Driving circuit of laser array, laser array system and electronic equipment

Abstract

The invention provides a driving circuit of a laser array, a laser array system and electronic equipment, the laser array comprises a plurality of laser units arranged in M columns and N rows, each column of laser units is connected with two symmetrically arranged anode pins, and the distances between the two anode pins corresponding to each column are the same, each row of laser units is connected with a cathode pin; the driving circuit comprises a plurality of energy storage units, a plurality of switch units, a voltage regulation and control unit, a boosting unit, a high-side gating module and a switch control unit; each energy storage unit is correspondingly connected with one anode pin, and each switch unit is correspondingly connected with one cathode pin and the ground end. The current paths from the two corresponding energy storage units in each column to any laser unit in the column are the same, so that the light emitting uniformity of different laser units is improved; in addition, the voltage regulation and control unit can adjust the charging voltage supplied to the corresponding energy storage unit of the column according to the position of the column where the laser unit is located when the laser unit is driven, it is ensured that the output power of different laser units is kept consistent when the different laser units are driven, and therefore the light emitting uniformity of the different laser units is further improved.

Description

Technical Field

[0001] The present invention relates to the field of laser driving, and in particular to a driving circuit of a laser array, a laser array system and electronic equipment. Background Art

[0002] Laser arrays mainly achieve stimulated emission of radiation through specific arrangements in semiconductor materials, that is, amplifying photons to produce concentrated and intense beams of light. Such lasers can be vertical cavity surface emitting lasers (VCSELs) or other types of semiconductor lasers, which usually have the advantages of high power, high efficiency, small size and low cost.

[0003] The laser array usually integrates M*N individual lasers, so the corresponding lasers in the laser array need to be illuminated by an adaptive driving circuit.

[0004] However, due to limitations in circuit structure and layout, existing driving circuits of laser arrays may result in large differences in current paths of lasers at different positions in the laser array, thereby causing poor light emission uniformity of lasers at different positions.

[0005] Therefore, providing a driving circuit that can improve the light emission uniformity of lasers at different positions in a laser array has become a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a driving circuit of a laser array, a laser array system and electronic equipment, which solve the problem of light emission uniformity of lasers at different positions in the laser array.

[0007] In order to solve the above technical problems, the technical solution of the present invention provides a driving circuit of a laser array, which is used to drive the laser units in the laser array. The laser array includes a plurality of laser units arranged in M ​​columns and N rows. Each column of laser units is connected to two symmetrically arranged anode pins, and the spacing between the two anode pins corresponding to each column is the same. Each row of laser units is connected to a cathode pin. The driving circuit includes:

[0008] A plurality of energy storage units, each of which is connected to one of the anode pins, and the energy storage unit is used to charge according to the connected charging voltage and output a corresponding lighting voltage, and the distance between each of the energy storage units and the anode pin is the same;

[0009] A plurality of switch units, each of which is connected to one of the cathode pins and the ground terminal, and is used to control itself to be turned on or off according to a switch control signal;

[0010] A voltage control unit, wherein the voltage control unit is used to output a corresponding voltage control signal according to the position of the column where the laser unit is located when the laser unit is driven;

[0011] A boost unit, the boost unit being used to output a corresponding charging voltage according to the voltage control signal;

[0012] A high-side gating module, wherein the high-side gating module is used to output the charging voltage to the energy storage unit corresponding to the laser unit according to the position of the column where the laser unit is located when the laser unit is driven;

[0013] A switch control unit is used for outputting the switch control signal to the switch unit corresponding to the laser unit according to the position of the row where the laser unit is located when the laser unit is driven, so as to turn on the switch unit.

[0014] Optionally, the energy storage unit includes a capacitor, a first end of the capacitor is connected to the anode pin, and a second end of the capacitor is connected to the ground.

[0015] Optionally, the switching unit includes a switching transistor.

[0016] Optionally, the switch control unit specifically includes a low-side driver chip, and the low-side driver chip is used to output the switch control signal to the control end of the switch transistor to turn on the switch transistor according to the position of the row where the laser unit is located when the laser unit is driven.

[0017] Optionally, the switch transistor includes at least an NMOS transistor or a gallium nitride transistor.

[0018] Optionally, the boost unit specifically includes an LC open-loop boost circuit.

[0019] Optionally, the voltage control unit includes a PWM controller, the voltage adjustment signal is specifically a pulse width modulation signal, and the PWM controller is used to adjust the duty cycle of the pulse width modulation signal according to the position of the laser unit in the column when the laser unit is driven.

[0020] Optionally, the voltage regulation unit and the switch control unit are integrated into the same chip.

[0021] Correspondingly, the technical solution of the present invention further provides a laser array system, including a laser array and a driving circuit of the laser array.

[0022] Correspondingly, the technical solution of the present invention also provides an electronic device, including the laser array system.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] In the driving circuit of the laser array of the technical solution of the present invention, each of the energy storage units is connected to one of the anode pins, and each of the switch units is connected to one of the cathode pins and the ground terminal. Since the distances between the energy storage units and the anode pins are the same, the current paths from the two energy storage units corresponding to each column to any laser unit in the column are the same, thereby improving the light uniformity of different laser units. At the same time, the voltage control unit will also adjust the charging voltage supplied to the energy storage unit corresponding to the column according to the position of the column in which the laser unit is located when the laser unit is driven, ensuring that the output power of different laser units remains consistent when different laser units are driven, thereby further improving the light uniformity of different laser units.

[0025] Furthermore, since the boost unit specifically includes an LC open-loop boost circuit and the voltage control unit specifically includes a PWM controller, the present invention provides the charging voltage through an adjustable inductor voltage. Compared with the prior art that provides a constant charging voltage through an RC constant voltage circuit, the present invention avoids the heating problem caused by the resistor and realizes the adjustable charging voltage.

[0026] Furthermore, the voltage regulation unit and the switch control unit of the driving circuit are integrated into the same chip, thereby reducing the layout area of ​​the circuit board where the driving circuit is located and improving the miniaturization design of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The circuit structure of the driving circuit of the laser array 1 provided by the technical solution of the present invention is shown in FIG. Figure 1 ;

[0028] Figure 2 The circuit structure of the driving circuit of the laser array 1 provided in the embodiment of the present invention is shown in FIG. Figure 2 ;

[0029] Figure 3 1 is a waveform diagram of various parameters of the driving circuit of the laser array 1 provided in an embodiment of the present invention;

[0030] Figure 4 The circuit structure of the laser array 1 provided in the embodiment of the present invention is shown in FIG. Figure 3 . DETAILED DESCRIPTION

[0031] As described in the background art, the existing driving circuit may cause the lasers at different positions in the laser array to have different light uniformity.

[0032] In view of this, the technical solution of the present invention provides a driving circuit for a laser array.

[0033] in, Figure 1 The circuit structure of the driving circuit of the laser array provided by the technical solution of the present invention is shown in FIG. Figure 1 .

[0034] The laser array includes a plurality of laser units arranged in M ​​columns and N rows. Among them, the plurality of laser units arranged in M ​​columns and N rows can specifically be laser units uniformly arranged in M ​​columns and N rows. For example, M is 4, N is also 4, and 4 laser units are arranged in the first to fourth columns of the laser array. The plurality of laser units arranged in M ​​columns and N rows can be laser units non-uniformly arranged in M ​​columns and N rows. For example, M is 4, N is also 4, and only 1 laser unit is arranged in the first column of the laser array, 4 laser units are arranged in the second column, 2 laser units are arranged in the third column, and 3 laser units are arranged in the fourth column. Of course, the two specific examples of the arrangement of laser units in the laser array mentioned above, the actual arrangement of laser units in the laser array can be set according to needs, and different limitations are made here. The laser unit is specifically a laser. For the convenience of description, the arrangement of laser units in the following laser array is set to be uniformly arranged in M ​​columns and N rows.

[0035] Please refer to Figure 1 The driving circuit of the laser array 1 provided by the technical solution of the present invention is used to drive the laser units in the laser array 1. The laser array 1 includes a plurality of laser units arranged in M ​​columns and N rows. Each column of laser units is connected to two symmetrically arranged anode pins, and the spacing between the two anode pins corresponding to each column is the same. Each row of laser units is connected to a cathode pin. The driving circuit includes:

[0036] A plurality of energy storage units 10, each of which is connected to one of the anode pins, and the energy storage unit 10 is used to charge according to the connected charging voltage and output a corresponding lighting voltage, and the distance between each of the energy storage units 10 and the anode pin is the same;

[0037] A plurality of switch units 20, each of which is connected to one of the cathode pins and the ground terminal, and the switch unit 20 is used to control itself to be turned on or off according to a switch control signal;

[0038] A voltage control unit 30, wherein the voltage control unit 30 is used to output a corresponding voltage control signal according to the position of the column where the laser unit is located when the laser unit is driven;

[0039] A boost unit 40, the boost unit 40 is used to output a corresponding charging voltage according to the voltage control signal;

[0040] A high-side gating module 50, wherein the high-side gating module 50 is used to output the charging voltage to the energy storage unit 10 corresponding to the laser unit according to the position of the column where the laser unit is located when the laser unit is driven;

[0041] The switch control unit 60 is used for outputting the switch control signal to the switch unit 20 corresponding to the laser unit according to the position of the row where the laser unit is located when the laser unit is driven, so as to turn on the switch unit 20.

[0042] Through the above technical means, the technical solution of the present invention can improve the light uniformity of laser units at different positions in the laser array. The specific principle is as follows:

[0043] Before explaining the technical effects that can be achieved by the technical solution of the present invention, it is necessary to first explain the lighting principle of the laser unit in the laser array. Each laser unit is connected to the corresponding energy storage unit 10 by connecting the corresponding anode pin and the corresponding switch unit 20 by connecting the corresponding cathode pin. When a laser unit needs to be lit, the energy storage unit 10 connected to the laser unit will be charged first. After the energy storage unit 10 is charged, the switch unit 20 connected to the laser unit is turned on. Because each switch unit 20 is connected to the ground terminal, after the switch unit 20 is turned on, the energy storage unit 10 will output a lighting voltage to form a current path from the energy storage unit 10 to the laser unit to the ground terminal, thereby lighting the laser unit.

[0044] However, when the driving circuit of the prior art lights up different laser units, the current paths of different laser units are different. The difference in current paths will lead to large differences in the peak power of different laser units, thereby causing the light uniformity of different laser units to deteriorate. Therefore, one key to improving the light uniformity of different laser units is to improve the similarity of the current paths of laser units at different positions.

[0045] Please refer to Figure 1 The present invention sets that each column of laser units is connected to two symmetrical anode pins, and the spacing between the two anode pins corresponding to each column is the same. It is also set that each energy storage unit 10 is connected to a corresponding anode pin, and the distance between each energy storage unit 10 and the corresponding anode pin is the same. Therefore, on the basis of ensuring that the sum of the spacings between each column of laser units and the corresponding two energy storage units 10 is the same, it is also ensured that the sum of the spacings between laser units in different columns and their corresponding two energy storage units 10 is also the same, so that when laser units at different positions are lit, the sum of the current paths from the corresponding two energy storage units 10 to the laser units is the same, thereby improving the light uniformity of the laser units at different positions.

[0046] In addition to the above configuration, the present invention further provides a voltage control unit 30, which controls the boost unit 40 to output a corresponding charging voltage according to the different positions of the laser units, so that when different laser units are lit, the output power of different laser units remains the same, thereby further improving the light uniformity of the laser units at different positions. It should be noted that the longer the current path corresponding to the laser unit, the greater the corresponding charging voltage output by the boost unit 40. The specific principle is common knowledge in the art and will not be repeated here.

[0047] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0048] Figure 2 The circuit structure of the driving circuit of the laser array 1 provided in the embodiment of the present invention is shown in FIG. Figure 2 .

[0049] Please refer to Figure 2 As a specific implementation, the energy storage unit 10 includes a capacitor, a first end of the capacitor is connected to the anode pin, and a second end of the capacitor is connected to the ground.

[0050] The switch unit 20 includes an NMOS tube, the drain of the NMOS tube is connected to the corresponding cathode pin, the gate of the NMOS tube is connected to the output end of the switch control unit 60, and the source of the NMOS tube is grounded. Of course, in addition to the NMOS tube, the switch unit 20 can also include a gallium nitride tube or other switch transistors for switching, which is not limited here.

[0051] As a specific implementation, the switch control unit 60 specifically includes a low-side driver chip, and the low-side driver chip is used to output the switch control signal to the control end of the switch transistor according to the position of the row where the laser unit is located when the laser unit is driven, so as to turn on the switch transistor.

[0052] As a specific implementation, the boost unit 40 specifically includes an LC open-loop boost circuit. The voltage control unit 30 includes a PWM controller, the voltage adjustment signal is specifically a pulse width modulation signal, and the PWM controller is used to adjust the duty cycle of the pulse width modulation signal according to the position of the laser unit in the column when the laser unit is driven.

[0053] It should be noted that the LC open-loop boost circuit can be provided in plurality as required. When one LC open-loop boost circuit outputs a charging voltage, other LC open-loop boost circuits are pre-charged, thereby improving the overall working efficiency of the driving circuit.

[0054] The above-mentioned embodiment has the beneficial effect that: the prior art usually adopts an RC constant voltage circuit to charge the energy storage unit 10 at a constant voltage. However, during the charging process, the RC constant voltage circuit will cause severe heat due to the resistance, thereby affecting the electro-optical conversion efficiency of the laser unit. At the same time, the RC constant voltage circuit can only output a constant voltage and cannot adjust the voltage of the laser units at different positions, thereby reducing the uniformity of light output at different positions. The above-mentioned embodiment sets an LC open-loop boost circuit as a boost unit 40 to charge the energy storage unit 10. Since the resistor is omitted, the heating problem when the boost unit 40 charges the energy storage unit 10 is greatly reduced, and the electro-optical conversion efficiency of the laser unit is improved. At the same time. The above-mentioned embodiment also sets a PWM controller as a voltage control unit 30 to adjust the output voltage of the LC open-loop boost circuit through a pulse width modulation signal, thereby improving the uniformity of light output at different positions.

[0055] As a specific implementation, the boost unit 40 and the voltage control unit 30 may also be integrated in the same chip, thereby reducing the layout area of ​​the circuit board where the drive circuit is located and improving the miniaturization design of the circuit board.

[0056] Figure 3 1 is a waveform diagram of various parameters of the driving circuit of the laser array 1 provided in an embodiment of the present invention.

[0057] Figure 4 The circuit structure of the laser array 1 provided in the embodiment of the present invention is shown in FIG. Figure 3 .

[0058] The following Figure 2 Taking the circuit structure schematic diagram shown as an example, the working process of the driving circuit of the laser array 1 provided in the embodiment of the present invention is described.

[0059] Please refer to Figure 2 and Figure 3 In this embodiment, the laser array includes 12 laser units evenly arranged in 3 rows and 4 columns. Four boost units 40 are provided, corresponding to the first LC open-loop boost circuit, the second LC open-loop boost circuit, the third LC open-loop boost circuit and the fourth LC open-loop boost circuit, respectively.

[0060] When it is necessary to light up the laser units in the 4th column and the 1st row and the laser units in the 2nd column and the 3rd row respectively.

[0061] Phase t0 - t1 : The high-side gating module 50 outputs a gating control signal D1 to respectively gating the energy storage cells 10 corresponding to the second column and the energy storage cells 10 corresponding to the fourth column.

[0062] The voltage control unit 30 outputs a first voltage control signal D2 corresponding to the laser units in the second column, and outputs a second voltage control signal D3 corresponding to the laser units in the fourth column.

[0063] The first LC open-loop boost circuit pre-charges the internal inductor according to the first voltage control signal D2, and the second LC open-loop boost circuit pre-charges the internal inductor according to the second voltage control signal D3.

[0064] Phase t1-t2: After completing pre-charging, the first LC open-loop boost circuit outputs a first charging voltage V1 to the high-side gating module 50 , and after completing pre-charging, the second LC open-loop boost circuit outputs a second charging voltage V2 to the high-side gating module 50 .

[0065] The first channel of the high-side gating module 50 outputs the first charging voltage V1 to the energy storage unit 10 corresponding to the second column, and the second channel of the high-side gating module 50 outputs the first charging voltage V1 to the energy storage unit 10 corresponding to the fourth column.

[0066] The energy storage cells 10 corresponding to the second column are charged according to the first charging voltage V1 , and the energy storage cells 10 corresponding to the fourth column are charged according to the second charging voltage V2 .

[0067] Phase t2-t3: The switch control unit 60 outputs the first switch control signal D4 to control the switch unit 20 corresponding to the first row to be turned on, and outputs the second switch control signal D5 to control the switch unit 20 corresponding to the third row to be turned on. After the switch unit 20 corresponding to the first row is turned on, the energy storage unit 10 corresponding to the fourth column outputs the second lighting voltage to light up the laser unit in the fourth column and the first row. After the switch unit 20 corresponding to the third row is turned on, the energy storage unit 10 corresponding to the second column outputs the first lighting voltage to light up the laser unit in the second column and the third row. Since the first lighting voltage and the second lighting voltage are adaptively adjusted for the laser unit in the second column and the third row and the laser unit in the fourth column and the first row, respectively, the light output uniformity of the laser unit in the second column and the third row and the laser unit in the fourth column and the first row is improved.

[0068] It should be noted that, in addition to arranging the anode pins in the column direction and the cathode pins in the row direction, the technical solution of the present invention can also arrange the anode pins in the row direction and the cathode pins in the column direction, which is equivalent to rotating the whole by 90 degrees. Both solutions fall within the protection scope of this application.

[0069] In summary, the driving circuit of the laser array provided in the embodiment of the present invention is configured such that each of the energy storage units is connected to one of the anode pins, and each of the switch units is connected to one of the cathode pins and the ground terminal. Since the distances between the energy storage units and the anode pins are the same, the current paths from the two energy storage units corresponding to each column to any laser unit in the column are the same, thereby improving the light uniformity of different laser units. At the same time, the voltage control unit will also adjust the charging voltage supplied to the energy storage unit corresponding to the column according to the position of the column in which the laser unit is located when the laser unit is driven, ensuring that the output power of different laser units remains consistent when different laser units are driven, thereby further improving the light uniformity of different laser units.

[0070] Furthermore, since the boost unit specifically includes an LC open-loop boost circuit and the voltage control unit specifically includes a PWM controller, the present invention provides the charging voltage through an adjustable inductor voltage. Compared with the prior art that provides a constant charging voltage through an RC constant voltage circuit, the present invention avoids the heating problem caused by the resistor and realizes the adjustable charging voltage.

[0071] Furthermore, by integrating the voltage regulation unit and the switch control unit into the driving chip, the layout area of ​​the circuit board where the driving circuit is located is reduced, thereby improving the miniaturization design of the circuit board.

[0072] The technical solution of the present invention also provides a laser array system, including a laser array and a driving circuit of the laser array. The laser array includes a plurality of laser units arranged in M ​​columns and N rows.

[0073] The technical solution of the present invention also provides an electronic device, comprising the above-mentioned laser array system.

[0074] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A driving circuit for a laser array, characterized in that: Used to drive the laser units in the laser array, the laser array includes a plurality of laser units arranged in M ​​columns and N rows, each column of laser units is connected to two symmetrically arranged anode pins, and the spacing between the two anode pins corresponding to each column is the same, and each row of laser units is connected to a cathode pin, the driving circuit includes: A plurality of energy storage units, each of which is connected to one of the anode pins, and the energy storage unit is used to charge according to the connected charging voltage and output a corresponding lighting voltage, and the distance between each of the energy storage units and the anode pin is the same; A plurality of switch units, each of which is connected to one of the cathode pins and the ground terminal, and is used to control itself to be turned on or off according to a switch control signal; A voltage control unit, wherein the voltage control unit is used to output a corresponding voltage control signal according to the position of the column where the laser unit is located when the laser unit is driven; A boost unit, the boost unit being used to output a corresponding charging voltage according to the voltage control signal; A high-side gating module, wherein the high-side gating module is used to output the charging voltage to the energy storage unit corresponding to the laser unit according to the position of the column where the laser unit is located when the laser unit is driven; A switch control unit is used for outputting the switch control signal to the switch unit corresponding to the laser unit according to the position of the row where the laser unit is located when the laser unit is driven, so as to turn on the switch unit.

2. The driving circuit of the laser array according to claim 1, characterized in that: The energy storage unit includes a capacitor, a first end of the capacitor is connected to the anode pin, and a second end of the capacitor is connected to the ground.

3. The driving circuit of the laser array according to claim 1, characterized in that: The switch unit includes a switch transistor.

4. The driving circuit of the laser array according to claim 3, characterized in that: The switch control unit specifically includes a low-side driver chip, and the low-side driver chip is used to output the switch control signal to the control end of the switch transistor according to the position of the row where the laser unit is located when the laser unit is driven, so as to turn on the switch transistor.

5. The driving circuit of the laser array according to claim 3, characterized in that: The switch transistor at least includes an NMOS transistor or a gallium nitride transistor.

6. The laser array driving circuit according to claim 1, characterized in that: The boost unit specifically includes an LC open-loop boost circuit.

7. The driving circuit of the laser array according to claim 6, characterized in that: The voltage control unit includes a PWM controller, the voltage adjustment signal is specifically a pulse width modulation signal, and the PWM controller is used to adjust the duty cycle of the pulse width modulation signal according to the position of the laser unit in the column when the laser unit is driven.

8. The laser array driving circuit according to claim 1, characterized in that: The voltage regulation unit and the switch control unit are integrated into the same chip.

9. A laser array system, characterized in that: A laser array comprising a laser array and a driving circuit of the laser array according to any one of claims 1 to 8.

10. An electronic device, characterized in that: A laser array system comprising the laser array system of claim 9.

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