High-power laser driving circuit

Abstract

The utility model discloses a high-power laser driving circuit, comprising an adjustable output DCDC power supply module used for outputting a driving signal to a laser; the current sampling module is used for monitoring a working current value of the laser and feeding back a corresponding voltage value to the MCU control module; the MCU control module is used for converting the feedback voltage value into a working current value, comparing the working current value with a target current value, and outputting a voltage regulation signal to the feedback regulation module; the feedback regulation module is used for carrying out voltage division on the driving signal and the voltage regulation signal and then superposing and outputting a feedback voltage signal to the adjustable output DCDC power supply module; and the adjustable output DCDC power supply module is also used for adjusting the voltage of the driving signal according to the comparison result of the feedback voltage signal and the internal reference voltage, so that the laser works under the target working current. According to the utility model, the precise control of the working current of the laser can be realized without arranging a large-current digital-to-analog conversion chip, and the circuit power consumption and the realization cost are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to laser control technical field, especially relates to a kind of high-power laser driver circuit. BACKGROUND

[0002] MZ silicon light modulation mode usually needs to use high-power (power is between 40~100mW) laser as light source, however this high-power laser needs larger direct current to drive, usually 150mA~300mA, and due to the change of environmental temperature, device loss, aging attenuation and other factors, the working current of laser needs to be controlled in the whole working process of optical module.

[0003] The related technology mainly controls the working current of laser through a current-mode digital-to-analog conversion chip (IDAC) of large current or several parallel current-mode digital-to-analog conversion chips of slightly smaller current, to realize the effect of controllable working current while realizing large-current drive. However, IDAC chip is scarce and high in price, and the power consumption is relatively large, so that the implementation cost and power consumption of the scheme are relatively high. At the same time, the IDAC chip scheme does not establish a real sampling feedback monitoring mechanism for the working current of laser, and the control effect is poor. SUMMARY

[0004] The main purpose of the utility model is to provide a kind of high-power laser driver circuit, to solve the technical problems, such as high implementation cost, large power consumption and poor control effect of laser working current in related technology.

[0005] To achieve the above purpose, the utility model provides a kind of high-power laser driver circuit, connected with laser, and the high-power laser driver circuit includes:

[0006] Adjustable output DCDC power module is connected with laser and feedback adjustment module respectively, for outputting driving signal to laser;

[0007] Current sampling module is connected between the output end of adjustable output DCDC power module and laser, for monitoring the working current value of laser, and corresponding voltage value is fed back to MCU control module;

[0008] MCU control module is used to compare the voltage value fed back by current sampling module with target current value after converting the voltage value into working current value, and output voltage adjustment signal to feedback adjustment module;

[0009] Feedback adjustment module is used to divide driving signal and voltage adjustment signal respectively, and then superimposes, and outputs feedback voltage signal to adjustable output DCDC power module;

[0010] The adjustable output DCDC power module is also used for comparing the feedback voltage signal with an internal reference voltage, and adjusting the voltage size of the driving signal according to the comparison result, so that the laser works at a target working current.

[0011] The current sampling module is used for monitoring the current value of the driving signal in real time, and outputting a corresponding voltage value to the MCU control module, so that the working current value of the laser is accurately sampled; the MCU control module adjusts the voltage adjustment signal output to the feedback adjustment module according to the comparison result of the sampled working current value and the target current value, so that the working current value of the laser is accurately fed back; the feedback adjustment module superimposes the driving signal and the voltage adjustment signal after voltage division to obtain a feedback voltage signal, and transmits the feedback voltage signal to the adjustable output DCDC power module, so that the adjustable output DCDC power module adjusts the voltage size of the driving signal according to the comparison result of the feedback voltage signal and the internal reference voltage, so as to change the working current value of the laser, thereby realizing accurate adjustment of the working current value of the laser. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a functional module diagram of the high-power laser driver circuit of the utility model;

[0013] Figure 2 It is a structural schematic diagram of the high-power laser driver circuit of the utility model.

[0014] The implementation, functional features and advantages of the utility model will be further described with reference to the accompanying drawings in combination with embodiments. DETAILED DESCRIPTION

[0015] It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0016] The technical solutions in the embodiments of the utility model will be clearly and completely described in combination with the accompanying drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0017] It should be noted that the description of "first", "second" and the like in the present application is only for the purpose of description and cannot be understood as indicating or implying the relative importance of the technical features or implying the number of the technical features indicated. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the present application.

[0018] Referring to Figure 1 , Figure 1 is a functional module diagram of the high-power laser driver circuit of the present application.

[0019] As Figure 1 shown, in the present embodiment, the high-power laser driver circuit is connected with the positive electrode of the laser, and the negative electrode of the laser is grounded. The high-power laser driver circuit can include an adjustable output DCDC power supply module, a current sampling module, an MCU control module and a feedback adjustment module.

[0020] Specifically, the out end of the adjustable output DCDC power supply module is connected with the laser through the current collection module, for outputting a driving signal to the laser.

[0021] In a specific implementation process, the adjustable output DCDC power supply module can adopt a DCDC power supply module with a maximum output current of 1A and an output voltage range of 1-3V.

[0022] The current sampling module is connected between the output end of the adjustable output DCDC power supply module and the laser, and is connected with the ADC end of the MCU control module, for monitoring the working current value I Q of the laser and outputting a corresponding voltage value V ADC to the MCU control module.

[0023] The DAC end of the MCU control module is connected with the input end of the feedback adjustment module, for converting the voltage value V ADC into the working current value I Q of the laser, comparing it with the target current value I o , and adjusting the voltage adjustment signal V DAC output to the feedback adjustment module according to the comparison result.

[0024] Specifically, when the working current value I Q of the laser is greater than the target current value I o , the voltage adjustment signal V DAC is increased; when the working current value I QThe target current value I o The voltage regulation signal V DAC .

[0025] The first end of the feedback regulation module is grounded, the second end is connected with the FB feedback end of the adjustable output DCDC power supply module, and the third end is connected with the output end of the adjustable output DCDC power supply module, for respectively superimposing the drive signal and the voltage regulation signal V DAC after voltage division, and transmitting the feedback voltage signal V FB obtained by superimposition to the FB feedback end of the adjustable output DCDC power supply module, so that the adjustable output DCDC power supply module adjusts the size of the voltage V FB of the drive signal according to the comparison result of the feedback voltage signal V ref and the internal reference voltage V out of the adjustable output DCDC power supply module, so as to change the size of the working current value of the laser, and make the laser work at the target working current.

[0026] Specifically, when the feedback voltage signal V FB is greater than the internal reference voltage V ref , the adjustable output DCDC power supply module reduces the output voltage (that is, the voltage V out of the drive signal) by reducing the output duty cycle, so as to reduce the feedback voltage signal V FB , and force the feedback voltage signal V FB to be equal to the internal reference voltage V ref . When the feedback voltage signal V FB is less than the internal reference voltage V ref , the adjustable output DCDC power supply module increases the output voltage by increasing the output duty cycle, so as to increase the feedback voltage signal V FB , and force the feedback voltage signal V FB to be equal to the internal reference voltage V ref .

[0027] Wherein, the internal reference voltage V ref of the adjustable output DCDC power supply module is a fixed value designed, and different adjustable output DCDC power supply modules are selected to correspond to different sizes of reference voltage.

[0028] In the embodiment, the current sampling module monitors the current value of the driving signal in real time, outputs the corresponding voltage value to the MCU control module, and realizes accurate sampling of the working current value of the laser; the MCU control module adjusts the voltage adjustment signal output to the feedback adjustment module according to the comparison result of the sampled working current value and the target current value, and realizes accurate feedback of the working current value of the laser; the feedback adjustment module superimposes the driving signal and the voltage adjustment signal after voltage division to obtain a feedback voltage signal, and transmits the feedback voltage signal to the adjustable output DCDC power module, so that the adjustable output DCDC power module adjusts the voltage of the driving signal according to the comparison result of the feedback voltage signal and the internal reference voltage, so as to change the working current value of the laser, thereby realizing accurate adjustment of the working current value of the laser. As can be seen, the utility model does not need to set a current type digital-analog conversion chip with large current, and can realize accurate control of the working current of the laser, greatly reducing the circuit power consumption and implementation cost.

[0029] Further, as shown in Figure 2 , the current sampling module can specifically include a sampling resistor Rs and a differential operational amplifier OPA.

[0030] Specifically, the output end of the adjustable output DCDC power module is connected with one end of the sampling resistor Rs and the positive input end of the amplifier OPA respectively, the other end of the sampling resistor Rs is connected with the negative input end of the amplifier OPA and the laser respectively; and the output end of the amplifier OPA is connected with the ADC end of the MCU control module.

[0031] When the working current of the laser flows through the sampling resistor Rs, a small voltage difference will be formed across the sampling resistor Rs. The amplifier OPA collects the voltage difference across the sampling resistor Rs through the positive input end and the negative input end, amplifies the voltage difference, and outputs the amplified voltage V ADC to the MCU control module.

[0032] In a specific implementation process, the sampling resistor Rs can adopt a 0.1Ω / 1% precision non-inductive resistor, and the amplifier OPA can adopt a high-precision amplifier such as AD8221.

[0033] Continuing to refer to Figure 2 , the feedback adjustment module can include a first resistor R1, a second resistor R2 and a third resistor R3.

[0034] Specifically, the DAC output end of the MCU control module is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with one end of the first resistor R1, one end of the second resistor R2 and the FB end of the adjustable output DCDC power module respectively; the other end of the first resistor R1 is connected with the out end of the adjustable output DCDC power module; and the other end of the second resistor R2 is grounded.

[0035] The working principle of the circuit is introduced in detail below in a specific working scenario of the laser:

[0036] During the working process of the laser, when the ambient temperature decreases, the actual output optical power of the laser will gradually be greater than the target optical power, and the MCU control module will detect that the current value I Q is greater than the target current value I o in the MCU control module, at which time the voltage adjustment signal V DAC output to the feedback module will gradually increase. The target current value is the working current value that the laser can reach when outputting the target optical power.

[0037] According to Kirchhoff's theorem, the input current of a circuit node is equal to the output current of the circuit node, and the voltages V out , V DAC , and V FB satisfy the following relationship:

[0038]

[0039] Therefore, the feedback voltage signal V FB can be calculated according to the above relationship:

[0040]

[0041] As can be seen, when the voltage adjustment signal V DAC increases, the feedback voltage signal V FB will also increase. At this time, in order to force the feedback voltage signal V FB to return to a state equal to the internal reference voltage V ref , the adjustable output DCDC power supply module will reduce the output voltage by reducing the output duty cycle, that is, by reducing the voltage V out of the drive signal. At this time, as the voltage V out of the drive signal decreases, the working current value I Q of the laser will also decrease. Thus, the working current of the laser gradually reaches the target working current, achieving precise control of the working current of the laser.

[0042] Similarly, when the ambient temperature increases, the actual output optical power of the laser will gradually be less than the target optical power, and the MCU control module will detect that the current value I Q is less than the target current value I o in the MCU control module, at which time the voltage adjustment signal V DAC output to the feedback module will gradually decrease. When the voltage adjustment signal V DAC decreases, the feedback voltage signal V FBThe voltage will decrease accordingly. At this time, the adjustable output DC-DC power module will force the feedback voltage signal V to decrease. FB Restored to the internal reference voltage V ref The state will increase the output voltage by increasing the output duty cycle, which is to say, increase the voltage V of the drive signal. out At this time, with the voltage V of the drive signal... out Increase the operating current value I of the laser. Q It will also increase.

[0043] In this embodiment, the sampling and feedback regulation of the laser's operating current can be achieved using simple discrete components such as four resistors and an amplifier, enabling precise closed-loop control of the laser's operating current. Overall, this solution features a simple circuit structure and lower component costs compared to solutions using high-current current-type digital-to-analog converter chips. Therefore, it significantly reduces the difficulty and cost of implementing laser operating current regulation, while also lowering the overall circuit's power consumption.

[0044] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A high power laser driver circuit, in connection with a laser, characterized in that, The application relates to a laser current closed-loop control system, which comprises the following parts: an adjustable output DCDC power module, which is connected with a laser and a feedback adjustment module respectively and is used for outputting a driving signal to the laser; a current sampling module, which is connected between the adjustable output DCDC power module and the laser and is used for monitoring a working current value of the laser and feeding back a corresponding voltage value to an MCU control module; the MCU control module, which is used for comparing the voltage value fed back by the current sampling module with a target current value after the voltage value is converted into the working current value and outputting a voltage adjustment signal to the feedback adjustment module; the feedback adjustment module, which is used for dividing the driving signal and the voltage adjustment signal and then superimposing the divided signals and outputting a feedback voltage signal to the adjustable output DCDC power module; the adjustable output DCDC power module is further used for comparing the feedback voltage signal with an internal reference voltage and adjusting the voltage size of the driving signal according to a comparison result, so that the laser works at a target working current.

2. The high power laser driver circuit of claim 1, wherein, The current sampling module comprises a sampling resistor and a differential operational amplifier. The adjustable output DCDC power module is connected with one end of the sampling resistor and a positive input end of the amplifier respectively, the other end of the sampling resistor is connected with a negative input end of the amplifier and the laser respectively, and an output end of the amplifier is connected with the MCU control module.

3. The high power laser driver circuit of claim 1, wherein, The feedback adjustment module comprises a first resistor, a second resistor and a third resistor. The MCU control module is connected with one end of the third resistor, the other end of the third resistor is connected with one end of the first resistor, one end of the second resistor and the adjustable output DCDC power module respectively, the other end of the first resistor is connected with the adjustable output DCDC power module, and the other end of the second resistor is grounded.

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