Laser element driving circuit, driving method, and optical module

Abstract

The invention discloses a laser element driving circuit, a driving method and an optical module, and the driving circuit comprises a power supply module which comprises a power supply output end; the main control module comprises a signal output end for outputting a current control signal; the conversion module comprises a power supply input end coupled to the power supply output end and a signal input end coupled to the signal output end; the conversion module is used for outputting a driving signal to a laser element according to the voltage at the power supply output end and the current control signal; wherein the main control module is also used for setting the voltage at the power supply output end as a first power supply voltage; when the power supply module outputs the first power supply voltage, a first element voltage is applied to the laser element, and the laser element works in a linear region; the difference value between the first power supply voltage and the first element voltage is smaller than an error threshold value. The driving circuit provided by the invention has the advantages of low power consumption and stable driving.

Description

Technical Field

[0001] The present invention relates to the field of laser driving technology, and in particular to a laser element driving circuit, a driving method and an optical module. Background Art

[0002] In the optical module provided by the prior art, in order to achieve a better working point, a controlled current source can be configured to drive the laser element (or laser). In order to achieve constant current output, some prior arts obtain output current by setting a sampling resistor or a sampling chip to achieve feedback control, but this technical solution introduces new power consumption at the sampling resistor, resulting in unnecessary increase in the overall power consumption of the circuit.

[0003] In order to ensure the driving capability of the laser element, some other existing technologies usually provide the laser element with a sufficiently large bias voltage, that is, reserve a sufficiently large current margin or voltage margin. However, this technical solution will cause the ineffective power consumption to be further increased, which is difficult to adapt to the low-power circuit construction requirements. Summary of the invention

[0004] One of the purposes of the present invention is to provide a laser element driving circuit to solve the technical problem that the driving scheme in the prior art generates excessive ineffective power consumption and cannot take into account the requirements of low power consumption and stable driving.

[0005] One of the objects of the present invention is to provide a laser element driving method.

[0006] One of the objectives of the present invention is to provide an optical module.

[0007] To achieve one of the above-mentioned purposes of the invention, an embodiment of the present invention provides a laser element driving circuit for driving the laser element to work, comprising: a power supply module, comprising a power supply output end, for outputting a first power supply voltage; a main control module, comprising a signal output end for outputting a current control signal, for controlling the power supply module; a conversion module, comprising a power supply input end coupled to the power supply output end of the power supply module, and a signal input end coupled to the signal output end of the main control module; the conversion module is used to output a driving signal to the laser element according to the voltage at the power supply output end and the current control signal output by the main control module; the conversion module is used to convert the voltage at the power supply output end into a voltage or current required for the laser element to work; wherein the main control module is also used to set the voltage at the power supply output end to be the first power supply voltage; when the power supply module outputs the first power supply voltage, a first element voltage is applied to the laser element, and the first element voltage makes the laser element work in a linear region; the difference between the first power supply voltage and the first element voltage is less than an error threshold; the main control module adjusts the voltage at the power supply output end by controlling the power supply module.

[0008] As a further improvement of an embodiment of the present invention, the main control module is further configured to: control the laser element to operate in the linear region by adjusting the conversion module, and simultaneously adjust the magnitude of the light emission power of the laser element.

[0009] As a further improvement of an embodiment of the present invention, the main control module is further configured to collect the signal at the drive output end of the conversion module, and control the magnitude of the voltage or current output by the conversion module according to the collected signal.

[0010] As a further improvement of an embodiment of the present invention, the power supply module further includes a feedback input end coupled to the sampling output end of the main control module; the power supply module is configured to adjust the magnitude of the voltage at the power supply output end according to the feedback input from the laser element.

[0011] As a further improvement of an embodiment of the present invention, a first resistor is connected in series between the power supply output end and the feedback input end, a second resistor is connected in series between the feedback input end and the sampling output end, the feedback input end is grounded through a third resistor, and the power supply output end is grounded through a first capacitor.

[0012] As a further improvement of an embodiment of the present invention, the power supply module further includes a control input end coupled to the signal output end; the power supply module is configured to adjust the magnitude of the voltage at the power supply output end according to the control input from the main control module.

[0013] As a further improvement of an embodiment of the present invention, a two-wire I 2 C communication is respectively formed between the main control module and the power supply module and the conversion module; the drive signal is a drive current.

[0014] As a further improvement of an embodiment of the present invention, the input end of the power supply module is coupled to the power supply module through a first inductor; the input end of the power supply module is grounded through a second capacitor; the power supply output end is grounded through a first capacitor; the main control module is coupled to the enable end of the power supply module through its input / output end.

[0015] To achieve one of the above-mentioned invention purposes, an embodiment of the present invention provides a method for driving a laser element. The method for driving a laser element is applied to the laser element driving circuit described in any of the above technical solutions, and includes: adjusting the supply voltage at the power supply output terminal from large to small according to a preset step size, receiving the element parameters of the corresponding laser element, and obtaining a number of test data groups; traversing the test data groups, fixing the test data groups that meet the first condition and the second condition, and using the supply voltage therein as the first supply voltage; the first condition is that the laser element operates in the linear region, and the second condition is that the difference between the supply voltage and the element voltage of the corresponding laser element is less than the error threshold; setting the voltage at the power supply output terminal to the first supply voltage through the main control module, and adjusting the control signal output to the conversion module according to the light emission requirement to control the conversion module to output a driving signal.

[0016] As a further improvement of an embodiment of the present invention, the "adjusting the supply voltage at the power supply output terminal from large to small according to a preset step size, receiving the element parameters of the corresponding laser element, and obtaining a number of test data groups" specifically includes: determining the maximum supply voltage and the maximum operating current according to the operating characteristics of the laser element; controlling the power supply module to output the maximum supply voltage through the power supply output terminal, adjusting the magnitude of the driving current output by the conversion module, and obtaining the first relationship characteristic between the driving current and the element voltage, or between the driving current and the average optical power of the laser element; determining the first linear demarcation point of the laser element according to the first relationship characteristic; wherein, a first critical current value is set at the first linear demarcation point. When the first critical current is applied to the laser element, the laser element operates in a critical state between the linear region and the non-linear region; fixing the maximum supply voltage and the first linear demarcation point as a set of test data groups; reducing the supply voltage at the power supply output terminal according to a preset step size, and iteratively determining the linear demarcation point corresponding to the supply voltage to obtain a number of test data groups.

[0017] To achieve one of the above-mentioned invention purposes, an embodiment of the present invention provides an optical module, including the laser element driving circuit described in any of the above technical solutions.

[0018] Compared with the prior art, the laser element driving circuit provided by the present invention can ensure the stability and controllability of the subsequent dimming process of the laser element by outputting a supply voltage that enables the laser element to operate in the linear region; by setting the first supply voltage, the difference between the first supply voltage and the corresponding first element voltage is controlled within the error threshold, so that the corresponding voltage margin or current margin is reduced, and the dissipated invalid power consumption is reduced, thereby enabling the laser element driving circuit to achieve both stable driving and low power consumption. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of a laser element driving circuit in an embodiment of the present invention.

[0020] Figure 2 It is a partial circuit schematic diagram of the laser element driving circuit in the first embodiment of the present invention.

[0021] Figure 3 It is a partial circuit schematic diagram of the laser element driving circuit in the second embodiment of the present invention.

[0022] Figure 4 It is a circuit schematic diagram of the main control module in an embodiment of the present invention.

[0023] Figure 5 (a) It is a schematic diagram showing the variation of voltage with current of the laser element at different temperatures under a certain supply voltage.

[0024] Figure 5 (b) It is a schematic diagram showing the variation of voltage with current of the laser element at different temperatures under another supply voltage.

[0025] Figure 6 It is a schematic diagram showing the variation of voltage with current of the laser element at different supply voltages at a certain temperature.

[0026] Figure 7 It is a schematic diagram of the steps of a laser element driving method in an embodiment of the present invention.

[0027] Figure 8 It is a partial schematic diagram of the steps of the first embodiment of the laser element driving method in an embodiment of the present invention.

[0028] Figure 9 It is a partial schematic diagram of the steps of the second embodiment of the laser element driving method in an embodiment of the present invention. Specific Embodiments

[0029] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, method, or functional transformation made by those of ordinary skill in the art based on these embodiments is included in the protection scope of the present invention.

[0030] An embodiment of the present invention provides an optical module, including the laser element driving circuit described in any of the following technical solutions.

[0031] In one embodiment, the optical module further includes a laser element. The laser element is coupled to the laser element driving circuit and emits light under drive.

[0032] In one embodiment, the optical module is a silicon-based optical module. The optical module is fabricated based on a silicon photonics (SiPh) platform.

[0033] The optical module is used to implement applications such as optical communication, optical sensing, lidar, etc. In particular, it can be used to prepare lasers, modulators, photodetectors, etc., and has advantages such as high integration, high performance, and miniaturization.

[0034] As Figure 1 shown, the present invention provides a driving circuit for a laser element.

[0035] The driving circuit for the laser element is used to provide a driving signal for the laser element LD1; the driving circuit for the laser element is used to drive the laser element LD1 to work. The driving of the laser element LD1 can be constructed on a silicon photonics (SiPh) platform. In this application scenario, the laser element LD1 can specifically be a high-power DFB laser (Distributed Feedback Laser Diode); for the convenience of description, in Figure 2 , Figure 3 it is replaced by the laser diode pattern.

[0036] The high-power DFB laser requires the driving circuit for the laser element to have a large driving ability. Correspondingly, the driving circuit for the laser element provided by the present invention can not only achieve stable output and control power consumption, but also be adapted to the driving of high-power laser elements. That is, the driving circuit for the laser element provided by the present invention also has a large driving ability.

[0037] The driving signal can be a driving current or a driving voltage. In one embodiment, the driving signal is a driving current; correspondingly, the part of the driving circuit for the laser element that is coupled to the laser element LD1 can be configured as an equivalent current source; further, the power supply of the equivalent current source can come from the DC voltage transmitted by the gold finger.

[0038] Next, various embodiments and examples of the driving circuit for the laser element provided by the present invention will be specifically described. The various embodiments or examples can be implemented independently or combined with each other.

[0039] Figure 1 , Figure 2 and Figure 4 show the first embodiment of the present invention.

[0040] As Figure 1 and Figure 2 shown, the driving circuit for the laser element includes a power supply module 11. In one embodiment, the power supply module 11 is configured as a DC voltage source and can provide a stable voltage output. The power supply module 11 includes a power supply output terminal Vout.

[0041] The power supply module 11 is used to output the first supply voltage VLD_SUPPLY. Such an output can be the result of adjustment by modules such as the main control unit 13; specifically, the main control module 13 can control the power supply module 11 so that the voltage at the power supply output terminal Vout is substantially equal to the set first supply voltage

[0042] The laser element driving circuit includes a main control module 13; the main control module 13 is used to control the power supply module 11.

[0043] In one embodiment, the main control module 13 can be configured as a microcontroller unit (MCU). The main control module 13 includes a signal output terminal, and the signal output terminal is used to output a current control signal. In one embodiment, the current control signal can be transmitted through the two-wire I 2 C (Inter-Integrated Circuit) communication protocol. Correspondingly, the signal output terminal can be configured to include a clock signal output terminal SCL and a data signal output terminal SDA.

[0044] The laser element driving circuit includes a conversion module 12; the conversion module 12 is used to convert the voltage at the power supply output terminal Vout into the voltage or current required for the operation of the laser element LD1.

[0045] In an embodiment where the drive signal of the laser element LD1 is a drive current, the conversion module 12 can specifically be a current-type signal conversion module, such as a current digital-to-analog converter circuit (IDAC).

[0046] The conversion module 12 includes a power supply input terminal SUPPLY; the power supply input terminal SUPPLY is coupled to the power supply output terminal Vout of the power supply module 11 to receive the output from the power supply module 11.

[0047] The conversion module 12 includes a signal input terminal; the signal input terminal is coupled to the signal output terminal of the main control module 13. In an embodiment where the signal output terminal is formed as a two-wire I 2 C bus communication interface, the signal input terminal can also be configured to include a clock signal input terminal SCL' and a data signal input terminal SDA'. The conversion module 12 receives the current control signal from the main control module 13 through the signal input terminal. When the conversion module 12 is coupled to the laser element LD1 through its output side, it is at least used to control the light emission intensity of the laser element LD1.

[0048] The conversion module 12 is configured to output a driving signal to the laser element LD1 according to the voltage at the power supply output terminal Vout and the current control signal output by the main control module 13.

[0049] The main control module 13 is further configured to set the voltage at the power supply output terminal Vout to the first power supply voltage VLD_SUPPLY; the main control module 13 is further configured to control the voltage at the power supply input terminal SUPPLY of the conversion module 12 to the first power supply voltage VLD_SUPPLY. The main control module 13 can directly adjust the voltage level at the power supply output terminal Vout or the power supply input terminal SUPPLY, or indirectly adjust it. For example, it provides the power supply module 11 with a feedback input or a control input signal to control the power supply module 11 to achieve the adjustment of the voltage at the power supply output terminal Vout.

[0050] When the power supply module 11 outputs the first voltage VLD_SUPPLY, a first element voltage VLD is correspondingly applied to the laser element LD1. It can be understood that the first element voltage VLD can be interpreted as the voltage formed across the laser element LD1 when the power supply module 11 outputs the first voltage VLD_SUPPLY; specifically, the first element voltage VLD can be a driving voltage corresponding to the driving signal output by the main control module 13.

[0051] The first element voltage VLD causes the laser element LD1 to operate in the linear region. In this way, the trend of the light-emitting characteristics of the laser element LD1 changing with voltage or current can be predicted, which is convenient for realizing stable control of the laser element LD1.

[0052] Wherein, the difference between the first power supply voltage VLD_SUPPLY and the first element voltage VLD is less than the error threshold. The first power supply voltage VLD_SUPPLY and the first element voltage VLD are as close as possible, which can minimize the ineffective power consumption in the circuit as much as possible. The error threshold can be set according to the energy loss allowed by the project design.

[0053] In one implementation, the error threshold is set in the range of 0.1V to 0.3V; the error threshold is any value in the range of 0.1V to 0.3V. In one embodiment, the error threshold is 0.2V.

[0054] Figure 5 (a) discloses the variation trend of the element voltage VLD at the laser element LD1 with the current Ibias at the laser element LD1 when the voltage at the power supply output terminal Vout is equal to 1.612V and the temperatures are 25°C and 70°C respectively. Figure 5(b) discloses the variation trends of the component voltage VLD at the laser component LD1 with the current Ibias at the laser component LD1 when the voltage at the power supply output terminal Vout is equal to 1.875V and the temperatures are 25°C and 70°C respectively. It can be seen that under the same power supply voltage, the voltage-current characteristics corresponding to the high temperature of 70°C and the low temperature of 25°C have small differences.

[0055] Figure 6 Discloses the variation trends of the component voltage VLD at the laser component LD1 with the current Ibias at the laser component LD1 when the voltages at the power supply output terminal Vout are 1.615V and 1.875V respectively and the temperature is 70°C. It can be seen that when the voltages at the power supply output terminal Vout are 1.615V and 1.875V respectively, the voltage-current characteristic curves of the two almost coincide in the linear region. Therefore, when the laser component drive circuit provided by the present invention is carried, when the laser component LD1 operates in the linear region, setting a smaller first power supply voltage VLD_SUPPLY can reduce the voltage margin or current margin and save the overall power consumption of the circuit.

[0056] The present invention can determine the first power supply voltage according to the demarcation point between the linear working region and the non-linear working region of the laser component LD1 and the preset maximum working current of the laser component LD1. The above determination process can be completed by the main control module 13; alternatively, after obtaining the first power supply voltage through external calculation, it can be burned and written into the main control module 13.

[0057] In the embodiment where the main control module 13 determines the first power supply voltage, the main control module 13 is further configured to: while controlling the laser component LD1 to operate in the linear region by adjusting the conversion module 12, adjust the magnitude of the light emission power of the laser component LD1. In this way, the light emission intensity of the laser component LD1 is kept controllable.

[0058] The main control module 13 is configured to determine the power supply voltage currently output by the power supply module 11 as the first power supply voltage when the critical current value corresponding to the linear demarcation point of the laser component LD1 is equal to the preset maximum working current value. Wherein, when the critical current is applied to the laser component LD1, or when the critical current flows through the laser component LD1, the laser component LD1 operates in a critical state between the linear region and the non-linear region, or the laser component LD1 operates in a critical state where the linear region is about to enter the non-linear region. In this way, a first power supply voltage as large as possible can be determined to meet the subsequent adjustment requirements for the laser component LD1, and at the same time, the overall ineffective power consumption of the circuit can be kept low.

[0059] In Figure 6For example, when the supply voltage at the power supply output terminal Vout is 1.615V, according to the variation trend of the component voltage VLD of the laser component LD1 with the current Ibias, it can be known that the laser component LD1 operates in the linear region before the linear demarcation point P, and the laser component LD1 operates in the non-linear region after the linear demarcation point P. Referring to the variation trend when the supply voltage at the power supply output terminal Vout in the figure is 1.875V, it can be known that the greater the supply voltage, the more backward the corresponding linear demarcation point is, and the greater the corresponding critical current value is.

[0060] The linear demarcation point P corresponds to a critical current value (for example, 250mA). At this time, when the critical current value is equal to the maximum operating current value, it can be determined that the supply voltage Vout currently output by the power supply module is the first supply voltage VLD_SUPPLY. In this way, on the one hand, it can be ensured based on the definition of the linear demarcation point P that it always operates in the linear region before the maximum operating current is applied to the laser component LD1, and on the other hand, it can be ensured based on the variation relationship between the linear demarcation point P and the critical current value with the supply voltage Vout that the determined first supply voltage VLD_SUPPLY is the smallest at this time. Therefore, the advantages of both linear stable regulation and energy consumption saving and avoidance of ineffective power consumption can be taken into account.

[0061] The process of determining whether the critical current value is equal to the maximum operating current value of the laser component LD1 described above can be used as a step in an iterative loop. In one implementation, the supply voltage at the power supply output terminal Vout can start from the maximum supply voltage that the laser component LD1 can withstand, and the supply voltage can be gradually reduced according to a preset step size. And at each cycle, it is confirmed whether the critical current value corresponding to the current supply voltage is equal to the maximum operating current value. If so, the loop is exited and the current supply voltage is fixed as the first supply voltage to take into account the advantages of driving ability and low energy consumption; if not, the supply voltage is reduced for further iteration. The specific steps can refer to the description of the laser component driving method later.

[0062] Continue to refer to Figure 2 and Figure 4 , the main control module 13 is further configured to collect the signal at the drive output terminal of the conversion module 12, and control the magnitude of the voltage or current output by the conversion module 12 according to the collected signal.

[0063] The main control module 13 includes a sampling input terminal ADC. In the implementation where the conversion module 12 is used to output a current signal, the sampling input terminal ADC is coupled to the drive output terminal Iout of the conversion module 12. Without considering losses and when the drive signal is a drive current, the drive current at the drive output terminal Iout can be regarded as the current Ibias at the laser component LD1. Thus, the main control module 13 can obtain the current on one side of the laser component LD1 to achieve feedback regulation and / or setting of the first supply voltage.

[0064] The main control module 13 is coupled to the power supply output terminal Vout. As Figure 2 shown, it is coupled to the power supply output terminal Vout through components such as resistors.

[0065] The main control module 13 is configured to, when the laser element LD1 is coupled to the drive output terminal Vout, set the power supply voltage at the power supply output terminal to the first power supply voltage VLD_SUPPLY according to the voltage at the laser element LD1 (i.e., the element voltage). Alternatively, the main control module 13 is configured to set the first power supply voltage VLD_SUPPLY according to the current at the laser element LD1. Alternatively, the main control module 13 is configured to set the first power supply voltage VLD_SUPPLY according to the voltage and current at the laser element LD1.

[0066] The power supply module 11 further includes a feedback input terminal FB. The feedback input terminal FB is coupled to the sampling output terminal DAC of the main control module 13. The feedback input terminal FB is used to receive the sampling output signal of the main control module 13, and particularly can be the feedback voltage on one side of the laser element LD1.

[0067] The power supply module 11 is configured to adjust the voltage at the power supply output terminal Vout to the first power supply voltage VLD_SUPPLY according to the feedback input from the laser element LD1. The power supply module 11 is configured to maintain the magnitude of the voltage output to the conversion module 12 according to this feedback input.

[0068] Specifically, the power supply module 11 is configured to maintain the voltage output to the conversion module 12 stable near the first power supply voltage VLD_SUPPLY according to the feedback input from the laser element LD1. Specifically, the voltage at the power supply output terminal Vout of the power supply module 11 is stabilized within a preset voltage range, and the voltage range is set based on the first power supply voltage VLD_SUPPLY, and can be a range formed by floating 0.1V above and below the first power supply voltage VLD_SUPPLY.

[0069] In one embodiment, a first resistor R1 is connected in series between the power supply output terminal Vout and the feedback input terminal FB; a second resistor R2 is connected in series between the feedback input terminal FB and the sampling output terminal DAC; the feedback input terminal FB is grounded through a third resistor R3. In this way, the feedback signal VDAC is stably fed and the first power supply voltage VLD_SUPPLY is stably formed.

[0070] In one embodiment, the power supply output terminal Vout is grounded through a first capacitor Cout1. In this way, it is ensured that the first power supply voltage VLD_SUPPLY is stably output to the conversion module 12.

[0071] Figure 1 、 Figure 3 and Figure 4The second embodiment of the present invention is shown.

[0072] The laser element driving circuit includes a power supply module 11. The power supply module 11 includes a power supply output terminal Vout. The power supply module 11 is used to output a first power supply voltage VLD_SUPPLY.

[0073] The laser element driving circuit includes a main control module 13; the main control module 13 is used to control the power supply module 11. The main control module 13 includes a signal output terminal, and the signal output terminal is used to output a current control signal.

[0074] The laser element driving circuit includes a conversion module 12; the conversion module 12 is used to convert the voltage at the power supply output terminal Vout into the voltage or current required for the operation of the laser element LD1.

[0075] The conversion module 12 includes a power supply input terminal SUPPLY; the power supply input terminal SUPPLY is coupled to the power supply output terminal Vout of the power supply module 11 to receive the output from the power supply module 11.

[0076] The conversion module 12 includes a signal input terminal; the signal input terminal is coupled to the signal output terminal of the main control module 13. In the embodiment where the signal output terminal is formed as a two-wire I 2 C bus communication interface, the signal input terminal can also be configured to include a clock signal input terminal SCL' and a data signal input terminal SDA'.

[0077] The conversion module 12 is used to output a driving signal to the laser element LD1 according to the voltage at the power supply output terminal Vout and the current control signal output by the main control module 13.

[0078] The main control module 13 is further used to set the voltage at the power supply output terminal Vout to the first power supply voltage VLD_SUPPLY; the main control module 13 is further used to control the voltage at the power supply input terminal SUPPLY of the conversion module 12 to be the first power supply voltage VLD_SUPPLY.

[0079] When the power supply module 11 outputs the first voltage VLD_SUPPLY, a first element voltage VLD is correspondingly applied to the laser element LD1. The first element voltage VLD causes the laser element LD1 to operate in the linear region. Wherein, the difference between the first power supply voltage VLD_SUPPLY and the first element voltage VLD is less than the error threshold.

[0080] In one embodiment, the error threshold is set in the range of 0.1V to 0.3V; the error threshold is any value in the range of 0.1V to 0.3V. In one embodiment, the error threshold is 0.2V.

[0081] In one embodiment, the main control module 13 is further configured to determine the first supply voltage according to the demarcation point between the linear working region and the non-linear working region of the laser element LD1 and the preset maximum working current of the laser element LD1. The main control module 13 is further configured to: while controlling the laser element LD1 to operate in the linear region by adjusting the conversion module 12, adjust the magnitude of the light emission power of the laser element LD1.

[0082] In another embodiment, after obtaining the first supply voltage through external calculation, it can be programmed and written into the main control module 13 so that the main control module 13 can implement control based on the first supply voltage.

[0083] Based on reference Figure 3 and Figure 4 , the main control module 13 is further configured to collect the signal at the drive output end of the conversion module 12 and control the magnitude of the voltage or current output by the conversion module 12 according to the collected signal.

[0084] The main control module 13 includes a sampling input terminal ADC. In an embodiment where the conversion module 12 is configured to output a current signal, the sampling input terminal ADC is coupled to the drive output end Iout of the conversion module 12. Without considering losses and when the drive signal is a drive current, the drive current at the drive output end Iout can be regarded as the current Ibias at the laser element LD1. Thus, the main control module 13 can obtain the current on one side of the laser element LD1 to achieve feedback regulation and / or setting of the first supply voltage.

[0085] The main control module 13 is coupled to the power supply output terminal Vout. As Figure 3 shown, after being coupled to the power supply module 11 through the clock signal output terminal SCL and the data signal output terminal SDA, a coupling relationship is established with the power supply output terminal Vout.

[0086] The main control module 13 is configured to, when the laser element LD1 is coupled to the drive output terminal Vout, set the supply voltage at the power supply output terminal to the first supply voltage VLD_SUPPLY according to the voltage at the laser element LD1 (i.e., the element voltage). Alternatively, the main control module 13 is configured to set the first supply voltage VLD_SUPPLY according to the current at the laser element LD1. Alternatively, the main control module 13 is configured to set the first supply voltage VLD_SUPPLY according to the voltage and current at the laser element LD1.

[0087] The above features may have the same configuration as the corresponding features in the foregoing first embodiment. In this case, the explanations and operation methods corresponding to the above features are the same as those in the foregoing first embodiment and will not be elaborated here.

[0088] For the second embodiment provided by the present invention, as Figure 3As shown, in particular, the power supply module 11 further includes control input terminals (for example, clock control input terminal "SCL" and data control input terminal "SDA"). The control input terminals are coupled to the signal output terminals of the main control module 13 (for example, clock signal output terminal SCL and data signal output terminal SDA). The control input terminals are used to receive the control signals of the main control module 13; in one embodiment, at least part of the control signals for the conversion module 12 can be multiplexed as the control signals for the power supply module 11 to achieve synchronous control of the two.

[0089] The power supply module 11 is used to adjust the voltage at the power supply output terminal Vout to the first power supply voltage VLD_SUPPLY according to the control input from the main control module 13. The power supply module 11 is used to maintain the magnitude of the voltage output to the conversion module 12 according to this control input.

[0090] Specifically, the power supply module 11 is used to keep the voltage output to the conversion module 12 stable near the first power supply voltage VLD_SUPPLY according to the control input from the main control module 13. Specifically, the voltage at the power supply output terminal Vout of the power supply module 11 is stabilized within a preset voltage range, and the voltage range is set based on the first power supply voltage VLD_SUPPLY, and can be the range formed by floating 0.1V above and below the first power supply voltage VLD_SUPPLY.

[0091] In one embodiment, a two-wire I 2 C communication is formed between the main control module 13 and the power supply module 11. In one embodiment, a two-wire I 2 C communication is formed between the main control module 13 and the conversion module 12. In one embodiment, the main control module 13 forms two-wire I 2 C communication with the power supply module 11 and the conversion module 12 respectively.

[0092] Specifically, the main control module 13 includes a data signal output terminal SDA and a clock signal output terminal SCL. The power supply module 11 includes a data control input terminal "SDA" and a clock control input terminal "SCL". The data signal output terminal SDA is coupled to the data control input terminal "SDA"; the clock signal output terminal SCL is coupled to the clock control input terminal "SCL".

[0093] Specifically, the main control module 13 includes a data signal output terminal SDA and a clock signal output terminal SCL. The conversion module 12 includes a data signal input terminal SDA' and a clock signal input terminal SCL'. The data signal output terminal SDA is coupled to the data signal input terminal SDA'; the clock signal output terminal SCL is coupled to the clock signal input terminal SCL'.

[0094] For the above first embodiment ( Figure 2 and Figure 4as shown in the first embodiment), the second embodiment ( Figure 3 and Figure 4 as shown), and the two may have the same configuration in the following features.

[0095] The input terminal Vin of the power supply module 11 is coupled to the power supply module VCC_IN through the first inductor L1. The input terminal Vin of the power supply module 11 is grounded through the second capacitor Cin1. The first inductor L1 and the second capacitor Cin1 are used to form an LC filter circuit to reduce power supply fluctuations and ripples.

[0096] The power supply output terminal Vout of the power supply module 11 is grounded through the first capacitor Cout1 to enhance the stability of the output of the power supply module 11.

[0097] The main control module 13 is coupled to the enable terminal EN of the power supply module 11 through its input / output terminal I / O1 to control whether the power supply module 11 is enabled to trigger.

[0098] As Figure 7 shown, an embodiment of the present invention provides a method for driving a laser element.

[0099] The method for driving a laser element is applied to the laser element driving circuit described in any of the above technical solutions. Specifically, the laser element driving circuit includes a power supply module 11, a conversion module 12, and a control module 13. Combining Figures 1 to 4 , the method for driving a laser element specifically includes the following steps.

[0100] Step S1, adjust the power supply voltage at the power supply output terminal Vout from large to small according to a preset step size, receive the component parameters of the corresponding laser element LD1, and obtain a number of test data groups.

[0101] Among them, the component parameters correspond to the power supply voltage. Under a certain power supply voltage, a series of component parameters can be obtained by changing other conditions at the laser element LD1. The other conditions can be the current Ibias applied at the laser element LD1, or the component voltage or the optical power of the laser element LD1.

[0102] Each group of the test data groups includes the power supply voltage and several component parameters corresponding thereto. It can be formed in the form of an array or a sequence, or can be visualized in the form of a fitting curve. For the latter, it can be specifically in the form as Figure 5 , Figure 6 shown.

[0103] Step S2, traverse the test data groups, fix the test data groups that meet the first condition and the second condition, and use the power supply voltage therein as the first power supply voltage VLD_SUPPLY.

[0104] Among them, the first condition is that the laser element operates in the linear region; the second condition is that the difference between the supply voltage and the element voltage of the corresponding laser element is less than the error threshold.

[0105] For the judgment of the two conditions in step S2, it can be a direct judgment. For example, directly judge whether the laser element operates in the linear region according to the trend of the fitting curve; it can also be an indirect judgment. For example, by simultaneously satisfying the two conditions of operating in the linear region and the critical current value being equal to the maximum operating current value, it is determined that the difference between the supply voltage and the element voltage is less than the error threshold.

[0106] Step S3, set the voltage at the power supply output terminal Vout to the first supply voltage VLD_SUPPLY through the main control module 13, and adjust the control signal output to the conversion module 12 according to the light emission requirement to control the conversion module to output a drive signal

[0107] Among them, the main control module 13 adjusts the current control signal output to the conversion module 12 to control the conversion module 12 to determine and output the corresponding drive current according to the first supply voltage VLD_SUPPLY and the current control signal.

[0108] Of course, in another implementation manner, the main control module 13 can also adjust the control signal output to the power supply module 11.

[0109] For the above step S1, as Figure 8 shown, the laser element driving method provided in the first embodiment of the present invention further includes the following steps.

[0110] Step S11, determine the maximum supply voltage and the maximum operating current according to the operating characteristics of the laser element LD1.

[0111] Among them, the maximum supply voltage and the maximum operating current can be determined by consulting or crawling the technical manual (datasheet) of the laser element LD1. In one implementation manner, the maximum supply voltage is 2V and the maximum operating current is 250mA.

[0112] Step S12, control the power supply module 11 to output the maximum supply voltage through the power supply output terminal Vout, adjust the magnitude of the drive current output by the conversion module 12, and obtain the relationship characteristic between the drive current and the element voltage of the laser element LD1 as the first relationship characteristic, or obtain the relationship characteristic between the drive current and the average optical power of the laser element LD1 as the first relationship characteristic.

[0113] Among them, the "relationship characteristic between the drive current and the element voltage" is, for example Figures 5 to 6 shown, and particularly can be to fit the curve of the element voltage with respect to the drive current as the first relationship characteristic.

[0114] The "relationship characteristic between the drive current and the average optical power" can particularly be fitting the curve of the change of the average optical power with respect to the drive current as the first relationship characteristic.

[0115] Step S13: Determine the first linear demarcation point of the laser element LD1 according to the first relationship characteristic.

[0116] Among them, the first linear demarcation point (for example Figure 6 midpoint P) is set with a first critical current value. When the first critical current is applied to the laser element LD1, the laser element LD1 operates in a critical state between the linear region and the non-linear region.

[0117] Step S14: Fix the maximum supply voltage and the first linear demarcation point as a set of test data groups.

[0118] For other supply voltages, fix the supply voltage and the corresponding linear demarcation point or fix the supply voltage and the corresponding critical current as a set of test data groups. Of course, what is defined here is the minimum content in the test data group. In other embodiments, contents such as visualization curves can also be included in the test data group.

[0119] Step S15: Reduce the supply voltage at the supply output end Vout in accordance with a preset step size, and iteratively determine the linear demarcation point corresponding to the supply voltage to obtain a number of test data groups.

[0120] The iterative loop defined in Step S15 can use the critical current value being equal to the maximum operating current value of the laser element LD1 as the exit condition. Of course, it can also use reducing the supply voltage to 0 as the exit condition to obtain all the test data groups, and then make judgments related to the maximum operating current value one by one.

[0121] In addition, Steps S2 to S3 in this embodiment are consistent with the foregoing, and will not be elaborated here.

[0122] For the above-mentioned Step S2, as Figure 9 shown, the laser element driving method provided in the second embodiment of the present invention further includes the following steps.

[0123] Step S21: Determine whether the critical current value corresponding to the linear demarcation point in the test data group is equal to the maximum operating current of the laser element; among them, when the critical current is applied to the laser element LD1, the laser element LD1 operates in a critical state between the linear region and the non-linear region.

[0124] If so, jump to step S22 to determine that the current test data set simultaneously satisfies the first condition and the second condition, and fix the supply voltage VLD corresponding to the linear demarcation point as the first supply voltage VLD_SUPPLY.

[0125] In addition, after step S21, the following steps may further be included:

[0126] If not, it is determined that the current test data set does not simultaneously satisfy the first condition and the second condition, and the supply voltage is iteratively decreased and it is continuously determined whether the critical current value corresponding to the new supply voltage is equal to the maximum operating current.

[0127] In addition, steps S1 and S3 in this embodiment are consistent with the foregoing, and will not be elaborated herein.

[0128] In an embodiment provided by the present invention, steps S11 to S15 and steps S21 to S22 described above may be included simultaneously. Step S3 may also be removed, and a fixed first supply voltage is used as the output of the laser element driving method (equivalent to providing a laser element driving circuit configuration method).

[0129] It can be seen that the above embodiments provided by the present invention can be split and recombined, and the formed technical solutions also fall within the protection scope of the present invention.

[0130] In summary, for the laser element driving circuit, driving method, and optical module provided by the present invention, by outputting a supply voltage that enables the laser element to operate in the linear region, it is possible to ensure that the subsequent dimming process of the laser element is stable and controllable; by setting the first supply voltage, the difference between the first supply voltage and the corresponding first element voltage is controlled within the error threshold, so that the corresponding voltage margin or current margin is reduced, and the dissipated ineffective power consumption is reduced, thereby enabling the laser element driving circuit to achieve both stable driving and low power consumption effects.

[0131] It should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment may also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0132] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser element driving circuit for driving a laser element to operate, characterized in that, Comprising: A power supply module, including a power supply output terminal for outputting a first power supply voltage; A main control module, including a signal output terminal for outputting a current control signal, for controlling the power supply module; A conversion module, including a power supply input terminal coupled to the power supply output terminal of the power supply module, and a signal input terminal coupled to the signal output terminal of the main control module; the conversion module is configured to output a drive signal to the laser element according to the voltage at the power supply output terminal and the current control signal output by the main control module; the conversion module is configured to convert the voltage at the power supply output terminal into the voltage or current required for the operation of the laser element; Wherein, the main control module is further configured to set the voltage at the power supply output terminal to the first power supply voltage; when the power supply module outputs the first power supply voltage, a first element voltage is applied to the laser element, and the first element voltage causes the laser element to operate in the linear region; the difference between the first power supply voltage and the first element voltage is less than the error threshold; the main control module adjusts the magnitude of the voltage at the power supply output terminal by controlling the power supply module.

2. The laser element drive circuit according to claim 1, wherein The main control module is further configured to: adjust the conversion module to control the laser element to operate in the linear region while adjusting the magnitude of the light emission power of the laser element.

3. The laser element drive circuit according to claim 1, characterized in that, The main control module is further configured to collect the signal at the drive output terminal of the conversion module, and control the magnitude of the voltage or current output by the conversion module according to the collected signal.

4. The laser element driving circuit according to claim 3, characterized in that, The power supply module further includes a feedback input terminal coupled to the sampling output terminal of the main control module; the power supply module is configured to adjust the magnitude of the voltage at the power supply output terminal according to the feedback input from the laser element.

5. The laser element driving circuit according to claim 4, characterized in that, A first resistor is connected in series between the power supply output terminal and the feedback input terminal, a second resistor is connected in series between the feedback input terminal and the sampling output terminal, the feedback input terminal is grounded through a third resistor, and the power supply output terminal is grounded through a first capacitor.

6. The laser element driving circuit according to claim 3, wherein The power supply module further includes a control input terminal coupled to the signal output terminal; the power supply module is configured to adjust the magnitude of the voltage at the power supply output terminal according to the control input from the main control module.

7. The laser element driving circuit according to claim 6, characterized in that, The main control module respectively forms two-wire I 2 C communication with the power supply module and the conversion module; The drive signal is a drive current.

8. The laser element driving circuit according to claim 1, characterized in that The input terminal of the power supply module is coupled to the power supply module through a first inductor; the input terminal of the power supply module is grounded through a second capacitor; the power supply output terminal is grounded through a first capacitor; the main control module is coupled to the enable terminal of the power supply module through its input / output terminal.

9. The laser element drive circuit according to claim 1, characterized in that, The error threshold is any value between 0.1V and 0.3V.

10. A method for driving a laser element, characterized in that, The laser element driving method is applied to the laser element driving circuit according to any one of claims 1-9, and includes: Adjusting the power supply voltage at the power supply output terminal from large to small in a preset step, receiving the element parameters of the corresponding laser element, and obtaining a plurality of test data groups; Traversing the test data groups, fixing the test data groups that meet the first condition and the second condition, and using the power supply voltage therein as the first power supply voltage; the first condition is that the laser element operates in the linear region, and the second condition is that the difference between the power supply voltage and the element voltage of the corresponding laser element is less than the error threshold; Set the voltage at the power supply output terminal as the first power supply voltage through the main control module, and adjust the control signal output to the conversion module according to the light emission requirement to control the conversion module to output a drive signal.

11. The laser element driving method according to claim 10, characterized in that, The step of "adjusting the power supply voltage at the power supply output terminal from large to small according to a preset step length, receiving the component parameters of the corresponding laser component, and obtaining a number of test data sets" specifically includes: Determine the maximum power supply voltage and the maximum operating current according to the operating characteristics of the laser component; Control the power supply module to output the maximum power supply voltage through the power supply output terminal, and adjust the magnitude of the drive current output by the conversion module to obtain the first relationship characteristic between the drive current and the component voltage or between the drive current and the average optical power of the laser component; Determine the first linear demarcation point of the laser component according to the first relationship characteristic; wherein, a first critical current value is set at the first linear demarcation point. When the first critical current is applied to the laser component, the laser component operates in a critical state between the linear region and the non-linear region; Fix the maximum power supply voltage and the first linear demarcation point as a set of test data; Reduce the power supply voltage at the power supply output terminal according to a preset step length, and iteratively determine the linear demarcation point corresponding to the power supply voltage to obtain a number of test data sets.

12. An optical module, characterized in that, It includes the laser component drive circuit according to any one of claims 1-9.

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