microcomputer and can be changed according to the change of the laser feedback signal PD; the DAC signal is connected to the forward input end of the first operational amplifier U1, and since the voltage at the forward input end and the voltage at the reverse input end are always equal and no current is input, the voltage at the reverse input end of the first operational amplifier U1 is constant, and according to I=U / R, the current flowing through the second third transistor Q2 is constant, so that the laser constant current source driving mode is realized.

[0067] The application further discloses a laser, which comprises the laser electrostatic protection circuit.

[0068] The application further discloses an instrument, which comprises the laser electrostatic protection circuit.

[0069] The application further discloses an electrostatic protection method of the laser electrostatic protection circuit, and the electrostatic protection method comprises the following steps:

[0070] When no electrostatic is generated: the power supply circuit provides voltage for the laser; the same direction input end of the first operational amplifier U1 in the constant current source circuit receives the controllable voltage signal DAC of the MCU, since the voltage at the forward input end and the voltage at the reverse input end are always equal and no current is input, the voltage at the reverse input end of the first operational amplifier U1 is constant, and according to I=U / R, the current flowing through the second third transistor Q2 is constant, so that the laser constant current source driving mode is realized; the PD signal is transmitted to the single-chip microcomputer as a feedback signal, and the single-chip microcomputer adjusts the controllable voltage signal DAC through the signal;

[0071] When electrostatic is generated: the semiconductor laser works by using the band-to-band transition of semiconductor substances (i.e. by using electrons) to emit light, using the cleavage surface of the semiconductor crystal to form two parallel reflecting mirrors as reflecting mirrors, forming a resonant cavity, so that light oscillates and feeds back, light radiation amplification is generated, and laser is emitted; the second ninth resistor R29, the first sixth diode D16 and the second inductor L2 are added at the power supply of the laser to limit the current, so as to prevent the laser from being damaged due to sudden change of current.

[0072] When static electricity is applied at the laser power supply (A5V): the first eighth diode D18, the first ninth diode D19 and the second twelfth diode D21 are reversely conducted, the protection device is connected to the power supply signal at one end and to the ground at the other end, forming an equipotential body, thereby preventing the accumulation and discharge of static electricity; the impedance of the first ninth diode D19 when reversely conducted is relatively small compared with the impedance inside the laser, so when static electricity is generated at the power supply, most of it is discharged to the ground, and only a small amount flows into the laser, thereby protecting the laser; Figure 1 As shown in the figure, although the laser internal COM and LD signal can be equivalent to a forward diode, the impedance of the first ninth diode D19 when reversely conducted is relatively small compared with the impedance inside the laser, so when static electricity is generated at the power supply, most of it is discharged to the ground, and only a small amount flows into the laser, thereby protecting the laser;

[0073] When static electricity of -4KV is applied at AGND: the second zero diode D20 is forward conducted, absorbing the static electricity spikes and then leading them to the ground; the laser internal photodiode PD and laser diode LD can be equivalent to a forward diode, and the current limiting effect of the third second resistor R32 and the impedance of the wire between the second connection terminal P2 and the laser inhibit static interference, so even when negative static electricity is generated, the laser is well protected.

[0074] When static electricity is applied at the signal end LD: the first eighth diode D18, the second zero diode D20 and the second twelfth diode D21 are close to the laser terminal and reversely conducted, so the static electricity is discharged to the ground by the ESD protection device, thereby protecting the laser; when static electricity is applied at the signal end PD: the second twelfth diode D22 is forward conducted, and the second fourth diode D24, the first eighth diode D18 and the second third diode D23 are close to the laser terminal and reversely conducted, so the static electricity is discharged to the ground by the ESD protection device, thereby protecting the laser; after the static electricity test, the light intensity of the laser is not changed.

[0075] In summary, the laser, the static electricity protection circuit, the static electricity protection method and the instrument and meter provided by the application can eliminate static electricity generated during the use of the laser and improve the beam quality of the laser.

[0076] It should be noted that the present application can be implemented in software and / or a combination of software and hardware; for example, it can be implemented by using an application specific integrated circuit (ASIC), a general purpose computer or any other similar hardware device. In some embodiments, the software program of the present application can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including the related data structure) can be stored in a computer readable recording medium; for example, a RAM memory, a magnetic or optical drive or a soft disk and similar devices. In addition, some steps or functions of the present application can be implemented by using hardware; for example, as a circuit cooperating with the processor to execute the respective steps or functions.

[0077] The technical features of the above-described embodiments can be combined in any manner, and for the sake of brevity, not all possible combinations are described. However, it is to be understood that any combination of the disclosed technical features is within the scope of the present specification.

[0078] The description and applications of the present application are illustrative, and not intended to limit the scope of the present application. The effects and advantages of the embodiments described above can be affected by various factors, and the description of the effects and advantages is not intended to limit the embodiments. Variations and modifications of the disclosed embodiments can be possible, and alternatives and equivalents of the embodiments are known to those of ordinary skill in the art. It will be apparent to those of ordinary skill in the art that the present application can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and elements without departing from the spirit or essential characteristics of the present application. Other variations and modifications of the disclosed embodiments are possible in light of the above teachings, and it is to be understood that within the scope of the appended claims, the present application can be practiced otherwise than as specifically described.

Claims

1. A laser electrostatic protection circuit, characterized in that: The laser electrostatic protection circuit includes: a laser signal input interface circuit, a constant current circuit, a signal detection circuit, a power supply circuit, a power supply electrostatic protection circuit and a signal electrostatic protection circuit; The constant current circuit is connected to the signal detection circuit, the power protection circuit and the signal protection circuit respectively, and provides a constant current power supply for the signal detection circuit, the power protection circuit and the signal protection circuit; The signal detection circuit is connected to the laser signal input interface circuit to detect the laser signal received by the laser signal input interface circuit; The power supply circuit is connected to the laser signal input interface circuit to provide power to the laser; The power supply electrostatic protection circuit is connected to the power supply circuit and is used to provide electrostatic protection for the power output by the power supply circuit; The signal electrostatic protection circuit is connected to the signal detection circuit to perform electrostatic protection on the signal output by the signal detection circuit; The power supply electrostatic protection circuit includes a first sixth diode D16, a first seventh diode D17, a first eighth diode D18, a first ninth diode D19, a second zeroth diode D20, a second first diode D21, a second inductor L2, a second ninth resistor R29, a third second resistor R32 and a second connection terminal P2; The cathode of the first seven diodes D17 is connected to the power supply voltage and the first end of the second nine resistor R29, and the anode of the first seven diodes D17 is grounded; The second end of the second-ninth resistor R29 is connected to the anode of the first sixth diode D16, and the cathode of the first sixth diode D16 is connected to the first end of the second inductor L2; The second end of the second inductor L2 is respectively connected to the first pin of the second connection terminal P2, the cathode of the first eight diode D18, the cathode of the first nine diode D19, and the cathode of the second zero diode D20; The anode of the first eight diodes D18 is grounded, and the second pin of the second connection terminal P2 is respectively connected to the anode of the first nine diodes D19, the anode of the second zero diode D20, and the cathode of the second one diode D21; An anode of the second-first diode D21 is grounded, a third pin of the second connection terminal P2 is connected to a first end of a third-second resistor R32 , and a second end of the third-second resistor R32 is grounded.

2. The laser electrostatic protection circuit according to claim 1, characterized in that: When a semiconductor laser is working, it uses semiconductor materials to emit light by transitioning between energy bands. The cleavage plane of the semiconductor crystal forms two parallel reflection surfaces as reflectors, forming a resonant cavity, which causes light oscillation and feedback, resulting in light radiation amplification and laser emission. The second resistor R29, the first diode D16, and the second inductor L2 are added to the laser power supply to limit the current and prevent current mutations from causing damage to the laser. When static electricity is applied to the laser power supply: the first eight diode D18, the first nine diode D19, and the second one diode D21 are reverse-conducted, one end of the protection device is connected to the power signal, and the other end is connected to the ground, forming an equipotential body, thereby preventing the accumulation and discharge of static electricity; although the COM and LD signals inside the laser can be equivalent to a forward diode, the impedance of the first nine diode D19 when reverse-conducting is relatively small compared to the impedance inside the laser. Therefore, when static electricity is generated at the power supply, most of it will be released to the ground, and only a small part will flow into the laser, thereby protecting the laser; When -4KV static electricity is applied at AGND: the forward conductivity of the second zero diode D20 will absorb the spike generated by the static electricity and then lead it to the ground; the photodiode PD and the laser diode LD inside the laser can be equivalent to a forward diode. Due to the current limiting effect of the third resistor R32 and the impedance of the wire between the second connection terminal P2 and the laser, the static electricity interference will be suppressed, and even if negative static electricity is generated, it will play a good protective role.

3. The laser electrostatic protection circuit according to claim 1, characterized in that: The signal electrostatic protection circuit includes a third operational amplifier U3, a first eight diode D18, a second zero diode D20, a second first diode D21, a second third diode D23, a second fourth diode D24, a third second resistor R32 and a third third resistor R33; The first pin of the second connection terminal P2 is respectively connected to the cathode of the first eight diodes D18, the cathode of the second zero diode D20, the cathode of the second second diode D22, and the cathode of the second fourth diode D24; the anode of the first eight diodes D18 is grounded; The second pin of the second connection terminal P2 is connected to the anode of the second zero diode D20 and the cathode of the second first diode D21 respectively, and the anode of the second first diode D21 is grounded; The third pin of the second connection terminal P2 is connected to the anode of the second-second diode D22, the anode of the second-fourth diode D24, the first end of the second-third diode D23, the first end of the third-second resistor R32, the first end of the third-third resistor R33, and the fourth pin of the third operational amplifier U3; the second end of the third-second resistor R32 is grounded, and the second end of the second-third diode D23 is grounded; The fourth pin of the third operational amplifier U3 serves as a non-inverting input terminal, the third pin of the third operational amplifier U3 serves as an inverting input terminal, and the first pin of the third operational amplifier U3 is connected to the second end of the third resistor R33.

4. The laser electrostatic protection circuit according to claim 3, characterized in that: When static electricity is applied to the signal end LD, since the first eight diodes D18, the second zero diodes D20, and the second first diodes D21 are close to the laser terminals and are in the reverse conduction state, the static electricity charge will be released to the ground, thereby protecting the laser; when static electricity is applied to the signal end PD, the second second diode D22 is forward-conducted, and the second fourth diode D24, the first eight diodes D18, and the second third diodes D23 are close to the laser terminals and are in the reverse conduction state, the static electricity charge will be released to the ground, thereby protecting the laser; after the two signal ends have undergone static electricity testing, the laser light intensity has not changed.

5. The laser electrostatic protection circuit according to claim 3, characterized in that: The constant current circuit includes a first operational amplifier U1, a second transistor Q2, a second sixth diode D26, a second seventh diode D27, a third fifth resistor R35, a third sixth resistor R36, a third seventh resistor R37, a third eighth resistor R38 and a first connecting terminal P1; The non-inverting input terminal of the first operational amplifier U1 is connected to the second end of the third resistor R36; the inverting input terminal of the first operational amplifier U1 is respectively connected to the emitter of the second transistor Q2, the first end of the second diode D26, and the first end of the third resistor R38, and the second end of the second diode D26 and the second end of the third resistor R38 are respectively grounded; The collector of the second transistor Q2 is connected to the second pin of the first connection terminal P1 and the cathode of the second seventh diode D27 respectively; the anode of the second seventh diode D27 is grounded; The third pin of the first connection terminal P1 is connected to a first end of the third fifth resistor R35 , and a second end of the third fifth resistor R35 is grounded.

6. The laser electrostatic protection circuit according to claim 5, characterized in that: The DAC signal is a controllable voltage output by the microcontroller, which can change according to the laser feedback signal PD. The DAC signal is connected to the positive input terminal of the first operational amplifier U1. Since the voltages of the positive input terminal and the reverse input terminal are always equal and there is no current input, the voltage of the reverse input terminal of the first operational amplifier U1 is constant. According to I=U / R, the current flowing through the second transistor Q2 is constant, thereby realizing the laser constant current source drive mode.

7. A laser, characterized in that: The laser includes the laser electrostatic protection circuit according to any one of claims 1 to 6.

8. An instrument, characterized in that: The instrument includes the laser electrostatic protection circuit according to any one of claims 1 to 6.

9. An electrostatic protection method using the laser electrostatic protection circuit according to any one of claims 3 to 6, characterized in that: The electrostatic protection method comprises: When no static electricity is generated: the power supply circuit provides voltage for the laser; the non-inverting input terminal of the first operational amplifier U1 in the constant current source circuit receives the controllable voltage signal DAC of the MCU. Since the voltages of the positive input terminal and the reverse input terminal are always equal and there is no current input, the voltage of the reverse input terminal of the first operational amplifier U1 is constant. According to I=U / R, the current flowing through the second transistor Q2 is constant, thus realizing the constant current source driving mode of the laser; the PD signal is transmitted to the single-chip microcomputer as a feedback signal, and the single-chip microcomputer adjusts the controllable voltage signal DAC through this signal; When static electricity is generated: When a semiconductor laser is working, it uses semiconductor materials to emit light by transitioning between energy bands. The cleavage surface of the semiconductor crystal forms two parallel reflection surfaces as reflectors to form a resonant cavity, which makes the light oscillate and feedback, generating light radiation amplification and emitting laser light. The second nine resistors R29, the first six diodes D16, and the second inductor L2 are added to the laser power supply to limit the current and prevent the laser from being damaged due to sudden current changes. When static electricity is applied to the laser power supply: the first eight diode D18, the first nine diode D19, and the second one diode D21 are reverse-conducted, one end of the protection device is connected to the power signal, and the other end is connected to the ground, forming an equipotential body, thereby preventing the accumulation and discharge of static electricity; although the COM and LD signals inside the laser can be equivalent to a forward diode, the impedance of the first nine diode D19 when reverse-conducting is relatively small compared to the impedance inside the laser. Therefore, when static electricity is generated at the power supply, most of it will be released to the ground, and only a small part will flow into the laser, thereby protecting the laser; When -4kV static electricity is applied at AGND: the forward conductivity of the second zero diode D20 absorbs the spike generated by the static electricity and then leads it to the ground; the photodiode PD and the laser diode LD inside the laser are equivalent to a forward diode. The current limiting effect of the third resistor R32 and the impedance of the wire between the second connection terminal P2 and the laser suppress static electricity interference, which provides good protection even when negative static electricity is generated; When static electricity is applied to the signal end LD, since the first eight diodes D18, the second zero diodes D20, and the second first diodes D21 are close to the laser terminals and are in the reverse conduction state, the static electricity charge will be released to the ground, thereby protecting the laser; when static electricity is applied to the signal end PD, the second second diode D22 is forward-conducted, and the second fourth diode D24, the first eight diodes D18, and the second third diodes D23 are close to the laser terminals and are in the reverse conduction state, the static electricity charge will be released to the ground, thereby protecting the laser; after the two signal ends have undergone static electricity testing, the laser light intensity has not changed.

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