Semiconductor laser pulse type driving circuit and driving current detection and control method thereof

Abstract

The invention discloses a semiconductor laser pulse type driving circuit and a driving current detection and control method thereof. The semiconductor laser pulse type driving circuit comprises a pulse driving control circuit, a pulse driving circuit and a pulse driving current detection circuit, wherein the pulse driving current detection circuit, the pulse driving control circuit and the pulse driving circuit are connected in sequence, the pulse driving current detection circuit adopts a high-side current detection circuit, and the pulse driving circuit comprises a laser switch chip; the pulse driving current detection circuit is used for acquiring a detection voltage according to a driving current of the semiconductor laser, the pulse driving control circuit is used for generating a driving signal and generating a control voltage according to the detection voltage, and the pulse driving control circuit is used for generating a driving current according to the driving signal and controlling the driving current according to the control voltage. And the size of the driving current is controlled according to the control voltage, and the semiconductor laser is controlled and driven through the driving current.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor lasers, and in particular relates to a semiconductor laser pulse drive circuit and a drive current detection and control method thereof. Background Art

[0002] Semiconductor lasers (LDs) have the advantages of small size, high brightness, good directivity, and long service life. They are widely used in optical communications, laser radar and other fields. The working modes of LDs can be divided into continuous light working mode and pulse light working mode. The continuous light working mode provides a stable driving current and temperature to the LD; the pulse light working mode injects a pulse current into it, accumulates a large amount of energy in a short time (picoseconds, nanoseconds, microseconds) and emits it to form pulse light.

[0003] The current pulse drive circuit is mainly composed of power supply, switching circuit and resistor and capacitor components, such as Figure 1 As shown. Narrow pulses are realized by charging and discharging through the cooperation of RC elements and switch tubes. However, due to the influence of circuit board manufacturing and layout wiring, the circuit board will have some parasitic parameters that affect the pulse width and amplitude of the narrow pulse, making it difficult to control and the debugging process is more complicated. In order to generate a larger driving current to drive the laser, a larger voltage needs to be provided, and its power supply will also be more complicated and costly. Therefore, it is necessary to provide a method to realize a pulsed driving circuit with high-precision narrow pulses.

[0004] In addition, the driving current of the pulsed laser affects the emission power of the laser, which in turn affects the measurement accuracy of the laser pulse in the field of laser radar. However, in the existing nanosecond narrow pulse driving circuit, there are few methods for detecting the driving current and the accuracy is low, making it difficult to achieve accurate control. Therefore, it is very important to design a driving current detection and control method. Summary of the invention

[0005] To solve the above technical problems, the present invention proposes a semiconductor laser pulse drive circuit and a drive current detection and control method thereof, which can generate high-precision narrow pulses and drive current detection and control to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides a semiconductor laser pulse drive circuit, comprising:

[0007] A pulse drive control circuit, a pulse drive circuit and a pulse drive current detection circuit; wherein the pulse drive current detection circuit, the pulse drive control circuit and the pulse drive circuit are connected in sequence, the pulse drive current detection circuit adopts a high-side current detection circuit, and the pulse drive circuit includes a laser switch chip;

[0008] The pulse drive current detection circuit is used to obtain a detection voltage according to the drive current of the semiconductor laser. The pulse drive control circuit is used to generate a drive signal and generate a control voltage according to the detection voltage. The pulse drive control circuit is used to generate a drive current according to the drive signal and control the size of the drive current according to the control voltage, and control the drive of the semiconductor laser through the drive current.

[0009] Optionally, the pulse drive control circuit includes an analog-to-digital converter, a main control module and a digital-to-analog converter connected in sequence, wherein the main control module is used to generate control information based on the detection voltage value converted by the analog-to-digital converter, and convert the control information into a control signal through the digital-to-analog converter and transmit it to the current drive circuit.

[0010] Optionally, the pulse drive circuit uses one or several laser switch chips, wherein when several laser switch chips are used, the several laser switch chips are connected in parallel, which has stronger scalability and can multiply the driving ability of the pulse drive circuit for the semiconductor laser.

[0011] Optionally, the pulse drive current detection circuit includes an operational amplifier and a sampling resistor, the sampling resistor is connected to a pulse current input terminal, the pulse current input terminal is used to receive the drive current of the semiconductor laser, the end of the sampling resistor away from the pulse current input terminal is connected to a load resistor and is grounded, a first shunt resistor, a PMOS tube, a second shunt resistor and a ground terminal which are connected in series in sequence are connected in parallel between the sampling resistor and the pulse current input terminal, a voltage output terminal is provided between the second shunt resistor and the PMOS tube, which is connected to the pulse drive control circuit for outputting a detection voltage; the non-phase input terminal of the operational amplifier is connected to the end of the sampling resistor away from the input terminal of the pulse drive control circuit, the inverting input terminal of the operational amplifier is connected between the first shunt resistor and the PMOS tube, and the output terminal of the operational amplifier is connected to the gate of the PMOS tube.

[0012] Optionally, the pulse drive control circuit is connected to a delayed power-on circuit, which is used to delay the control voltage and then transmit it to the pulse drive circuit, so as to delay the voltage at the Clx end of the pulse drive circuit to rise to the target value, thereby making the corresponding drive current rise to the target value slowly instead of rising to the target value all at once, preventing the semiconductor laser from being damaged by excessive pulse changes at the moment of power-on and current overshoot, thereby effectively protecting the laser.

[0013] Optionally, the laser switch chip adopts iC-HG30 laser switch chip.

[0014] Based on the above-mentioned pulse drive circuit, the present invention also provides a drive current detection and control method, including:

[0015] The driving current of the semiconductor laser is collected and detected by the pulse driving current detection circuit to generate a detection voltage;

[0016] Generate a drive signal through a pulse drive control circuit and generate a drive current value according to the detection voltage, judge the drive current value, generate control information based on the judgment result, and generate a control voltage according to the control information;

[0017] The pulse drive circuit generates a drive current according to a drive signal, controls the size of the drive current according to a control voltage, and controls and drives the semiconductor laser through the drive current.

[0018] Optionally, the process of generating the driving current value includes:

[0019] The detection voltage is converted into a digital form to obtain a detection voltage value, and the detection voltage value is calculated using a relationship between the driving current value and the detection voltage value to obtain a driving current value.

[0020] Optionally, the process of generating the control signal includes:

[0021] The driving current value is judged according to the initially set driving current value, and if the error between the driving current value and the initially set driving current value is within a threshold range, the driving current value is gradually increased, and the corresponding control information is obtained through the fitting relationship between the driving current value and the control voltage according to the increased driving current value, and the control information is converted into digital-to-analog format to obtain the control voltage;

[0022] If the error between the driving current value and the initially set driving current value is outside the threshold range, error correction control is directly performed.

[0023] Optionally, the process of detecting the driving current of the semiconductor laser includes:

[0024] In the pulse drive current detection circuit, the drive current is sampled to obtain a sampling current corresponding to the drive current, and the detection voltage is obtained according to the relationship between the drive current value and the detection voltage value;

[0025] The relationship between the driving current value and the detection voltage value is:

[0026] I test =(I R2 ×R1) / R test =(V out ×R1) / (R2×R test )

[0027] Among them, I tset is the sampling current corresponding to the driving current, Vout is the detection voltage, I R2 represents the current passing through resistor R2, R1 represents the first shunt resistor, R2 represents the second shunt resistor, R test Represents the sampling resistor.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] The present invention uses an integrated laser switch chip iC-HG30 as a pulse drive circuit, and the maximum values ​​of the rising and falling edges of the pulse current do not exceed 1ns, and the drive current value can be easily adjusted. A high-side current detection circuit is used in the pulse drive current detection circuit to obtain a high-precision sampling current value for feedback. FPGA is used as the main control in the pulse drive control circuit, and its system clock operating frequency is high, often above 100 MHz, and the control pulse drive signal has high precision, and it is convenient to modify parameters and has high flexibility. And because the time delay is at the ns level, the feedback drive current value can be corrected in time, which improves the accuracy of the pulse current amplitude and width. The present invention is suitable for semiconductor lasers, generates high-precision narrow pulses and drive current detection and control, and can be applied to laser radar, medical and other measurement fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0031] Figure 1 A block diagram of a conventional pulse drive circuit according to an embodiment of the present invention;

[0032] Figure 2 A system block diagram of the present invention providing a solution for an embodiment of the present invention;

[0033] Figure 3 A low-side and high-side current detection circuit according to an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of a high-side current detection circuit according to an embodiment of the present invention;

[0035] Figure 5 The present invention provides an overall system flow chart of a solution according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Embodiment 1

[0039] like Figure 2 As shown, the semiconductor laser pulse drive circuit provided by the present invention mainly includes: a pulse drive control circuit, a pulse drive circuit and a pulse drive current detection circuit. Among them, the pulse drive current detection circuit, the pulse drive control circuit and the pulse drive circuit are connected in sequence.

[0040] The pulse control circuit is mainly composed of a main control module-field programmable gate array (FPGA), a digital-to-analog converter (DAC) and an analog-to-digital converter (ADC). Among them, the analog-to-digital converter, the main control module and the digital-to-analog converter are connected in sequence, the main control module is connected to the pulse drive circuit for transmitting a drive signal to the pulse drive circuit; the digital-to-analog converter is connected to the pulse drive circuit through a delayed power-on circuit for delaying the control voltage of the pulse drive circuit through the delayed power-on circuit, and the analog-to-digital converter is connected to the pulse drive current detection circuit for receiving the drive current corresponding detection voltage value detected by the pulse drive current detection circuit.

[0041] The pulse drive circuit is composed of the laser switch chip iC-HG30, which is simpler, more efficient and more precise than the traditional drive circuit. The pulse drive circuit can control the semiconductor laser with different drive pulse current values ​​according to the size of the input control voltage.

[0042] The pulse current detection circuit adopts a high-side current detection method and uses a differential operational amplifier with a high common mode rejection ratio (CMRR) to form a current detection circuit to detect the driving current of the semiconductor laser.

[0043] 1. Design of pulse drive circuit

[0044] The traditional LD ​​pulse drive circuit is composed of a high-speed switch and a resistor and capacitor, and the drive pulse is generated by charging and discharging the resistor and capacitor by closing the switch. The basic principle is: the closing of the high-speed switch is controlled by an external signal source. When the switch is disconnected, the power supply charges the energy storage capacitor. When the switch is closed, the energy stored in the capacitor is released to drive the LD to generate periodic narrow pulse light. However, this structure and method have high requirements on the power supply, and the value of the resistor, inductor and capacitor (RLC) needs to be reasonably designed. The modification of parameters will be more complicated and not flexible. It will also be affected by the parasitic parameters of the circuit board, and its pulse width and amplitude are more difficult to control.

[0045] Therefore, the present invention uses an integrated laser switch chip iC-HG30 in a pulse drive circuit. The laser switch chip iC-HG30 has six channels, which can realize spike-free switching of LD with a repetition frequency of DC to 250MHz. Each channel can operate at up to 1A of continuous light and 5A of pulse current according to the frequency, duty cycle and heat dissipation. The six channels can be used in parallel, and the driving current can reach 5A of continuous light and 30A of pulse current. If multiple laser switch chips iC-HG30 are connected in parallel, their driving current capacity will be doubled. The driving current of LD is determined by the Clx terminal voltage on the laser switch chip iC-HG30. In the present invention, the Clx terminal voltage is a control voltage generated by a pulse drive control circuit and transmitted to the Clx terminal. And the thermal protection function integrated in the chip can protect iC-HG30 from damage caused by excessive temperature. The maximum value of the rising and falling edges of its pulse current is 1ns, which has high performance. And combined with the pulse drive control circuit, a high-precision, high-flexibility, narrow pulse light drive circuit can be realized.

[0046] 2. Design of pulse drive current detection circuit

[0047] In the pulse drive circuit, the monitoring of the drive current is very important. If the system drive current deviates from the set value or a short circuit occurs, it can be fed back to the main control unit in time to make corresponding corrections and error correction measures, thus realizing a high-precision narrow pulse drive circuit.

[0048] The pulse drive current detection circuit is mainly divided into low-side current detection circuit and high-side current detection circuit. The difference is as follows Figure 3 shown. Figure 3 (a) is low-side current detection, where the sampling resistor is between the power supply and the ground of the load resistor; Figure 3 (b) is the high-side current detection, and the sampling resistor is at the positive pole of the power supply and the power input of the load. The low-side current detection circuit adds a sampling resistor R in the ground path. test , the ground potential of the monitored circuit will be higher than the ground potential of the system ground, which will bring some ground noise. In addition, when a short circuit occurs between the power supply of the monitored circuit and the system ground, the fault current will not flow through the sampling resistor, and fault detection cannot be performed. In contrast, high-side current detection can detect fault conditions in the monitored circuit under the sampling resistor, but the high-side current detection circuit needs to receive a larger common-mode voltage, which requires a differential amplifier with a higher CMRR, and the cost and circuit complexity will be higher than low-side current detection. However, in order to detect the drive current with higher accuracy, this invention selects a high-side current detection circuit. The circuit schematic diagram is shown in the figure. Figure 4 shown.

[0049] Among them, U1 is an operational amplifier with high CMRR, Rtest is the current sampling resistor, R1 and R2 are the first shunt resistor and the second shunt resistor respectively, R L is the load resistor, Q1 is a PMOS tube, VCC is a positive voltage, VEE is a negative voltage, I current is the driving current input, I test The invention relates to a sampling current, specifically, a driving current input terminal inputs a driving current, one end of a sampling resistor is connected to the driving current input terminal, and the other end is grounded through a load resistor, one end of a first shunt resistor is connected in parallel between the sampling resistor and the driving current input terminal, the other end of the first shunt resistor is respectively connected to the S pole of a PMOS tube and the inverting input terminal of an operational amplifier, the G pole of the PMOS tube is connected to the output terminal of the operational amplifier, the D pole is grounded through a second shunt resistor, an output terminal is set between the D pole and the second shunt resistor, a detection voltage output terminal outputs a detection voltage corresponding to the driving current, a non-inverting input terminal of the operational amplifier is connected to an end of the sampling resistor away from the driving current input terminal, a positive voltage is introduced into the positive power supply terminal, and a negative voltage is introduced into the negative power supply terminal.

[0050] 3. Pulse drive control circuit design

[0051] The pulse drive control circuit of the present invention is composed of a main control module - a field programmable gate array (FPGA), a digital-to-analog converter (DAC) and an analog-to-digital converter (ADC). The advantage of using FPGA in the main controller is that it can generate a driving pulse signal with an adjustable pulse width range and high pulse width and frequency adjustment accuracy. In addition, it can realize nanosecond narrow pulses by multiplying the frequency according to the internal phase-locked loop of FPGA.

[0052] According to the design of the pulse drive circuit, the driving current of the LD is determined by the voltage at the Clx terminal of the iC-HG30, so the FPGA is used to control the DAC to generate an analog voltage value (control voltage) to input the control voltage into the Clx terminal of the pulse drive circuit to set the driving current of the semiconductor laser. The digital-to-analog converter uses a high-precision 16-bit DAC (such as DAC8830 from Texas Instruments), and a voltage follower is added to the analog voltage output terminal of the DAC to improve its load capacity, and a delayed power-on circuit is added later to protect the LD.

[0053] The pulse current is converted into a detection voltage through the pulse current detection circuit on the high side, and the detection voltage is collected through the ADC and fed back to the FPGA. The FPGA processes the converted detection voltage value to obtain the corresponding drive current value, and judges whether there is an error with the set value or a fault according to the drive current value. If the error exceeds the threshold, it is corrected. If a fault occurs, error correction is performed and the control voltage output is turned off. The analog-to-digital converter can choose a high-precision 16-bit ADC (such as ADI's LTC2203).

[0054] Embodiment 2

[0055] The LD pulse drive circuit in this invention is mainly composed of a pulse drive control circuit, a pulse drive circuit and a pulse drive current detection circuit. The drive current detection and control method of the present invention is described in detail in view of the above technical scheme. There are mainly analysis of the drive current control method and analysis of the pulse drive current detection method.

[0056] 1. Analysis of driving current control method

[0057] like Figure 5 As shown, combined with Figure 2 The system block diagram shown in FIG. 1 shows a specific driving current control process as follows: the main control module FPGA generates a narrow pulse with a corresponding repetition frequency and pulse width as a driving signal by writing Verilog code. The repetition frequency can be set below 250MHz, and the pulse width is set according to the main frequency of the FPGA. The maximum value of the pulse current rising edge and falling edge of the laser switch chip iC-HG30 is 1ns. The driving signal is input to the EN port to control the driving pulse driving circuit to generate a driving current to drive the pulse driving circuit to work. At the same time, the magnitude of the driving current is controlled by the magnitude of the voltage input at the Clx terminal in the driving pulse driving circuit. Specifically, the corresponding conversion relationship is derived from the fitting curve of the relationship between the Clx terminal voltage (control voltage) and the driving current value of the laser switch chip iC-HG30 used in the driving pulse driving circuit. According to this conversion relationship, the FPGA can be used to control the DAC to generate the voltage at the Clx terminal corresponding to the target driving current value. The laser switch chip iC-HG30 generates the driving current of the LD through the input voltage at the Clx terminal, thereby completing the setting of the pulse driving current of the laser switch chip iC-HG30 to control the LD. The laser switch chip iC-HG30 will drive the LD to emit light according to the above settings.

[0058] A pulse drive current detection circuit is added to the LD loop to detect the drive current and convert the current relationship into a voltage relationship to obtain the detection voltage, which is subsequently collected by the ADC and transmitted to the FPGA. The FPGA will calculate the real-time drive current size based on the detection voltage value collected by the ADC and the corresponding relationship in the pulse current detection circuit, and then compare the calculated drive current value with the initial set drive current value (target drive current value). If the error is within a certain threshold range, it will be corrected, and the drive current value will be gradually reset, and then the voltage value of the corrected Clx terminal will be reset; if the error is too large, it will be determined that a fault has occurred and error correction control, such as power-off protection, will be performed.

[0059] In FPGA control and correction, because the FPGA system clock has a high operating frequency, often above 100 MHz, the control pulse drive signal has high accuracy, and the parameters can be easily modified, which is highly flexible. And because the delay is at the ns level, the feedback drive current value can be corrected in a timely manner.

[0060] During the actual test, it was found that the drive current setting needs to be increased slowly from small to large, and the target drive current value cannot be set all at once (below the maximum value without damaging the LD). The reason is that the peaks and pulses of the current waveform at the moment of power-on will damage the LD. Therefore, in order to ensure the convenience of the drive circuit and reduce the damage to the LD, a delayed power-on circuit is added after the DAC circuit. The zero-output zero-state response of the resistor-capacitor circuit and the charging and discharging principle of the capacitor are used to make the voltage rise in a buffered manner during the circuit startup process to protect the LD.

[0061] 2. Analysis of pulse drive current detection method

[0062] The present invention adopts a high-side current detection method. Based on the characteristics of a high-side current detection circuit having a large input common-mode voltage, an operational amplifier with a high CMRR is used. The principle of the current detection circuit or the detection method is analyzed below. Figure 4 shown.

[0063] According to Kirchhoff's current law:

[0064] I test =I p +I L (1)

[0065] Among them, I tset ,I p ,I L It represents the current corresponding to the sampling resistor, the positive input terminal, and the load resistor in turn;

[0066] And, when the PMOS tube is turned on, we can get:

[0067] I R1 +I n =I R2 (2)

[0068] Among them, I R1 ,I n ,I R2 represents the current corresponding to the first shunt resistor, the reverse input terminal, and the second shunt resistor in sequence;

[0069] The circuit has a negative feedback loop. When the circuit reaches deep negative feedback, the op amp will reach virtual short and virtual disconnect conditions. + =V - , I p =In ≈0. Therefore, we can get:

[0070] V1-V2=I test ×R test =V1-V - =I R1 ×R1 (3)

[0071] I test =(I R1 ×R1) / R test (4)

[0072] Among them, V1 and V2 represent the voltage across the sampling resistor, V + 、V - represents the voltage at the non-inverting input and the inverting input of the operational amplifier, R1 represents the first shunt resistor, R2 represents the second shunt resistor, R test Represents the sampling resistor.

[0073] Because the on-resistance of the PMOS tube is small, we can get I R1 =I R2 ,so:

[0074] I test =(I R2 ×R1) / R test =(V out ×R1) / (R2×R test ) (5)

[0075] Formula (5) is the relationship equation between the corresponding driving current and the voltage after acquisition. In FPGA, the voltage value acquired by ADC can be converted into the corresponding driving current value according to this equation. In the above formula, I represents the current, and different subscripts of I represent the current of the corresponding subscript device.

[0076] In addition, to ensure accurate measurement of the driving current, the current sampling resistor uses Kelvin connection during PCB production to eliminate the voltage drop on the wire and reduce interference.

[0077] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A semiconductor laser pulse drive circuit, characterized in that: include: A pulse drive control circuit, a pulse drive circuit and a pulse drive current detection circuit; wherein the pulse drive current detection circuit, the pulse drive control circuit and the pulse drive circuit are connected in sequence, the pulse drive current detection circuit adopts a high-side current detection circuit, and the pulse drive circuit includes a laser switch chip; The pulse drive current detection circuit is used to obtain a detection voltage according to the drive current of the semiconductor laser. The pulse drive control circuit is used to generate a drive signal and generate a control voltage according to the detection voltage. The pulse drive control circuit is used to generate a drive current according to the drive signal and control the size of the drive current according to the control voltage, and control the drive of the semiconductor laser through the drive current.

2. The pulse drive circuit according to claim 1, characterized in that: The pulse drive control circuit includes an analog-to-digital converter, a main control module and a digital-to-analog converter connected in sequence, wherein the main control module is used to generate control information according to the detection voltage value converted by the analog-to-digital converter, and convert the control information into a control voltage through the digital-to-analog converter and transmit it to the current drive circuit.

3. The pulse drive circuit according to claim 1, characterized in that: The pulse drive circuit adopts one or several laser switch chips, wherein when several laser switch chips are adopted, the several laser switch chips are connected in parallel to improve the scalability and multiply the driving capability of the pulse drive circuit for the semiconductor laser.

4. The pulse drive circuit according to claim 1, characterized in that: The pulse drive current detection circuit includes an operational amplifier and a sampling resistor, wherein the sampling resistor is connected to a pulse current input terminal, and the pulse current input terminal is used to receive the drive current of a semiconductor laser, and one end of the sampling resistor away from the pulse current input terminal is connected to a load resistor and grounded, and a first shunt resistor, a PMOS tube, a second shunt resistor and a grounding terminal which are connected in series in sequence are connected in parallel between the sampling resistor and the pulse current input terminal, and a voltage output terminal is provided between the second shunt resistor and the PMOS tube, which is connected to the pulse drive control circuit for outputting a detection voltage; the non-phase input terminal of the operational amplifier is connected to one end of the sampling resistor away from the input terminal of the pulse drive control circuit, the inverting input terminal of the operational amplifier is connected between the first shunt resistor and the PMOS tube, and the output terminal of the operational amplifier is connected to the gate of the PMOS tube.

5. The pulse drive circuit according to claim 1, characterized in that: The pulse drive control circuit is connected to a delayed power-on circuit, which is used to delay the control voltage and transmit it to the pulse drive circuit to prevent the semiconductor laser from being damaged by the pulse at the moment of power-on.

6. The pulse drive circuit according to claim 3, characterized in that: The laser switch chip adopts iC-HG30 laser switch chip.

7. A driving current detection and control method for a pulse driving circuit according to any one of claims 1 to 6, characterized in that: include: The driving current of the semiconductor laser is collected and detected by the pulse driving current detection circuit to generate a detection voltage; Generate a drive signal through a pulse drive control circuit and generate a drive current value according to the detection voltage, judge the drive current value, generate control information based on the judgment result, and generate a control voltage according to the control information; The pulse drive circuit generates a drive current according to a drive signal, controls the size of the drive current according to a control voltage, and controls and drives the semiconductor laser through the drive current.

8. The method according to claim 7, characterized in that The generation process of the driving current value includes: The detection voltage is converted into a digital form to obtain a detection voltage value, and the detection voltage value is calculated using a relationship between the driving current value and the detection voltage value to obtain a driving current value.

9. The method according to claim 7, characterized in that: The generation process of the control signal includes: The driving current value is judged according to the initially set driving current value, and if the error between the driving current value and the initially set driving current value is within a threshold range, the driving current value is gradually increased, and the corresponding control information is obtained according to the increased driving current value through the fitting relationship between the driving current value and the control voltage, and the control information is converted into digital-to-analog format to obtain the control voltage; If the error between the driving current value and the initially set driving current value is outside the threshold range, error correction control is directly performed.

10. The method according to claim 7, characterized in that The process of detecting the driving current of a semiconductor laser includes: In the pulse drive current detection circuit, the drive current is sampled to obtain a sampling current corresponding to the drive current, and the detection voltage is obtained according to the relationship between the drive current value and the detection voltage value; The relationship between the driving current value and the detection voltage value is: I test =(I R2 ×R1) / R test =(V out ×R1) / (R2×R test ) Among them, I tset is the sampling current corresponding to the driving current, V out is the detection voltage, I R2 represents the current passing through the resistor R2, R1 represents the first shunt resistor, R2 represents the second shunt resistor, R test Represents the sampling resistor.

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