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Circuit boards are an important component of automotive electronics, and the rationality of circuit board design and the maturity of the production process directly affects the reliability of automotive electronics. Circuit board defects not only cost automakers a lot of money but also jeopardize people's safety.
Recalls of cars due to circuit board problems occur from time to time, for example, XXCars brand recalled more than 8,000 cars in 2021 due to the vehicle due to taillight circuit board patch manufacturing problems, which may lead to the taillight flicker or taillight does not light up, and can not provide effective signals for the rear vehicle, there is a potential safety hazard. The automotive printed circuit board with the Tiny defects may bring important safety risks, There must be rigorous testing to control the quality of the automotive printed circuit board, in the entire automotive printed circuits board PCBA process is over, first after the ICT online test, in the case of the circuit board does not add power to the PCBA board to diagnose process defects in the electrical test To determine whether the circuit board has open circuits, short circuits, virtual welding, missing devices, device failure, etc., the fault must be pinpointed to the level of the device pin. According to the test report, the circuit board fault repair, while feedback to the circuit board manufacturing process, adjust the SMT assembly line related equipment operating parameters, improve circuit board yield.
New energy vehicle circuit boards are a key component used to control and manage the electrical system of new energy vehicles. They are usually composed of a series of electronic components and connectors that are used to monitor, regulate, and distribute electrical energy to ensure the normal operation of the vehicle. These circuit boards are responsible for controlling the electric motor, battery management system, charging system, and other critical functions that enable new energy vehicles to operate efficiently and meet their performance and safety requirements.
After confirming that the circuit boards of the automotive electronics products are free of process defects, the products are packaged and become finished products that are ultimately installed in the corresponding parts of the vehicle and then begin to enter the next test station of the products - FCT (Functionality Testing) station, to carry out functional testing of the finished automotive electronics products. The test system provides the product in the actual working environment of the excitation signal, and the normal operation of the product needs to control the relevant load unit, through the excitation/response test to diagnose whether there are functional defects in the product.
It is necessary to pay attention to the quality control of the product.
Which part of a car needs to use PCBA?
(1) Car computer: generally installed under the driver's seat dashboard or near the wiper linkage.
(2) GPS positioning system: installed in the vehicle's A-pillar, B-pillar, and C-pillar, inside the car engine compartment, around the dashboard, under the seat, inside the trunk, under the front windshield, and other locations.
(3) Engine control module: usually located near the battery.
(4) In-vehicle surveillance camera: installed around the sun visor of the main driver's seat, installed around the sun visor of the passenger's seat, and at the roof in the middle of the front and passenger seats. Rear camera: similar to the front camera location, but the exact location may vary.
(5) Airbag control module: mounted near the handbrake.
(6) Other circuit boards: may be distributed in other parts of the vehicle, such as the top of the passenger's hand clasp box, the lower side of the central air conditioner, on the side list, under the feet of the passenger, and inside the engine room.
(7) Automotive gateway: the location is generally located in the rear of the car dashboard.
There are also differences in process requirements between automotive PCBA and consumer product PCB boards. Since automotive PCBA needs to withstand a more severe working environment and vibration impact, its process requirements are higher. For example, automotive PCBA requires more stringent soldering and protection processing to ensure circuit stability and reliability. In addition, automotive PCBA also needs to meet higher fire ratings and corrosion resistance.
Automotive PCBA needs to have better resistance to high temperature, humidity, and vibration because automotive PCBA needs to adapt to more complex automotive operating environments, such as high temperature, low temperature, humidity, vibration, and so on.
Often heard of 77Ghz millimeter wave radar is used in the automotive field. Millimeter wave radar is a kind of radar sensor that uses an antenna to emit a millimeter wave (Millimeter Wave, MMW) with a wavelength of 1-10mm and a frequency of 24-300GHz as a radiating wave. Based on the time difference between receiving and transmitting the millimeter wave, the millimeter wave radar, combined with the millimeter wave propagation speed, carrier speed, and monitoring target speed, can obtain information about the physical environment, such as the relative distance between the car and other objects, the relative speed, the angle, and the direction of movement. The wavelength of millimeter waves is between centimeter waves and light waves, so millimeter waves have the advantages of both microwave guidance and photoelectric guidance. Compared with laser radar (LiDAR), millimeter-wave radar technology is now more mature, more widely used, and cheaper; compared with visible light cameras, millimeter-wave radar has better accuracy and stability, and the price gap is shrinking. In particular, the irreplaceable advantage of all-weather work has become the mainstream choice recognized by automotive electronics manufacturers, with huge market demand.
Automotive millimeter wave radar can be divided into three major categories 24GHz, 77GHz, and 79GHz millimeter wave radar according to the millimeter wave frequency. A millimeter wave is called a very high-frequency electromagnetic wave, is a kind of 1-10 mm electromagnetic wave, his both microwave and infrared wave characteristics, frequency between 30-300 GHz, according to the open frequency band to define the 77 GHz millimeter wave radar refers to the working frequency band in 76 GHz - 81 GHz millimeter wave radar, is used as the main radar of the automobile front collision avoidance.
77GHz Millimeter Wave Radar Operating Principle.
77GH2 millimeter wave radar through the transmitting antenna continuously sends out the corresponding band of directional millimeter wave microwave, when the millimeter wave microwave encounters the obstacle target and reflects, through the 77GHz millimeter wave radar receiving antenna to receive the reflected millimeter wave, according to the millimeter wave band, combined with the speed change of the car, using the relevant formula to calculate the millimeter wave on the way to the time of flight x the speed of light / 2, you can know Then we can know the speed change and bearing change of the vehicle in front of us, and then deduce the relative distance between the vehicle and the vehicle in front of us, and then we can grasp and monitor the position, distance and running direction of the vehicle in front of us in real-time. Therefore, 77 GHz millimeter wave radar senses objects by sending out and receiving reflected meter waves.
77 GHz vehicle lidar has significant advantages and is gradually replacing 24 GHz as the mainstream. (1) 77 GHz radar resolution and accuracy are higher: due to the speed resolution and accuracy and RF is inversely proportional to the higher RF frequency leads to better speed resolution and accuracy. 77 GHz millimeter wave radar than 24 GHz speed resolution and accuracy increased by 3 times; (2) 77 GHz radar size is smaller: 77 GHz antenna array spacing is only one-third of 24 GHz, so the whole millimeter radar size is also smaller. Therefore, the volume of the whole millimeter radar can also realize one-third of it.
Detection distance is far, 150-200 meters; anti-interference ability, not affected by rain, snow, and fog weather, stable work; sensitive to metal substances, accurate detection distance, location, direction, and other reasons for the rapid development of 77GHz millimeter wave radar module.
In short, from the perspective of PCB manufacturers, automotive printed circuit board is a very promising direction, but need to pay attention to the quality control of the product.