The application processor (AP) is an essential core component of many electronic devices, including smartphones, and is constantly evolving to improve computational performance and power efficiency while incorporating new technologies. The evolution of APs is central to the performance of electronic devices and will become increasingly important in the future.
AP stands for Application Processor and is literally the “brain” of an electronic device, where all logic operations are based. It’s a key component that can have a huge impact on a device’s performance, power consumption, and more. The reason why APs are classified and developed separately from other common computer components, such as CPUs and GPUs, is that APs are found in all electronic devices, large and small. In other words, APs are a combination of specialized computation and the ability to control numerous interface devices, such as communication chips, USB, NPUs, and so on. Therefore, when new features are added, AP development must be done together.
As you can see, APs are not just developed for computational performance alone, and this is one of the areas that has seen tremendous advancements in the last decade as new technologies are constantly being applied. A prime example is the smartphone. Considering that Steve Jobs unveiled the iPhone 1 in 2007, it took about 15 years for the smartphone to evolve into what it is today. Long ago, when I was in elementary school, cell phones were uncommon, and playing high-performance games on them or using LTE internet communication was unthinkable. At the center of how phones have gotten bigger, thinner, and faster is AP technology, and it’s only going to get better from here. Below, we’ll explain this AP technology in more detail.
AP chips are smaller than the size of your fingernail and are found in smartphones from every company. While the features that make up an AP are increasingly diverse, there are a few key components that an AP must have: First, you need a CPU, a so-called “microprocessor”. In the past, these were often transistors, but nowadays they are produced using nano processes. Modern APs are made with a process of about 10 nanometers (nm) and can integrate about 6 billion transistors. The smaller the nanometer scale of the process, the more transistors can be integrated. After the CPU, the next most important component is memory. In an AP, there is a memory block that is responsible for RAM and memory. This part is basically solved by increasing the capacity, which is currently mostly DDR memory.
In addition to the two core components described above, APs are also developed for special features of the product or performance that needs to be emphasized. The latest industry to lead the way in APs is the smartphone industry, so let’s take a look at some of the other ancillary parts of APs applied to smartphones.
Graphics are the most important element when a user is enjoying an app or entertainment, as they handle the output to the screen, and while they don’t require very high performance, they do require a large amount of computation. The main processor would be at a speed disadvantage if it were to handle this computation, so GPUs are used, which are a collection of small cores in parallel. As smartphone image quality improves, better GPU performance is required, and the more demanding the game, the more important the graphics. GPUs are also more power efficient than CPUs.
Communication is the most important aspect of a smartphone and defines its identity. Without communication, a smartphone would be nothing more than a portable entertainment device. There are two types of communication: wired and wireless. While wired communications provide high speeds over wires, smartphones prioritize wireless communications. Wireless communications include phone calls, texting, LTE, Wi-Fi, Bluetooth, USB-C, NFC, and more. Unlike phone calls and texts, internet communication requires a high level of technology to send and receive massive amounts of data. The internet communication technologies that we are familiar with are 4G, 5G LTE, which require special modems to communicate. Recently, APs are being equipped with 5G modems to support 5G technology. In addition to wireless Internet communication, APs are also equipped with related technologies to support specific terminals such as USB, HDMI, and USB-C type.
The last but not least is the power management circuitry. This circuit, which is essential for increasing the power efficiency of the AP, plays an important role in the stability of the electronics. It regulates the operation of the CPU to manage power, such as low-power mode and high-performance mode.
In addition to the CPU, smartphones have processors with various computational functions, such as gyroscopes, temperature sensors, magnetic field sensors, and other micro-sensors. NPUs that perform artificial intelligence computations are also being mass-produced in various processors.
To develop these APs with better performance, new technologies are being applied. Before explaining the latest technologies, let’s explain the basic process of how semiconductors are made. All APs are made using the semiconductor process. The process of designing and drawing circuits on silicon wafers using high energy is repeated to produce APs, which are then used as components in electronic devices. Modern APs aren’t made with large transistors or wires like they were in the 1900s, so the process is relatively simple, but it requires a great deal of precision and accuracy.
There are two ways to improve AP performance. To improve performance hardware-wise, the goal is to be as precise as possible and pack as many circuits into a given space as possible. The method of choice for this is to reduce thickness, which has recently been commercialized with 7nm processes. However, as the spacing of the process decreases, it becomes quantum mechanically unstable. For example, when a current is applied to two wires, if the wires are spaced close enough, electrons can jump across the wires and have unexpected current values. Therefore, there are limits to reducing the spacing of the process, and techniques for drawing more stable and accurate wires have been developed in recent years.
Until now, circuits were drawn using argon fluoride light. Since shorter wavelengths are needed for the 7nm process, the refractive index of the fluid was used to reduce the wavelength. However, this creates difficulties in drawing the circuit neatly. To solve this problem, a technology using ultraviolet light is being developed. Ultraviolet light has a shorter wavelength and can be used to draw circuits without the need for fluids, resulting in cleaner circuits.
The latest software advancements include techniques to increase energy efficiency. These days, power efficiency is more important than performance in AP processors, and when choosing a smartphone, we tend to value battery life over performance. To increase power efficiency, we reduce unnecessary operations and manage the operation of cores fluidly to optimize performance and power. This is done by partitioning the CPU into a big and little structure: big cores perform high-performance operations but have high power dissipation, and little cores perform low-performance operations but have low power dissipation. In recent years, this structure has been broken down further into big, medium, and little to make power management more efficient.
AP technology is not a new technology; it has been applied to embedded systems in the past and has been an integral part of common electronic devices. However, the development of the smartphone industry over the past decade has pushed the investment and development of AP technology forward significantly. Ten years may seem like a long time, but from an industry perspective, it’s a very short time. Hardware-wise, we’ve been able to refine the process and use extreme ultraviolet light to do more accurate work, and software-wise, we’re still working on minimizing power loss. There are still many improvements to be made, and new technologies and methods will continue to try to solve problems. As electronics become more and more a part of our lives, the role they play is becoming more and more important. AP technology will continue to evolve, and with each new electronic device, AP technology will evolve with it. Therefore, it is very important to know about AP, and understanding the new technologies that have been applied to AP in recent years is important for predicting the future of the industry.
