Modularized PCB circuit structure of all-solid-state 3D laser radar

Abstract

The utility model discloses a modularized PCB circuit structure of an all-solid-state 3D laser radar, and relates to the technical field of laser radars, the modularized PCB circuit structure is characterized in that a laser receiving module and a central processing module are both integrated on a first PCB, a laser transmitting module and a power supply module are both integrated on a second PCB, and the first PCB is connected with the second PCB; the laser emitting module is used for emitting laser to a target object; the laser receiving module is connected with the central processing module, the central processing module is connected with the lower computer, the laser receiving module is used for receiving reflected laser reflected by a target object, and the central processing module is used for obtaining the phase difference between the emitted laser and the reflected laser and transmitting the phase difference downwards. According to the application, the PCBs are modularly designed, and the two PCBs which are connected with each other are respectively integrated with different functional modules, so that independent operation and efficient cooperation among the modules are realized, later module expansion is facilitated, and the maintenance and upgrading convenience and the heat dissipation efficiency of the system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser radar, in particular to a modular PCB circuit structure of a solid-state 3D laser radar. BACKGROUND

[0002] The current solid-state 3D laser radar hardware circuit design often arranges all components on a single PCB, which leads to compact system structure, difficult heat dissipation, and inconvenient maintenance and upgrading. With the continuous development of laser radar technology, the requirements for system performance, reliability and maintainability are increasing, so a PCB layout structure with higher convenience for maintenance and upgrading and higher heat dissipation efficiency is needed. CONTENT OF THE INVENTION

[0003] The purpose of the present application is to provide a modular PCB circuit structure of a solid-state 3D laser radar, which can realize independent operation and efficient cooperation between modules, facilitate later module expansion, and improve the convenience of system maintenance and upgrading and the heat dissipation efficiency.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] In a first aspect, the present application provides a modular PCB circuit structure of a solid-state 3D laser radar, comprising: a central processing module, a laser receiving module, a laser emitting module, a power supply module, a first PCB and a second PCB; the laser receiving module and the central processing module are integrated on the first PCB, the laser emitting module and the power supply module are integrated on the second PCB, and the first PCB is connected with the second PCB; the laser emitting module is used for emitting laser to a target object; the laser receiving module is connected with the central processing module, the central processing module is connected with a lower computer, the laser receiving module is used for receiving reflected laser reflected by the target object, and the central processing module is used for acquiring a phase difference between the emitted laser and the reflected laser and sending the phase difference to the lower computer; and the power supply is used for supplying power to the central processing module, the laser receiving module and the laser emitting module.

[0006] According to the specific embodiments provided by the present application, the following technical effects are disclosed:

[0007] The present application realizes independent operation and efficient cooperation between modules by modularizing the PCB, integrating different functional modules on two interconnected PCBs, facilitating later module expansion, and improving the convenience of system maintenance and upgrading and the heat dissipation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0009] Figure 1 A structural schematic diagram of a modular PCB circuit structure of a full solid-state 3D laser radar provided by the embodiment of the present application.

[0010] Figure 2 A physical diagram of a full solid-state 3D laser radar provided by the embodiment of the present application.

[0011] Figure 3 A structural schematic diagram of a power module provided by the embodiment of the present application.

[0012] Figure 4 A structural schematic diagram of a central processing module provided by the embodiment of the present application.

[0013] Figure 5 A driving circuit diagram of a laser emitting module provided by the embodiment of the present application.

[0014] Figure 6 A structural schematic diagram of an EPC660 of a laser receiving module provided by the embodiment of the present application.

[0015] Figure 7 A circuit diagram of a laser receiving module provided by the embodiment of the present application.

[0016] Figure 8 A wiring structure diagram of a first PCB provided by the embodiment of the present application.

[0017] Figure 9 A wiring structure diagram of a first top layer provided by the embodiment of the present application.

[0018] Figure 10 A wiring structure diagram of a first inner layer provided by the embodiment of the present application.

[0019] Figure 11 A wiring structure diagram of a second inner layer provided by the embodiment of the present application.

[0020] Figure 12 A wiring structure diagram of a third inner layer provided by the embodiment of the present application.

[0021] Figure 13 A wiring structure diagram of a fourth inner layer provided by the embodiment of the present application.

[0022] Figure 14 A wiring structure diagram of a first bottom layer provided by the embodiment of the present application.

[0023] Figure 15 This is a wiring diagram of the second PCB board provided in an embodiment of this application.

[0024] Figure 16 This is a wiring structure diagram of the second top layer provided in an embodiment of this application.

[0025] Figure 17 This is a wiring structure diagram of the fifth inner layer provided in an embodiment of this application.

[0026] Figure 18 This is a wiring structure diagram of the sixth inner layer provided in an embodiment of this application.

[0027] Figure 19 This is a wiring structure diagram of the second bottom layer provided in an embodiment of this application.

[0028] Symbol explanation:

[0029] Central processing module-1; laser receiving module-2; laser emitting module-3; power supply module-4; first PCB board-5; second PCB board-6. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1, such as Figures 1-2 As shown, this embodiment provides a modular PCB circuit structure for an all-solid-state 3D LiDAR, including: a central processing module 1, a laser receiving module 2, a laser emitting module 3, a power supply module 4, a first PCB board 5, and a second PCB board 6.

[0033] The laser receiving module 2 and the central processing module 1 are integrated on the first PCB board 5, the laser emitting module 3 and the power module 4 are integrated on the second PCB board 6, the first PCB board 5 is connected with the second PCB board 6; the laser emitting module 3 is used for emitting laser to a target object; the laser receiving module 2 is connected with the central processing module 1, the central processing module 1 is connected with a lower computer, the laser receiving module 2 is used for receiving reflected laser reflected by the target object, the central processing module 1 is used for obtaining a phase difference between the emitted laser and the reflected laser and sending the phase difference to the lower computer; the power supply is used for supplying power for the central processing module 1, the laser receiving module 2 and the laser emitting module 3. The central processing module stores an existing program used for calculating the phase difference between the emitted laser and the reflected laser.

[0034] Optionally, the emitted laser is a continuous sinusoidal wave laser.

[0035] Further, the first PCB board 5 and the second PCB board 6 are provided with connectors at edges thereof, the first PCB board 5 and the second PCB board 6 are connected through a flexible flat cable; interfaces of the connectors include: an external power supply interface, a network cable interface and a JTAG debugging interface. The edge of the second PCB board 6 is a side edge position of the second PCB board.

[0036] Optionally, the flexible flat cable is a PFC flexible flat cable, which is used for transmitting high-speed data and control signals.

[0037] Further, the central processing module 1, the laser receiving module 2, the laser emitting module 3 and the power module 4 are all provided with interface circuits; the interface circuits include: a too net interface, an IIC interface and a high-speed parallel data interface. The interface circuits need to consider signal integrity and electromagnetic compatibility to ensure stable communication between the modules.

[0038] In actual application, interface design needs to consider electromagnetic compatibility (copper foil is laid in the inner layer of the PCB as a ground layer, which helps to suppress electromagnetic noise) (reasonable wiring avoids cross interference between high-speed signal lines and low-frequency signal lines and power lines as much as possible) and signal integrity (multi-layer board design is adopted, the first PCB layer adopts 6 layers and the second PCB layer adopts 4 layers) (the power module 4 adopts a DC-DC step-down chip) problems to ensure the reliability of system operation.

[0039] Further, the edges of the first PCB board 5 and the second PCB board 6 are further provided with heat dissipation holes. The heat dissipation holes can dissipate heat through natural convection.

[0040] Further, the laser emitting module 3 is further provided with a heat sink or a fan. The heat sink or the fan can actively dissipate heat.

[0041] Optionally, the first PCB board 5 is a 6-layer board design, with a size of 15 cm x 6 cm. The laser receiving module 2 and the central processing module 1 are placed on the first top layer, as shown in Figure 8 The left side is the EPC660 laser receiving module 2, the middle is the FPGA chip of the central processing module 1, and the right side is the SDRAM chip and the Ethernet communication part. Since the system voltage requirement is high, a 6-layer board design is adopted.

[0042] Optionally, the second PCB board 6 is a 4-layer board design, with a size of 10 cm x 6 cm. The SFH4715AS laser transmitter is placed on the bottom layer, and other components are placed on the top layer. As shown in Figure 9 The left side is the laser transmitting module 3, the middle and right side are the power module 4, and the 12V input power is connected from the right side interface. Since the laser transmitting module 3 and the power module 4 generate a lot of heat, multiple layers of copper are designed.

[0043] In actual application process:

[0044] 1) Central processing module 1: as shown in Figure 4 The function of the central processing module 1 is to use FPGA as the core to control other hardware circuit modules, carry the solid-state 3D laser radar software, and realize the complete function of the solid-state 3D laser radar. The central processing module 1: selects Altera's EP4CGX75CF23C8N, FPGA as the main control chip, and cooperates with SDRAM chip, Flash chip and Ethernet PHY chip to realize data processing, communication and control function.

[0045] The central processing module 1 takes FPGA as the core, including FPGA, SDRAM chip, Flash chip, Ethernet PHY chip, passive crystal oscillator and other devices, to realize the functions of laser radar control, calculation and communication.

[0046] The selected FPGA model in this embodiment is EP4CGX75CF23C8N, which has 73920 logic units, 4158Kbits of embedded memory, 198 multipliers, 290 user I / O pins and 6 phase-locked loops.

[0047] The serial configuration device is usually a Flash chip. Flash chip is a non-volatile memory widely used in various electronic products such as mobile phones, computers and tablets. The read-write speed of Flash chip is very fast, and it has a special structure that can automatically read and execute the program stored in it when the system starts, which makes it very suitable for use as a system startup device. Therefore, one of its most important applications is to store the FPGA program. The high-speed read-write characteristics of Flash chip can greatly improve the system startup speed.

[0048] For the FPGA model (EP4CGX75CF23C8N) selected in the application, after comparative analysis, the Flash chip is finally selected as the W25Q64JW model of Winbond. The chip capacity is 64Mbit, which can meet the needs of the system.

[0049] 4) Laser receiving module 2: as shown in Figures 6-7 The function of the laser receiving module 2 is to receive the laser reflected back by the target object, and to convert the received optical signal into a digital signal and transmit it to the central processing module 1.

[0050] The laser receiving module 2 takes EPC660 as the core and contains its peripheral circuit, including signal amplification, filtering and interface circuit. In the embodiment, since the EPC660 chip is difficult to solder, the damage rate is high, and it cannot be reused, so the EPC660 and the peripheral circuit use the EPC660 CC (Card-edge Connector Chip Carrier) produced by the manufacturer, which simplifies the design of the laser receiving module 2 and is easy to reuse and debug.

[0051] The EPC660 uses a 4MHz passive crystal oscillator externally, and generates the clock required by the EPC660 system through the internal phase-locked loop frequency multiplication. The EPC660 has an IIC interface, supports a 7-bit IIC address, of which the lower two bits can be defined by A0 and A1 two pin initialization, and supports Fast Mode plus (FM+), with a maximum rate of 1Mbit / s. The FPGA performs read-write operation on the RW register and programming of the EEPROM register for storing configuration parameters through the IIC interface, which is convenient for parameter configuration and control.

[0052] The EPC660 outputs the original differential sampling data through the high-speed parallel data output interface (ToF Camera Module Interface, TCMI) interface. TCMI is a programmable high-speed parallel data output interface used to download pixel data. When the integration period is completed and the ADC conversion is completed, the readout result is moved to the data output buffer, which is immediately transmitted to the outside through the TCMI interface. The ADC conversion is parallel to two complete rows at a time, one from the top pixel field and the other from the bottom pixel field, with a response time of 26.7μs for each ADC conversion under the default clock setting of 24MHz.

[0053] The TCMI interface has a DCLK clock signal, two synchronization signals of HSYNC and VSYNC, 12-bit signed data and 1-bit saturation flag. When the saturation flag is low, the data is valid, and the transmission rate can reach 312Mbit / s.

[0054] 3) Laser emitting module 3: as shown inFigure 5 As shown, the function of the laser emission module 3 is to accurately emit continuous sinusoidal waveform laser.

[0055] The core of the laser emission module 3 is a laser, and the performance of the laser will directly determine the performance of the laser radar. In this embodiment, the SFH4715AS model transmitter of the OSRAM company is selected, which is directly powered by a 12V5A main power supply, 4-way emission in parallel, 3 in each way, and a total of 12 SFH4715AS transmitters.

[0056] 4) Power module 4: as shown in Figure 3 As shown, the function of the power module 4 is to convert the input voltage into the voltage required by each component (central processing module 1, laser receiving module 2, laser emitting module 3 and power module 4), while meeting the requirements of the system and each module for power, voltage, current and ripple. The power module 4: select TPS54386 and LT1931 DC-DC buck chip to meet different voltage requirements and ensure the stability and efficiency of the power supply.

[0057] The power supply bucking process of the power module 4 usually has two schemes of low dropout voltage regulator (LDO) and DC-DC bucking chip:

[0058] Scheme one LDO bucking chip: the principle is equivalent to resistance voltage division, the stability of the output voltage is good, and the load response is rapid. The disadvantage is low efficiency, large energy loss, the energy loss is converted into heat, the load current and the pressure drop amplitude are larger, the chip efficiency is lower, and the heat is larger. Therefore, for LDO, the pressure drop and the load cannot be too large. In addition, the package of LDO chip is relatively large, which is to facilitate heat dissipation.

[0059] Scheme two DC-DC bucking chip: the principle is buck circuit, the advantages are high efficiency and wide input voltage range. The energy loss is relatively small, so the DC-DC bucking chip does not heat obviously, can realize smaller package, and the buck circuit can realize PWM digital control. The disadvantage is that the load response is worse than LDO, and the output ripple is larger than LDO. The full solid 3D laser radar of this embodiment requires large power supply power after bucking, large load, large pressure drop, and small heat, so the DC-DC bucking chip scheme is selected. After research and analysis, 3 TPS54386 and 1 LT1931 DC-DC bucking chips are finally selected to provide the voltage required by the system.

[0060] 5) First PCB board 5: as shown in Figure 8As shown, the main placement of central processing module 1 and laser receiving module 2. FPGA chip is located in the center of the PCB, surrounded by SDRAM chip, Flash chip and Ethernet PHY chip. EPC660 laser receiving module 2 is placed at the edge of the PCB, which is convenient for receiving laser signal. PCB1 adopts 6 layer board design to improve signal integrity and heat dissipation performance.

[0061] 6) second PCB board 6: as shown in Figure 15 As shown, the main placement of central processing module 1 and laser receiving module 2. FPGA chip is located in the center of the PCB, surrounded by SDRAM chip, Flash chip and Ethernet PHY chip. EPC660 laser receiving module 2 is placed at the edge of the PCB, which is convenient for receiving laser signal. PCB1 adopts 6 layer board design to improve signal integrity and heat dissipation performance.

[0062] Further, the central processing module 1 comprises: FPGA, SDRAM chip, Flash chip and Ethernet PHY chip; the FPGA is connected with the SDRAM chip, the Flash chip, the Ethernet PHY chip and the laser receiving module 2 respectively.

[0063] Further, the model of the FPGA is EP4CGX75CF23C8N.

[0064] Further, the model of the laser emitting module 3 is SFH4715AS.

[0065] Further, as shown in Figures 9-14 The first PCB board 5 comprises first top layer, first inner layer, second inner layer, third inner layer, fourth inner layer and first bottom layer in turn.

[0066] The first top layer is used for placing FPGA, SDRAM chip, Flash chip, Ethernet PHY chip and laser receiving module 2.

[0067] The first inner layer is used for providing +3.3V power supply for FPGA, SDRAM chip, Flash chip, Ethernet PHY chip and laser receiving module 2.

[0068] The second inner layer is used for providing +2.5V power supply for FPGA.

[0069] The third inner layer is used for providing +1.2V power supply for FPGA.

[0070] The fourth inner layer is used for wiring and grounding.

[0071] The first bottom layer is used for welding and fixing FPGA, SDRAM chip, Flash chip, Ethernet PHY chip and laser receiving module 2.

[0072] Among them, the FPGA stores the existing program for calculating the phase difference of the emitted laser and the reflected laser.

[0073] Optionally, the edge portion of the first top layer and the first bottom layer is also paved with copper foil as a grounding ring to reduce interference and improve signal integrity; the first inner layer, the second inner layer, and the third inner layer are also paved with copper foil as a power supply layer and a grounding layer to enhance electromagnetic compatibility and heat dissipation performance; the copper paving design can improve the performance and stability of the circuit board.

[0074] The first bottom layer is also used for placing an Ethernet PHY chip and an RJ45 interface.

[0075] Further, as shown in Figures 16-19 the second PCB board 6 includes a second top layer, a fifth inner layer, a sixth inner layer, and a second bottom layer sequentially attached.

[0076] The second top layer is used for placing the power supply module 4.

[0077] The fifth inner layer is used for providing +12V power supply for the laser emission module 3.

[0078] The sixth inner layer is used for wiring and grounding.

[0079] The second bottom layer is used for placing the laser emission module 3.

[0080] Optionally, the edge portion of the second top layer is also paved with copper foil as a grounding ring connected with the grounding layer of the second bottom layer to form a complete grounding network; the fifth inner layer is also paved with copper foil as a +12V power supply layer; and the sixth inner layer is also paved with copper foil to enhance the stability and heat dissipation performance of the power supply.

[0081] Optionally, for the parts of the laser emission module 3 and the power supply module 4 with relatively large heat generation, multi-layer copper paving, increasing the thickness of the copper foil, and increasing the heat dissipation holes can be used for heat dissipation optimization.

[0082] Optionally, auxiliary heat dissipation devices such as heat dissipation fins or fans can be arranged around the first PCB board 5 and the second PCB board 6 to further improve the heat dissipation performance of the system.

[0083] The second PCB board 6 adopts a 4-layer board design to optimize the cost and meet the electrical requirements of power conversion and laser emission.

[0084] Voltage distribution of the second PCB board 6:

[0085] The second top layer: placing power supply chips, filter capacitors, and laser emitter driving circuit components, etc.

[0086] The fifth inner layer: copper paving +12V, providing main power supply for the laser emitter.

[0087] The sixth inner layer: copper paving GND as a grounding layer to enhance electromagnetic compatibility.

[0088] In practical application process, when the lower computer receives the phase difference, the data collected by the laser radar can be processed through MATLAB and other software, and the imaging effect and measurement accuracy are analyzed.

[0089] The technical effects of the utility model are as follows:

[0090] First, improve maintainability: modular design makes system maintenance and troubleshooting more convenient and fast, and modular design makes system maintenance and upgrading more convenient. When a module fails, only the corresponding PCB board needs to be replaced to quickly restore the normal operation of the system; when the system performance needs to be upgraded, only the corresponding functional module needs to be replaced or added to realize flexible expansion of the system.

[0091] Second, improve scalability: the system can flexibly add or replace functional modules according to actual needs to meet the needs of different application scenarios.

[0092] Third, improve heat dissipation performance: by optimizing the layout and heat dissipation design of the PCB board, the operating temperature of the system is effectively reduced, and the service life of the components is prolonged.

[0093] Fourth, reduce cost: modular design makes PCB production and testing more convenient and efficient, which helps to reduce production cost and shorten production cycle.

[0094] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0095] In this paper, specific examples are applied to explain the principles and implementation modes of the present application, and the above embodiment is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A modular PCB circuit structure for an all-solid-state 3D laser radar, characterized by, The modular PCB circuit structure of the all-solid-state 3D laser radar comprises a central processing module, a laser receiving module, a laser emitting module, a power supply module, a first PCB and a second PCB. The laser receiving module and the central processing module are integrated on the first PCB, the laser emitting module and the power supply module are integrated on the second PCB, and the first PCB is connected with the second PCB; the laser emitting module is used for emitting laser to a target object; the laser receiving module is connected with the central processing module, the central processing module is connected with a lower computer, the laser receiving module is used for receiving reflected laser reflected by the target object, and the central processing module is used for acquiring a phase difference between the emitted laser and the reflected laser and sending the phase difference to the lower computer; and the power supply is used for supplying power to the central processing module, the laser receiving module and the laser emitting module.

2. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized in that, The central processing module comprises an FPGA, an SDRAM chip, a Flash chip and an Ethernet PHY chip. The FPGA is connected with the SDRAM chip, the Flash chip, the Ethernet PHY chip and the laser receiving module respectively.

3. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 2, characterized in that, The first PCB comprises a first top layer, a first inner layer, a second inner layer, a third inner layer, a fourth inner layer and a first bottom layer which are sequentially attached. The first top layer is used for placing the FPGA, the SDRAM chip, the Flash chip, the Ethernet PHY chip and the laser receiving module. The first inner layer is used for providing +3.3V power supply for the FPGA, the SDRAM chip, the Flash chip, the Ethernet PHY chip and the laser receiving module. The second inner layer is used for providing +2.5V power supply for the FPGA. The third inner layer is used for providing +1.2V power supply for the FPGA. The fourth inner layer is used for wiring and grounding. The first bottom layer is used for welding and fixing the FPGA, the SDRAM chip, the Flash chip, the Ethernet PHY chip and the laser receiving module.

4. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 2, characterized in that, The model of the FPGA is EP4CGX75CF23C8N.

5. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized in that, The second PCB comprises a second top layer, a fifth inner layer, a sixth inner layer and a second bottom layer which are sequentially attached. The second top layer is used for placing the power supply module. The fifth inner layer is used for providing +12V power supply for the laser emitting module. The sixth inner layer is used for wiring and grounding. The second bottom layer is used for placing the laser emitting module.

6. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized in that, The edges of the first PCB and the second PCB are provided with connectors, the first PCB and the second PCB are connected through a flexible flat cable, and the interfaces of the connectors comprise an external power supply interface, a network cable interface and a JTAG debugging interface.

7. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized by, The edges of the first PCB and the second PCB are further provided with heat dissipation holes.

8. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized by, The laser emitting module is further provided with a heat sink or a fan.

9. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized by, The central processing module, the laser receiving module, the laser emitting module and the power module are provided with interface circuits; the interface circuits comprise a too net interface, an IIC interface and a high-speed parallel data interface.

10. The modular PCB circuit structure of an all-solid-state 3D laser radar according to claim 1, characterized by, The model of the laser emitting module is SFH4715AS.

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