A driving circuit of a VCSEL laser and a DTOF receiving chip

Abstract

The utility model discloses a kind of driving circuit and DTOF receiving chip of VCSEL laser, for VCSEL laser technical field.The circuit, switch module includes input end, output end, power end and ground end, for according to the signal received by input end, output end is connected to its power end or ground end;Constant current source is connected between first power supply and the drain of second NMOS tube, the source of second NMOS tube is grounded, and the gate of second NMOS tube is connected with drain;The cathode of first NMOS tube drain connection VCSEL laser, and the source of first NMOS tube is connected ground;The anode of VCSEL laser is connected with second power supply, and the voltage of second power supply is greater than or equal to the voltage of first power supply;Pulse generating circuit is connected with the input end of switch module, and the gate of first NMOS tube is connected with the output end of switch module;The gate of second NMOS tube is connected with the power end of switch module, and the ground end of switch module is connected with ground.Under the change of PVT, the driving current of VCSEL laser does not occur deviation, avoid the change of the laser output power of VCSEL laser.

Description

Technical Field

[0001] This utility model relates to the field of VCSEL laser technology, and in particular to a driving circuit for a VCSEL laser and a DTOF receiving chip. Background Technology

[0002] A vertical-cavity surface-emitting laser (VCSEL) is a type of semiconductor laser in which the laser emission direction is perpendicular to the chip surface. VCSEL lasers are widely used in data communication, sensing, and consumer electronics due to their advantages such as low power consumption, high speed, and low manufacturing cost.

[0003] In existing VCSEL laser driving circuits, the VCSEL laser is connected to an NMOS transistor. The driving current of the VCSEL laser is typically adjusted by directly controlling the voltage / current at the source or drain of the NMOS transistor. However, when the driving circuit experiences process changes, voltage fluctuations, or temperature variations (PVT variations), the driving current of the VCSEL laser is prone to shift, leading to changes in the laser output power and affecting system stability. Utility Model Content

[0004] This invention provides a driving circuit for a VCSEL laser and a DTOF receiving chip, which ensures that the driving current of the VCSEL laser will not shift under changes in PVT, thus avoiding changes in the laser output power of the VCSEL laser.

[0005] This invention provides a driving circuit for a VCSEL laser, including a pulse generation circuit and a first NMOS transistor;

[0006] It also includes: a constant current source, a second NMOS transistor, and a switching module;

[0007] The switching module includes an input terminal, an output terminal, a power supply terminal, and a ground terminal, and is used to connect the output terminal to its power supply terminal or ground terminal according to the signal received at the input terminal.

[0008] The constant current source is connected between the first power supply and the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, and the gate and drain of the second NMOS transistor are connected.

[0009] The drain of the first NMOS transistor is connected to the cathode of the VCSEL laser, and the source of the first NMOS transistor is connected to ground;

[0010] The anode of the VCSEL laser is connected to a second power supply, the voltage of which is greater than or equal to the voltage of the first power supply.

[0011] The pulse generation circuit is connected to the input terminal of the switching module, and the output terminal of the switching module is connected to the gate of the first NMOS transistor.

[0012] The power supply terminal of the switching module is connected to the gate of the second NMOS transistor, and the ground terminal of the switching module is connected to ground.

[0013] Furthermore, the pulse generation circuit is used to control the switching module. The output of the switching module controls the first NMOS transistor to close or open, thereby controlling the on / off state of the VCSEL laser.

[0014] Furthermore, when the pulse generation circuit outputs a low level, the switching module outputs a low level, the first NMOS transistor is turned off, and the VCSEL laser is turned off.

[0015] When the pulse generation circuit outputs a high level, the switching module outputs a high level, the first NMOS transistor closes, and the VCSEL laser is turned on.

[0016] Furthermore, the aspect ratio of the first NMOS transistor is 50-100 times that of the second NMOS transistor.

[0017] Furthermore, the switching module includes a first inverter and a second inverter connected together. The power supply terminals of the first inverter and the second inverter are both connected to the gate of the second NMOS transistor. The ground terminals of the first inverter and the second inverter are both grounded. The input terminal of the first inverter is connected to the pulse generation circuit, and the output terminal of the second inverter is connected to the gate of the first NMOS transistor.

[0018] Furthermore, the size of the second inverter is greater than or equal to that of the first inverter.

[0019] Furthermore, the driving circuit also includes a pre-driving circuit, which is connected between the pulse generating circuit and the input terminal of the switching module.

[0020] Furthermore, the driving circuit also includes a voltage buffer connected between the gate of the second NMOS transistor and the power supply terminal of the switching module.

[0021] Furthermore, the driving circuit also includes a capacitor connected between the power supply terminal and ground of the switching module.

[0022] This invention also provides a DTOF receiver chip, which includes the driving circuit of the VCSEL laser described above.

[0023] As can be seen from the above technical solutions, this utility model has the following advantages:

[0024] The driving circuit for a VCSEL laser includes: a pulse generation circuit and a first NMOS transistor; it also includes: a constant current source, a second NMOS transistor, and a switching module; the switching module includes an input terminal, an output terminal, a power supply terminal, and a ground terminal, used to connect the output terminal to its power supply terminal or ground terminal according to the signal received at the input terminal; the constant current source is connected between the first power supply and the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, and the gate of the second NMOS transistor is connected to the drain; the drain of the first NMOS transistor is connected to the cathode of the VCSEL laser, and the source of the first NMOS transistor is connected to ground; the anode of the VCSEL laser is connected to a second power supply, the voltage of the second power supply being greater than or equal to the voltage of the first power supply; the pulse generation circuit is connected to the input terminal of the switching module, and the output terminal of the switching module is connected to the gate of the first NMOS transistor; the power supply terminal of the switching module is connected to the gate of the second NMOS transistor, and the ground terminal of the switching module is connected to ground.

[0025] When the output of the switching module is connected to its power supply, the first NMOS transistor and the second NMOS transistor form a current mirror. The cathode of the VCSEL laser is connected to the drain of the first NMOS transistor. The reference current provided by the constant current source connected to the second NMOS transistor is copied to the first NMOS transistor through the current mirror and used as the driving current of the VCSEL laser. That is, the driving current of the VCSEL laser is determined by the reference current provided by the constant current source. The reference current provided by the constant current source is a constant current and is not affected by the PVT change. That is, the driving current of the VCSEL laser will not deviate under the PVT change, avoiding the change of laser output power of the VCSEL laser and ensuring system stability. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0027] Figure 1 This is a driving circuit diagram of a VCSEL laser disclosed in this utility model;

[0028] Figure 2 This is a driving circuit diagram for another VCSEL laser disclosed in this utility model;

[0029] Figure 3This is a circuit diagram of a voltage buffer disclosed in this utility model;

[0030] Figure 4 This is a schematic diagram of a pre-drive circuit disclosed in this utility model;

[0031] Figure 5 This is a simplified circuit diagram of a VCSEL in different states disclosed in this utility model;

[0032] Figure 6 This is a schematic diagram of a driving circuit for a conventional VCSEL laser disclosed in this utility model. Detailed Implementation

[0033] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0034] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0036] A vertical-cavity surface-emitting laser (VCSEL) is a type of semiconductor laser in which the laser emission direction is perpendicular to the chip surface. VCSEL lasers are widely used in data communication, sensing, and consumer electronics due to their advantages such as low power consumption, high speed, and low manufacturing cost. In existing VCSEL laser driving circuits, the VCSEL laser is connected to an NMOS transistor, and the driving current of the VCSEL laser is typically adjusted by directly controlling the voltage / current at the source or drain of the NMOS transistor.

[0037] like Figure 6 As shown, the anode of the VCSEL laser is connected to a high-voltage power supply, which includes a charge pump and a high-voltage power clamp circuit. The cathode of the VCSEL laser is connected to the drain of an NMOS transistor (NM0), the source of the NMOS transistor (NM0) is grounded, and the gate of the NMOS transistor (NM0) is connected to a pulse generation circuit. The pulse generation circuit controls the drain voltage of the NMOS transistor (NM0) to adjust the drive current of the VCSEL laser, thereby driving the VCSEL laser. However, under different process variations, the turn-on resistance of the NMOS transistor varies, resulting in different drive currents for the VCSEL. Furthermore, fluctuations in the voltage supplied by the high-voltage power supply cause changes in the drive current of the VCSEL. Additionally, changes in the operating temperature of the NMOS transistor cause variations in the current flowing through it, meaning the drive current of the VCSEL also changes. In other words, when the driving circuit experiences changes in process, voltage fluctuations, and operating temperature (PVT variations), the driving current of the VCSEL laser is prone to shift, leading to changes in the laser output power and affecting system stability. Therefore, this invention discloses a driving circuit for a VCSEL laser that prevents the driving current from shifting under PVT variations, thus avoiding changes in the laser output power. Figure 1 As shown, the specific circuit is as follows:

[0038] In this invention, the driving circuit of the VCSEL laser includes: a pulse generation circuit 100 and a first NMOS transistor NM1; it also includes: a constant current source I, a second NMOS transistor NM2, and a switching module 200. The switching module 200 includes an input terminal, an output terminal, a power supply terminal, and a ground terminal, and is used to connect the output terminal to its power supply terminal or ground terminal according to the signal received at the input terminal; that is, the switching module can switch the output terminal to be connected to the power supply terminal, or switch the output terminal to be connected to the ground terminal.

[0039] The constant current source I is connected between the first power supply VDD1 and the drain of the second NMOS transistor NM2. This constant current source I can be understood as a reference branch, and can be a constant reference current IB generated by a bandgap reference source, independent of temperature, power supply voltage, and process variations. The source of the second NMOS transistor NM2 is grounded, and its gate is connected to its drain.

[0040] The drain of the first NMOS transistor NM1 is connected to the cathode of the VCSEL laser, and the source of the first NMOS transistor NM1 is connected to ground. The anode of the VCSEL laser is connected to the second power supply VDD2. The voltage of the second power supply VDD2 is greater than or equal to the voltage of the first power supply VDD1 to ensure that the anode voltage of the VCSEL laser can be greater than the cathode voltage of the VCSEL laser to turn on the VCSEL laser. For example, the first power supply VDD1 is 3.3V, and the second power supply VDD2 can be determined according to actual needs, and can be 3.3V or 10V, or greater.

[0041] The pulse generation circuit 100 is connected to the input terminal of the switching module 200, and the output terminal of the switching module 200 is connected to the gate of the first NMOS transistor NM1. The power supply terminal of the switching module 200 is connected to the gate of the second NMOS transistor NM2, and the ground terminal of the switching module 200 is connected to ground. When the output terminal of the switching module 200 is connected to the power supply terminal, the gate of the first NMOS transistor NM1 is connected to the gate of the second NMOS transistor NM2. At this time, the first NMOS transistor NM1 and the second NMOS transistor NM2 form a current mirror, i.e., a mirror branch. The current mirror copies the reference current IB on the drain of the second NMOS transistor to the drain of the first NMOS transistor as the driving current ID of the VCSEL laser. At this time, the driving current ID of the VCSEL laser is determined by the reference current IB, and the reference current IB provided by the constant current source I is constant. Therefore, the driving current ID of the VCSEL laser is constant and is not affected by changes in the supply voltage of the second power supply, the temperature changes of the NMOS transistor, or process fluctuations. That is, the driving current ID of the VCSEL laser is independent of PVT changes. The current mirror structure is used to generate the driving current ID of the VCSEL laser, which effectively resists changes in process (P), supply voltage (V) and temperature (T), achieves high PVT robustness, and provides a precise and stable driving current for the VCSEL laser, thus achieving the goal of stable driving of the VCSEL.

[0042] As can be seen, the driving circuit of the VCSEL laser in this invention includes: a pulse generation circuit and a first NMOS transistor; it also includes: a constant current source, a second NMOS transistor, and a switching module; the switching module includes an input terminal, an output terminal, a power supply terminal, and a ground terminal, used to connect the output terminal to its power supply terminal or ground terminal according to the signal received at the input terminal; the constant current source is connected between the first power supply and the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, and the gate of the second NMOS transistor is connected to the drain; the drain of the first NMOS transistor is connected to the cathode of the VCSEL laser, and the source of the first NMOS transistor is connected to ground; the anode of the VCSEL laser is connected to the second power supply, and the voltage of the second power supply is greater than or equal to the voltage of the first power supply; the pulse generation circuit is connected to the input terminal of the switching module, and the output terminal of the switching module is connected to the gate of the first NMOS transistor; the power supply terminal of the switching module is connected to the gate of the second NMOS transistor, and the ground terminal of the switching module is connected to ground.

[0043] When the output of the switching module is connected to its power supply, the first NMOS transistor and the second NMOS transistor form a current mirror. The cathode of the VCSEL laser is connected to the drain of the first NMOS transistor. The reference current provided by the constant current source on the drain of the second NMOS transistor is copied into the driving current of the VCSEL laser through the current mirror. That is, the driving current of the VCSEL laser is determined by the reference current provided by the constant current source. The reference current provided by the constant current source is a constant current and is not affected by the PVT change. That is, the driving current of the VCSEL laser will not deviate under the PVT change, avoiding the change of laser output power of the VCSEL laser and ensuring system stability.

[0044] Furthermore, in this invention, the pulse generating circuit 100 is used to control the switching module 200. The output of the switching module 200 controls the first NMOS transistor NM1 to close or open, thereby controlling the on / off state of the VCSEL laser. That is, the pulse generating circuit 100 can send a pulse signal to the switching module 200, controlling the output terminal of the switching module 200 to connect to the power supply terminal, or controlling the output terminal of the switching module 200 to connect to the ground terminal.

[0045] like Figure 5As shown, when the output terminal of the pulse generation circuit 100 controls the switch module 200 to ground, the gate of the first NMOS transistor NM1 is grounded, and the first NMOS transistor NM1 is turned off, thereby controlling the VCSEL laser to turn off, and the VCSEL is in the off state. When the output terminal of the pulse generation circuit 100 controls the switch module 200 to power supply, the gate of the first NMOS transistor NM1 is connected to the gate of the second NMOS transistor NM2, the gate voltage of the second NMOS transistor NM2 is transmitted to the gate of the first NMOS transistor NM1, the first NMOS transistor NM1 is closed, thereby controlling the VCSEL laser to conduct, and the VCSEL laser is in the on state; at this time, the first NMOS transistor NM1 and the second NMOS transistor NM2 form a current mirror, and the reference current IB passing through the first NMOS transistor NM1 is proportional to the driving current ID of the VCSEL laser passing through the second NMOS transistor NM2, that is... .

[0046] As can be seen, the pulse generation circuit 100 controls the opening and closing of the gate voltage of the current mirror formed by the first NMOS transistor NM1 and the second NMOS transistor NM2 through the control switching module 200, thereby turning the VCSEL laser on or off. The switching state of the VCSEL laser is controlled by the gate and does not directly affect the reference current IB in the mirror branch, that is, it does not affect the driving current ID of the VCSEL laser, thus avoiding current disturbances caused by switching. The switching control of the VCSEL laser only affects the current path connectivity and does not interfere with the reference current IB, so that the system is free of glitches and jitter when turning the VCSEL laser on / off, achieving low-noise switching control of the VCSEL laser.

[0047] Furthermore, in this invention, when the pulse generation circuit 100 outputs a low level, the output terminal of the switching module 200 is connected to the ground terminal, the switch module 200 outputs a low level, the gate of the first NMOS transistor NM1 is at a low level, the first NMOS transistor NM1 is turned off, and the VCSEL laser is turned off; when the pulse generation circuit 100 outputs a high level, the output terminal of the switching module 200 is connected to the power supply terminal, the switch module 200 outputs a high level, the gate of the first NMOS transistor NM1 is at a high level, the first NMOS transistor NM1 is closed, and the VCSEL laser is turned on. That is, when the VCSEL laser needs to be turned on, the pulse generation circuit 100 outputs a high level, and when the VCSEL laser needs to be turned off, the pulse generation circuit 100 outputs a low level.

[0048] As can be seen, in this utility model, the switch module 200 controls NM1, thereby realizing the switching control of the VCSEL laser. The pulse generation circuit 100 controls the grid connection state of the current mirror by controlling the switch module 200, thereby realizing the switching of the VCSEL laser without changing the driving current of the VCSEL laser. It can maintain the accuracy and stability of the driving current when the VCSEL laser is turned on or off.

[0049] Furthermore, the drive current ID of the VCSEL laser is proportional to the reference current IB provided by the constant current source I. Because the drive current ID of the VCSEL laser needs to be very large, in this drive circuit, it can be set that the aspect ratio of the first NMOS transistor NM1 is 50-100 times that of the second NMOS transistor NM2; the first NMOS transistor NM1 is the mirror transistor in the current mirror, and the second NMOS transistor NM2 is the reference transistor in the current mirror. At this time, the corresponding scaling factor N is 50-100 times, that is, the drive current ID of the VCSEL laser is amplified to 50-100 times the reference current IB.

[0050] Furthermore, the following will combine Figure 2 The driving circuit of the VCSEL laser in this utility model is described as follows: Figure 2 As shown:

[0051] In this invention, the switching module includes a first inverter and a second inverter connected together. The first inverter and the second inverter can be CMOS inverters. The first inverter includes a PMOS transistor SP1 and an NMOS transistor SN1. The source of PMOS transistor SP1 serves as the power supply terminal of the first inverter, and the source of NMOS transistor SN1 serves as the ground terminal of the first inverter. The gates of PMOS transistor SP1 and NMOS transistor SN1 are shorted to serve as the input terminal of the first inverter, and the drains of PMOS transistor SP1 and NMOS transistor SN1 are shorted to serve as the output terminal of the first inverter. The corresponding second inverter includes a PMOS transistor SP2 and an NMOS transistor SN2. The source of PMOS transistor SP2 serves as the power supply terminal of the second inverter, and the source of NMOS transistor SN2 serves as the ground terminal of the second inverter. The gates of PMOS transistor SP2 and NMOS transistor SN2 are shorted to serve as the input terminal of the second inverter, and the drains of PMOS transistor SP2 and NMOS transistor SN2 are shorted to serve as the output terminal of the second inverter.

[0052] In this circuit, the power supply terminals of both the first and second inverters are connected to the gate of the second NMOS transistor NM2, and the ground terminals of both inverters are grounded. The input terminal of the first inverter is connected to the pulse generation circuit 100, and the output terminal of the second inverter is connected to the gate of the first NMOS transistor NM1. It can be understood that when the pulse generation circuit 100 outputs a high-level signal, the PMOS transistor SP1 in the first inverter is off, and the NMOS transistor SN1 is closed, meaning the first inverter outputs a low-level signal. Conversely, when the pulse generation circuit 100 outputs a low-level signal, the PMOS transistor in the first inverter is closed, and the NMOS transistor SN1 is off, meaning the first inverter outputs a high-level signal, and the PMOS transistor SP1 in the second inverter is off, and the NMOS transistor SN1 is closed, meaning the second inverter outputs a low-level signal, and the first NMOS transistor NM1 is off.

[0053] Furthermore, in this invention, the size of the second inverter is greater than or equal to that of the first inverter. It can be understood that when the size of the second inverter is greater than that of the first inverter, the strong driving capability of the larger second inverter can reduce signal delay and enable the rapid switching of the first NMOS transistor NM1 to achieve rapid switching of the VCSEL laser. The smaller first inverter can reduce power consumption and improve the noise immunity of the circuit.

[0054] Furthermore, in this invention, the driving circuit of the VCSEL laser also includes a pre-drive circuit 300, which is connected between the pulse generation circuit 100 and the input terminal of the switching module 200. It is understood that the pre-drive circuit 300 amplifies the current driving capability of the pulse signal output by the pulse generation circuit 100 to meet the driving requirements of the subsequent switching module 200. The pre-drive circuit 300 may include multiple inverters connected in series, such as... Figure 4 As shown, the current driving capability of the pulse signal can be amplified by 4 times, 16 times, or N times through multiple inverters.

[0055] Furthermore, in this invention, because the size of the first NMOS transistor NM1 is relatively large, the sizes of the corresponding PMOS transistors SP1 and SN1 in the first inverter, and the sizes of the PMOS transistors SP2 and SN2 in the second inverter are also relatively large. The gate voltage terminals (VG terminals) of PMOS transistors SP1 and SP2 have large parasitic capacitances. To quickly pull the sources of PMOS transistors SP1 and SP2 up to the gate voltage of the second NMOS transistor NM2, a voltage buffer is needed. Specifically, in this invention, the driving circuit also includes a voltage buffer 400, which is connected between the gate of the second NMOS transistor NM2 and the power supply terminal of the switching module 200. This voltage buffer 400 can be an operational amplifier, such as... Figure 3 As shown, the non-inverting input of the operational amplifier is connected to the gate of the second NMOS transistor NM2, the inverting input is connected to the output, and the output is connected to the power supply of the switching module 200. Since the inverting input is directly connected to the output, the operational amplifier gain is 1, and the input voltage is approximately equal to the output voltage. The input voltage of the voltage buffer 400 is approximately equal to the output voltage, and this input voltage is the gate voltage of the second NMOS transistor NM2, meaning the gate voltage of NM2 is approximately equal to the power supply voltage of the switching module 200. This prevents voltage attenuation, enhances current drive capability, and ensures sufficient drive capability for the first NMOS transistor NM1 during VCSEL laser operation, enabling rapid switching of the first NMOS transistor NM1, i.e., achieving rapid switching of the VCSEL laser. In addition to enhancing the driving capability, the voltage buffer 400 can also achieve signal isolation, isolating the gate of the second NMOS transistor NM2 from the power supply terminal of the switching module 200, and avoiding parasitic coupling or interference to the second NMOS transistor NM2 and the constant current source I due to the switching of the VCSEL laser.

[0056] Furthermore, in this invention, the driving circuit of the VCSEL laser also includes a capacitor C1, which is connected between the power supply terminal and ground of the switching module 200. This capacitor C1 is used to provide a large current during switching of the switching module, further improving the current driving capability and causing the gate voltage of NM1 to rise rapidly to the gate voltage of NM2.

[0057] This invention also provides a DTOF (Direct Time-of-Flight) receiver chip, including the driving circuit of the VCSEL laser described above. When performing distance measurement, the DTOF receiver chip uses the aforementioned VCSEL laser driving circuit, ensuring that the driving current of the VCSEL laser does not shift when the PVT changes, thus preventing changes in laser output power and ensuring the accuracy of distance measurement.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A driving circuit for a VCSEL laser, characterized in that, Includes a pulse generation circuit and a first NMOS transistor; It also includes: a constant current source, a second NMOS transistor, and a switching module; The switching module includes an input terminal, an output terminal, a power supply terminal, and a ground terminal, and is used to connect the output terminal to its power supply terminal or ground terminal according to the signal received at the input terminal. The constant current source is connected between the first power supply and the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, and the gate and drain of the second NMOS transistor are connected. The drain of the first NMOS transistor is connected to the cathode of the VCSEL laser, and the source of the first NMOS transistor is connected to ground; The anode of the VCSEL laser is connected to a second power supply, the voltage of which is greater than or equal to the voltage of the first power supply. The pulse generation circuit is connected to the input terminal of the switching module, and the output terminal of the switching module is connected to the gate of the first NMOS transistor. The power supply terminal of the switching module is connected to the gate of the second NMOS transistor, and the ground terminal of the switching module is connected to ground.

2. The driving circuit according to claim 1, characterized in that, The pulse generation circuit is used to control the switching module. The output of the switching module controls the first NMOS transistor to close or open, thereby controlling the on / off state of the VCSEL laser.

3. The driving circuit according to claim 1, characterized in that, When the pulse generation circuit outputs a low level, the switching module outputs a low level, the first NMOS transistor is turned off, and the VCSEL laser is turned off. When the pulse generation circuit outputs a high level, the switching module outputs a high level, the first NMOS transistor closes, and the VCSEL laser is turned on.

4. The driving circuit according to claim 3, characterized in that, The aspect ratio of the first NMOS transistor is 50-100 times that of the second NMOS transistor.

5. The driving circuit according to claim 1, characterized in that, The switching module includes a first inverter and a second inverter connected together. The power supply terminals of the first inverter and the second inverter are both connected to the gate of the second NMOS transistor. The ground terminals of the first inverter and the second inverter are both grounded. The input terminal of the first inverter is connected to the pulse generation circuit, and the output terminal of the second inverter is connected to the gate of the first NMOS transistor.

6. The driving circuit according to claim 5, characterized in that, The size of the second inverter is greater than or equal to that of the first inverter.

7. The driving circuit according to claim 1, characterized in that, The driving circuit further includes a pre-driving circuit, which is connected between the pulse generation circuit and the input terminal of the switching module.

8. The driving circuit according to claim 1, characterized in that, The driving circuit also includes a voltage buffer, which is connected between the gate of the second NMOS transistor and the power supply terminal of the switching module.

9. The driving circuit according to claim 1, characterized in that, The driving circuit also includes a capacitor connected between the power supply terminal and ground of the switching module.

10. A DTOF receiver chip, characterized in that, The driving circuit includes the VCSEL laser as described in any one of claims 1 to 9.

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