Constant current source driving circuit, constant current source driving method and related device

Abstract

The invention provides a constant current source driving circuit, a constant current source driving method and a related device. The circuit comprises a first voltage type digital-to-analog converter used for converting numerical control input data into digital-to-analog conversion voltage; the reference current generating circuit is used for generating reference current according to the digital-to-analog conversion voltage under the driving of the first voltage source; the current value adjusting circuit is used for adjusting the current value of the reference current under the driving of the second voltage source so as to obtain constant current source driving current for driving the laser diode, and the first voltage source provides working voltage for elements in the current value adjusting circuit; the second voltage source provides working current for the laser diode through elements in the current value adjusting circuit. According to the invention, the low-voltage application range of the output-stage power supply is expanded. The second voltage is dynamically adjusted according to the current driving voltage of the laser diode, normal work of elements in the current value adjusting circuit is guaranteed, and the low-power-consumption requirements of laser diodes of different models and different manufacturers are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and in particular relates to a constant current source driving circuit, a constant current source driving method and related devices. Background Art

[0002] In laser systems, it is often necessary to consider the physical properties of laser light sources such as laser diodes (LDs), and the driving current requirements for laser diodes are very high, which must be a low-noise, high-stability constant current source. In the related art, a PMOS output stage circuit is often used in a constant current source drive circuit for a laser diode. The PMOS output stage circuit amplifies the reference current generated by programming according to the numerical control input data to generate a constant current source drive current. The laser diode generates a stable laser pulse signal under the drive of the constant current source drive current. Specifically, a negative feedback loop composed of an operational amplifier and PMOS is used in the PMOS output stage circuit to amplify the reference current into a constant current source drive current. The output stage power supply provides an operating voltage for the operational amplifier and PMOS, which results in that the voltage value of the output stage power supply cannot be lower than a first value (for example, 1V). However, in an application scenario where the operating voltage of the laser diode is relatively low, in order to reduce its power consumption, it is necessary to reduce the voltage value of the output stage power supply, even lower than the first value (for example, reducing the voltage value of the output stage power supply to 0.5 V), which will cause the operating point of the operational amplifier and PMOS in the PMOS output stage circuit to be abnormal. Therefore, in the constant current source driving circuit in the related art, it is necessary to limit the output stage power supply to above a certain voltage value, which increases the power consumption of the constant current source driving circuit in the related art. Summary of the invention

[0003] In view of the above problems, the present disclosure provides a constant current source driving circuit, a constant current source driving method and related devices, aiming to expand the low-voltage application range of the output stage power supply in the constant current source driving circuit and reduce the power consumption of the constant current source driving circuit.

[0004] According to a first aspect of the present disclosure, there is provided a constant current source driving circuit for a laser diode, comprising:

[0005] A first voltage-type digital-to-analog converter, used for converting digital control input data into a digital-to-analog conversion voltage;

[0006] A reference current generating circuit, used for generating a reference current according to the digital-to-analog conversion voltage under the driving of a first voltage source;

[0007] A current value adjustment circuit is used to adjust the current value of the reference current under the drive of a second voltage source to obtain a constant current source driving current for driving a laser diode, wherein the first voltage source provides an operating voltage for the elements in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the elements in the current value adjustment circuit.

[0008] Optionally, the constant current source driving circuit further includes a power supply circuit for the second voltage source, wherein the power supply circuit includes a voltage value adaptive adjustment module and a DC-DC converter.

[0009] The voltage value adaptive adjustment module is used to calculate the current target second voltage that the DC-DC converter should output according to the current driving voltage provided by the current value adjustment circuit to the laser diode and the preset voltage drop of the preset element in the current value adjustment circuit;

[0010] The DC-DC converter is used to provide a current adjustment signal according to the difference between the second voltage currently actually output by the DC-DC converter and the current target second voltage, and adjust the second voltage actually output by the DC-DC converter according to the current adjustment signal until the second voltage actually output is equal to the sum of the current driving voltage and the preset voltage drop.

[0011] Optionally, the voltage value adaptive adjustment module includes a voltage-type analog-to-digital converter, a logic calculation module and a second voltage-type digital-to-analog converter.

[0012] The voltage-type analog-to-digital converter is used to convert the current driving voltage into a first digital code;

[0013] The logic calculation module is used to perform logic calculation on the first digital code and the second digital code corresponding to the preset voltage drop to obtain a third digital code;

[0014] The second voltage-type digital-to-analog converter is used to convert the third digital code into a current target second voltage that the DC-DC converter should output.

[0015] Optionally, the third digital code changes in value according to the first step size, so that the current target second voltage output by the second voltage-type digital-to-analog converter changes in value according to the second step size, and the first step size and the second step size are adjustable according to the adaptive adjustment requirement of the voltage value of the second voltage.

[0016] Optionally, the current value adjustment circuit includes a first operational amplifier, a first transistor, a first resistor and a second resistor.

[0017] The first operational amplifier has a non-inverting input terminal receiving the reference current and connected to the first end of the first resistor, an inverting input terminal connected to a connection node between the second path terminal of the first transistor and the first end of the second resistor, and an output terminal connected to the control terminal of the first transistor.

[0018] The connection node between the second end of the first resistor and the second end of the second resistor is used to provide the constant current source driving current.

[0019] The first channel terminal of the first transistor is connected to the second current source.

[0020] Optionally, the current value adjustment circuit includes a first operational amplifier, a second operational amplifier, a first transistor, a first resistor and a second resistor.

[0021] The first operational amplifier has a non-inverting input terminal receiving the reference current and connected to the first end of the first resistor, an inverting input terminal connected to a connection node between the second path terminal of the first transistor and the first end of the second resistor, and an output terminal connected to the control terminal of the first transistor.

[0022] The second end of the first resistor is connected to the output end of the second operational amplifier, the second end of the second resistor is connected to the non-inverting input end of the second operational amplifier, the connection node between the non-inverting input end of the second operational amplifier and the second end of the second resistor is used to provide the constant current source driving current, the inverting input end of the second operational amplifier is connected to the output end of the second operational amplifier, and the first path end of the first transistor is connected to the second current source.

[0023] Optionally, the reference current generating circuit includes a third operational amplifier, a second transistor and a third resistor.

[0024] The third operational amplifier has a positive input terminal receiving the digital-to-analog conversion voltage, an inverting input terminal and a connection node between the first path terminal of the second transistor and the first end of the third resistor, and an output terminal connected to the control terminal of the second transistor.

[0025] The second end of the third resistor is connected to the first current source, and the second channel end of the second transistor provides the reference current.

[0026] Optionally, the reference current generating circuit includes a fourth operational amplifier, a fifth operational amplifier, a third transistor, a fourth transistor, a fourth resistor, a fifth resistor and a sixth resistor.

[0027] The fourth operational amplifier has an inverting input terminal receiving the digital-to-analog conversion voltage, a non-inverting input terminal and a second path terminal of the third transistor connected to a connection node of the first terminal of the fourth resistor, an output terminal connected to a control terminal of the third transistor, and a second terminal of the fourth resistor grounded.

[0028] The non-inverting input terminal of the fifth operational amplifier and the first path terminal of the third transistor are connected to the connection node of the first end of the fifth resistor, the inverting input terminal and the first end of the sixth resistor are connected to the connection node of the first path terminal of the fourth transistor, and the output terminal is connected to the control terminal of the fourth transistor.

[0029] The second end of the fifth resistor and the second end of the sixth resistor are both connected to the first voltage source, and the second path end of the fourth transistor provides the reference current.

[0030] Optionally, the preset element includes the first transistor, and the preset voltage drop is equal to a drain-source voltage of the first transistor.

[0031] According to a second aspect of the present disclosure, a constant current source driving method for a laser diode is provided, wherein the constant current source driving method is applied to the constant current source driving circuit as described above, and comprises:

[0032] Converting the digital control input data into a digital-to-analog conversion voltage using a first voltage-type digital-to-analog converter;

[0033] Using a reference current generating circuit to generate a reference current according to the digital-to-analog conversion voltage under the driving of a first voltage source;

[0034] A current value adjustment circuit is used to adjust the current value of the reference current under the drive of a second voltage source to obtain a constant current source driving current for driving a laser diode, wherein the first voltage source provides an operating voltage for the elements in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the elements in the current value adjustment circuit.

[0035] According to a third aspect of the present disclosure, there is provided a laser system, comprising:

[0036] Laser diodes;

[0037] The constant current source driving circuit as described above is used to provide a constant current source driving current for driving the laser diode.

[0038] According to a fourth aspect of the present disclosure, an electronic device is provided, comprising a memory, a processor, and a program stored in the memory and executable on the processor, wherein the program can implement the constant current source driving method as described above when executed by the processor.

[0039] The present disclosure brings the following beneficial effects:

[0040] In the constant current source driving circuit of the embodiment of the present disclosure, the first voltage-type digital-to-analog converter converts the digital control input data into a digital-to-analog conversion voltage, the reference current generating circuit generates a reference current according to the digital-to-analog conversion voltage under the drive of the first voltage source, and the current value adjusting circuit adjusts the current value of the reference current under the drive of the second voltage source (also referred to as the output stage power supply) to obtain a constant current source driving current for driving the laser diode. Among them, the first voltage source provides a working voltage for the components in the current value adjustment circuit, and the second voltage source provides a working current for the laser diode through the components in the current value adjustment circuit. The first voltage source and the second voltage source are independent of each other, and when the voltage value of the second current source is reduced, the operating point of the components (for example, operational amplifiers and transistors) in the current value adjustment circuit will not be abnormal. Therefore, the driving voltage provided to the laser diode can be reduced by reducing the voltage value of the second current source, thereby reducing the power consumption of the laser diode. Obviously, in the embodiment of the present disclosure, the low-voltage application range of the output stage power supply in the constant current source driving circuit is expanded, and the power consumption of the constant current source driving circuit is reduced. In addition, the driving current with a higher current value is drawn from the second voltage source, which will not affect the power supply current capacity of the first voltage source.

[0041] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or understood by practicing the present disclosure. The purpose and other advantages of the present disclosure are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0042] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0044] Figure 1 It is a structural schematic diagram of a constant current source driving circuit for a laser diode in the related art;

[0045] Figure 2 It is a structural schematic diagram of a constant current source driving circuit 200 for a laser diode provided according to an embodiment of the present disclosure;

[0046] Figure 3 It is a structural schematic diagram of a constant current source driving circuit 300 for a laser diode provided according to an embodiment of the present disclosure;

[0047] Figure 4It is a structural schematic diagram of a constant current source driving circuit 400 for a laser diode provided according to an embodiment of the present disclosure;

[0048] Figure 5 It is a structural schematic diagram of a constant current source driving circuit 500 for a laser diode provided according to an embodiment of the present disclosure;

[0049] Figure 6 A schematic flow chart of a constant current source driving method for a laser diode provided according to an embodiment of the present disclosure;

[0050] Figure 7 The present invention is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] Various embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by the same or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0052] Figure 1 FIG. 1 is a schematic diagram of a constant current source driving circuit for a laser diode in the related art. Figure 1As shown, the constant current source driving circuit 100 includes a voltage-type digital-to-analog converter 130, a reference current generating circuit 110 and a current value adjusting circuit 120. The voltage-type digital-to-analog converter 130 converts the digital control input data (e.g., 010...101) into a digital-to-analog conversion voltage VDAC. The reference current generating circuit 110 generates a reference current I1 according to the digital-to-analog conversion voltage VDAC. The reference current generating circuit 110 includes an operational amplifier A1, a transistor (e.g., an N-type transistor) M1 and a resistor R1. The non-inverting input terminal of the operational amplifier A1 is connected to the output terminal of the voltage-type digital-to-analog converter 130, the inverting input terminal is connected to the connection node of the second path terminal (e.g., source terminal) of the transistor M1 and the first terminal of the resistor R1, the output terminal is connected to the control terminal (e.g., gate terminal) of the transistor M1, and the second terminal of the resistor R1 is grounded. The operational amplifier A1 and the transistor M1 form a negative feedback loop. The reference current I1=VDAC / R1. The current value adjustment circuit 120 amplifies the current value of the reference current I1 to obtain a constant current source drive current Iout for driving the laser diode LD. The current value adjustment circuit 120 adopts a PMOS output stage circuit, and the current value adjustment circuit 120 includes an operational amplifier A2, a transistor (e.g., a P-type transistor) M2, a resistor R2, and a resistor R3. The positive input terminal of the operational amplifier A2 is connected to the connection node of the first channel end (e.g., the drain end) of the transistor M1 and the first end of the resistor R2, the negative input terminal is connected to the connection node of the first channel end (e.g., the drain end) of the transistor M2 and the first end of the resistor R3, the output terminal is connected to the control end (e.g., the gate end) of the transistor M2, the second end of the resistor R2 and the second end of the resistor R3 are both connected to the output stage power supply PVDD, and the second channel end (e.g., the source end) of the transistor M2 provides a constant current source drive current Iout to drive the laser diode LD. The operational amplifier A2 and the transistor M2 form a negative feedback loop. The constant current source drive current Iout=I1*R2 / R3. The output stage power supply PVDD provides the operating voltage for the operational amplifier A2 and the transistor M2, which results in that the voltage value of the output stage power supply PVDD cannot be lower than a first value (e.g., 1 V). However, in the application scenario where the operating voltage of the laser diode LD is relatively low, in order to reduce its power consumption, the voltage value of the output stage power supply PVDD needs to be reduced, even lower than the first value (e.g., reducing the voltage value of the output stage power supply PVDD to 0.5 V), which will cause abnormal operating points of the operational amplifier A2 and the transistor M2 in the PMOS output stage circuit. Therefore, if Figure 1 As shown, in the constant current source driving circuit, the output stage power supply PVDD needs to be limited to above a certain voltage value, which increases the power consumption of the constant current source driving circuit.

[0053] Based on this, the embodiments of the present disclosure provide a constant current source driving circuit, a constant current source driving method and related devices to expand the low-voltage application range of the output stage power supply in the constant current source driving circuit and reduce the power consumption of the constant current source driving circuit.

[0054] Figure 2 FIG. 2 is a schematic diagram of a constant current source driving circuit 200 for a laser diode according to an embodiment of the present disclosure. Figure 2 As shown, the constant current source driving circuit 200 includes a first voltage-type digital-to-analog converter 230, a reference current generating circuit 210 and a current value adjusting circuit 220. In some embodiments, the first voltage-type digital-to-analog converter 230 is used to convert digital control input data (for example, 010...101) into a digital-to-analog conversion voltage VDAC. The reference current generating circuit 210 is used to generate a reference current I1 according to the digital-to-analog conversion voltage VDAC under the drive of the first voltage source AVDD. The current value adjusting circuit 220 is used to adjust the current value I1 of the reference current under the drive of the second voltage source PVDD to obtain a constant current source driving current Iout for driving the laser diode LD. It should be noted that the first voltage source AVDD provides an operating voltage for the components in the current value adjusting circuit 220, and the second voltage source PVDD provides an operating current for the laser diode LD through the components in the current value adjusting circuit 220.

[0055] In some embodiments, the reference current generating circuit 210 includes an operational amplifier A3, a transistor M3 (e.g., a P-type transistor), and a resistor R4. The non-inverting input terminal of the operational amplifier A3 receives the digital-to-analog conversion voltage VDAC, the inverting input terminal and the first channel terminal (e.g., the drain terminal) of the transistor M3 are connected to the connection node of the first terminal of the resistor R4, and the output terminal is connected to the control terminal (e.g., the gate terminal) of the transistor M3. The second terminal of the resistor R4 is connected to the first current source AVDD, and the second channel terminal (e.g., the source terminal) of the transistor M3 provides the reference current I1. The operational amplifier A3 and the transistor M3 form a negative feedback loop. The reference current I1=(AVDD-VDAC) / R4.

[0056] In some embodiments, the current value adjustment circuit 220 includes an operational amplifier A4, a transistor M4 (e.g., an N-type transistor), a resistor R5, and a resistor R6. The current value adjustment circuit 220 is an NMOS output stage circuit. The non-inverting input terminal of the operational amplifier A4 is connected to the second path terminal (e.g., source terminal) of the transistor M3 to receive the reference current, and the non-inverting input terminal of the operational amplifier A4 is connected to the first end of the resistor R5, the inverting input terminal and the second path terminal (e.g., source terminal) of the transistor M4 are connected to the connection node of the first end of the resistor R6, and the output terminal is connected to the control terminal (e.g., gate terminal) of the transistor M4. The connection node of the second end of the resistor R5 and the second end of the resistor R6 is used to provide a constant current source drive current Iout. The first path terminal (e.g., drain terminal) of the transistor M4 is connected to the second current source PVDD (which can be called the output stage power supply PVDD). The operational amplifier A4 and the transistor M4 form a negative feedback loop. Constant current source driving current Iout=I1*R5 / R6+I1=(AVDD-VDAC)*(R5+R6) / (R6*R4).

[0057] It is understandable that by adjusting the resistor R5 and the resistor R6, a precise current gain can be provided for the reference current I1, the current value of the driving current Iout can be precisely adjusted, and a large current output can be provided for loads such as the laser diode LD. The first voltage source AVDD provides an operating voltage for the operational amplifier A4 and the transistor M4. The first voltage source AVDD and the second voltage source PVDD are independent of each other. When the voltage value of the second current source PVDD is reduced, only the drain-source voltage of the transistor M4 is reduced, and the operating point of the operational amplifier A4 and the transistor M4 in the current value adjustment circuit 220 will not be abnormal. Therefore, the driving voltage provided to the laser diode LD can be reduced by reducing the voltage value of the second current source PVDD, thereby reducing the power consumption of the laser diode LD. Obviously, in the embodiment of the present disclosure, the low-voltage application range of the output stage power supply in the constant current source driving circuit is expanded, and the power consumption of the constant current source driving circuit 200 is reduced. In addition, the driving current Iout with a higher current value is drawn from the second current source PVDD, which will not affect the power supply current capability of the first voltage source AVDD.

[0058] Figure 3 FIG. 3 is a schematic diagram of a constant current source driving circuit 300 for a laser diode according to an embodiment of the present disclosure. Figure 3 As shown, the constant current source driving circuit 300 includes a first voltage-type digital-to-analog converter 330 , a reference current generating circuit 310 and a current value adjusting circuit 320 . Figure 3 The first voltage type digital-to-analog converter 330 and the current value adjustment circuit 320 in Figure 2 The first voltage-type digital-to-analog converter 230 and the current value adjustment circuit 220 are basically the same, and the similarities are not repeated here.

[0059] In some embodiments, Figure 3 As shown, the reference current generating circuit 310 includes an operational amplifier A5, an operational amplifier A6, a transistor M5, a transistor M6, a resistor R7, a resistor R8 and a resistor R9. The inverting input terminal of the operational amplifier A5 receives the digital-to-analog conversion voltage VDAC, the non-inverting input terminal and the connection node of the second channel terminal (e.g., source terminal) of the transistor (e.g., N-type transistor) M5 and the first terminal of the resistor R7 are connected, the output terminal is connected to the control terminal (e.g., gate terminal) of the transistor M5, and the second terminal of the resistor R7 is grounded. The non-inverting input terminal of the operational amplifier A6 and the connection node of the first channel terminal (e.g., drain terminal) of the transistor M5 and the first terminal of the resistor R8 are connected, the inverting input terminal and the first terminal of the resistor R9 are connected to the connection node of the first channel terminal (e.g., drain terminal) of the transistor (e.g., P-type transistor) M6, and the output terminal is connected to the control terminal (e.g., gate terminal) of the transistor M6. The second end of the resistor R8 and the second end of the resistor R9 are both connected to the first voltage source AVDD, the first channel end (e.g., the drain end) of the transistor M5 provides the programming current I0, and the second channel end (e.g., the source end) of the transistor M6 provides the reference current I1. The operational amplifier A6 and the transistor M6 form a negative feedback loop. The reference current I1=I0*R8 / R9, where I0=VDAC / R7. The constant current source driving current Iout=I1*R5 / R6+I1=VDAC*(R5+R6)*R8 / (R6*R9*R7).

[0060] It can be understood that by adjusting the resistor R8 and the resistor R9, a precise current gain can be provided for the programming current I0, so that the current value of the programming current I0 can be accurately adjusted. By adjusting the resistor R5 and the resistor R6, a precise current gain can be provided for the reference current I1, so that the current value of the driving current Iout can be accurately adjusted. After the programming current I0 is amplified by two precise current gains, it can provide a large current output for loads such as the laser diode LD. The first voltage source AVDD provides an operating voltage for the operational amplifier A4 and the transistor M4. When the voltage value of the second current source PVDD is reduced, only the drain-source voltage of the transistor M4 is reduced, and the operating point of the operational amplifier A4 and the transistor M4 in the current value adjustment circuit 220 will not be abnormal. Therefore, the driving voltage provided to the laser diode LD can be reduced by reducing the voltage value of the second current source PVDD, thereby reducing the power consumption of the laser diode LD. Obviously, in the embodiment of the present disclosure, the low-voltage application range of the output stage power supply in the constant current source drive circuit is expanded, and the power consumption of the constant current source drive circuit 300 is reduced. In addition, the driving current Iout with a relatively high current value is drawn from the second current source PVDD, which will not affect the power supply current capability of the first voltage source AVDD.

[0061] Figure 4 FIG. 4 is a schematic diagram of a constant current source driving circuit 400 for a laser diode according to an embodiment of the present disclosure. Figure 4 As shown, the constant current source driving circuit 400 includes a first voltage-type digital-to-analog converter 430 , a reference current generating circuit 410 and a current value adjusting circuit 420 . Figure 4 The first voltage type digital-to-analog converter 430 and the reference current generating circuit 410 are connected with Figure 2 The first voltage-type digital-to-analog converter 230 and the reference current generating circuit 210 are basically the same, and the similarities are not repeated here.

[0062] In some embodiments, Figure 4 As shown, the current value adjustment circuit 420 includes an operational amplifier A4, an operational amplifier A7, a transistor M4 (e.g., an N-type transistor), a resistor R5, and a resistor R6. The current value adjustment circuit 220 is an NMOS output stage circuit. The non-inverting input terminal of the operational amplifier A4 is connected to the second path terminal (e.g., source terminal) of the transistor M3 to receive the reference current, and the non-inverting input terminal of the operational amplifier A4 is connected to the first end of the resistor R5, the inverting input terminal and the second path terminal (e.g., source terminal) of the transistor M4 are connected to the connection node of the first end of the resistor R6, and the output terminal is connected to the control terminal (e.g., gate terminal) of the transistor M4. The second end of the resistor R5 is connected to the output terminal of the operational amplifier M7, the second end of the resistor R6 is connected to the non-inverting input terminal of the operational amplifier A7, the connection node of the non-inverting input terminal of the operational amplifier A7 and the second end of the resistor R6 is used to provide a constant current source drive current Iout, and the inverting input terminal of the operational amplifier A7 is connected to the output terminal of the operational amplifier A7. The first channel end (eg, drain end) of the transistor M4 is connected to the second current source PVDD (which may be referred to as the output stage power supply PVDD). The operational amplifier A4 and the transistor M4 form a negative feedback loop. Figure 4 As shown, the reference current I1 provided by the reference current generating circuit 210 is equal to (AVDD-VDAC) / R4. The constant current source driving current Iout is equal to I1*R5 / R6=(AVDD-VDAC)*R5 / (R6*R4).

[0063] It can be understood that a voltage follower composed of an operational amplifier A7 is provided in the non-inverting input branch of the operational amplifier A4 to isolate the current of the non-inverting input branch, thereby isolating the load such as the laser diode LD from the reference current generating circuit 410, preventing the load such as the laser diode LD from affecting the power supply current capacity of the first current source AVDD in the reference current generating circuit 410, thereby improving the reliability of the first current source AVDD in the reference current generating circuit 410, and thus improving the reliability of the constant current source driving circuit 400.

[0064] Figure 5Schematic diagram of a constant current source driving circuit 500 for a laser diode provided according to an embodiment of the present disclosure. As Figure 5 shown, the constant current source driving circuit 500 includes a first voltage-mode digital-to-analog converter 530, a reference current generation circuit 510, a current value adjustment circuit 520, and a power supply circuit 550 for a second current source PVDD (which can be referred to as an output stage power supply PVDD). Figure 5 The first voltage-mode digital-to-analog converter 530, the reference current generation circuit 510, and the current value adjustment circuit 520 in Figure 2 are basically the same as the first voltage-mode digital-to-analog converter 230, the reference current generation circuit 210, and the current value adjustment circuit 220 in

[0065] In some embodiments, as Figure 5 shown, the power supply circuit 550 includes a voltage value adaptive adjustment module 540 and a DC-DC converter 551. The voltage value adaptive adjustment module 540 is configured to calculate a current target second voltage PVDDt that the DC-DC converter 551 should output according to the current driving voltage Vout provided by the current value adjustment circuit 520 to the laser diode LD and the preset voltage drop V of a preset component in the current value adjustment circuit 520. The DC-DC converter 551 is configured to provide a current adjustment signal Scontrol according to the difference between the second voltage PVDD currently actually output by the DC-DC converter 551 and the current target second voltage PVDDt, and adjust the second voltage PVDD actually output by the DC-DC converter 551 according to the current adjustment signal Scontrol until the actually output second voltage PVDD is equal to the sum of the current driving voltage Vout and the preset voltage drop V. For example, when the second voltage PVDD currently actually output by the DC-DC converter 551 is less than the current target second voltage PVDDt (i.e., PVDD < Vout + △V), the control increases the second voltage PVDD currently actually output by the DC-DC converter 551. When the second voltage PVDD currently actually output by the DC-DC converter 551 is greater than the current target second voltage PVDDt (i.e., PVDD > Vout + △V), the control decreases the second voltage PVDD currently actually output by the DC-DC converter 551.

[0066] In some embodiments, as Figure 5 shown, the preset component includes a transistor M4, and the preset voltage drop V is equal to the drain-source voltage Vds of the transistor M4.

[0067] In some embodiments, as Figure 5As shown, the voltage value adaptive adjustment module 540 includes a voltage-type analog-to-digital converter 541, a logic calculation module 542, and a voltage-type digital-to-analog converter 543. The voltage-type analog-to-digital converter 541 is connected to the node connecting the transistor M4 and the resistor R6 to collect the current driving voltage Vout provided to the laser diode LD by the current value adjustment circuit 520, and convert the current driving voltage Vout into a first digital code Code1. The logic calculation module 542 converts the first digital code Code1 and the preset voltage drop V is subjected to logical calculation to obtain the third digital code Code3. The second voltage-type digital-to-analog converter 543 converts the third digital code Code3 into the current target second voltage PVDDt that the DC-DC converter 551 should output. In some embodiments, the third digital code Code3 is numerically changed according to the first step length, so that the current target second voltage PVDDt output by the second voltage-type digital-to-analog converter 543 is numerically changed according to the second step length. The first step length and the second step length are adjustable according to the demand for adaptive adjustment of the voltage value of the second voltage. In the adaptive adjustment process of adjusting the second voltage PVDD output by the DC-DC converter 551 to the target second voltage PVDDt, the adaptive adjustment period of the second voltage PVDD can be adjusted by adjusting the first step length and the second step length.

[0068] It is understandable that the operating voltages of laser diodes LD of different models and manufacturers are different. In order to save power consumption, it is necessary to dynamically adjust the second voltage PVDD actually output by the DC-DC converter 551 according to the current driving voltage Vout provided to the laser diode LD by the current value adjustment circuit 520. By continuous adjustment, the voltage drop of the preset components in the current value adjustment circuit 520 can be kept at the preset voltage drop. V, thereby reducing the second voltage PVDD actually output by the DC-DC converter 551 as much as possible without causing abnormal working points of the operational amplifier A4 and the transistor M4 in the current value adjustment circuit 220. Furthermore, the driving voltage provided to the laser diode LD can be reduced by reducing the voltage value of the second voltage PVDD actually output by the DC-DC converter 551 to adapt to the low power consumption requirements of laser diodes LD of different models and manufacturers.

[0069] Figure 6 FIG. 1 is a flow chart of a constant current source driving method for a laser diode according to an embodiment of the present disclosure. The constant current source driving method is applied to Figures 2 to 5 The constant current source drive circuit shown in Figure 1 is shown in Figure 1. Figure 6 , the constant current source driving method includes steps S610 to S630.

[0070] In step S610 , a first voltage-type digital-to-analog converter is used to convert digital control input data into a digital-to-analog conversion voltage.

[0071] In step S620, a reference current generating circuit is driven by a first voltage source to generate a reference current according to the digital-to-analog conversion voltage.

[0072] In step S630, the current value of the reference current is adjusted by a current value adjustment circuit under the drive of a second voltage source to obtain a constant current source driving current for driving a laser diode, wherein the first voltage source provides an operating voltage for the elements in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the elements in the current value adjustment circuit.

[0073] Since the process of driving the laser diode using the constant current source driving method in the embodiment of the present disclosure has been described in detail above, it will not be repeated here.

[0074] The present disclosure also provides an electronic device, such as Figure 7 As shown, it includes a memory 720, a processor 710, and a program stored in the memory 720 and executable on the processor 710. When the program is executed by the processor 710, each process of each embodiment of the above-mentioned constant current source driving method can be implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0075] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructions, or by controlling related hardware through instructions, and the instructions can be stored in a computer-readable storage medium and loaded and executed by a processor. To this end, the present disclosure also provides a storage medium on which a computer program or instruction is stored, and when the computer program or instruction is executed by the processor, each process of each embodiment of the above constant current source driving method can be implemented.

[0076] Since the instructions stored in the storage medium can execute the steps in the constant current source driving method provided in the embodiment of the present disclosure, the beneficial effects that can be achieved by the constant current source driving method provided in the embodiment of the present disclosure can be achieved, as detailed in the previous embodiments, which will not be repeated here. The specific implementation of each of the above operations can be referred to in the previous embodiments, which will not be repeated here.

[0077] In summary, in the constant current source driving circuit of the embodiment of the present disclosure, the first voltage-type digital-to-analog converter converts the digital control input data into a digital-to-analog conversion voltage, the reference current generating circuit generates a reference current according to the digital-to-analog conversion voltage under the drive of the first voltage source, and the current value adjustment circuit adjusts the current value of the reference current under the drive of the second voltage source (also referred to as the output stage power supply) to obtain a constant current source driving current for driving the laser diode. Among them, the first voltage source provides an operating voltage for the components in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the components in the current value adjustment circuit. The first voltage source and the second voltage source are independent of each other, and when the voltage value of the second current source is reduced, the operating point of the components (for example, operational amplifiers and transistors) in the current value adjustment circuit will not be abnormal. Therefore, the driving voltage provided to the laser diode can be reduced by reducing the voltage value of the second current source, thereby reducing the power consumption of the laser diode LD. Obviously, in the embodiment of the present disclosure, the low-voltage application range of the output stage power supply in the constant current source driving circuit is expanded, and the power consumption of the constant current source driving circuit is reduced. In addition, the driving current with a higher current value is drawn from the second current source, which will not affect the power supply current capacity of the first voltage source.

[0078] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly illustrating the present disclosure, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present disclosure.

Claims

1. A constant current source driving circuit for a laser diode, comprising: A first voltage-type digital-to-analog converter, used for converting digital control input data into a digital-to-analog conversion voltage; A reference current generating circuit, used for generating a reference current according to the digital-to-analog conversion voltage under the driving of a first voltage source; A current value adjustment circuit is used to adjust the current value of the reference current under the drive of a second voltage source to obtain a constant current source driving current for driving a laser diode, wherein the first voltage source provides an operating voltage for the elements in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the elements in the current value adjustment circuit.

2. The constant current source driving circuit according to claim 1, wherein: The constant current source driving circuit also includes a power supply circuit of the second voltage source, and the power supply circuit includes a voltage value adaptive adjustment module and a DC-DC converter. The voltage value adaptive adjustment module is used to calculate the current target second voltage that the DC-DC converter should output according to the current driving voltage provided by the current value adjustment circuit to the laser diode and the preset voltage drop of the preset element in the current value adjustment circuit; The DC-DC converter is used to provide a current adjustment signal according to the difference between the second voltage currently actually output by the DC-DC converter and the current target second voltage, and adjust the second voltage actually output by the DC-DC converter according to the current adjustment signal until the second voltage actually output is equal to the sum of the current driving voltage and the preset voltage drop.

3. The constant current source driving circuit according to claim 2, wherein: The voltage value adaptive adjustment module includes a voltage-type analog-to-digital converter, a logic calculation module and a second voltage-type digital-to-analog converter. The voltage-type analog-to-digital converter is used to convert the current driving voltage into a first digital code; The logic calculation module is used to perform logic calculation on the first digital code and the second digital code corresponding to the preset voltage drop to obtain a third digital code; The second voltage-type digital-to-analog converter is used to convert the third digital code into a current target second voltage that the DC-DC converter should output.

4. The constant current source driving circuit according to claim 3, wherein: The third digital code changes in value according to the first step length, so that the current target second voltage output by the second voltage-type digital-to-analog converter changes in value according to the second step length, and the first step length and the second step length are adjustable according to the adaptive adjustment requirements of the voltage value of the second voltage.

5. The constant current source driving circuit according to claim 3, wherein: The current value adjustment circuit includes a first operational amplifier, a first transistor, a first resistor and a second resistor. The first operational amplifier has a non-inverting input terminal receiving the reference current and connected to the first end of the first resistor, an inverting input terminal connected to a connection node between the second path terminal of the first transistor and the first end of the second resistor, and an output terminal connected to the control terminal of the first transistor. The connection node between the second end of the first resistor and the second end of the second resistor is used to provide the constant current source driving current. The first channel terminal of the first transistor is connected to the second current source.

6. The constant current source driving circuit according to claim 3, wherein: The current value adjustment circuit includes a first operational amplifier, a second operational amplifier, a first transistor, a first resistor and a second resistor. The first operational amplifier has a non-inverting input terminal receiving the reference current and connected to the first end of the first resistor, an inverting input terminal connected to a connection node between the second path terminal of the first transistor and the first end of the second resistor, and an output terminal connected to the control terminal of the first transistor. The second end of the first resistor is connected to the output end of the second operational amplifier, the second end of the second resistor is connected to the non-inverting input end of the second operational amplifier, the connection node between the non-inverting input end of the second operational amplifier and the second end of the second resistor is used to provide the constant current source driving current, the inverting input end of the second operational amplifier is connected to the output end of the second operational amplifier, and the first path end of the first transistor is connected to the second current source.

7. The constant current source driving circuit according to claim 5 or 6, wherein: The reference current generating circuit includes a third operational amplifier, a second transistor and a third resistor. The third operational amplifier has a positive input terminal receiving the digital-to-analog conversion voltage, an inverting input terminal and a connection node between the first path terminal of the second transistor and the first end of the third resistor, and an output terminal connected to the control terminal of the second transistor. The second end of the third resistor is connected to the first current source, and the second channel end of the second transistor provides the reference current.

8. The constant current source driving circuit according to claim 5 or 6, wherein: The reference current generating circuit includes a fourth operational amplifier, a fifth operational amplifier, a third transistor, a fourth transistor, a fourth resistor, a fifth resistor and a sixth resistor. The fourth operational amplifier has an inverting input terminal receiving the digital-to-analog conversion voltage, a non-inverting input terminal and a second path terminal of the third transistor connected to a connection node of the first terminal of the fourth resistor, an output terminal connected to a control terminal of the third transistor, and a second terminal of the fourth resistor grounded. The non-inverting input terminal of the fifth operational amplifier and the first path terminal of the third transistor are connected to the connection node of the first end of the fifth resistor, the inverting input terminal and the first end of the sixth resistor are connected to the connection node of the first path terminal of the fourth transistor, and the output terminal is connected to the control terminal of the fourth transistor. The second end of the fifth resistor and the second end of the sixth resistor are both connected to the first voltage source, and the second path end of the fourth transistor provides the reference current.

9. The constant current source driving circuit according to claim 5 or 6, wherein: The preset element includes the first transistor, and the preset voltage drop is equal to a drain-source voltage of the first transistor.

10. A constant current source driving method for a laser diode, the constant current source driving method being applied to the constant current source driving circuit as claimed in any one of claims 1 to 9, comprising: Converting the digital control input data into a digital-to-analog conversion voltage using a first voltage-type digital-to-analog converter; Using a reference current generating circuit to generate a reference current according to the digital-to-analog conversion voltage under the driving of a first voltage source; A current value adjustment circuit is used to adjust the current value of the reference current under the drive of a second voltage source to obtain a constant current source driving current for driving a laser diode, wherein the first voltage source provides an operating voltage for the elements in the current value adjustment circuit, and the second voltage source provides an operating current for the laser diode through the elements in the current value adjustment circuit.

11. A laser system comprising: Laser diodes; The constant current source driving circuit according to any one of claims 1 to 9, used to provide a constant current source driving current for driving the laser diode.

12. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, wherein the program can implement the constant current source driving method as claimed in claim 10 when executed by the processor.

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