In the initial stage of system design, we must not only consider the functions, performance, operability, etc., but also the use environment in the field. The harsh conditions such as high temperature and high humidity put new requirements on system design. . Today, we use the oil well camera detection system to give you some ideas.
This system is a dual color camera application for downhole inspection. The required functions include embedded image processing, color reconstruction, communication, and high dynamic (HDR) image stabilization. The oil well requires the system to work at least at an ambient temperature of 125 degrees Celsius. In combination, we use the Xilinx Spartan-6 XA6SLX45 FPGA device because of its wide operating temperature range, robustness, small package size, memory and LUT resources are relatively rich. (Figure 1 Schematic diagram of the oil well environment)
In many system designs, heat dissipation needs to be considered, and it can be roughly classified into two types: passive heat dissipation and active heat dissipation. Passive heat dissipation generally increases the area of ​​contact with air. Active heat dissipation is generally a measure to actively reduce the temperature, such as increasing the fan and water cooling. Thermoelectric cooling methods are commonly used on electronic systems, such as the Peltier effect: the use of electrical current through the junction of two suitable materials produces a temperature drop. Although this solution can help reduce the temperature of the device, it has the disadvantage of requiring a large amount of external power supply.
For our case, air cooling is not applicable, because a large amount of air is generally closed, the air temperature will rise quickly, and the water cooling scheme is less suitable, because cold water circulation transportation is a big problem, so we consider the above considerations. The Peltier effect can only be used for thermal design. But we also need to provide a larger current and conductor material, the actual situation is that we can only provide a limited extra current, so it can only achieve a small temperature drop effect.
And our devices also include a camera, image acquisition quality will exponentially decrease with increasing temperature, so we must also optimize our cooling measures, focusing on the image sensor instead of the FPGA, memory and power circuit parts, because It is almost impossible to dissipate the FPGA using the Peltier effect. The only way we can reduce the peak temperature inside the FPGA, and we also use FPGA devices in small packages, because the larger the device, the more static it will be. Power consumption will generate more heat.
We also optimize our FPGA code to use as few logic resources (LUTs) as possible. At the same time we also optimize the clock frequency, the dynamic power consumption is related to the always frequency. We use as few I/O pins as possible to treat unused I/O pins as virtual, shortening current flow distance and reducing the effect of Joule effect, which also reduces the power consumption of the internal I/O blocks of the FPGA.
In the design of the circuit board (PCB), we can use multiple layers to increase heat conduction and thermal cycling. This design also increases the reliability of the board (PCB). The most important thing is to optimize the FPGA code design so that the FPGA works at a suitable clock frequency to meet performance requirements without excessive power consumption.
Figure 2 Image acquisition module designed with Xilinx Spartan-6 FPGA
Through the above aspects of heat dissipation considerations, the board that we finally realized can work normally at an ambient temperature of 125 degrees Celsius. The functions include SDRAM management, bus communication and image acquisition processing. Of course, it is necessary to meet the system requirements. Field testing and aging testing, etc., can only be considered a qualified system design if these are met.
In summary, there are still many aspects of the system cooling solution that can be used as an entry point. It is important to select a suitable method based on the actual application environment of the system.
Uv Screen Protector,Anti-Blue Light Uv Film,Anti-Fingerprint Uv Glass Film,Full Screen Tempered Glass
Shenzhen TUOLI Electronic Technology Co., Ltd. , https://www.tlhydrogelprotector.com