The FPGA invasion
Let’s come back 20 years ago. FPGA are mystical devices used in exotic applications. They came from programmable PAL memories that could be used to execute simple logic operations, and not only simple but the amount of logic that they could execute was also very low. These simple devices were evolving and increasing the number of resources that they had and some years later the FPGA were born. At that moment, the development of the devices that several years later will become in FPGA, was founded by a military entity, so the first applications of FPGA were in the field of defense. Although they were in our lives since the ’80s (eejournal), in the 2000’s FPGA are used for very specific applications, specific and complex, at least they seem that. Networking, communications, defense, IC design… are applications where we can find FPGA in 90s, applications where power consumption and cost are not a big deal. At that moment, FPGA were used in cases where the design and manufacture of a custom IC was even more expensive, especially in applications where the number of devices built was no more than a few units. Then, the 2000s arrive, and the FPGA invasion began.
Since the 2000s, FPGA has been more and more used in many applications where some years later, analog circuits, processors or ASIC are used. In this article, I want to show you some applications where FPGA are not used some years ago but now, their use is very common.
Radio circuits are one of these examples. Although for applications up to 1 GHz FPGA are used for years, in applications for the newest bands like LTE, 5G, Bluetooth or WIFI, where the frequency is above 2 GHz, specific application circuits are almost the unique option. ICs like the ones created by Realtek are often used for WIFI or Bluetooth applications, but now, we can find WIFI applications where the FPGA is the center of the system. indeed, this couldn’t be possible if the speed of ADCs and DACs don’t follow the speed of the FPGA. We can say that the couple FPGA + ADC/DAC has been possible products like USRP or HackRF, in this case, it uses a CPLD and an ARM microcontroller.
Another field where FPGA have arrived is in video processing. High definition (HD), Full High Definition (Full HD or 1080p), 2K, 4K or the new ones that have to come, are the number of points in each frame that the processing system has to process to determine their color, looking for shapes… and all of this data has to be processed at 100 Hz in the new televisions. The amount of data to process is huge, and for that ASIC are often used, but we also can find some TV manufacturers that include FPGA inside their products. Including FPGA in this kind of device has a great advantage over the use of ASIC, the updating capability. Using FPGA we can update the design that is loaded inside, so we can make improvements in the product or fix errors with new versions.
Radio and video are two applications that we use many times as users, but there are other applications less common than television where FPGA has become a standard, hardware acceleration. For many years, Graphics Processing Units (GPU), or graphic cards, were used to accelerate the execution of some algorithms. The strongest point of these devices was the number of little processors that a GPU has inside. 64, 128 or 256 are a big number of microprocessors, but they are designed for one purpose, graphics. They are designed to compute rotations, and they do this very efficiently. They are ASIC designed for that, but, what happens if our application has to perform many divisions instead of matrix rotations? We also can use GPU, but since they are not designed to execute these operations, we will have a loss of performance. We will get the best performance using a device like a gPU but with many cores designed to perform divisions, and here is where FPGA are the best choice. We can implement many division cores, so we will be able to compute many divisions at the same time.
And finally, the field where I work, power electronics. This is maybe the field where someone does not expect to find FPGA, since power electronics control is a field where digital signal processors are used for many years, but the need for improved performance by using multi-level converters with complex modulation schemas makes the FPGA the best option. Texas Instruments, the most important digital signal processors manufacturer, include in its devices a (very) small number of logic cells used to compute some basic logic operations in parallel to the CPU. This, far from being a new competitor for FPGA, makes the power electronics manufacturers discover the power of the FPGA in this field, and not just for modulation. In this blog, we have already seen that FPGA are the best option (or at least a very good option) for digital signal processing, and the regulators used to control this kind of devices are also digital signal processing algorithms.
The applications seen in this article are just a small amount of all the applications in which FPGA are used now. Cost reduction and high level synthesis will make that FPGA continue growing and who knows if, in some years, processors or digital signal processors will be just IP cores to be deployed on FPGA. Happy new year!