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

Abstract

The present invention provides a driving device and method for a laser radar light-emitting device, as well as a laser radar including the driving device. The driving device includes: a voltage regulation module configured to receive an input pulse voltage signal and output an intermediate voltage level, wherein the equivalent resistance of the voltage regulation module can be adjusted to change the output intermediate voltage level; and a driving module that receives the intermediate voltage level and provides a driving current to the light-emitting device to drive the light-emitting device to emit light, wherein the driving current is at least partially dependent on the intermediate voltage level. The solution of the present invention can directly control the driving current of the light-emitting device used in the laser radar, and has a relatively simple circuit design, a short current transmission path, and a fast response speed.

Description

Technical Field

[0001] The present invention relates to the field of laser radar, and more specifically, to a driving device and a driving method for a laser radar light-emitting device, and a laser radar including the driving device. Background Art

[0002] With the rapid development of artificial intelligence (AI), applications such as autonomous driving, facial recognition, and 3D photography are gradually maturing. LiDAR, as an important stereoscopic imaging sensor, has become a fundamental requirement for the implementation of these applications. Figure 1 FIG. 1 is a schematic diagram showing the working principle of an exemplary laser radar 100. Figure 1 As shown in FIG, the laser radar 100 is, for example, a 16-line laser radar, which can be along Figure 1 16 laser beams, L1, L2, ..., L15, L16, are emitted in the vertical direction of the laser radar 100. Each laser beam corresponds to a channel of the laser radar 100, with a total of 16 channels for detecting the surrounding environment. During the detection process, the laser radar 100 can rotate along its vertical axis. During the rotation, the light emitting device ( Figure 1 (not shown) laser beams L1, L2, ..., L15, L16 are emitted through each channel in sequence according to a certain time interval (for example, 1 microsecond) and detected, thereby completing a line scan on the vertical field of view. Afterwards, the laser radar 100 performs the next line scan of the vertical field of view at a certain angle (for example, 0.1 degrees or 0.2 degrees) in the horizontal field of view. The receiver of the laser radar 100 can receive the echo reflected back after the laser beam emitted by each channel encounters an obstacle, and detect the distance and direction of the obstacle (or a point on the obstacle) by calculating the round-trip flight time of the laser beam, thereby forming point cloud data. Multiple detections are performed during the entire rotation process of the laser radar 100 to form point cloud data of the obstacle, thereby sensing the conditions of the surrounding environment.

[0003] For example, Figure 1 The 16-channel laser radar 100 shown rotates one circle (360 degrees) to scan and detect, which can form a frame of point cloud data. The laser radar 100 continuously rotates and scans to detect, which can form multiple frames of point cloud data. Figure 1 The laser radar 100 in the figure is only an example used to illustrate the working principle of the laser radar, and the laser beams do not have to be uniformly distributed in the vertical direction.

[0004] As can be seen from the operating principle of LiDAR described above, the LiDAR's light-emitting device is a crucial component of the entire LiDAR system, requiring consistent and stable light energy across temperatures, batches, and channels. Currently, the design of the driver circuit for LiDAR's light-emitting device is a major challenge in LiDAR circuit implementation.

[0005] In actual applications, since the distance and reflectivity of the target detected by the laser radar are constantly changing, the light intensity of the light-emitting device is required to be able to be adjusted quickly accordingly, which puts higher requirements on the driving circuit of the light-emitting device.

[0006] Figure 2 FIG. 1 shows a schematic diagram of a driving circuit for a laser radar light emitting device in the prior art. Figure 2 As shown, 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. Figure 2 In the driver circuit shown, 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 (such as the aspect ratio) of M0 to M5, a current ratio of 1:K1:K2:K3:KN can be easily achieved.

[0007] like Figure 2 As shown in , assuming the input current source of the driver circuit is I1, the maximum output current (i.e., the input current of light-emitting device D1) is KN*I1*(K1+K2+K3) / K3, and the minimum is KN*I1 / K3. Resistor R2 controls the gate-source voltage of PMOS transistors M4 and M5, and S1 and S1N, S2 and S2N, and S3 and S3N are three pairs of mutually exclusive switches. Mutually exclusive switches refer to switches that, in the same state, one switch is on and the other is off.

[0008] In such Figure 2 In the prior art solution shown, the output current is adjusted by controlling the states of switches S1 and S1N; S2 and S2N; and S3 and S3N. Because the current mirror circuit requires step-by-step current conversion, its response speed is slow, making it difficult to achieve precise nanosecond current control. Furthermore, the circuit is relatively complex, with large parasitic capacitance and resistance in the nodes, which can significantly interfere with the circuit. Summary of the Invention

[0009] In response to the above problems, the present invention proposes a driving device and a driving method for a laser radar light-emitting device that eliminates the current mirror structure, as well as a laser radar including the driving device.

[0010] According to one aspect of the present invention, a driving device for a laser radar light-emitting device is provided. The driving device includes: a voltage regulation module configured to receive an input pulse voltage signal and output an intermediate voltage level, wherein the equivalent resistance of the voltage regulation module can be adjusted to change the output intermediate voltage level; and a driving module that receives the intermediate voltage level and provides a driving current to the light-emitting device to drive the light-emitting device to emit light, wherein the driving current is at least partially dependent on the intermediate voltage level.

[0011] In one embodiment, the voltage regulating module includes a plurality of selectable portions connected in parallel, each of the plurality of selectable portions may correspond to an equivalent resistor, and the plurality of selectable portions are connected to the same connection point to output an intermediate level to the driving module via the connection point.

[0012] In one embodiment, each of the multiple selectable sections includes: a selectable transistor and a pair of mutually exclusive switches; the mutually exclusive switch includes a ground switch and an input switch; the first electrode of the selectable transistor receives the input pulse voltage signal via the input switch and is grounded via the ground switch, the second electrode is grounded, and the third electrode is connected to the driving module to output the intermediate level to the driving module.

[0013] In one embodiment, the driving module includes a driving transistor, a first pole of the driving transistor is connected to the voltage regulation module to receive the intermediate level; a second pole of the driving transistor is connected to the power supply voltage of the driving module; and a third pole of the driving transistor is connected to the light-emitting device of the laser radar to provide a driving current for the light-emitting device.

[0014] In one embodiment, the first electrode of the driving transistor is connected to the third electrode of each pass transistor in the plurality of passable parts of the voltage regulating module.

[0015] In one embodiment, the driving module further includes a first resistor and at least one charging diode connected in parallel with the driving transistor, wherein the positive electrode of the charging diode is connected to the power supply voltage of the driving module, and the negative electrode is connected to the voltage regulating module to charge the intermediate level output by the voltage regulating module when the driving module is turned off.

[0016] In one embodiment, the driving module further includes at least one inverting diode connected in parallel with the driving transistor, and the cathode of the inverting diode is connected to the power supply voltage of the driving module, and the anode of the inverting diode is connected to the voltage regulating module to limit excessive current from the voltage regulating module.

[0017] In one embodiment, the maximum value of the driving current is determined based on the power supply voltage of the driving transistor, the intrinsic parameters of the driving transistor, the parasitic resistance of the light-emitting device, and the intermediate level.

[0018] In one embodiment, the intermediate level is determined by an equivalent resistance of the voltage regulating module, and the equivalent resistance of the voltage regulating module is determined by an on-resistance of each selectable transistor and the number of on-state selectable transistors in the voltage regulating module.

[0019] In one embodiment, the on-resistance of the pass transistor is determined by the high potential of the pulse voltage signal and inherent parameters of the pass transistor.

[0020] In one embodiment, the selectable transistor is an NMOS transistor; and the driving transistor is a PMOS transistor.

[0021] In one embodiment, the selectable transistor is an NPN transistor; and the driving transistor is a PNP transistor.

[0022] According to another aspect of the present invention, a laser radar is provided. The laser radar includes: the driving device described above; and a light-emitting device of the laser radar, the light-emitting device including a parasitic resistor, a parasitic inductor, and a light-emitting device connected in series to the second electrode of the driving transistor, wherein the parasitic resistor and parasitic inductor are connected in series to the high-side of the light-emitting device, and the low-side of the light-emitting device is grounded.

[0023] In one embodiment, the light emitting device includes an edge emitting laser (EEL) or a vertical cavity surface emitting laser (VCSEL).

[0024] According to another aspect of the present invention, a method for driving a laser radar light-emitting device is provided. The method employs the laser radar described above. The method comprises the following steps: a voltage regulation module receives an input pulse voltage signal and adjusts an equivalent resistance of the voltage regulation module to adjust an intermediate voltage level; and a driver module provides a driving current to the light-emitting device based on the intermediate voltage level to drive the light-emitting device to emit light, wherein the driving current is at least partially dependent on the intermediate voltage level.

[0025] In one embodiment, the voltage regulation module includes multiple selectable parts connected in parallel, and the multiple selectable parts are connected to the same connection point; wherein, the step of adjusting the equivalent resistance of the voltage regulation module to adjust the intermediate level further includes: selecting one or more selectable parts from the multiple selectable parts and enabling them to adjust the intermediate level.

[0026] In one embodiment, the step of the driving module providing the driving current to the light emitting device based on the intermediate level further includes: when the intermediate level is at a low level, the driving transistor is turned on, and the driving module outputs the driving current to the light emitting device.

[0027] The solution of the present invention simplifies the circuit structure of the driving device of the light-emitting device of the laser radar, the circuit implementation is simpler, the control method is more direct, and nanosecond (ns) level control is easy to achieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram illustrating the working principle of an exemplary laser radar is shown;

[0029] Figure 2 A schematic diagram of a driving circuit for a laser radar light emitting device in the prior art is shown;

[0030] Figure 3 A schematic structural diagram of a laser radar according to an embodiment of the present invention is shown;

[0031] Figure 4 Shown for Figure 3 A schematic structural diagram of a driving device of a light emitting device of a laser radar shown;

[0032] Figure 5 A schematic diagram of signal waveforms of a driving device according to an embodiment of the present invention is shown;

[0033] Figure 6 Shown Figure 4 A schematic structural diagram of an embodiment of a driving device shown; and

[0034] Figure 7 Shown Figure 4 FIG. 1 is a schematic structural diagram of another embodiment of a driving device shown. DETAILED DESCRIPTION

[0035] The following will describe in detail various embodiments of the present invention in conjunction with the accompanying drawings to provide a clearer understanding of the objectives, features and advantages of the present invention. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0036] In the following description, for the purpose of illustrating the various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, 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.

[0037] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, that is, should be interpreted to mean "including, but not limited to."

[0038] Reference throughout this specification to "one embodiment" or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "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 manner in one or more embodiments.

[0039] 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.

[0040] The inventive concept of the present invention is to replace the current mirror structure that uses step-by-step current conversion with a direct control method to control the driving current output to the light-emitting device for the laser radar. Specifically, the driver device for the laser radar light-emitting device of the present invention can input a pulse voltage signal and adjust the output current of the driver device (i.e., the driving current of the light-emitting device) by adjusting the equivalent resistance of the voltage regulation module of the driver device.

[0041] Figure 3 FIG. 1 shows a schematic structural diagram of a laser radar 1 according to an embodiment of the present invention. Figure 3 As shown in FIG, the laser radar 1 includes a light emitting device 20 and a driving device 10 for providing a driving current Id to the light emitting device 20. The driving device 10 receives an input pulse voltage signal Vin and a power supply voltage VDD1, and outputs a driving current Id for driving the light emitting device 20. The light emitting device 20 includes a parasitic resistor 22, a parasitic inductor 24, and a light emitting device 26 connected in series, wherein the parasitic resistor 22 and the parasitic inductor 24 are connected in series on the power supply side (i.e., the high-end side) of the light emitting device 26, and the low-end side of the light emitting device 26 is grounded (GND). Since the driving current Id of the driving device 10 is injected into the light emitting device 26 from the power supply side of the light emitting device 26, Figure 2 The structure shown can also be called a high-side driven laser radar light-emitting device. Those skilled in the art will understand that for the sake of simplicity, only the light-emitting device and its driver portion of the laser radar 1 are shown here, while other parts of the laser radar 1, such as the receiver, are omitted.

[0042] In some embodiments, the light emitting device 26 may be an edge emitting laser (EEL) or a vertical cavity surface emitting laser (VCSEL), among others.

[0043] Figure 4 Shown for Figure 3The schematic diagram of the structure of the driving device 10 of the light emitting device 20 of the laser radar 1 is shown. Figure 4 As shown in , the driving device 10 may include a voltage regulating module 12, which receives an input pulse voltage signal Vin and outputs an intermediate voltage level Vx. The equivalent resistance of the voltage regulating module 12 can be adjusted to change the output intermediate voltage level Vx.

[0044] The driving device 10 further includes a driving module 14 that receives the intermediate signal Vx and provides a driving current Id to the light-emitting device 20 to cause the light-emitting device 20 to emit light. The magnitude of the driving current Id depends at least in part on the magnitude of the intermediate voltage level Vx. Therefore, if the hardware components of the entire driving device 10 are fixed, the intermediate voltage level Vx, and thus the driving current Id, can be adjusted by adjusting the equivalent resistance of the voltage regulating module 12.

[0045] Figure 5 FIG. 1 shows a schematic diagram of signal waveforms of a driving device according to an embodiment of the present invention. Figure 5 As shown in , it is assumed that the high potential of the pulse voltage signal Vin of the input voltage regulating module 12 is a first potential, such as the power supply voltage VDD of the signal generator of the pulse voltage signal Vin, and the low potential is a second potential, such as 0V.

[0046] In one embodiment, the pulse voltage signal Vin may be a short pulse signal, that is, a high potential duration ( Figure 5 The Tpulse shown in FIG is much smaller than the duration of the low potential. The specific embodiment of the voltage regulating module 12 will be described below in conjunction with FIG. Figure 6 and Figure 7 Provide a detailed description.

[0047] In addition, the driving device 10 may further include one or more power supply modules (not shown) to respectively provide a high potential VDD of the pulse voltage signal Vin and a power supply voltage VDD1 of the driving module 14. In one embodiment, the high potential VDD of the pulse voltage signal Vin is, for example, 5V, and the power supply voltage VDD1 of the driving module 14 is, for example, 30V.

[0048] Figure 6 Shown Figure 4 A schematic diagram of an embodiment of a drive device 10 is shown.

[0049] In such Figure 6In the embodiment shown, the voltage regulating module 12 may include a plurality of selectable sections 121, 122, ..., 12n (hereinafter, each selectable section is collectively referred to as 12i, where 1≤i≤n, and n is a positive integer greater than 1). Each selectable section 12i may have an equivalent resistance, and the equivalent resistance of the voltage regulating module 12 may be determined by the equivalent resistance of each selectable section 12i and the number of selectable sections 12i, as described below. Figure 6 As shown in FIG, the plurality of selectable portions 121, 122, ..., 12n are connected to the same connection point to output the intermediate voltage level Vx to the driving module 14 via the connection point.

[0050] The selectable portions 121, 122, ..., 12n may each include a corresponding selectable transistor PM1, PM2, ..., PMn (hereinafter collectively referred to as PMi) and a pair of mutually exclusive switches (S11, S12), (S21, S22), ..., (Sn1, Sn2), hereinafter collectively referred to as Si1 and Si2. Each pair of mutually exclusive switches includes an input switch Si1 and a grounding switch Si2. The first electrode of each selectable transistor PMi receives the input pulse voltage signal Vin via the corresponding input switch Si1 and is grounded via the grounding switch Si2. The second electrode of the selectable transistor PMi is grounded, and the third electrode is connected to the driver module 14 to output the intermediate voltage level Vx to the driver module 14.

[0051] Here, the input switch Si1 and the ground switch Si2 of each pass transistor PMi are mutually exclusive to control the gating of the pass transistor PMi. That is, when Si1 is turned on, Si2 is turned off, thereby gating the corresponding transistor PMi, and when Si1 is turned off, Si2 is turned on, thereby not gating the corresponding transistor PMi.

[0052] Here, the present invention is described using the example of using mutually exclusive switches to select each pass transistor PMi. However, those skilled in the art will appreciate that each pass transistor PMi can also be selected using various other methods, such as using a multi-way switch to control multiple pass transistors PMi, applying simple combinational logic to multiple pass transistors PMi, etc. Furthermore, the voltage regulation module 12 is described herein using multiple pass transistors as an example. However, those skilled in the art will appreciate that the voltage regulation module 12 is not limited to the specific structure shown in the figure, but can also be implemented using various other structures capable of achieving voltage regulation functions.

[0053] In one embodiment, if Figure 6As shown in FIG, the third electrodes of the plurality of selectable pass transistors PM1, PM2, ..., PMn are connected and output the intermediate level Vx, so that the plurality of selectable pass transistors PM1, PM2, ..., PMn are connected in parallel.

[0054] The driving module 14 may include a driving transistor 142, wherein a first electrode of the driving transistor 142 is connected to the voltage regulating module 12 to receive the intermediate level Vx, a second electrode of the driving transistor 142 is connected to the power supply voltage VDD1 of the driving module 14, and a third electrode of the driving transistor 142 is connected to the light-emitting device 20 of the laser radar for providing a driving current Id to the light-emitting device 20.

[0055] In one embodiment, if Figure 6 As shown in FIG, a first electrode of the driving transistor 142 is connected to a third electrode of each of the pass transistors PM1, PM2, ..., PMn to receive the intermediate voltage level Vx.

[0056] In such Figure 6 In the embodiment shown, the plurality of selectable transistors PM1, PM2, ..., PMn may be NMOS transistors, and in the specification, the first electrode corresponds to the gate (G), the second electrode corresponds to the source (S), and the third electrode corresponds to the drain (D).

[0057] In addition, the driving transistor 142 may be a PMOS transistor, and in the specification, the first electrode corresponds to the gate (G), the second electrode corresponds to the source (S), and the third electrode corresponds to the drain (D).

[0058] Here, the MOS tube refers to a MOSFET, namely a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the PMOS tube refers to a P-channel MOS tube, and the NMOS tube refers to an N-channel MOS tube.

[0059] In addition, in some embodiments, the driving module 14 may further include a first resistor 144 connected in parallel with the driving transistor 142 and at least one charging diode 146. The at least one charging diode 146 has an anode connected to the power supply voltage VDD1 of the driving module 14 and a cathode connected to the voltage regulating module 12, so as to charge the intermediate voltage level Vx output by the voltage regulating module 12 when the driving module 14 (e.g., the driving transistor 142) is turned off.

[0060] Optionally or additionally, the driving module 14 includes at least one inverter diode 148 connected in parallel with the driving transistor 142. The negative electrode of the inverter diode 148 is connected to the power supply voltage VDD1 of the driving module 14, and the positive electrode of the inverter diode 148 is connected to the voltage regulation module 12 to limit excessive current from the voltage regulation module 12, that is, to limit the intermediate level Vx. With the inverter diode 148, the level value of the intermediate level Vx is limited to Vx < VDD1 + Vth1, where Vth1 is the conduction voltage threshold of the inverter diode 148.

[0061] With the driving device 10 disclosed in the present invention, by adjusting the equivalent resistance of the voltage regulation module 12, the output intermediate level Vx is changed accordingly. For example, in the embodiment shown in Figure 6 , the equivalent resistance of the voltage regulation module 12 is determined by the on-resistance of each selectable transistor PMi and the number of on-selectable transistors PMi. The on-resistance Rdson ,

[0067] of each selectable transistor PMi can be expressed by the following formula (1):

[0062]

[0063] where W i is the channel width of the selectable transistor PMi, L i is the channel length of the selectable transistor PMi, Vth 1i is the on-threshold of the selectable transistor PMi, which are all inherent parameters of the selectable transistor PMi. k is a constant, and VDD is the high potential of the pulse voltage signal Vin. Here, those skilled in the art can know that the constant k is a constant determined by the properties of silicon-based devices and depends on Planck's constant.

[0064] In one example, assuming that the multiple selectable transistors PMi are the same transistors, their respective on-resistances Rdson 1i are equal. In this case, the equivalent resistance Rdsonl of the voltage regulation module 12 can be expressed by the following formula (2):

[0065] Rdson1 = Rdson 1i / M, (2)

[0066] where M is the number of on-selectable transistors PMi.

[0067] In the case where the multiple pass transistors PMi are different transistors, the equivalent resistance Rdson1 of the voltage regulation module 12 can be calculated based on the equivalent resistance of each pass transistor PMi and the number of transistors that are turned on. For example, assuming that transistors PM1 and PM2 are turned on, the equivalent resistance of the voltage regulation module 12 can be expressed as the following formula (3):

[0068] Rdson1=Rdson 11 *Rdson 12 / (Rdson 11 +Rdson 12 ), (3)

[0069] Among them Rdson 11 and Rdson 12 are the equivalent resistances of transistors PM1 and PM2 respectively, which can be calculated according to the above formula (1).

[0070] It can be seen that the equivalent resistance Rdson1 of the voltage regulation module 12 decreases as the number of transistors PMi that are turned on increases.

[0071] A current is formed between the intermediate level Vx and the power supply voltage VDD1 of the driving module 14. The current flows through the first resistor 144 and the charging diode 146, thereby forming a voltage difference ΔV across the first resistor 144 and the charging diode 146. At this time, the intermediate level Vx can be expressed as the difference between VDD1 and ΔV, that is, Vx=VDD1-ΔV.

[0072] Assume that the equivalent resistance of the voltage regulating module 12 is Rdson1, the output current of the second electrode of the voltage regulating module 12 is I, and the slope of the point corresponding to the output current I on the voltage-current characteristic curve of the charging diode 146 (equivalent to the resistance value of the charging diode 146 when the output current I) is K d , then the output current I can be expressed as the following formula (4):

[0073]

[0074] It can be converted into the following formula (5):

[0075]

[0076] Therefore, it can be seen that when the number of on-state transistors PMi increases, the equivalent resistance Rdson1 of the voltage regulating module 12 decreases, and the intermediate level Vx decreases. Therefore, the intermediate level Vx can be adjusted by adjusting the number of on-state transistors PMi.

[0077] The change of the intermediate voltage level Vx will affect the on-resistance of the driving transistor 142, thereby affecting the driving current Id output by the driving transistor 142. Specifically, the maximum value of the driving current Id is determined by the power supply voltage VDD1 of the driving transistor 142, the parasitic resistance 22 of the light-emitting device 20, and the equivalent resistance Rdson2 of the driving transistor 142, which can be expressed as the following formula (6):

[0078] Imax=VDD1 / (R1+Rdson2). (6)

[0079] The equivalent resistance Rdson2 of the driving transistor 142 can be expressed as the following formula (7):

[0080]

[0081] Wherein, W2 is the channel width of the driving transistor 142 , L2 is the channel length of the driving transistor 142 , Vth2 is the on-threshold of the driving transistor 142 , which are all inherent parameters of the driving transistor 142 , k is the constant as described above, and VDD1 is the power supply voltage of the driving transistor 142 .

[0082] That is, the maximum value of the driving current Id is determined by the power supply voltage VDD1 of the driving transistor 142 , the inherent parameters of the driving transistor 142 , the parasitic resistance 22 of the light emitting device 20 , and the intermediate level Vx.

[0083] like Figure 5 As shown in FIG, when the input pulse voltage signal Vin is at a low potential (e.g., 0V), all the selectable transistors PMi are turned off, so that the intermediate potential Vx is the power supply voltage VDD1 of the driver module 14, the driver transistor 142 is turned off, and the drive current Id is 0. When the input pulse voltage signal Vin changes to a high potential VDD and some of the multiple selectable transistors PMi are turned on, a voltage difference of ΔV is generated between the power supply voltage VDD1 of the driver module 14 and the intermediate potential Vx, the intermediate potential Vx becomes VDD1-ΔV, and the drive current Id reaches its maximum value Imax.

[0084] Therefore, when the hardware composition of the driving device 10 and the light-emitting device 20 remains unchanged, the intermediate level Vx can be adjusted by adjusting the equivalent resistance of the voltage regulation module 12, for example, by controlling the number of conductive selectable transistors PMi, thereby affecting the equivalent resistance Rdson2 of the driving transistor 142 to achieve regulation of the driving current Id.

[0085] In summary, using the driver device 10 according to an embodiment of the present invention, a short pulse voltage signal Vin can be input to generate a short pulse current signal Id as the driving current provided to the light-emitting device 20. Furthermore, by adjusting the equivalent resistance of the voltage regulation module 12 of the driver device 10, for example, by changing the conduction of the selectable transistor PMi, the maximum value Imax of the output driving current Id can be conveniently adjusted, thereby achieving precise control from current to light emission. Furthermore, the driver device 10 of the present invention eliminates the current mirror structure, resulting in a simpler circuit implementation and a more direct control method, even capable of short pulse control at the nanosecond (ns) level.

[0086] Figure 7 Shown Figure 4 A schematic diagram of another embodiment of a drive device 10 is shown.

[0087] In such Figure 7 In the embodiment shown, the voltage regulating module 12 may include a plurality of selectable sections 121', 122', ..., 12n' (hereinafter, each selectable section is collectively referred to as 12i', where 1≤i≤n, and n is a positive integer greater than 1). Each selectable section 12i' may have an equivalent resistance, and the equivalent resistance of the voltage regulating module 12 may be determined by the equivalent resistance of each selectable section 12i' and the number of selectable sections 12i', as described below. Figure 7 As shown in FIG, the plurality of selectable portions 121 ′, 122 ′, . . . , 12n′ are connected to the same connection point to output the intermediate voltage level Vx to the driving module 14 via the connection point.

[0088] The selectable parts 121', 122', ..., 12n' can respectively include a corresponding selectable transistor PM1', PM2', ..., PMn' (hereinafter collectively referred to as PMi') and a pair of mutually exclusive switches (S11, S12), (S21, S22), ..., (Sn1, Sn2), hereinafter collectively referred to as Si1 and Si2. Each pair of mutually exclusive switches includes an input switch Si1 and a grounding switch Si2. The first electrode of each selectable transistor PMi' receives the input pulse voltage signal Vin via the corresponding input switch Si1 and is grounded via the grounding switch Si2. The second electrode of the selectable transistor PMi' is grounded, and the third electrode is connected to the driving module 14 to output the intermediate level Vx to the driving module 14. Here, Figure 6 Similar to the embodiment of FIG. 1 , the ground switch Si2 and the input switch Si1 of each pass transistor PMi′ are mutually exclusive to control the gating of the pass transistor PMi′, which will not be described in detail here.

[0089] In one embodiment, if Figure 7As shown in FIG, the third electrodes of the plurality of selectable pass transistors PM1 ′, PM2 ′, . . . , PMn′ are connected and output the intermediate level Vx, so that the plurality of selectable pass transistors PM1 ′, PM2 ′, . . . , PMn′ are connected in parallel.

[0090] The driving module 14 may include a driving transistor 142', wherein a first electrode of the driving transistor 142' is connected to the voltage regulating module 12 to receive the intermediate level Vx, a second electrode of the driving transistor 142' is connected to the power supply voltage VDD1 of the driving module 14, and a third electrode of the driving transistor 142' is connected to the light-emitting device 20 of the laser radar for providing a driving current Id to the light-emitting device 20.

[0091] In such Figure 7 In the embodiment shown, the selectable transistor PMi' may be an NPN transistor, and in the specification, the first electrode corresponds to the base (B), the second electrode corresponds to the emitter (E), and the third electrode corresponds to the collector (C).

[0092] In addition, the driving transistor 142 ′ may be a PNP transistor, and in the specification, the first electrode corresponds to the base (B), the second electrode corresponds to the emitter (E), and the third electrode corresponds to the collector (C).

[0093] Here, PNP tube refers to PNP type transistor, which is a triode composed of two P-type semiconductors with one N-type semiconductor sandwiched in the middle. Similarly, NPN tube refers to NPN type transistor, which is a triode composed of two N-type semiconductors with one P-type semiconductor sandwiched in the middle.

[0094] Those skilled in the art will appreciate that the present invention is not limited to Figure 6 and Figure 7 Instead of the embodiment shown, various transistors can be mixed. For example, in Figure 6 In the embodiment shown, part or all of the pass transistor PMi may be implemented as an NPN transistor, and / or the driving transistor 142 may be implemented as a PNP transistor. Figure 7 In the illustrated embodiment, a portion or all of the pass transistor PMi' may be implemented as an NMOS transistor, and / or the driving transistor 142' may be implemented as a PMOS transistor.

[0095] The above-mentioned scheme of the present invention simplifies the circuit structure of the driving device of the light-emitting device of the laser radar, reduces the various parasitic resistances, parasitic capacitances and other problems caused by the complexity of the circuit, and since the driving current can be adjusted without step-by-step accumulation, direct control of the driving current is achieved, making the adjustment speed faster and easily achieving nanosecond (ns) level control.

[0096] Those skilled in the art will appreciate that, depending on different application scenarios, the solutions according to the inventive concept of the present invention can be easily implemented as hardware circuits (such as FPGA or ASIC), driving methods or corresponding driver programs.

[0097] When the light-emitting device 20 of the laser radar is driven by the driving device 10 according to the present invention, if the light intensity of the echo received by the receiver of the laser radar (not shown in the figure) is too strong or too weak and cannot detect obstacles well, the controller of the laser radar (not shown in the figure) can automatically send a control signal to the driving device 10 according to the echo intensity to reduce or increase the driving current Id of the light-emitting device 20, thereby reducing or increasing the light intensity emitted by the light-emitting device 20.

[0098] In one embodiment, the driver 10 receives a control signal from the controller requesting an increase in the light intensity of the light-emitting device 20. Before the next pulse voltage signal Vin is input to the driver 10, the controller (not shown) of the driver 10 increases the number of selectable transistors PMi or PMi' that are turned on based on the control signal, thereby reducing the intermediate voltage Vx. At this time, due to the reduction in the intermediate voltage Vx, the on-resistance Rdson2 of the driver module 14 decreases (as shown in the above formula (7)), thereby increasing the maximum value Imax of the drive current Id (as shown in the above formula (6)).

[0099] In another example, the driver 10 receives a control signal from the controller requesting a reduction in the light intensity of the light-emitting device 20. Before the next pulse voltage signal Vin is input to the driver 10, the controller (not shown) of the driver 10 reduces the number of selectable transistors PMi or PMi' that are turned on based on the control signal, thereby increasing the intermediate voltage Vx. At this point, due to the increase in intermediate voltage Vx, the on-resistance Rdson2 of the driver module 14 increases (as shown in formula (7) above), thereby reducing the maximum value Imax of the drive current Id (as shown in formula (6) above).

[0100] In this way, each time the light emitting device 20 of the laser radar emits light (for example, in combination with Figure 1 When the laser radar performs the next line scan of the vertical field of view in the horizontal field of view direction, the control signal is used to control the number of conductive transistors that can be selected, thereby adjusting the driving current Imax of the light-emitting device 20.

[0101] Various aspects of the embodiments of the present invention have been described above with reference to the accompanying drawings. It should be understood that the above description is merely exemplary, and the present invention is not limited to the specific implementations described above and shown in the accompanying drawings. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the embodiments described. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A driving device for a laser radar light emitting device, wherein: The driving device comprises: a voltage regulating module configured to receive an input pulse voltage signal and output an intermediate voltage level, wherein an equivalent resistance of the voltage regulating module can be adjusted to change the output intermediate voltage level; and a driving module receiving the intermediate level and providing a driving current to the light emitting device to drive the light emitting device to emit light, wherein the driving current is at least partially dependent on the intermediate level; The voltage regulating module includes a plurality of selectable parts connected in parallel, each of which corresponds to an equivalent resistor, and the plurality of selectable parts are connected to the same connection point to output an intermediate level to the driving module via the connection point. The pass portion may include a pass transistor, and the equivalent resistance is determined based on an on-resistance of the pass transistor and a number of on-states of the pass transistor.

2. The driving device according to claim 1, wherein: Each of the plurality of gate sections comprises: A gate transistor and a pair of mutually exclusive switches; The mutually exclusive switch includes a ground switch and an input switch; the first electrode of the selectable transistor receives the input pulse voltage signal through the input switch and is grounded through the ground switch, the second electrode is grounded, and the third electrode is connected to the driving module to output the intermediate level to the driving module.

3. The driving device according to claim 1 or 2, wherein: The driving module includes a driving transistor, the first pole of the driving transistor is connected to the voltage regulation module to receive the intermediate level; the second pole of the driving transistor is connected to the power supply voltage of the driving module; the third pole of the driving transistor is connected to the light-emitting device of the laser radar, and is used to provide a driving current for the light-emitting device.

4. The driving device according to claim 3, wherein: The first electrode of the driving transistor is connected to the third electrode of each of the pass transistors in the plurality of pass sections of the voltage regulating module.

5. The driving device according to claim 3, wherein: The driving module further includes a first resistor and at least one charging diode (146) connected in parallel with the driving transistor, wherein the positive electrode of the charging diode is connected to the power supply voltage of the driving module and the negative electrode is connected to the voltage regulating module so as to charge the intermediate level output by the voltage regulating module when the driving module is turned off.

6. The driving device according to claim 5, wherein: The driving module further includes at least one inverting diode (148) connected in parallel with the driving transistor, wherein the cathode of the inverting diode (148) is connected to the power supply voltage of the driving module, and the anode of the inverting diode is connected to the voltage regulating module to limit excessive current from the voltage regulating module.

7. The driving device according to claim 3, wherein: The maximum value of the driving current is determined based on a power supply voltage of the driving transistor, inherent parameters of the driving transistor, a parasitic resistance of the light emitting device, and the intermediate level.

8. The driving device according to claim 7, wherein: The intermediate level is determined by the equivalent resistance of the voltage regulating module, and the equivalent resistance of the voltage regulating module is determined by the on-resistance of each selectable transistor and the number of on-state selectable transistors in the voltage regulating module.

9. The driving device according to claim 7, wherein: The on-resistance of the pass transistor is determined by the high potential of the pulse voltage signal and inherent parameters of the pass transistor.

10. The driving device according to claim 3, wherein the selectable transistor is an NMOS transistor; and the driving transistor is a PMOS transistor.

11. The driving device according to claim 3, wherein the selectable transistor is an NPN transistor; and the driving transistor is a PNP transistor.

12. A laser radar comprising: The drive device according to any one of claims 1 to 11; as well as The light-emitting device of the laser radar includes a parasitic resistance, a parasitic inductance and a light-emitting device connected in series to the second electrode of the driving transistor, and the parasitic resistance and parasitic inductance connected in series are connected to the high-end side of the light-emitting device, and the low-end side of the light-emitting device is grounded.

13. The laser radar according to claim 12, wherein: The light emitting device includes an edge emitting laser (EEL) or a vertical cavity surface emitting laser (VCSEL).

14. A method for driving a laser radar light emitting device, the method using the laser radar according to claim 12 or 13, wherein: The method comprises the following steps: The voltage regulating module receives the input pulse voltage signal and adjusts the equivalent resistance of the voltage regulating module to adjust the intermediate level; and The driving module provides a driving current to the light emitting device based on the intermediate level to drive the light emitting device to emit light, wherein the driving current is at least partially dependent on the intermediate level.

15. The method according to claim 14, wherein The voltage regulating module includes a plurality of selectable portions connected in parallel, and the plurality of selectable portions are connected to the same connection point; wherein the step of adjusting the equivalent resistance of the voltage regulating module to adjust the intermediate level further includes: One or more selectable sections are selected from the plurality of selectable sections and are enabled to adjust the intermediate level.

16. The method according to claim 14 or 15, wherein The step of providing the driving current to the light emitting device based on the intermediate level by the driving module further includes: When the intermediate level is at a low level, the driving transistor is turned on, and the driving module outputs the driving current to the light-emitting device.

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