A laser driving control system

Abstract

The application relates to a laser driving control system, comprising: a double-voltage power supply module, a power supply selection module, an FPGA module, an energy storage module, a laser, a first ITOF sensor, a second ITOF sensor and a laser driving circuit; wherein the power supply selection module is electrically connected with the double-voltage power supply module, the FPGA module and the energy storage module respectively, the laser is electrically connected with the energy storage module and the laser driving circuit respectively, and the FPGA module is further electrically connected with the first ITOF sensor, the second ITOF sensor and the laser driving circuit respectively, so as to simultaneously meet the requirements of ITOF ranging and DTOF ranging.

Description

Technical Field

[0001] This invention relates to the field of laser driving technology, and in particular to a laser driving control system. Background Technology

[0002] Time of Flight (ToF) technology is a technique used to measure the time difference between the emission and return of light or other signals, thereby calculating distance or depth information. As a result, it is widely used in fields such as 3D imaging, robot navigation, autonomous vehicles, virtual reality (VR), and augmented reality (AR).

[0003] Furthermore, there are two types of time-of-flight (TOF) technology: Indirect Time of Flight (ITOF) and Direct Time of Flight (DTOF). They differ in their modulation methods for infrared light emission. Typically, ITOF and DTOF require different driving circuits for different application scenarios.

[0004] However, existing laser driving circuits are all driving circuits specifically designed for ITOF or DTOF modes. Their driving modes are limited and cannot meet the needs of switching between near and far scenes in practical applications. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a laser drive control system to meet the needs of scene switching in practical applications.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] This invention provides a laser driving control system, including a dual-voltage power supply module, a power selection module, an FPGA module, an energy storage module, a laser, a first ITOF sensor, a second ITOF sensor, and a laser driving circuit; wherein the power selection module is electrically connected to the dual-voltage power supply module, the FPGA module, and the energy storage module, and the laser is electrically connected to the energy storage module and the laser driving circuit, and the FPGA module is also electrically connected to the first ITOF sensor, the second ITOF sensor, and the laser driving circuit.

[0010] The FPGA module is used to send a SYNC signal to one of the first and second ITOF sensors in a time-division multiplexing manner, receive the STROBE and LVDS signals sent by one of the sensors, control the power selection module to select a voltage corresponding to the frequency of the LVDS signal to power the energy storage module, control the energy storage module to discharge during exposure, and superimpose a DTOF signal on the LVDS signal when one of the sensors is idle to obtain a superimposed signal. When the exposure time of one of the sensors is determined by the STROBE signal, the superimposed signal is sent to the laser driving circuit so that the laser driving circuit processes the superimposed signal and controls the laser to output laser based on the processed signal.

[0011] In one possible embodiment, the laser drive control system further includes a discharge control module, which is electrically connected to the power selection module, the FPGA module, and the energy storage module, respectively. The discharge control module is used to discharge under the control of the FPGA module when switching from high voltage to low voltage.

[0012] In one possible embodiment, the laser drive control system further includes: a current limiting protection module, which is electrically connected to the energy storage module, the laser, and the laser drive circuit, respectively, and is used to limit the current of the laser drive circuit.

[0013] In one possible embodiment, the laser driving circuit includes a differential-to-single-ended module, which is electrically connected to an FPGA module. The differential-to-single-ended module is used to convert the superimposed signal into a single-ended signal.

[0014] In one possible embodiment, the laser driving circuit further includes: a high-frequency driving module, which is electrically connected to a differential-to-single-ended module. The high-frequency driving module is used to shape the single-ended signal and increase its driving capability.

[0015] In one possible embodiment, the laser driving circuit further includes a high-frequency MOS module, which is electrically connected to both the high-frequency driving module and the laser. The high-frequency MOS module is used to provide a low-impedance, high-current loop for high-frequency modulation of the laser.

[0016] In one possible embodiment, the laser driving circuit further includes an absorption module, which is electrically connected to the high-frequency MOS module and the laser, respectively, and is used to absorb overshoot signals.

[0017] In one possible embodiment, both the energy storage module and the high-frequency MOS module are connected to the power supply ground.

[0018] (III) Beneficial Effects

[0019] The beneficial effects of this invention are:

[0020] This invention proposes a laser drive control system that is compatible with two types of TOF ranging laser drive control schemes and circuit implementation methods, and can simultaneously meet the requirements of ITOF 30m ranging and DTOF 50m ranging.

[0021] To make the above-mentioned objectives, features and advantages to be achieved by the embodiments of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of an ITOF in the prior art is shown;

[0024] Figure 2 A schematic diagram of the structure of a DTOF in the prior art is shown;

[0025] Figure 3 This paper shows a structural block diagram of an overall system solution provided in an embodiment of this application;

[0026] Figure 4 A schematic diagram of a laser drive control system provided in an embodiment of this application is shown. Detailed Implementation

[0027] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Currently, there are no products on the market that combine both ITOF and DTOF capabilities. Furthermore, ITOF products typically have a ranging range of 0.1–6 meters, rarely exceeding 10 meters, and their horizontal field of view is also relatively small. Additionally, in obstacle avoidance scenarios, ITOF struggles to address the problem of multi-aircraft interference.

[0029] And, such as Figure 1 and Figure 2As shown, currently available ITOF (In-Time-of-Flight) sensors are characterized by low power supply voltage, wide modulation frequency range (3MHz~200MHz), long exposure time, low laser power, and short range, while DTOF (Deep-Time-of-Flight) sensors are characterized by high power supply voltage, low repetition rate (≤2MHz), high laser peak power, and long range. Therefore, these two types of TOF sensors differ significantly in laser driving circuits, control methods, power supply circuits, laser selection, and specific implementation details, making them incompatible.

[0030] Based on this, the present invention proposes a laser drive control system that is compatible with two types of TOF ranging laser drive control schemes and circuit implementation methods, and can simultaneously meet the requirements of ITOF 30m ranging and DTOF 50m ranging.

[0031] It should be understood that the name of this application may also be referred to as a laser driving system, etc.

[0032] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0033] Please see Figure 3 , Figure 3 A structural block diagram of an overall system solution provided in an embodiment of this application is shown. Figure 3 As shown, the overall system scheme includes an FPGA module, a laser emission module, a collimating lens, a light homogenizer, two ITOF sensors (i.e., ITOF SENSOR1 and ITOF SENSOR2), two optical lenses (i.e., optical lens 1 and optical lens 2), an SIPM, and a focusing lens.

[0034] The FPGA module mainly handles the logic timing required for operation, such as the control of the laser generator module, the control of peripheral devices, the register configuration of the ITOF SENSOR, MIPI data reception and processing, image algorithms, and interaction with the host computer.

[0035] The laser emitting module mainly includes power supply for the laser driving circuit, signal processing, driving and protection circuits for high-frequency MOS, and energy storage circuits.

[0036] Collimating lenses are used to compress the divergence angle of a laser into a point light source;

[0037] A diffuser transforms a point light source into a diffused light source with a wide angle.

[0038] Both optical lenses are used to project the reflected signal from the target object onto the corresponding ITOF sensor after passing through a filter.

[0039] ITOF sensors are used to image the reflected signals of target objects and output them through a MIPI interface;

[0040] A focusing lens is used to focus the reflected signal from the target object onto the SIPM sensor;

[0041] SIPM, as a receiving sensor for DTOF, is used to receive signals emitted by target objects and image the reflected signals of the target objects. It is mainly used to help solve problems such as multi-machine interference and cycle switching.

[0042] To facilitate understanding of the specific structural diagrams of the laser emission module, FPGA module, and 2-channel ITOF sensor in this application, the following description is provided through specific embodiments.

[0043] Please see Figure 4 , Figure 4 A schematic diagram of a laser drive control system provided in an embodiment of this application is shown. Figure 4 As shown, the laser drive control system includes a dual-voltage power supply module, a power selection module, an FPGA module, a discharge control module, a current limiting protection module, an energy storage module, a laser, a laser protection module, a first ITOF sensor (i.e., ITOF SENSOR1), a second ITOF sensor (i.e., ITOF SENSOR2), and a laser drive circuit.

[0044] The power selection module is electrically connected to the dual-voltage power supply module, the FPGA module, the discharge control module, and the current limiting protection module. The current limiting protection module is also electrically connected to the energy storage module, the laser, and the laser protection module. The laser is also electrically connected to the laser driving circuit. Furthermore, the FPGA module is also electrically connected to the first ITOF sensor, the second ITOF sensor, and the laser driving circuit.

[0045] And, see also Figure 4 The laser driving circuit includes a differential-to-single-ended module, a high-frequency driving module, and a high-frequency MOS module connected in sequence. The differential-to-single-ended module is also connected to an FPGA module. The high-frequency MOS module is connected to the laser. The laser driving circuit further includes an absorption module, which is electrically connected to the high-frequency MOS module, the laser, and the laser protection module.

[0046] The dual-voltage power supply module can provide two voltages for the laser driving circuit. It is used to supply power to the three frequencies of ITOF. Different frequencies correspond to different power supply voltages. High frequency uses high voltage, and medium and low frequency use low voltage. It should be noted that the specific frequencies of high frequency, medium frequency and low frequency can be set according to actual needs. This application embodiment is not limited to this.

[0047] The system includes a power selection module controlled by an FPGA module, which can select different supply voltages based on different frequencies. Furthermore, the laser drive circuit offers two voltage options: a high-voltage and a low-voltage option, both controlled by the FPGA module.

[0048] The system includes a discharge control module, which is controlled by an FPGA module. The FPGA selects different supply voltages for different frequencies, especially when switching from high to low voltage, requiring FPGA control of the discharge circuit. In other words, the FPGA controls the power selection module to choose voltages corresponding to different frequencies for the first and second ITOF sensors. When switching from high to low voltage, the FPGA controls the discharge control module to discharge. Because the exposure intervals between frequencies are relatively short, the discharge time must be strictly controlled to ensure the voltage discharges to the required value. Otherwise, insufficient or no discharge before switching to a different frequency may damage the laser.

[0049] The current limiting protection module is used to protect the drive circuit from overcurrent damage;

[0050] The laser protection module is used to provide reverse voltage protection;

[0051] The energy storage module is used to discharge during exposure, and due to the different frequencies (especially low frequencies) and long exposure times of ITOF, a suitable energy storage capacitor is required. In other words, after the supply voltage passes through the current-limiting resistor, a large energy storage capacitor is needed (ITOF exposure time is very long, up to nearly 1ms) to ensure that the laser can work normally in both ITOF and DTOF exposures;

[0052] The differential-to-single-ended module is used to convert the two LVDS signals output by the two TOF sensors into a single LVDS signal after superimposing the DTOF signal through the FPGA and processing. After passing through the differential-to-single-ended module, it becomes a single-ended signal.

[0053] The high-frequency drive module is used to shape single-ended signals and increase their driving capability;

[0054] High-frequency MOS is used to provide a low-impedance, high-current loop for high-frequency modulation of laser light, and the specific current loop of the low-impedance, high-current loop can be set according to actual needs. The embodiments of this application are not limited thereto.

[0055] The absorption module is used to absorb overshoot signals;

[0056] Both the first and second ITOF sensors have three different frequencies, each with a different exposure time, controlled by an FPGA module. The frequency and voltage correspondence is as follows: the first frequency corresponds to high voltage for long-distance measurement; the second and third frequencies correspond to low voltage for short-distance measurement and anti-tumble cycles. The first frequency is higher than the second, and the second frequency is higher than the third.

[0057] Based on the aforementioned device, the FPGA module is used to send a SYNC signal to one of the first and second ITOF sensors in a time-division multiplexing manner (e.g., sending a SYNC1 signal to the first ITOF sensor at a first time and a SYNC2 signal to the second ITOF sensor at a second time), and to receive the STROBE and LVDS signals sent by one of the sensors. For example, after sending the SYNC1 signal to the first ITOF sensor, it receives the STROBE1 and LVDS1 signals sent by the first ITOF sensor; as another example, when sending the SYNC2 signal to the second ITOF sensor, it receives the STROBE2 and LVDS2 signals sent by the second ITOF sensor. Furthermore, when the ITOF sensor that needs subsequent exposure is idle (i.e., not exposed), the FPGA module superimposes a DTOF signal onto the LVDS signal corresponding to the ITOF sensor that needs subsequent exposure, obtaining the superimposed signal. Furthermore, when the exposure time is determined by the STROBE signal corresponding to the ITOF sensor that needs to be exposed subsequently, the superimposed signal is sent to the laser driving circuit so that the laser driving circuit processes the superimposed signal and controls the laser to output laser based on the processed signal.

[0058] Furthermore, the first ITOF sensor, the second ITOF sensor, and the DTOF sensor receive the echo signal from the target object and perform image algorithm processing to output intensity, depth map, and point cloud map.

[0059] It should be noted that the scanning range of the first ITOF sensor and the scanning range of the second ITOF sensor overlap, and the first ITOF sensor and the second ITOF sensor operate at different times. Therefore, the STROBE signal and LVDS signal they feed back are also fed back at different time periods.

[0060] It should be understood that the specific method for superimposing a DTOF signal on an LVDS signal can be set according to actual needs, and the embodiments of this application are not limited thereto.

[0061] It should also be noted that the FPGA module can control the differential-to-single-ended module to turn on or off. Thus, when the ITOF sensor is being exposed, the differential-to-single-ended module is turned on, and when the ITOF sensor exposure is finished, the differential-to-single-ended module is turned off. This can prevent the differential-to-single-ended module from receiving incorrect signals and causing circuit damage.

[0062] To facilitate understanding of the embodiments of this application, specific embodiments are described below.

[0063] Specifically, at the first instant, the FPGA module sends a SYNC1 signal to the first ITOF sensor and receives the STROBE1 and LVDS1 signals fed back by the first ITOF sensor. Furthermore, when the first ITOF sensor is determined to be idle via the STROBE1 signal, a DTOF signal is superimposed on the LVDS1 signal to obtain a superimposed signal. Subsequently, when the exposure time of the first ITOF sensor is determined via the STROBE1 signal, the superimposed signal is sent to the laser driving circuit so that the laser driving circuit processes the superimposed signal and controls the laser to output laser light based on the processed signal.

[0064] Subsequently, upon reaching the second time interval, the FPGA module sends a SYNC2 signal to the second ITOF sensor and receives the STROBE2 and LVDS2 signals from the second ITOF sensor. Furthermore, upon determining that the second ITOF sensor is idle via the STROBE2 signal, a DTOF signal is superimposed on the LVDS2 signal to obtain a superimposed signal. Then, upon determining that the exposure time of the second ITOF sensor has been reached via the STROBE2 signal, the superimposed signal is sent to the laser drive circuit so that the laser drive circuit processes the superimposed signal and controls the laser to output laser light based on the processed signal.

[0065] Therefore, by means of the above technical solution, this application can be compatible with two kinds of laser drive control schemes and circuit implementation methods for TOF ranging, and can simultaneously meet the requirements of ITOF 30m ranging and DTOF 50m ranging.

[0066] Furthermore, it helps in product miniaturization and allows it to adapt to more application scenarios.

[0067] It should be understood that the above-described laser drive control system is merely exemplary, and those skilled in the art can make various modifications based on the above method, and such modified solutions also fall within the protection scope of this application.

[0068] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0069] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0070] It should be noted that any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In claims that enumerate several means, several of these means may be embodied by the same hardware. The use of the terms first, second, third, etc., is merely for convenience of expression and does not indicate any order. These terms can be understood as part of the component names.

[0071] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0073] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

Claims

1. A laser drive control system, characterized in that, The device includes a dual-voltage power supply module, a power selection module, an FPGA module, an energy storage module, a laser, a first ITOF sensor, a second ITOF sensor, and a laser driving circuit. The power selection module is electrically connected to the dual-voltage power supply module, the FPGA module, and the energy storage module, respectively. The laser is electrically connected to the energy storage module and the laser driving circuit, respectively. Furthermore, the FPGA module is also electrically connected to the first ITOF sensor, the second ITOF sensor, and the laser driving circuit, respectively. The FPGA module is used to send a SYNC signal to one of the first ITOF sensor and the second ITOF sensor in a time-division multiplexing manner, and to receive the STROBE signal and LVDS signal sent by the first ITOF sensor. It also controls the power selection module to select a voltage corresponding to the frequency of the LVDS signal to power the energy storage module, controls the energy storage module to discharge during exposure, and, when the first ITOF sensor is idle, superimposes a DTOF signal onto the LVDS signal to obtain a superimposed signal. Furthermore, when the exposure time to the first ITOF sensor is determined by the STROBE signal, the module sends the superimposed signal to the laser driving circuit so that the laser driving circuit processes the superimposed signal, and controls the laser to output laser light based on the processed signal. The scanning ranges of the first ITOF sensor and the second ITOF sensor overlap.

2. The laser drive control system according to claim 1, characterized in that, The laser drive control system further includes: The discharge control module is electrically connected to the power selection module, the FPGA module, and the energy storage module. The discharge control module is used to discharge under the control of the FPGA module when switching from high voltage to low voltage.

3. The laser drive control system according to claim 2, characterized in that, The laser drive control system further includes: A current limiting protection module is provided, which is electrically connected to the energy storage module, the laser, and the laser driving circuit, respectively. The current limiting protection module is used to provide current limiting protection for the laser driving circuit.

4. The laser drive control system according to claim 3, characterized in that, The laser driving circuit includes: A differential-to-single-ended module is electrically connected to the FPGA module, and the differential-to-single-ended module is used to convert the superimposed signal into a single-ended signal.

5. The laser drive control system according to claim 4, characterized in that, The laser driving circuit further includes: A high-frequency drive module is electrically connected to the differential-to-single-ended module. The high-frequency drive module is used to shape the single-ended signal and increase its driving capability.

6. The laser drive control system according to claim 5, characterized in that, The laser driving circuit further includes: A high-frequency MOS module is electrically connected to the high-frequency drive module and the laser, respectively. The high-frequency MOS module is used to provide a low-impedance, high-current loop for high-frequency modulation of the laser.

7. The laser drive control system according to claim 6, characterized in that, The laser driving circuit further includes: An absorption module is electrically connected to both the high-frequency MOS module and the laser, and is used to absorb overshoot signals.

8. The laser drive control system according to claim 6, characterized in that, Both the energy storage module and the high-frequency MOS module are connected to the power supply ground.

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