CN114076926A

CN114076926A - Driving device and method for laser radar light-emitting device and laser radar

Info

Publication number: CN114076926A
Application number: CN202010807238.0A
Authority: CN
Inventors: 尹辉; 朱雪洲; 向少卿
Original assignee: Hesai Technology Co Ltd
Current assignee: Hesai Technology Co Ltd
Priority date: 2020-08-12
Filing date: 2020-08-12
Publication date: 2022-02-22

Abstract

The invention provides a driving device and a method for a laser radar light-emitting device and a laser radar comprising the driving device. The driving device includes: the input end of the inverting module is connected with the pulse voltage signal and an adjustable level and outputs a first intermediate level signal, and the first intermediate level signal and the pulse voltage signal are inverted; an isolation capacitor that receives the first intermediate level signal and outputs a second intermediate level signal; and the driving module receives the second intermediate level signal and provides a driving current to the light-emitting device to drive the light-emitting device to emit light, wherein the driving current is adjusted according to the adjustable level. The scheme of the invention can realize direct control of the driving current of the light-emitting device for the laser radar, and has the advantages of relatively simple circuit design, short current transmission path and high response speed.

Description

Driving device and method for laser radar light-emitting device and laser radar

Technical Field

The present invention relates to the field of laser radars, and more particularly, to a driving apparatus for a laser radar light emitting device, a driving method, and a laser radar including the driving apparatus.

Background

With the rapid development of artificial intelligence technology, application scenarios such as automatic driving, face recognition, 3D photographing and the like are gradually mature. Lidar, as an important stereo imaging sensing device, is a basic condition for landing of these applications. Fig. 1 shows a schematic diagram of the operating principle of an exemplary lidar 100. As shown in fig. 1, the lidar 100 is, for example, a 16-line lidar, and may emit 16 lines of laser beams L1, L2, …, L15, and L16 along the vertical direction in fig. 1, where each line of laser beams corresponds to one channel of the

lidar

100, and 16 channels are used for detecting the surrounding environment. During the detection, the laser radar 100 can rotate along the vertical axis thereof, and during the rotation, a light emitting device (not shown in fig. 1) inside the laser radar 100 sequentially emits laser beams L1, L2, …, L15, and L16 through respective channels according to a certain time interval (e.g., 1 microsecond) and detects, thereby completing a line scan on the vertical field of view. Thereafter, the laser radar 100 performs the next line scan of the vertical field of view at an angle (e.g., 0.1 degree or 0.2 degree) in the horizontal field of view direction. The receiver of the lidar 100 may receive echoes reflected from the laser beams transmitted by the respective channels after encountering an obstacle, and detect the distance and orientation of the obstacle (or a point on the obstacle) by calculating the round-trip flight time of the laser beams, thereby forming point cloud data. The point cloud data forming the obstacle is detected a plurality of times throughout the entire rotation of the laser radar 100, thereby sensing the condition of the surrounding environment.

For example, a frame of point cloud data can be formed by scanning and detecting a 16-channel laser radar 100 shown in fig. 1 by rotating it one turn (360 degrees). The laser radar 100 continuously performs the rotation scanning detection, so that the multi-frame point cloud data can be formed. Note that the lidar 100 in fig. 1 is only one example for explaining the operating principle of the lidar, and the laser beams are not necessarily uniformly distributed in the vertical direction.

It can be seen from the above working principle of the laser radar that the light emitting device of the laser radar is an important component of the whole laser radar, and it is necessary to achieve the consistency and stability of the light emitting energy among different temperatures, different batches and different channels. The design of a driving circuit of the existing laser radar light-emitting device is a difficult problem for realizing a laser radar circuit.

In the practical application process, because the distance and the reflectivity of the laser radar detection target are constantly changed, the light intensity of the light-emitting device is required to be correspondingly and rapidly adjusted, and therefore higher requirements are put forward for a driving circuit of the light-emitting device.

Fig. 2 shows a schematic diagram of a prior art drive circuit for a lidar light-emitting device. As shown in fig. 2, the driving circuit includes devices M0 to M5, wherein M0 to M3 are high voltage NMOS devices, and M4 to M5 are high voltage PMOS devices. In the drive circuit shown in fig. 2, M0 to M3 form a typical NMOS current mirror circuit, and M4 to M5 form a typical PMOS current mirror circuit. By controlling the device dimensions (e.g., width to length ratio) of M0 to M5, a current ratio of 1: K1: K2: K3: KN can be easily achieved.

As shown in fig. 2, assuming that the input current source of the driving circuit is I1, the maximum value of the output current (i.e., the input current of the light emitting device D1) is KN × I1 × (K1+ K2+ K3)/K3, and the minimum value is KN × I1/K3. Wherein the resistor R2 is used for controlling the grid source voltage of the PMOS tubes M4 and M5, and S1 and S1N; s2 and S2N; s3 and S3N are three pairs of exclusive switches. Here, the exclusive switch means that one switch is turned on and the other switch is turned off in the same state.

In the prior art solution as shown in fig. 2, by controlling the switches S1 and S1N; s2 and S2N; the states of S3 and S3N adjust the output current. Because the current mirror circuit needs to carry out current conversion step by step, the response speed is low, and the nanosecond-level current accurate control is difficult to realize; moreover, the circuit is relatively complex, the ratio of parasitic capacitance to parasitic resistance in the node is large, and the interference to the circuit is also large.

Disclosure of Invention

In view of the above problems, the present invention provides a driving apparatus for a lidar light-emitting device, a driving method, and a lidar including the driving apparatus, in which a current mirror structure is removed.

According to an aspect of the present invention, there is provided a driving apparatus for a laser radar light emitting apparatus. The driving device includes: the input end of the inverting module is connected with the pulse voltage signal and an adjustable level and outputs a first intermediate level signal, and the first intermediate level signal and the pulse voltage signal are inverted; an isolation capacitor that receives the first intermediate level signal and outputs a second intermediate level signal; and the driving module receives the second intermediate level signal and provides a driving current to the light-emitting device to drive the light-emitting device to emit light, wherein the driving current is adjusted according to the adjustable level.

In one embodiment, the inverter module includes a first transistor and a second transistor, and wherein first poles of the first transistor and the second transistor are both connected to the input pulsed voltage signal, a second pole of the first transistor is connected to the adjustable level, a third pole of the first transistor is connected to a third pole of the second transistor, and the second pole of the second transistor is connected to ground.

In one embodiment, the driving module includes a third transistor, and wherein a first pole of the third transistor is connected to the second intermediate level signal, a second pole of the third transistor is connected to a power supply voltage of the driving module, and a third pole of the third transistor is connected to a light emitting device of the lidar to supply the driving current to the light emitting device.

In one embodiment, the first transistor is a PNP transistor or a PMOS transistor, and the second transistor is an NPN transistor or an NMOS transistor.

In one embodiment, the third transistor is a PNP transistor or a PMOS transistor.

In one embodiment, the high potential of the pulse voltage signal is a first potential, the low potential is a second potential, and the high potential of the first intermediate level signal output by the inverting module is determined by the adjustable level, and the low potential is the second potential.

In one embodiment, the input terminal of the isolation capacitor is connected to the third pole of the first transistor and the third pole of the second transistor to receive the first intermediate level signal, and the output terminal of the isolation capacitor outputs the second intermediate level signal to the driving module, where the second intermediate level signal is in phase with the first intermediate level signal and a high potential of the second intermediate level signal is a power supply voltage of the driving module, and a low potential is a difference between the power supply voltage of the driving module and the adjustable level.

In one embodiment, the driving module further comprises a first resistor and at least one diode connected in parallel between the output terminal of the isolation capacitor and the supply voltage of the driving module.

In one embodiment, the at least one diode includes a first diode, and a cathode of the first diode is coupled to the supply voltage of the driver module, and an anode of the first diode is coupled to the second intermediate level signal to limit the second intermediate level signal.

In one embodiment, the at least one diode includes a second diode, and an anode of the second diode is coupled to the power supply voltage of the driving module, and a cathode of the second diode is coupled to the second intermediate level signal for charging the second intermediate level signal when the third transistor is turned off.

In one embodiment, the maximum value of the driving current is determined based on a power voltage of the driving module, intrinsic parameters of the third transistor, parasitic resistance of the light emitting device, and the second intermediate level signal.

In one embodiment, the second intermediate level signal is determined by a power voltage of the driving module and the adjustable level.

In one embodiment, the driving device further comprises: a stabilizing transformation module configured to receive an input of an adjustable voltage source and output the adjustable level such that when the adjustable voltage source is adjusted, the adjustable level is stably adjusted with the adjustable voltage source.

In one embodiment, the stabilizing transformation module includes a low dropout linear regulator (LDO).

In one embodiment, the pulsed voltage signal is a short pulse signal.

According to another aspect of the present invention, there is provided a lidar comprising: the drive device as described above; and a light emitting device of the lidar, the light emitting device including a parasitic resistor, a parasitic inductance, and a light emitting device connected in series to a third pole of the third transistor, and the parasitic resistor and the parasitic inductance connected in series are connected to a high-side of the light emitting device, and a low-side of the light emitting device is grounded.

In one embodiment, the light emitting device comprises an Edge Emitting Laser (EEL) or a Vertical Cavity Surface Emitting Laser (VCSEL).

According to still another aspect of the present invention, there is provided a method for driving a lidar light-emitting device, the method employing the lidar as described above. The method comprises the following steps: receiving an input pulse voltage signal and an adjustable level and outputting a first intermediate level signal by using an inverting module, wherein the first intermediate level signal is inverted with respect to the pulse voltage signal; receiving the first intermediate level signal by using an isolation capacitor and outputting a second intermediate level signal to a driving module; and providing a driving current to the light-emitting device by using the driving module to drive the light-emitting device to emit light, wherein the driving current is adjusted by adjusting the adjustable level.

The scheme of the invention simplifies the circuit structure of the driving device of the light-emitting device of the laser radar, reduces the problems of various parasitic resistances, parasitic capacitances and the like caused by the complicated circuit, and realizes the direct control of the driving current because the driving current can be adjusted without accumulating step by step, so that the adjusting speed is higher, and the nanosecond (ns) level control is easy to realize.

Drawings

FIG. 1 shows a schematic diagram of the working principle of an exemplary lidar;

FIG. 2 shows a schematic diagram of a prior art driving circuit for a lidar light-emitting device;

FIG. 3 shows a schematic diagram of a lidar in accordance with an embodiment of the invention;

fig. 4 shows a schematic view of a drive arrangement for the light emitting arrangement of the lidar shown in fig. 3;

fig. 5 shows a signal waveform diagram of a driving apparatus according to an embodiment of the present invention;

FIG. 6 shows a schematic view of an embodiment of the drive arrangement shown in FIG. 4;

fig. 7 shows a schematic structural diagram of a stabilized voltage transformation module that may be used in the driving apparatus according to the embodiment of the present invention; and

fig. 8 shows a schematic view of another embodiment of the drive device shown in fig. 4.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings in order to more clearly understand the objects, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are merely intended to illustrate the spirit of the technical solution of the present invention.

In the following description, for the purposes of illustrating various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details. In other instances, well-known devices, structures and techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Throughout the specification and claims, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be understood as an open, inclusive meaning, i.e., as being interpreted to mean "including, but not limited to," unless the context requires otherwise.

Reference throughout this specification to "one embodiment" or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise.

The invention is characterized in that the driving current output to the light-emitting device is controlled by adopting a direct control mode instead of a step-by-step current conversion mode aiming at the driving of the light-emitting device of the laser radar. Specifically, the driving device for the laser radar lighting device of the invention can input a low-voltage adjustable level (V2), and the output current of the driving device (namely the driving current of the lighting device) is adjusted by adjusting the adjustable level.

Fig. 3 shows a schematic structural diagram of a lidar 1 according to an embodiment of the invention. As shown in fig. 3, the laser radar 1 includes a light emitting device 20 and a driving device 10 for supplying a driving current Id to the light emitting device 20. The light emitting apparatus 20 includes a parasitic resistance 22, a parasitic inductance 24, and a light emitting device 26 connected in series, wherein the parasitic resistance 22 and the parasitic inductance 24 are connected in series on a power supply side (i.e., a high end side) of the light emitting device 26, and a low end side of the light emitting device 26 is Grounded (GND). Since the drive current Id of the drive apparatus 10 is injected from the power supply side of the light emitting device 26 to the light emitting device 26, the structure shown in fig. 2 may also be referred to as a high-side-driven lidar light emitting apparatus. It will be appreciated by those skilled in the art that only the light emitting means of the lidar 1 and its drive means parts are shown here for the sake of simplicity, while other parts of the lidar 1, such as the receiver etc., are omitted.

In some embodiments, the light emitting device 26 may be an Edge Emitting Laser (EEL) or a Vertical Cavity Surface Emitting Laser (VCSEL), or the like.

Fig. 4 shows a schematic diagram of a drive device 10 for the light-emitting device 20 of the lidar 1 shown in fig. 3. As shown in fig. 4, the driving apparatus 10 may include an inverting module 12 having an input terminal connected to the pulse voltage signal Vin and an adjustable level V2 and outputting a first intermediate level signal Vy. The inverting module 12 inverts the output first intermediate level signal Vy and the input pulse voltage signal Vin. That is: when the input pulse voltage signal Vin is at a high level, the output first intermediate level signal Vy is at a low level; when the input pulse voltage signal Vin is at a low level, the output first intermediate level signal Vy is at a high level.

Wherein the high level of the pulse voltage signal Vin and the high level of the first intermediate level signal Vy may not have the same value.

Preferably, according to the solution of the present embodiment, the high level of the first intermediate level signal Vy is determined by the adjustable level V2. For example, the high level of the pulse voltage signal Vin is the power supply voltage VDD of the signal generator, and the high level of the first intermediate level signal Vy has a value of the adjustable voltage V2.

More preferably, the low level of the pulse voltage signal Vin and the low level of the first intermediate level signal Vy are both 0V.

Fig. 5 shows a signal waveform diagram of a driving apparatus according to an embodiment of the present invention. As shown in fig. 5, with the inverting module 12, when the input signal Vin is at a low potential (e.g., 0V), the output signal Vy is at a high potential (e.g., an adjustable level V2); conversely, when the input signal Vin is at a high level (e.g., VDD), the output signal Vy is at a low level (e.g., 0V). It will be appreciated by those skilled in the art that the above-described high and low potential settings of the pulsed voltage signal Vin are merely exemplary, and the present invention is not limited to the specific settings described above, but that other high and low potential settings may be used.

In one embodiment, the pulse voltage signal Vin may be a short pulse signal, i.e. the duration of the high potential (Tpulse) is much shorter than the duration of the low potential. Specific embodiments of inversion module 12 are described in detail below in conjunction with fig. 6 and 8.

The driving apparatus 10 further includes an isolation capacitor 14, and the isolation capacitor 14 is configured to receive the first intermediate level signal Vy from the inverting module 12 and output a second intermediate level signal Vx. Wherein the second intermediate level signal Vx is in phase with the first intermediate level signal Vy, and a level value of the second intermediate level signal Vx depends on a level value of the first intermediate level signal Vy. But the two may differ in magnitude due to load effects. In one embodiment, as shown in fig. 5, when the first intermediate level signal Vy is at a high level and has a level value of the adjustable level V2, the output second intermediate level signal Vx is also at a high level and has a level value of the power supply voltage VDD1 of the driving module 16; on the contrary, when the first intermediate level signal Vy is at a low potential and has a level value of 0V, the second intermediate level signal Vx is also at a low potential and has a level value of VDD 1-V2.

The driving module 16 of the driving apparatus 10 receives the second intermediate level signal Vx and supplies a driving current Id to the light emitting apparatus 20 to cause the light emitting apparatus 20 to emit light. The magnitude of the drive current Id depends on the magnitude of the second intermediate level signal Vx. Therefore, with the hardware composition of the entire drive apparatus 10 fixed, the drive current Id can be adjusted by adjusting the adjustable level V2.

To achieve precise control of the adjustable level V2, in one embodiment, the driving apparatus 10 may further include a stabilizing transformation module 17 configured to receive a reference level VREF of the adjustable voltage source 18 and keep the adjustable level V2 of the output varying stably while the adjustable voltage source 18 is being adjusted. That is, the stabilizing transformation module 17 is used to implement the conversion from the level VREF to the level V2, where the transmission coefficient is K, K being V2/VREF. In this way, a steadily changing adjustable level V2 can be obtained by adjusting the adjustable voltage source 18. A specific embodiment of the stabilizing transformer module 17 will be described in detail below in conjunction with fig. 7.

In addition, the driving apparatus 10 may further include one or more power modules (not shown in the figure) to respectively provide the high level VDD of the pulse voltage signal Vin, the power voltage VDD1 of the driving module 16, and the power voltage VDD2 of the adjustable voltage source 18.

Fig. 6 shows a schematic view of an embodiment of the drive device 10 shown in fig. 4.

In the embodiment shown in fig. 6, inverting module 12 may include a first transistor 122 and a second transistor 124. First poles of the first transistor 122 and the second transistor 124 are both connected to the pulse voltage signal Vin, a third pole of the first transistor 122 is connected to a third pole of the second transistor 124 to output a first intermediate level signal Vy to the isolation capacitor 14, a second pole of the first transistor 122 is connected to the adjustable level V2, and a second pole of the second transistor 124 is connected to Ground (GND).

The driving module 16 may include a third transistor 162, wherein a first pole of the third transistor 162 receives the second intermediate level signal Vx from the isolation capacitor 14, a second pole of the third transistor 162 is connected to the power voltage VDD1 of the driving module 16, and a third pole of the third transistor 162 is connected to the light emitting device 20 of the laser radar 1 for supplying the driving current Id to the light emitting device 20.

An input terminal of the isolation capacitor 14 is connected to the third pole of the first transistor 122 and the third pole of the second transistor 124 to receive the first intermediate level signal Vy, and an output terminal of the isolation capacitor 14 outputs the second intermediate level signal Vx to the driving module 16. Here, for convenience of description, both ends of the isolation capacitor 14 are referred to as an input end and an output end from the viewpoint of a direction of influence of voltage in the circuit configuration, and in fact, both ends of the isolation capacitor 14 are not particularly distinguished in general.

With the driving apparatus 10 shown in fig. 6, the inverting module 12 continuously inputs the low adjustable level V2, when the input pulse voltage signal Vin is at a low level (e.g. 0V), the first transistor 122 is turned on, and the second transistor 124 is turned off, so that the first intermediate level signal Vy is at the adjustable level V2, the second intermediate level signal Vx is the power voltage VDD1 of the driving module 16, and the voltage difference between the two sides of the isolation capacitor 14 is VDD 1-V2; when the input pulse voltage signal Vin changes to the high potential VDD, the first transistor 122 is turned off, the second transistor 124 is turned on, the first intermediate level signal Vy and the second transistor 124 are grounded and are at 0V, the voltage on the two sides of the isolation capacitor 14 changes in an equal difference manner, and the second intermediate level signal Vx changes to VDD 1-V2. Therefore, by adjusting the adjustable level V2, a varying adjustment of the second intermediate level signal Vx can be achieved, which in turn affects the equivalent resistance Rdson of the third transistor 162 to achieve an adjustment of the drive current Id.

In the embodiment shown in fig. 6, the first transistor 122 may be a PMOS transistor (more specifically, it is a high voltage PMOS transistor), the second transistor 124 may be an NMOS transistor (more specifically, it is a high voltage NMOS transistor), and the first pole corresponds to the gate (G), the second pole corresponds to the source (S), and the third pole corresponds to the drain (D) in the specification.

Further, the third transistor 162 may be a PMOS transistor (more specifically, it is a high voltage PMOS transistor), and the first pole corresponds to the gate (G), the second pole corresponds to the source (S), and the third pole corresponds to the drain (D) in the specification.

Here, the MOS Transistor is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), the PMOS Transistor is a P-channel MOS Transistor, and the NMOS Transistor is an N-channel MOS Transistor.

Furthermore, in some embodiments, the driver module 16 may further include a first resistor 164 and at least one diode (diodes 166 and/or 168) connected in parallel between the output of the isolation capacitor 14 and the supply voltage (VDD1) of the driver module 16.

In one embodiment, the at least one diode includes a first diode 166, wherein a cathode of the first diode 166 is coupled to the supply voltage VDD1 of the driver module 16 and an anode of the first diode 166 is coupled to the second intermediate level signal Vx to limit the second intermediate level signal Vx. With this first diode 166, the level value of the second intermediate level signal Vx is limited to Vx < VDD1+ Vth1, where Vth1 is the on-voltage threshold of the first diode 166.

Alternatively or additionally, the at least one diode comprises a second diode 168, wherein the anode of the second diode 168 is connected to the supply voltage VDD1 of the driving module 16 and the cathode of the second diode 168 is connected to the second intermediate level signal Vx for charging the second intermediate level signal Vx when the third transistor 162 is turned off.

As shown in fig. 5, in the embodiment shown in fig. 4, the minimum value of the drive current Id is 0 and the maximum value of the drive current Id is Imax. In the embodiment according to the present invention, the maximum value Imax of the driving current Id is determined by the power supply voltage VDD1 of the driving module 16, the on-resistance Rdson of the driving module 16, and the parasitic resistance 22 of the light emitting device 20. For example, the maximum value Imax of the drive current Id can be expressed as the following formula (1):

Imax＝VDD1/(R1+Rdson)，(1)

where R1 is the resistance value of the parasitic resistor 22 of the light emitting device 20 and Rdson is the on-resistance of the driving module 16.

Further, the on-resistance Rdson of the driving module 16 is determined by the intrinsic parameter of the third transistor 162 and the second intermediate level signal Vx. For example, in the embodiment shown in fig. 6, the on-resistance Rdson of the driving module 16 can be expressed as the following formula (2):

where W is a channel width of the third transistor 162, L is a channel length of the third transistor 162, Vth is a turn-on threshold of the third transistor 162, which are intrinsic parameters of the third transistor 162, and k is a constant. Here, as one skilled in the art will appreciate, the constant k is a constant determined by the properties of the silicon-based device, which depends on the planckian constant.

Accordingly, in the embodiment as shown in fig. 6, the maximum value Imax of the driving current may be determined based on the power supply voltage VDD1 of the driving module 16, the intrinsic parameter of the third transistor 162, the parasitic resistance 22 of the light emitting device 20, and the second intermediate level Vx.

As mentioned above and as shown in fig. 5, the second intermediate level Vx is in turn determined by the supply voltage VDD1 of the driver module 16 and the adjustable level V2. That is, in the case where the hardware composition of the driving device 10 and the light emitting device 20 is not changed, the maximum value of the driving current Id may be different according to the inputted adjustable level V2.

In summary, with the driving device 10 according to the embodiment of the present invention, the short pulse current signal Id can be obtained as the driving current supplied to the light emitting device 20 by inputting the short pulse voltage signal Vin and the adjustable level V2, and the maximum value Imax of the output driving current Id can be conveniently adjusted by adjusting the level value of the input adjustable level V2.

Therefore, the stabilizing transformer module 17 for precisely adjusting the adjustable level V2 is very important for adjusting the magnitude of the driving current Id.

In one embodiment, the stabilizing transformation module 17 may include a low dropout linear regulator (LDO). The LDO may operate in a low voltage domain to output a low voltage domain control signal V2.

Fig. 7 shows a schematic structural diagram of a stabilizing transformer module 17 that may be used in the driving apparatus 10 according to an embodiment of the present invention.

As shown in fig. 7, the stabilizing transformer module 17 includes an error amplifier 172, a driver stage 174, an output stage 176, and a feedback loop 178. The error amplifier 172 is configured to perform error amplification on the input reference level VREF and the level Vfb obtained by the feedback loop 178, and finally obtain VREF equal to Vfb, thereby realizing an open-loop high gain of the system.

The driver stage 174 is used to drive an output stage 176 of the stabilizing transformer module 17. Since the output stage 176 is generally larger in device size, a dedicated driver stage 174 is provided for driving.

The output stage 176 is an output module of the stabilizing transformer module 17, and is used for outputting the target level V2.

Feedback loop 178 is used to sample output level V2 and feed the sampled signal back to error amplifier 172 to achieve a closed loop transmission coefficient K.

Fig. 8 shows a schematic view of a further embodiment of the drive device 10 shown in fig. 4.

In the embodiment shown in fig. 8, inverting module 12 may include a first transistor 122 'and a second transistor 124'. First poles of the first transistor 122 'and the second transistor 124' are connected to the pulse voltage signal Vin, a third pole of the first transistor 122 'is connected to a third pole of the second transistor 124' to output the first intermediate level signal Vy to the isolation capacitor 14, a second pole of the first transistor 122 'is connected to the adjustable level V2, and a second pole of the second transistor 124' is connected to the Ground (GND).

The driving module 16 may include a third transistor 162 ', wherein a first pole of the third transistor 162' receives the second intermediate level signal Vx from the isolation capacitor 14, a second pole of the third transistor 162 'is connected to the power voltage VDD1 of the driving module 16, and a third pole of the third transistor 162' is connected to the light emitting device 20 of the laser radar 1 for providing the driving current Id to the light emitting device 20.

The input terminal of the isolation capacitor 14 is connected to the third pole of the first transistor 122 'and the third pole of the second transistor 124' to receive the first intermediate level signal Vy, and the output terminal of the isolation capacitor 14 outputs the second intermediate level signal Vx to the driving module 16.

In the embodiment shown in fig. 8, the first transistor 122 'may be a PNP transistor, the second transistor 124' may be an NPN transistor, and the first pole corresponds to a base (B), the second pole corresponds to an emitter (E), and the third pole corresponds to a collector (C) in the specification.

In addition, the third transistor 162' may be a PNP transistor, and the first pole in the specification is a base (B), the second pole corresponds to an emitter (E), and the third pole corresponds to a collector (C).

Here, the PNP transistor is a PNP transistor and is a transistor formed by 2P-type semiconductors with 1N-type semiconductor sandwiched therebetween, and similarly, the NPN transistor is an NPN transistor and is a transistor formed by 2N-type semiconductors with 1P-type semiconductor sandwiched therebetween.

In the embodiment shown in fig. 6, the third transistor 162 is described as a PMOS transistor of the same type as the first transistor 122, and in the embodiment shown in fig. 8, the third transistor 162 'is described as a PNP transistor of the same type as the first transistor 122'. However, those skilled in the art will appreciate that the present invention is not limited thereto, and various transistors may be mixedly used. For example, in the embodiment shown in fig. 6, the first transistor 122 may be implemented as a PMOS transistor and the third transistor 162 may be implemented as a PNP transistor, or in the embodiment shown in fig. 8, the first transistor 122 'may be implemented as a PNP transistor and the third transistor 162' may be implemented as a PMOS transistor.

The technical scheme of the invention simplifies the circuit structure of the driving device of the light-emitting device of the laser radar, reduces the problems of various parasitic resistances, parasitic capacitances and the like caused by the complicated circuit, and realizes the direct control of the driving current because the driving current can be adjusted without accumulating step by step, so that the adjusting speed is higher, and the nanosecond (ns) level control is easy to realize.

Those skilled in the art will appreciate that the solution according to the inventive concept of the present invention can be easily implemented as a hardware circuit (such as FPGA or ASIC), a driving method, or a corresponding driver, depending on different application scenarios.

When the light emitting device 20 of the laser radar is driven by using the driving device 10 according to the present invention, if the light intensity of the echo received by the receiver (not shown) of the laser radar is too strong or too weak to detect an obstacle well, the controller (not shown) of the laser radar may automatically send a control signal to the driving device 10 according to the intensity of the echo to reduce or increase the driving current Id of the light emitting device 20, so as to reduce or increase the light intensity emitted by the light emitting device 20.

In one example, the driving apparatus 10 receives a control signal from the controller requesting to increase the light intensity of the light emitting apparatus 20, and the stabilizing transforming module 17 increases the voltage value of the outputted adjustable level V2 (for example, by increasing the reference level VREF of the adjustable voltage source 18) according to the control signal before the next pulse voltage signal Vin is inputted to the driving apparatus 10, and since the high level of the first intermediate level signal Vy corresponds to the adjustable level V2, the level value of the high level of Vy is increased at this time. And accordingly, the low level (VDD1-V2) of the second intermediate level signal Vx output from the isolation capacitor 14 decreases. According to the formula (2), when Vx decreases, the on-resistance Rdson of the drive module 16 decreases, and the maximum value Imax of the drive current Id increases (as shown in the above formula (1)).

In another example, the driving apparatus 10 receives a control signal from the controller requesting to decrease the light intensity of the light emitting apparatus 20, and the stabilizing transforming module 17 decreases the output adjustable level V2 (for example, by decreasing the reference level VREF of the adjustable voltage source 18) according to the control signal before the next pulse voltage signal Vin is inputted to the driving apparatus 10, thereby decreasing the level value of the high level of the first middle level signal Vy (V2). At this time, since the adjustable level V2 is lowered, the low level (VDD1-V2) of the second intermediate level signal Vx output by the isolation capacitor 14 is raised, the on-resistance Rdson of the driving module 16 is raised (as shown in the above equation (2)), and the maximum value Imax of the driving current Id is lowered (as shown in the above equation (1)).

In this way, the stabilizing transformer module 17 is controlled by the control signal to stably adjust the level value of the output variable level every time the light emitting device 20 of the laser radar emits light (for example, when the laser radar described above with reference to fig. 1 performs the next line scanning of the vertical field of view in the horizontal field of view direction), thereby stably adjusting the driving current Imax of the light emitting device 20.

Various aspects of embodiments according to the invention are described above with reference to the drawings. It is to be understood that the above description is intended to be exemplary only and that the present invention is not limited to the specific implementations described above and shown in the drawings. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A driving apparatus for a laser radar light emitting device, comprising:

-an inverting module, the input of which is connected to the pulsed voltage signal (Vin) and to an adjustable level (V2), and which outputs a first intermediate level signal (Vy), said first intermediate level signal (Vy) being inverted with respect to said pulsed voltage signal (Vin);

an isolation capacitor receiving the first intermediate level signal (Vy) and outputting a second intermediate level signal (Vx); and

a driving module receiving the second intermediate level signal (Vx) and providing a driving current to the light emitting device to drive the light emitting device to emit light,

wherein the drive current is adjusted according to the adjustable level (V2).

2. The driving apparatus of claim 1, wherein the inverting module comprises a first transistor and a second transistor, and wherein

First poles of the first transistor and the second transistor are connected with an input pulse voltage signal (Vin),

a second pole of the first transistor is connected to the adjustable level (V2),

a third pole of the first transistor is connected to a third pole of the second transistor, an

The second pole of the second transistor is grounded.

3. The driving apparatus of claim 1, wherein the driving module comprises a third transistor, and wherein

A first pole of the third transistor is connected to the second intermediate level signal (Vx), a second pole of the third transistor is connected to a power supply voltage (VDD1) of the driving module, and a third pole of the third transistor is connected to a light emitting device of the laser radar to supply the driving current to the light emitting device.

4. The driving device according to claim 1, wherein the first transistor is a PNP transistor or a PMOS transistor, and the second transistor is an NPN transistor or an NMOS transistor.

5. The driving apparatus according to claim 4, wherein the third transistor is a PNP transistor or a PMOS transistor.

6. The driving apparatus as claimed in claim 1, wherein the high potential of the pulse voltage signal is a first potential (VDD), the low potential is a second potential, and the high potential of the first intermediate level signal (Vy) output by the inverting module is determined by the adjustable level (V2), and the low potential is the second potential.

7. The driving apparatus of claim 1, wherein an input of the isolation capacitor is connected to a third pole of the first transistor and a third pole of the second transistor to receive the first intermediate level signal (Vy), an output of the isolation capacitor outputs the second intermediate level signal (Vx) to the driving module, wherein the second intermediate level signal (Vx) is in phase with the first intermediate level signal (Vy) and a high potential of the second intermediate level signal (Vx) is a supply voltage (VDD1) of the driving module, a low potential is a difference between the supply voltage (VDD1) of the driving module and the adjustable level (V2).

8. The driving apparatus of claim 1, wherein the driving module further comprises a first resistor and at least one diode connected in parallel between an output terminal of the isolation capacitor and a supply voltage (VDD1) of the driving module.

9. The driving arrangement of claim 8, wherein the at least one diode comprises a first diode (166) and a cathode of the first diode is connected to a supply voltage (VDD1) of the driving module and an anode of the first diode is connected to the second intermediate level signal to limit the second intermediate level signal.

10. A driving arrangement as claimed in claim 8 or 9, wherein the at least one diode comprises a second diode (168), and the anode of the second diode is connected to the supply voltage (VDD1) of the driving module, and the cathode of the second diode is connected to the second intermediate level signal for charging the second intermediate level signal when the third transistor is switched off.

11. The driving apparatus of claim 1, wherein the maximum value of the driving current is determined based on a power supply voltage (VDD1) of the driving module, an intrinsic parameter of the third transistor, a parasitic resistance of the light emitting apparatus, and the second intermediate level signal (Vx).

12. The driving arrangement according to claim 11, wherein the second intermediate level signal (Vx) is determined by a supply voltage (VDD1) of the driving module and the adjustable level (V2).

13. The drive device according to claim 1, further comprising:

a stabilizing transformation module configured to receive an input of an adjustable voltage source and output the adjustable level (V2) such that when the adjustable voltage source is adjusted, the adjustable level is stably adjusted with the adjustable voltage source.

14. The driving apparatus of claim 13, wherein the stabilizing transformation module comprises a low dropout linear regulator (LDO).

15. The driving device according to claim 1, wherein the pulse voltage signal is a short pulse signal.

16. A lidar comprising:

a drive arrangement according to any one of claims 1 to 15; and

the light emitting apparatus of the lidar includes a parasitic resistor, a parasitic inductor, and a light emitting device connected in series to a third pole of the third transistor, and the parasitic resistor and the parasitic inductor connected in series are connected to a high end side of the light emitting device, and a low end side of the light emitting device is grounded.

17. The lidar of claim 16, wherein the light emitting device comprises an edge-emitting laser (EEL) or a vertical cavity surface-emitting laser (VCSEL).

18. A method for driving a lidar light-emitting device, the method employing the lidar of claim 16 or 17, the method comprising:

receiving an input pulsed voltage signal (Vin) and an adjustable level (V2) with an inverting module and outputting a first intermediate level signal (Vy), the first intermediate level signal (Vy) being inverted from the pulsed voltage signal (Vin);

receiving the first intermediate level signal (Vy) with an isolation capacitor and outputting a second intermediate level signal (Vx) to a drive module; and

providing a driving current to the light emitting device by using the driving module to drive the light emitting device to emit light,

wherein the drive current is adjusted by adjusting the adjustable level (V2).

19. The method of claim 18, wherein the high potential of the pulsed voltage signal is a first potential (VDD), the low potential is a second potential, and the high potential of the first intermediate level signal (Vy) output by the inverting module is determined by the adjustable level (V2), the low potential is the second potential.