Laser current protection device and method

Abstract

The present invention relates to the field of lasers, and in particular to a current protection device and method for a laser; a driving unit, a power supply unit, a current control unit, a voltage limiting unit and a voltage regulating unit, wherein the output end of the power supply unit is connected to the first input end of the driving unit; the first input end of the voltage limiting unit is connected to the output end of the current control unit, and the output end of the voltage limiting unit is connected to the second input end of the driving unit; the first output end of the voltage regulation is connected to the second input end of the voltage limiting unit; the voltage regulating unit regulates the clamping voltage of the voltage limiting unit, and the voltage limiting unit limits the voltage input by the current control unit according to the clamping voltage and outputs the voltage to the driving unit; the circuit principle of the current protection device is simple and easy to implement, and only requires low hardware cost to achieve accurate protection of the maximum driving current of the laser, and is more reliable than a software protection solution.

Description

Technical Field

[0001] The present invention relates to the field of lasers, and in particular to a current protection device and method for lasers. Background Art

[0002] With the development of optical communication technology, more and more dual-core semiconductor lasers with the same package and power supply have begun to be commercialized. In order to prevent the driving current from exceeding its maximum operating current range and causing damage to the semiconductor laser, it is necessary to protect the maximum driving current of each laser core in actual use.

[0003] Existing software current limiting protection solutions still have the risk of causing damage to semiconductor lasers. Therefore, designing a safe and reliable protection device and method for the maximum operating current of semiconductor lasers is crucial in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a safe and reliable protection device and method for the maximum operating current of a semiconductor laser in response to the above-mentioned defects of the prior art, thereby overcoming the defect of the software current limiting solution in the prior art that program errors may lead to current limiting failure.

[0005] The technical solution adopted by the present invention to solve the technical problem is to provide a current protection device for a laser. The preferred solution is that the current protection device for a laser comprises:

[0006] A driving unit, used to drive the laser to work;

[0007] a power supply unit, wherein an output end of the power supply unit is connected to the first input end of the driving unit;

[0008] A current control unit, used to control the working driving current of the laser;

[0009] a voltage limiting unit, wherein a first input terminal of the voltage limiting unit is connected to an output terminal of the current control unit, and an output terminal of the voltage limiting unit is connected to a second input terminal of the driving unit;

[0010] a voltage regulating unit, wherein a first output terminal of the voltage regulating unit is connected to a second input terminal of the voltage limiting unit;

[0011] The power supply unit provides power to the driving unit, the voltage regulating unit regulates the clamping voltage of the voltage limiting unit, and the voltage limiting unit limits the voltage input by the current control unit according to the clamping voltage and outputs the voltage to the driving unit.

[0012] Among them, a preferred solution is: the power supply unit is an adjustable power supply, and the second output end of the voltage adjustment unit is connected to the input end of the adjustable power supply to adjust the output voltage of the adjustable power supply.

[0013] Among them, the preferred solution is: the adjustable power supply includes a power supply chip, the voltage output pin of the power supply chip is connected to the first input end of the driving unit to output voltage, and the feedback pin of the power supply chip is connected to the second output end of the voltage regulation unit.

[0014] Among them, the preferred solution is: the adjustable power supply also includes a first resistor, a second resistor and a third resistor, the first resistor is arranged between the voltage output pin and the feedback pin, the second resistor is arranged between the feedback pin and the second output end of the voltage regulation unit, and the feedback pin is connected to the ground through the third resistor.

[0015] Among them, the preferred solution is: the voltage limiting unit includes a first operational amplifier module and a second operational amplifier module, the positive input end of the first operational amplifier module is connected to the current control unit, the output end of the first operational amplifier module is connected to the positive input end of the second operational amplifier module, the output end of the second operational amplifier module is connected to the driving unit, and the positive input end of the first operational amplifier module, the reverse input end of the second operational amplifier module and the output end of the second operational amplifier module are all connected to the voltage regulating unit.

[0016] Among them, the preferred solution is: the voltage limiting unit also includes a fourth resistor and a first filtering circuit, one end of the fourth resistor is connected to the output end of the first operational amplifier module, the other end of the fourth resistor is connected to one end of the first filtering circuit, and the other end of the first filtering circuit is connected to the positive input end of the second operational amplifier module.

[0017] Among them, the preferred solution is: the voltage limiting unit also includes a second filter circuit and a third filter circuit, one end of the second filter circuit is connected to the inverting input end of the first op amp module, and the other end of the second filter circuit is connected to the output end of the first op amp module, one end of the third filter circuit is connected to the inverting input end of the second op amp module, and the other end of the third filter circuit is connected to the output end of the second op amp module.

[0018] Among them, the preferred solution is: a fifth resistor is also provided between the positive input terminal of the first operational amplifier module and the current control unit, a sixth resistor is also provided between the positive input terminal of the first operational amplifier module and the voltage regulating unit, and a seventh resistor is also provided between the inverting input terminal of the second operational amplifier module and the voltage regulating unit.

[0019] In order to solve the problems existing in the prior art, the present invention further provides a current protection method for a laser. A preferred embodiment thereof is that the current protection method for a laser is implemented by the current protection device for the laser as described above, and the current protection method comprises:

[0020] The voltage regulating unit inputs a first voltage to the voltage limiting unit, and the current control unit inputs a second voltage to the voltage limiting unit;

[0021] The voltage limiting unit obtains a voltage difference between its own power supply voltage and the first voltage, and compares a second voltage value with the voltage difference;

[0022] When the second voltage value is smaller than the voltage difference, the voltage limiting unit outputs a voltage having the second voltage value to the driving unit; when the second voltage value is larger than the voltage difference, the voltage limiting unit outputs a voltage having the voltage difference to the driving unit.

[0023] Among them, a preferred solution is that the current protection method further includes the following steps:

[0024] The output voltage of the adjustable power supply is adjusted by the voltage adjustment unit, and the adjustable power supply outputs the adjusted voltage to the driving unit.

[0025] The beneficial effect of the present invention is that, compared with the prior art, the present invention realizes separate current protection for each laser in a multi-core laser by designing a current protection device for the laser, through the cooperation of a current control unit, a voltage limiting unit and a driving unit, making the protection safer, more reliable and more accurate; the circuit principle of the current protection device is simple and easy to implement, and only requires a relatively low hardware cost to achieve accurate protection of the maximum driving current of each core laser, and has higher reliability than the software protection solution for the maximum driving current of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0027] Figure 1 This is a schematic diagram of the structure of a current protection device for a laser in the present invention. Figure 1 ;

[0028] Figure 2 This is a schematic diagram of the structure of a current protection device for a laser in the present invention. Figure 2 ;

[0029] Figure 3 is a circuit diagram of the adjustable power supply in the present invention;

[0030] Figure 4 is a circuit diagram of the voltage limiting unit in the present invention;

[0031] Figure 5 This is a process of a laser current protection method in the present invention Figure 1 ;

[0032] Figure 6 This is a process of a laser current protection method in the present invention Figure 2 . DETAILED DESCRIPTION

[0033] Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] like Figure 1 As shown, the present invention provides a preferred embodiment of a current protection device for a laser.

[0035] A current protection device for a laser, and reference Figure 1 The current protection device of the laser includes a driving unit 1 for driving the laser to work; a power supply unit 2, the output end of the power supply unit 2 is connected to the first input end of the driving unit 1; a current control unit 3, for controlling the working driving current of the laser; a voltage limiting unit 4, the first input end of the voltage limiting unit 4 is connected to the output end of the current control unit 3, and the output end of the voltage limiting unit 4 is connected to the second input end of the driving unit 1; a voltage regulating unit 5, the first output end of the voltage regulating unit 5 is connected to the second input end of the voltage limiting unit 4.

[0036] The power supply unit 2 provides power to the driving unit 1 , the voltage regulating unit 5 regulates the clamping voltage of the voltage limiting unit 4 , and the voltage limiting unit 4 limits the voltage input by the current control unit 3 according to the clamping voltage and outputs the voltage to the driving unit 1 .

[0037] Specifically, the driving unit 1 is mainly used to realize the normal operation of the voltage-controlled constant current driving laser; the power supply unit 2 is mainly used to provide a voltage source to the driving unit 1; the current control unit 3 is mainly used to set the working driving current of the laser according to the control command; the voltage regulating unit 5 can be used to adjust the clamping voltage of the voltage limiting unit 4; the voltage limiting unit 4 is mainly used to compare the voltage of the voltage regulating unit 5 with the power supply of the voltage limiting unit 4, so as to determine the voltage clamped by the voltage limiting unit 4, and ensure that the voltage output by the current control unit 3 is always less than the voltage clamped by the voltage limiting unit 4 after passing through the voltage limiting unit 4, thereby realizing the limitation of the maximum driving current of a single laser.

[0038] Furthermore, the output end of the power supply unit 2 is connected to the first input end of the drive unit 1, the first input end of the voltage limiting unit 4 is connected to the output end of the current control unit 3, the output end of the voltage limiting unit 4 is connected to the second input end of the drive unit 1, and the first output end of the voltage regulating unit 5 is connected to the second input end of the voltage limiting unit 4.

[0039] The specific protection path for limiting the maximum driving current of the laser is: first, the voltage is output to the voltage limiting unit 4 through the voltage regulating unit 5 to control the clamping voltage of the voltage limiting unit 4. Further, the voltage output by the current control unit 3 is input to the driving unit 1 through the voltage limiting unit 4. In this process, the voltage output by the current control unit 3 is limited by the clamping voltage of the voltage limiting unit 4, thereby limiting the maximum driving current of this laser.

[0040] It should be noted that the laser maximum drive current protection path can provide safe, reliable and precise protection for the laser maximum current drive according to the characteristic parameters of the laser, which is a precise protection method. In addition, the laser maximum drive current protection path can be expanded according to the number of lasers; that is, in a multi-core semiconductor laser system, a plurality of the voltage regulating units 5, a plurality of the voltage limiting units 4 and a plurality of the current control units 3 can be set, and each of the voltage regulating units 5, the voltage limiting unit 4 and the current control unit 3 cooperates to adjust the maximum drive current of a laser.

[0041] Among them, the existing method is to set the maximum driving current threshold of the laser in the control chip program according to the maximum operating current parameters of each core of the dual-core semiconductor laser, so that the maximum operating current of each core of the dual-core semiconductor laser does not exceed the threshold. This scheme belongs to the software current limiting protection scheme. When the control program does not work normally, the current limiting function will be lost, causing damage to the semiconductor laser.

[0042] In this embodiment, a current protection device for a laser is designed. Through the cooperation of a current control unit 3, a voltage limiting unit 4, and a driving unit 1, individual current protection is achieved for each laser in a multi-core laser, making the protection safer, more reliable, and more accurate. On the one hand, it does not need to rely on software programs for control, effectively avoiding the risk of laser damage due to program errors and effectively improving the stability of the system. On the other hand, the voltage limiting unit 4 and the voltage regulating unit 5 are added between the driving unit 1 and the current control unit 3. The voltage regulating unit 5 adjusts the clamping voltage value of the voltage limiting unit 4 to limit the input value of the laser driving unit 1. The circuit principle is simple and easy to implement. Only a low hardware cost is required to achieve accurate protection of the maximum drive current of each core laser. Compared with the software protection laser maximum drive current solution, it has higher reliability.

[0043] like Figure 1-Figure 2 As shown, the present invention provides a preferred embodiment of a power supply unit.

[0044] Option 1

[0045] And refer to Figure 1 The power supply unit 2 is a power supply with a fixed voltage output. When the voltage required by the laser is a voltage that a general power supply can output fixedly, such as 3V, 5V or 12V, a power supply with a corresponding fixed voltage output can be used directly.

[0046] Option 2

[0047] And refer to Figure 2 The voltage unit is an adjustable power supply 2', and the second output end of the voltage regulating unit 5 is connected to the input end of the adjustable power supply 2' to adjust the output voltage of the adjustable power supply 2'.

[0048] Specifically, the second output end of the voltage regulating unit 5 is connected to the input end of the adjustable power supply 2' to control the voltage output of the adjustable power supply 2', limit the supply voltage of all driving units 1 sharing the adjustable power supply 2', and further limit the maximum driving current of all lasers.

[0049] Among them, the protection path of the maximum driving current of the laser is mainly used to achieve safe and reliable protection of the maximum current drive of all lasers sharing the power supply, which is an extensive protection method; it cooperates with the current control unit 3, the voltage limiting unit 4 and the drive unit 1 to further implement safe and reliable protection of the maximum current drive of each laser sharing the power supply, making the entire laser system more stable and reliable.

[0050] It should be noted that if the current power supply uses a power supply with a suitable fixed voltage output, this protection path can be omitted, that is, the solution of solution 1 can be adopted.

[0051] like Figure 3 As shown, the present invention provides a preferred embodiment of an adjustable power supply.

[0052] refer to Figure 3 The adjustable power supply 2' includes a power chip U3, a voltage output pin Vout of the power chip U3 is connected to the first input terminal of the driving unit 1, and a feedback pin FB of the power chip U3 is connected to the second output terminal of the voltage regulating unit 5.

[0053] Specifically, the feedback pin FB of the power chip U3 is connected to the second output end of the voltage regulating unit 5, and the voltage output pin Vout of the power chip U3 is connected to the first input end of the driving unit 1. The voltage regulating unit 5 can control the voltage output by the power chip U3 of the adjustable power supply 2', thereby limiting the maximum driving current of all lasers sharing the adjustable power supply 2'.

[0054] Furthermore, the adjustable power supply 2' also includes a first resistor R9, a second resistor R11 and a third resistor R10, the first resistor R9 is arranged between the voltage output pin Vout and the feedback pin FB, the second resistor R11 is arranged between the feedback pin FB and the second output end of the voltage regulating unit 5, and the feedback pin FB is connected to the ground through the third resistor R10.

[0055] Specifically, the voltage regulating unit 5 is connected to the feedback pin FB of the power chip U3 through the second resistor R11, and the feedback pin FB of the power chip U3 is connected to the voltage output pin Vout of the power chip U3 through the first resistor R9. At the same time, the feedback pin FB of the power chip U3 is connected to the ground line GND through the third resistor R10, and the voltage output pin Vout of the power chip U3 is directly output to the drive unit 1.

[0056] The first resistor R9 , the second resistor R11 , and the third resistor R10 may be selected to have appropriate resistance values ​​according to the requirements of the selected power chip U3 , and the resistance accuracy requirement is 1%.

[0057] Specifically, according to Ohm's law, by adjusting the power supply voltage of the driving unit 1 (i.e., the output voltage Vout of the adjustable power supply 2'), the maximum drive current of all lasers sharing the power supply can be limited. The output voltage formula of the adjustable power supply unit 2 is derived as follows:

[0058] According to the superposition principle: the voltage generated by the voltage output pin Vout of the power supply chip U3 at its feedback pin FB is: Vr1 = (R10 / / R11) / ((R10 / / R11)+R9)*Vout; the voltage generated by the voltage Va output by the voltage regulation unit 5 at the feedback pin FB of the power supply chip U3 is: Vr1 = (R9 / / R10) / ((R9 / / R10)+R11)*Va; the voltage of the feedback pin FB of the power supply chip U3 is Vref, and the combination can be obtained: Vref = Vr1+Vr2; when the first resistor R9 and the second resistor R11 have the relationship R9=R11, it can be deduced that the output voltage Vout of the adjustable power supply 2' is Vout = (2+R9 / R10)*Vref-Va.

[0059] like Figure 4 As shown, the present invention provides a preferred embodiment of a voltage limiting unit.

[0060] refer to Figure 4 The voltage limiting unit 4 includes a first operational amplifier module U1 and a second operational amplifier module U2, the positive input end of the first operational amplifier module U1 is connected to the current control unit 3, the output end of the first operational amplifier module U1 is connected to the positive input end of the second operational amplifier module U2, the output end of the second operational amplifier module U2 is connected to the driving unit 1, and the positive input end of the first operational amplifier module U1, the negative input end of the second operational amplifier module U2 and the output end of the second operational amplifier module U2 are all connected to the voltage regulating unit 5.

[0061] Specifically, the first operational amplifier module U1 and the second operational amplifier module U2 are rail-to-rail, low offset voltage, single-power supply operational amplifiers of the same model. The lower the power supply voltage of the operational amplifier, the better, generally lower than 3.3V. In this embodiment, the output voltage of the first operational amplifier module U1 and the second operational amplifier module U2 are both 3.3V, and the bandwidth is 20MHZ.

[0062] Furthermore, the voltage limiting unit 4 also includes a fourth resistor R5 and a first filtering circuit, one end of the fourth resistor R5 is connected to the input end of the first operational amplifier module U1, the other end of the fourth resistor R5 is connected to one end of the first filtering circuit, and the other end of the first filtering circuit is connected to the positive input end of the second operational amplifier module U2.

[0063] Specifically, the first filtering circuit is mainly used for filtering, and the first filtering circuit includes a resistor R6 and a capacitor C2, and the resistor R6 and the capacitor C2 are connected in parallel; in this embodiment, since the output voltage of the first operational amplifier module U1 and the second operational amplifier module U2 are both 3.3V and the bandwidth is 20MHZ, the fourth resistor R5 and the resistor R6 are both 10K resistors, and their resistance accuracy levels are both 0.1%, and the capacitor C2 is 10pF.

[0064] Furthermore, the voltage limiting unit 4 also includes a second filtering circuit and a third filtering circuit, one end of the second filtering circuit is connected to the inverting input end of the first operational amplifier module U1, and the other end of the second filtering circuit is connected to the output end of the first operational amplifier module U1, one end of the third filtering circuit is connected to the inverting input end of the second operational amplifier module U2, and the other end of the third filtering circuit is connected to the output end of the second operational amplifier module U2.

[0065] Specifically, the second filter circuit and the third filter circuit are both used for filtering, the second filter circuit includes a resistor R4 and a capacitor C1, and the third filter circuit includes a resistor R7 and a capacitor C3, wherein the value of the capacitor C1 is the same as the value of the capacitor C2, and the value of the capacitor C3 is required to be greater than the value of the capacitor C2. The preferred value range of the capacitors C1, C2 and C3 is 10pF-100pF; in this embodiment, since the output voltages of the first operational amplifier module U1 and the second operational amplifier module U2 are both 3.3V and the bandwidth is 20MHZ, the resistor R4 and the resistor R7 are both 10K resistors with a resistance accuracy level of 0.1%. The capacitor C1 is 10pF and the capacitor C3 is 22pF.

[0066] Furthermore, a fifth resistor R1 is provided between the positive input terminal of the first operational amplifier module U1 and the current control unit 3, a sixth resistor R2 is provided between the positive input terminal of the first operational amplifier module U1 and the voltage regulating unit 5, and a seventh resistor R8 is provided between the inverting input terminal of the second operational amplifier module U2 and the voltage regulating unit.

[0067] In this embodiment, since the output voltage of the first operational amplifier module U1 and the second operational amplifier module U2 are both 3.3V and the bandwidth is 20MHZ, the fifth resistor R1, the sixth resistor R2 and the seventh resistor R8 are all 10K resistors, and the resistance accuracy level is 0.1%.

[0068] It should be noted that the values ​​of the above-mentioned resistors and capacitors are only one embodiment, and other values ​​can also be used, as long as specific conditions are met, that is, the corresponding relationship between the fifth resistor R1, the sixth resistor R2, the resistor R3, the resistor R4, the fourth resistor R5, the resistor R6, the resistor R7 and the seventh resistor R8 is: R1 = R2 = R5 = R6 = R7 = R8, and R3 = R4. The specific values ​​are selected according to the load output characteristics of the first operational amplifier module U1 and the second operational amplifier module U2 (to achieve rail power supply voltage output), preferably R1 = R2 = R5 = R6 = R7 = R8, R3 = R4, and all values ​​are within the range of 4.7K-20K, and the resistance accuracy level is 0.1%. The corresponding relationship among the capacitor C1, the capacitor C2 and the capacitor C3 is: C1=C2, and C3≥C2. Preferably, the value range of the capacitor C1, the capacitor C2 and the capacitor C3 is within the range of 10pF-100pF.

[0069] like Figure 5 and Figure 6 As shown, the present invention provides a best embodiment of a current protection method for a laser.

[0070] refer to Figure 5 The present invention also provides a current protection method for a laser, which is implemented by the current protection device for the laser as described above, and includes:

[0071] S1, the voltage regulating unit inputs a first voltage to the voltage limiting unit, and the current control unit inputs a second voltage to the voltage limiting unit;

[0072] S2. The voltage limiting unit obtains a voltage difference between its own power supply voltage and the first voltage, and compares a second voltage value with the voltage difference;

[0073] S21. When the second voltage value is less than the voltage difference, the voltage limiting unit outputs a voltage having the second voltage value to the driving unit; when the second voltage value is greater than the voltage difference, the voltage limiting unit outputs a voltage having the voltage difference to the driving unit.

[0074] Specific and refer to Figures 1-6, the voltage regulating unit 5 outputs a first voltage Vpm to the voltage limiting unit 4, and the current control unit 3 outputs a second voltage Vs to the voltage limiting unit 4. After receiving the first voltage Vpm input by the voltage regulating unit 5, the voltage limiting unit 4 calculates and obtains the voltage difference between the first voltage Vpm and the power supply voltage VCC of the voltage limiting unit 4 itself, that is, obtains the value of VCC-Vpm. After receiving the second voltage Vs input by the current control unit 3, the voltage limiting unit 4 compares Vs with VCC-Vpm and outputs Vo2 to the driving unit according to the comparison result.

[0075] Furthermore, when Vs<VCC-Vpm, Vo2=Vs, that is, the voltage limiting unit 4 outputs a voltage of Vo2=Vs to the drive unit 1; when Vs>VCC-Vpm, the output voltage of the voltage limiting unit 4 will be limited to VCC-Vpm, and the voltage limiting unit 4 enters a clamping state, and its clamping voltage is VCC-Vpm, that is, the voltage limiting unit 4 outputs a voltage of VCC-Vpm to the drive unit 1.

[0076] Furthermore, in this embodiment, a process for deriving the clamping voltage of the voltage limiting unit 4 is also provided. The clamping voltage formula of the voltage limiting unit 4 is derived as follows:

[0077] According to the virtual short characteristic of the op amp, the voltages at the non-inverting and inverting terminals of the op amp are substantially equal. Based on the settings of R1=R2=R5=R6=R7=R8 and R3=R4, the output voltage Vo1 of the first op amp module U1 is obtained to be Vs+Vpm, and the output voltage Vo2 of the second op amp module U2 is obtained to be Vo1-Vpm. The maximum value of Vo1 is the rail voltage VCC of the first op amp module U1, that is, Vs+Vpm≤VCC. Therefore, when the voltage value Vs output by the current control unit 3 is less than or equal to the clamping voltage VCC-Vpm of the voltage limiting unit 4, Vo2=Vs+Vpm-Vpm=Vs. When the voltage value Vs of the current control unit 3 is greater than the clamping voltage VCC-Vpm of the voltage limiting unit 4, the output Vo1 of the first op amp module U1 is obtained to be VCC, and the output Vo2 of the second op amp module U2 is obtained to be obtained to be Vo1-Vpm=VCC-Vpm.

[0078] It should be noted that the laser maximum drive current protection method can provide safe, reliable and precise protection for the laser maximum current drive according to the characteristic parameters of the laser, and is a precise protection method. In addition, the laser maximum drive current protection method can be expanded according to the number of lasers; that is, in a multi-core semiconductor laser system, a plurality of the voltage regulating units 5, a plurality of the voltage limiting units 4 and a plurality of the current control units 3 can be set, and each of the voltage regulating units 5, the voltage limiting unit 4 and the current control unit 3 cooperates to precisely adjust the maximum drive current of one of the lasers.

[0079] Among them, the existing method is to set the maximum driving current threshold of the laser in the control chip program according to the maximum operating current parameters of each core of the dual-core semiconductor laser, so that the maximum operating current of each core of the dual-core semiconductor laser does not exceed the threshold. This scheme belongs to the software current limiting protection scheme. When the control program does not work normally, the current limiting function will be lost, causing damage to the semiconductor laser.

[0080] In this embodiment, a current protection method for a laser is designed. Through the cooperation of a current control unit 3, a voltage limiting unit 4, and a driving unit 1, separate current protection is achieved for each laser in a multi-core laser, making the protection safer, more reliable, and more accurate. On the one hand, it does not need to rely on software programs for control, effectively avoiding the risk of laser damage due to program errors and effectively improving the stability of the system. On the other hand, the voltage limiting unit 4 and the voltage regulating unit 5 are added between the driving unit 1 and the current control unit 3. The voltage regulating unit 5 adjusts the clamping voltage value of the voltage limiting unit 4 to limit the input value of the laser driving unit 1. The circuit principle is simple and easy to implement. Only a low hardware cost is required to achieve accurate protection of the maximum drive current of each core laser. Compared with the software protection laser maximum drive current solution, it has higher reliability.

[0081] Further, and with reference to Figure 6 , the current protection method further includes the following steps:

[0082] S0. Regulating the output voltage of the adjustable power supply by the voltage regulating unit, and the adjustable power supply outputting the regulated voltage to the driving unit.

[0083] Specific and refer to Figures 1-6The protection method for the maximum driving current of the laser is mainly used to achieve safe and reliable protection for the maximum driving current of all lasers sharing the adjustable power supply 2', which belongs to an extensive protection method; it cooperates with the current control unit 3, the voltage limiting unit 4 and the driving unit 1 to further implement safe and reliable protection for the maximum driving current of each laser sharing the power supply, thereby achieving dual protection of the maximum driving current of the laser, making the entire laser system more stable and reliable.

[0084] The above description is only the best embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes or modifications made within the scope of the patent application of the present invention are covered by the present invention.

Claims

1. A current protection device for a laser, characterized in that: The current protection device of the laser comprises: A driving unit, used to drive the laser to work; A power supply unit, wherein the power supply unit is an adjustable power supply, and an output end of the power supply unit is connected to the first input end of the driving unit; A current control unit, used to control the working driving current of the laser; a voltage limiting unit, wherein a first input terminal of the voltage limiting unit is connected to an output terminal of the current control unit, and an output terminal of the voltage limiting unit is connected to a second input terminal of the driving unit; a voltage regulating unit, wherein the first output end of the voltage regulating unit is connected to the second input end of the voltage limiting unit, and the second output end of the voltage regulating unit is connected to the input end of the adjustable power supply to adjust the output voltage of the adjustable power supply; The power supply unit provides power to the driving unit, the voltage regulating unit regulates the clamping voltage of the voltage limiting unit, and the voltage limiting unit limits the voltage input by the current control unit according to the clamping voltage and outputs the voltage to the driving unit.

2. The current protection device according to claim 1, characterized in that: The adjustable power supply includes a power chip, a voltage output pin of the power chip is connected to the first input terminal of the driving unit to output voltage, and a feedback pin of the power chip is connected to the second output terminal of the voltage regulating unit.

3. The current protection device according to claim 2, characterized in that: The adjustable power supply also includes a first resistor, a second resistor and a third resistor, the first resistor is arranged between the voltage output pin and the feedback pin, the second resistor is arranged between the feedback pin and the second output end of the voltage regulating unit, and the feedback pin is connected to the ground through the third resistor.

4. The current protection device according to claim 1, characterized in that: The voltage limiting unit includes a first operational amplifier module and a second operational amplifier module, the positive input terminal of the first operational amplifier module is connected to the current control unit, the output terminal of the first operational amplifier module is connected to the positive input terminal of the second operational amplifier module, the output terminal of the second operational amplifier module is connected to the driving unit, and the positive input terminal of the first operational amplifier module, the reverse input terminal of the second operational amplifier module, and the output terminal of the second operational amplifier module are all connected to the voltage regulating unit.

5. The current protection device according to claim 4, characterized in that: The voltage limiting unit also includes a fourth resistor and a first filtering circuit, one end of the fourth resistor is connected to the output end of the first operational amplifier module, the other end of the fourth resistor is connected to one end of the first filtering circuit, and the other end of the first filtering circuit is connected to the positive input end of the second operational amplifier module.

6. The current protection device according to claim 5, characterized in that: The voltage limiting unit also includes a second filtering circuit and a third filtering circuit, one end of the second filtering circuit is connected to the inverting input terminal of the first operational amplifier module, and the other end of the second filtering circuit is connected to the output terminal of the first operational amplifier module, one end of the third filtering circuit is connected to the inverting input terminal of the second operational amplifier module, and the other end of the third filtering circuit is connected to the output terminal of the second operational amplifier module.

7. The current protection device according to claim 4, characterized in that: A fifth resistor is further provided between the positive input terminal of the first operational amplifier module and the current control unit, a sixth resistor is further provided between the positive input terminal of the first operational amplifier module and the voltage regulating unit, and a seventh resistor is further provided between the inverting input terminal of the second operational amplifier module and the voltage regulating unit.

8. A current protection method for a laser, characterized in that: The laser current protection method is implemented by the laser current protection device according to any one of claims 1 to 7, and the current protection method includes: The voltage regulating unit regulates the output voltage of the adjustable power supply, and the adjustable power supply outputs the regulated voltage to the driving unit; The voltage regulating unit inputs a first voltage to the voltage limiting unit, and the current control unit inputs a second voltage to the voltage limiting unit; The voltage limiting unit obtains a voltage difference between its own power supply voltage and the first voltage, and compares a second voltage value with the voltage difference; When the second voltage value is smaller than the voltage difference, the voltage limiting unit outputs a voltage having the second voltage value to the driving unit; when the second voltage value is larger than the voltage difference, the voltage limiting unit outputs a voltage having the voltage difference to the driving unit.

Images