Laser tube pulse modulation driving circuit

Abstract

The utility model discloses a laser tube pulse modulation drive circuit, which comprises a differential circuit module, a mirror image constant current source module, a first common collector amplification circuit module, a second common collector amplification circuit module and a laser tube direct drive circuit module, the differential circuit module is respectively connected with the mirror image constant current source module and the first common collector amplification circuit module; the second common collector amplification circuit module is respectively connected with the first common collector amplification circuit module and the laser tube direct drive circuit module; the output power of the laser tube is further controlled by introducing the bias voltage to modulate the pulse input signal under the condition of not changing the original input pulse signal, so that the problem that the matching degree of the input signal and the adjustment flexibility of the output power are insufficient is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to laser tube pulse modulation technical field especially relates to a laser tube pulse modulation drive circuit. BACKGROUND

[0002] The prior art laser tube pulse modulation drive circuit generally adopts integrated laser drive scheme such as operational amplifier or special drive chip, and the existing integrated laser drive chip generally has relatively fixed operating parameter interval, and it is difficult to customize for some special scenes, and the matching degree of input signal and the output power regulation flexibility are insufficient. UTILITY MODEL CONTENTS

[0003] In order to overcome the insufficient of prior art, the utility model provides a laser tube pulse modulation drive circuit, realize under the condition of not changing original input pulse signal, through introducing bias voltage modulation pulse input signal, further control laser tube output power, thereby solve the problem of the matching degree of input signal and the output power regulation flexibility

[0004] In order to realize the utility model purpose above, the utility model adopts following technical scheme:

[0005] A laser tube pulse modulation drive circuit, including difference circuit module, mirror image constant current source module, first common collector amplification circuit module, second common collector amplification circuit module and laser tube direct drive circuit module, difference circuit module is connected with mirror image constant current source module and first common collector amplification circuit module respectively, second common collector amplification circuit module is connected with first common collector amplification circuit module and laser tube direct drive circuit module respectively, mirror image constant current source module provides constant current for difference circuit module, difference circuit module transmits pulse amplitude modulation signal to first common collector amplification circuit module, first common collector amplification circuit module isolates output pulse amplitude modulation signal to second common collector amplification circuit module, second common collector amplification circuit module carries out signal power amplification to pulse amplitude modulation signal, and laser tube direct drive circuit module is used to improve the driving capacity of pulse amplitude modulation signal.

[0006] Further, the differential circuit module comprises resistors R1, R2, R3, R11, R12, R16, R17, capacitors C1, C2, C4, C12, fast non-saturated switch tubes Q1 and Q3, one end of the capacitor C2 is connected to the input pulse voltage signal, the other end of the capacitor C2 is connected to one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 respectively, the other end of the resistor R6 is connected to the base of the fast non-saturated switch tube Q1, the emitter of the fast non-saturated switch tube Q1 is connected to one end of the resistor R16, the collector of the fast non-saturated switch tube Q1 is connected to one end of the resistor R2, the other end of the resistor R1, one end of the capacitor C1, the other end of the resistor R2 and one end of the resistor R3 are connected to the positive pole of the power supply, the other end of the resistor R7 and the other end of the capacitor C1 are grounded, one end of the resistor R11 is connected to the input DC level signal, the other end of the resistor R11 is connected to one end of the resistor R12 and one end of the capacitor C12 respectively, the other end of the resistor R12 is connected to the base of the fast non-saturated switch tube Q3, the emitter of the fast non-saturated switch tube Q3 is connected to one end of the resistor R16, the collector of the fast non-saturated switch tube Q3 is connected to the other end of the resistor R3 and one end of the capacitor C4 respectively, the other end of the capacitor C1 is grounded, the other end of the resistor R16 and the other end of the resistor R17 are connected to the mirror constant current source module, and the other end of the capacitor C4 is connected to the first common collector amplification circuit module.

[0007] Further, the mirror constant current source module comprises resistors R19, R20, R49, R50, R52, capacitors C17, C18, super high frequency low noise switch tubes Q7 and Q8, one end of the resistor R19 is connected to the differential circuit module, the other end of the resistor R19 is connected to the collector of the super high frequency low noise switch tube Q7, the base of the super high frequency low noise switch tube Q7 is connected to the base of the super high frequency low noise switch tube Q8, the collector of the super high frequency low noise switch tube Q8 and one end of the resistor R20 respectively, the emitter of the super high frequency low noise switch tube Q7 is connected to one end of the resistor R49, the other end of the resistor R49 is connected to one end of the capacitor C17, one end of the capacitor C18, one end of the resistor R50 and one end of the resistor R52 respectively, the other end of the resistor R50 is connected to the emitter of the super high frequency low noise switch tube Q8, the other end of the resistor R52 is connected to the negative pole of the power supply, the other end of the resistor R20, the other end of the capacitor C17 and the other end of the capacitor C18 are grounded.

[0008] Further, the first common collector amplification circuit module comprises a resistor R4, a resistor R5, a resistor R9, a resistor R13, a resistor R14, a capacitor C3 and a high-frequency switch tube Q2, one end of the resistor R4 and one end of the resistor R5 are connected to the positive pole of the power supply, the differential circuit module is connected to the other end of the resistor R4, one end of the resistor R9 and the base of the high-frequency switch tube Q2 respectively, the collector of the high-frequency switch tube Q2 is connected to the other end of the resistor R5 and one end of the capacitor C3 respectively, the emitter of the high-frequency switch tube Q2 is connected to one end of the resistor R13 and one end of the resistor R14 respectively, the other end of the resistor R13 is connected to the second common collector amplification circuit module, the other end of the resistor R14, the other end of the capacitor C3 and the other end of the resistor R9 are grounded.

[0009] Further, the second common collector amplification circuit module comprises a resistor R8, a resistor R15, a resistor R18, a resistor R21, a variable resistor R22, a resistor R23, a capacitor C5, a capacitor C13, a capacitor C14 and a power switch tube Q4, one end of the resistor R8 and one end of the capacitor C5 are connected to the positive pole of the power supply, the base of the power switch tube Q4 is connected to the first common collector amplification circuit module, the collector of the power switch tube Q4 is connected to the other end of the resistor R8, the emitter of the power switch tube Q4 is connected to one end of the resistor R15, one end of the resistor R18 and one end of the resistor R21 respectively, the other end of the resistor R21 is connected to one end of the variable resistor R22, the other end of the variable resistor R22 is connected to one end of the resistor R23, one end of the capacitor C13 and one end of the capacitor C14 respectively, the other end of the resistor R15 is connected to the laser tube direct drive circuit, the other end of the resistor R18 is connected to the laser tube direct drive circuit, the other end of the resistor R23 is connected to the negative pole of the power supply, the other end of the capacitor C5, the other end of the capacitor C13 and the other end of the capacitor C14 are grounded.

[0010] Further, in the circuit debugging stage, by adjusting the resistance value of the variable resistor R22, the on-current of the power switch tube Q4 is fine-tuned to match the drive signal of the power switch tube Q5 and the power switch tube Q6 direct drive circuit.

[0011] Further, the laser tube direct drive circuit module comprises a power switch tube Q5, a power switch tube Q6, a resistor R10, a resistor R51, a variable resistor R24, a capacitor C10, a capacitor C11, a capacitor C15, a capacitor C16 and a laser diode LD1, one end of the resistor R10 is connected to the positive pole of a power supply, the other end of the resistor R10 is connected to one end of the capacitor C10, one end of the capacitor C11, the collector of the power switch tube Q5 and the collector of the power switch tube Q6 respectively, one end of the laser diode LD1 is connected to the emitter of the power switch tube Q5 and the emitter of the power switch tube Q6 respectively, the base of the power switch tube Q5 is connected to the second common collector amplification circuit module, the base of the power switch tube Q6 is connected to the second common collector amplification circuit module, the other end of the laser diode LD1 is connected to one end of the variable resistor R24, the other end of the variable resistor R24 is connected to one end of the resistor R51, one end of the capacitor C15 and one end of the capacitor C16 respectively, the other end of the resistor R51 is connected to the negative pole of the power supply, the other end of the capacitor C10, the other end of the capacitor C11, the other end of the capacitor C15 and the other end of the capacitor C16 are grounded.

[0012] The application has the beneficial effects that the bias voltage is introduced to modulate the pulse input signal without changing the original input pulse signal, the output power of the laser tube is further controlled, and the matching degree of the input signal and the flexibility of the output power adjustment are improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0014] Figure 1 It is a laser tube pulse modulation driving circuit diagram of the present application. DETAILED DESCRIPTION

[0015] The embodiments of the present application will be described in detail below with reference to the drawings.

[0016] The following will illustrate the embodiments of the present application through specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. Obviously, the described embodiments are only some of the embodiments of the present application, not all. The present application can also be implemented or applied through other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0017] Embodiment one:

[0018] A laser tube pulse modulation driving circuit, comprising a differential circuit module, a mirror constant current source module, a first common collector amplification circuit module, a second common collector amplification circuit module and a laser tube direct driving circuit module, the differential circuit module is connected with the mirror constant current source module and the first common collector amplification circuit module respectively, the second common collector amplification circuit module is connected with the first common collector amplification circuit module and the laser tube direct driving circuit module respectively, the mirror constant current source module provides constant current for the differential circuit module, the differential circuit module transmits a pulse amplitude modulation signal to the first common collector amplification circuit module, the first common collector amplification circuit module isolates and outputs the pulse amplitude modulation signal to the second common collector amplification circuit module, the second common collector amplification circuit module amplifies the signal power of the pulse amplitude modulation signal, and the laser tube direct driving circuit module is used for improving the driving capacity of the pulse amplitude modulation signal.

[0019] The differential circuit module comprises resistors R1, R2, R3, R11, R12, R16, R17, capacitors C1, C2, C4, C12, fast non-saturation switch tubes Q1 and Q3, one end of the capacitor C2 is connected to an input pulse voltage signal, the other end of the capacitor C2 is connected to one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 respectively, the other end of the resistor R6 is connected to the base of the fast non-saturation switch tube Q1, the emitter of the fast non-saturation switch tube Q1 is connected to one end of the resistor R16, the collector of the fast non-saturation switch tube Q1 is connected to one end of the resistor R2, the other end of the resistor R1, one end of the capacitor C1, the other end of the resistor R2 and one end of the resistor R3 are connected to the positive pole of a power supply, the other end of the resistor R7 and the other end of the capacitor C1 are grounded, one end of the resistor R11 is connected to an input DC level signal, the other end of the resistor R11 is connected to one end of the resistor R12 and one end of the capacitor C12 respectively, the other end of the resistor R12 is connected to the base of the fast non-saturation switch tube Q3, the emitter of the fast non-saturation switch tube Q3 is connected to one end of the resistor R16, the collector of the fast non-saturation switch tube Q3 is connected to the other end of the resistor R3 and one end of the capacitor C4 respectively, the other end of the capacitor C1 is grounded, the other end of the resistor R16 and the other end of the resistor R17 are connected to a mirror constant current source module, and the other end of the capacitor C4 is connected to a first common collector amplification circuit module.

[0020] The mirror constant current source module comprises resistors R19, R20, R49, R50, R52, capacitors C17, C18, super high frequency low noise switch tubes Q7 and Q8, one end of the resistor R19 is connected to the differential circuit module, the other end of the resistor R19 is connected to the collector of the super high frequency low noise switch tube Q7, the base of the super high frequency low noise switch tube Q7 is connected to the base of the super high frequency low noise switch tube Q8, the collector of the super high frequency low noise switch tube Q8 and one end of the resistor R20 respectively, the emitter of the super high frequency low noise switch tube Q7 is connected to one end of the resistor R49, the other end of the resistor R49 is connected to one end of the capacitor C17, one end of the capacitor C18, one end of the resistor R50 and one end of the resistor R52 respectively, the other end of the resistor R50 is connected to the emitter of the super high frequency low noise switch tube Q8, the other end of the resistor R52 is connected to the negative pole of a power supply, the other end of the resistor R20, the other end of the capacitor C17 and the other end of the capacitor C18 are grounded.

[0021] The first common collector amplification circuit module comprises resistors R4, R5, R9, R13, R14, capacitor C3 and high-frequency switch tube Q2, one end of the resistor R4 and one end of the resistor R5 are connected to the positive pole of the power supply, the differential circuit module is connected to the other end of the resistor R4, one end of the resistor R9 and the base of the high-frequency switch tube Q2 respectively, the collector of the high-frequency switch tube Q2 is connected to the other end of the resistor R5 and one end of the capacitor C3 respectively, the emitter of the high-frequency switch tube Q2 is connected to one end of the resistor R13 and one end of the resistor R14 respectively, the other end of the resistor R13 is connected to the second common collector amplification circuit module, the other end of the resistor R14, the other end of the capacitor C3 and the other end of the resistor R9 are grounded.

[0022] The second common collector amplification circuit module comprises resistors R8, R15, R18, R21, variable resistor R22, resistor R23, capacitor C5, capacitor C13, capacitor C14 and power switch tube Q4, one end of the resistor R8 and one end of the capacitor C5 are connected to the positive pole of the power supply, the base of the power switch tube Q4 is connected to the first common collector amplification circuit module, the collector of the power switch tube Q4 is connected to the other end of the resistor R8, the emitter of the power switch tube Q4 is connected to one end of the resistor R15, one end of the resistor R18 and one end of the resistor R21 respectively, the other end of the resistor R21 is connected to one end of the variable resistor R22, the other end of the variable resistor R22 is connected to one end of the resistor R23, one end of the capacitor C13 and one end of the capacitor C14 respectively, the other end of the resistor R15 is connected to the laser tube direct drive circuit, the other end of the resistor R18 is connected to the laser tube direct drive circuit, the other end of the resistor R23 is connected to the negative pole of the power supply, the other end of the capacitor C5, the other end of the capacitor C13 and the other end of the capacitor C14 are grounded. In the circuit debugging stage, by adjusting the resistance value of the variable resistor R22, the on-current of the power switch tube Q4 is fine-tuned, and the driving signal of the power switch tube Q5 and the power switch tube Q6 direct drive circuit is matched.

[0023] The laser tube direct drive circuit module comprises a power switch tube Q5, a power switch tube Q6, a resistor R10, a resistor R51, a variable resistor R24, a capacitor C10, a capacitor C11, a capacitor C15, a capacitor C16 and a laser diode LD1. One end of the resistor R10 is connected to the positive pole of a power supply. The other end of the resistor R10 is connected to one end of the capacitor C10, one end of the capacitor C11, the collector of the power switch tube Q5 and the collector of the power switch tube Q6 respectively. One end of the laser diode LD1 is connected to the emitter of the power switch tube Q5 and the emitter of the power switch tube Q6 respectively. The base of the power switch tube Q5 is connected to the second common collector amplification circuit module. The base of the power switch tube Q6 is connected to the second common collector amplification circuit module. The other end of the laser diode LD1 is connected to one end of the variable resistor R24. The other end of the variable resistor R24 is connected to one end of the resistor R51, one end of the capacitor C15 and one end of the capacitor C16 respectively. The other end of the resistor R51 is connected to the negative pole of the power supply. The other end of the capacitor C10, the other end of the capacitor C11, the other end of the capacitor C15 and the other end of the capacitor C16 are grounded. The laser tube current is controlled by adjusting the variable resistor R24 to limit the laser power.

[0024] As shown in Figure 1 P1 input pulse voltage signal, P2 input DC level signal, through the differential circuit module, realize pulse input signal amplitude modulation. Among them, the resistor R11 and the capacitor C12 constitute an RC low-pass filter, further filter the DAC signal to obtain the pulse amplitude signal. The mirror constant current source module is used to provide constant current for the differential circuit module. The differential circuit module and the mirror constant current source module are used as the input stage circuit to constitute the pulse amplitude modulation circuit, TP1 is the amplitude modulation signal output test point, connected to the next stage circuit through the capacitor C4. It should be noted that P1 is an input pulse signal source; P2 is a bias signal, that is, without changing the P1 input signal source, only by adjusting the bias signal of P2, the output power of the laser tube is flexibly adjusted to adapt to multiple scene applications. Although the resistor R24 can adjust the output power, the adjustment capacity is limited, and it will cause large loss, mainly for fine tuning.

[0025] The first common collector amplification circuit module isolates and outputs the pulse amplitude modulation signal, and the amplification multiple is 1 (emitter output device). TP1 is coupled through the capacitor C4. TP2 is an isolated output signal test point connected to the next stage circuit through the resistor R13, and the amplitude modulation signal is isolated and followed.

[0026] The amplification factor of the second common collector amplification circuit module is 1, the driving capacity of the pulse amplitude modulation signal is improved, and the signal power is amplified (for example, the power switch tube Q4 first stage amplification power max 500mW). The laser tube direct drive circuit module, the power switch tube Q5 and the power switch tube Q6 are driven in parallel, and the driving capacity of the amplitude modulation signal is further improved (the power switch tube Q5 and the power switch tube Q6 second stage amplification power, max 2*500mW), and TP3 is a laser tube driving signal test point. The resistance R24 adjusts the laser tube current and can limit the emission power. The second common collector amplification circuit module and the laser tube direct drive circuit module serve as the output stage circuit and directly drive the laser tube LD1.

[0027] Optionally, in order to ensure the high precision and continuous stable operation characteristics of the circuit, the selection of key devices of the circuit is given as a reference. The selection of key devices of the circuit: Q1 and Q3 are selected from fast non-saturated switch tubes, model BFR92PE6327HTSA1, hfe=100, fT=5GHz, Pd=280mW. Q7, Q8 are selected from super high frequency low noise switch tubes, model 2SC3356-R26, hfe=300, fT=7GHz, Pd=200mW. Q4, Q5, Q are selected from general power switch tubes, model 2N3904U, hfe=300, fT=300MHz, Pd=500mW. Q2 is selected from general high frequency switch tubes, model S9018, hfe=100, fT=600MHz, Pd=500mW. Among them, Q1, Q3 and Q7, Q8 must be switch tubes of the same type and batch to reduce the error caused by the difference between devices. All resistors in the circuit are high-precision low-temperature drift devices, with a typical value accuracy of ±0.1% and a temperature coefficient of ±25ppm / ℃.

[0028] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and the unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0029] The terms "first", "second", and "third" and the like in the specification of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser tube pulse modulation driving circuit, characterized in that, The application relates to a laser driving circuit, which comprises a differential circuit module, a mirror constant current source module, a first common collector amplification circuit module, a second common collector amplification circuit module and a laser tube direct driving circuit module, wherein the differential circuit module is connected with the mirror constant current source module and the first common collector amplification circuit module, the second common collector amplification circuit module is connected with the first common collector amplification circuit module and the laser tube direct driving circuit module, the mirror constant current source module provides constant current for the differential circuit module, the differential circuit module transmits a pulse amplitude modulation signal to the first common collector amplification circuit module, the first common collector amplification circuit module isolates and outputs the pulse amplitude modulation signal to the second common collector amplification circuit module, the second common collector amplification circuit module amplifies the signal power of the pulse amplitude modulation signal, and the laser tube direct driving circuit module is used for improving the driving capacity of the pulse amplitude modulation signal.

2. The laser diode pulse modulation driving circuit according to claim 1, wherein, The differential circuit module comprises resistors R1, R2, R3, R11, R12, R16, R17, capacitors C1, C2, C4, C12, fast non-saturation switch tubes Q1 and Q3, one end of the capacitor C2 is connected with an input pulse voltage signal, the other end of the capacitor C2 is connected with one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7, the other end of the resistor R6 is connected with the base of the fast non-saturation switch tube Q1, the emitter of the fast non-saturation switch tube Q1 is connected with one end of the resistor R16, the collector of the fast non-saturation switch tube Q1 is connected with one end of the resistor R2, the other end of the resistor R1, one end of the capacitor C1, the other end of the resistor R2 and one end of the resistor R3 are connected with the positive pole of a power supply, the other end of the resistor R7 and the other end of the capacitor C1 are grounded, one end of the resistor R11 is connected with an input direct current level signal, the other end of the resistor R11 is connected with one end of the resistor R12 and one end of the capacitor C12, the other end of the resistor R12 is connected with the base of the fast non-saturation switch tube Q3, the emitter of the fast non-saturation switch tube Q3 is connected with one end of the resistor R16, the collector of the fast non-saturation switch tube Q3 is connected with the other end of the resistor R3 and one end of the capacitor C4, the other end of the capacitor C1 is grounded, the other end of the resistor R16 and the other end of the resistor R17 are connected with the mirror constant current source module, and the other end of the capacitor C4 is connected with the first common collector amplification circuit module.

3. The laser diode pulse modulation driving circuit according to claim 1, wherein, The mirror constant current source module comprises resistance R19, resistance R20, resistance R49, resistance R50, resistance R52, capacitor C17, capacitor C18, ultra-high frequency low noise switch tube Q7 and ultra-high frequency low noise switch tube Q8, one end of the resistance R19 is connected with the differential circuit module, the other end of the resistance R19 is connected with the collector of the ultra-high frequency low noise switch tube Q7, the base of the ultra-high frequency low noise switch tube Q7 is connected with the base of the ultra-high frequency low noise switch tube Q8, the collector of the ultra-high frequency low noise switch tube Q8 and one end of the resistance R20 respectively, one end of the resistance R49 is connected with the emitter of the ultra-high frequency low noise switch tube Q7, the other end of the resistance R49 is connected with one end of the capacitor C17, one end of the capacitor C18, one end of the resistance R50 and one end of the resistance R52 respectively, the other end of the resistance R50 is connected with the emitter of the ultra-high frequency low noise switch tube Q8, the other end of the resistance R52 is connected with the negative pole of the power supply, the other end of the resistance R20, the other end of the capacitor C17 and the other end of the capacitor C18 are grounded.

4. The laser diode pulse modulation driving circuit according to claim 1, wherein, The first common collector amplification circuit module comprises resistance R4, resistance R5, resistance R9, resistance R13, resistance R14, capacitor C3 and high-frequency switch tube Q2, one end of the resistance R4 and one end of the resistance R5 are connected with the positive pole of the power supply, the differential circuit module is connected with the other end of the resistance R4, one end of the resistance R9 and the base of the high-frequency switch tube Q2 respectively, the collector of the high-frequency switch tube Q2 is connected with the other end of the resistance R5 and one end of the capacitor C3 respectively, the emitter of the high-frequency switch tube Q2 is connected with one end of the resistance R13 and one end of the resistance R14 respectively, the other end of the resistance R13 is connected with the second common collector amplification circuit module, the other end of the resistance R14, the other end of the capacitor C3 and the other end of the resistance R9 are grounded.

5. The laser diode pulse modulation driving circuit according to claim 1, wherein, The second common collector amplification circuit module comprises resistance R8, resistance R15, resistance R18, resistance R21, variable resistance R22, resistance R23, capacitor C5, capacitor C13, capacitor C14 and power switch tube Q4, one end of the resistance R8 and one end of the capacitor C5 are connected with the positive pole of the power supply, the base of the power switch tube Q4 is connected with the first common collector amplification circuit module, the collector of the power switch tube Q4 is connected with the other end of the resistance R8, the emitter of the power switch tube Q4 is connected with one end of the resistance R15, one end of the resistance R18 and one end of the resistance R21 respectively, the other end of the resistance R21 is connected with one end of the variable resistance R22, the other end of the variable resistance R22 is connected with one end of the resistance R23, one end of the capacitor C13 and one end of the capacitor C14 respectively, the other end of the resistance R15 is connected with the laser tube direct driving circuit, the other end of the resistance R18 is connected with the laser tube direct driving circuit, the other end of the resistance R23 is connected with the negative pole of the power supply, the other end of the capacitor C5, the other end of the capacitor C13 and the other end of the capacitor C14 are grounded.

6. The laser diode pulse modulation driving circuit according to claim 1, wherein, The laser tube direct drive circuit module comprises a power switch tube Q5, a power switch tube Q6, a resistor R10, a resistor R51, a variable resistor R24, a capacitor C10, a capacitor C11, a capacitor C15, a capacitor C16 and a laser diode LD1, one end of the resistor R10 is connected to the positive pole of a power supply, the other end of the resistor R10 is connected to one end of the capacitor C10, one end of the capacitor C11, the collector of the power switch tube Q5 and the collector of the power switch tube Q6 respectively, one end of the laser diode LD1 is connected to the emitter of the power switch tube Q5 and the emitter of the power switch tube Q6 respectively, the base of the power switch tube Q5 is connected to the second common collector amplification circuit module, the base of the power switch tube Q6 is connected to the second common collector amplification circuit module, the other end of the laser diode LD1 is connected to one end of the variable resistor R24, the other end of the variable resistor R24 is connected to one end of the resistor R51, one end of the capacitor C15 and one end of the capacitor C16 respectively, the other end of the resistor R51 is connected to the negative pole of the power supply, the other end of the capacitor C10, the other end of the capacitor C11, the other end of the capacitor C15 and the other end of the capacitor C16 are grounded.

7. The laser diode pulse modulation driving circuit according to claim 5, wherein, In the circuit debugging stage, by adjusting the resistance value of the variable resistor R22, the on current of the power switch tube Q4 is fine tuned, and the driving signal of the power switch tube Q5 and the power switch tube Q6 direct drive circuit is matched.

8. The laser diode pulse modulation driving circuit according to claim 6, wherein, By adjusting the variable resistor R24, the laser tube current is controlled to limit the laser power.

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