Overview: This article explores field-programmable gate array technology to improve performance in modern electronics, highlighting their structure, advantages, challenges, and applications in power electronics and embedded systems. 

For high-performance digital control of power electronics systems, the field-programmable gate array (FPGA) is a potent platform that can be essential. FPGA devices are becoming increasingly common due to reduced time-to-market and minimal cost. They can be programmed to do certain hardware functions and are frequently employed to accelerate some specialized processes. 

What is an FPGA?

Field-programmable gate arrays, as shown in Fig. 1, are a type of integrated circuit that is composed of a bi-dimensional array of interconnected logic blocks. The implementation of complex functions can also be achieved by combining these logic blocks. 

Fig. 1 LOGI-EDU-2 Development Boards & Evaluation Kits - An FPGA module Source: oemsecrets

They are highly versatile semiconductor devices used in a wide range of applications across various industries. These devices are known for their ability to be programmed and reprogrammed after manufacturing, making them ideal for applications that require flexibility and adaptability.

Structure of FPGA

The FPGA structure enables the implementation of any combinational and sequential circuit, which can range from a basic logic function to a complex soft processor. A shown in Fig. 2, the key components of FPGA structures include:

  • Configurable Logic Blocks (CLB)
  • Programmable Interconnects
  • I/O Blocks

Fig. 2 Structure of FPGA Source: Rakesh Kumar, Ph.D.

Configurable Logic Blocks (CLB)

These blocks perform the logic operations and are the core building units of an FPGA. CLBs comprise four basic components: 

  • Look-up table
  • Multiplexor
  • Flip-Flop 
  • Full adder

Look-up tables (LUTs) are built over simple memory and store boolean functions, which make up the logical blocks. To create sequential circuits, each LUT is connected to a Flip-Flop and a multiplexor, and each LUT has a fixed number of inputs. 

Programmable Interconnects

They connect the logical blocks and facilitate communication between different parts of the FPGA. 

I/O Blocks

These blocks handle the input and output functions, allowing the FPGA to interface with other components. They facilitate external connections to carry signals into or out of FPGA.

Advantages Of FPGA Over Traditional Integrated Circuits

The design of an FPGA system differs significantly from that of a digital signal processor or a conventional microprocessor with added advantages. 

Reprogrammable Ability

Implementing FPGA controllers necessitates using hardware description languages (HDL) like Verilog and VHDL, where hardware function can be altered by reconfiguration. The fact that they are reprogrammable differentiates FPGA from PLD (Programmable Logic Device) or ASIC (Application-Specific Integrated Circuit) chips, which are integrated circuits designed to perform specific tasks. 

FPGA devices are premanufactured, and the hardware designers do not have to wait to produce their designs. Additionally, it is possible to update implementations to incorporate a new feature, even during runtime.

Rapid Processing Capability

Based on components like high-speed multipliers and adders, FPGAs have strong processing capabilities. These high-speed multipliers and adders operate at the highest frequency. As a result, FPGAs can offer powerful cryptographic features and fast algorithm acceleration for tasks like image processing, routing, and compression. 

Rapid Prototyping

The potential for reconfiguration also increases interest in using FPGA technology as a platform for prototyping, functional verification, and characterization of hardware designs. In contrast, with ASIC technology, trying out a new circuit is impossible, mostly because it takes time and money to build one or a small number of chips.

Affordable

Their expenses are significantly less than those of custom IC production using ASIC.

Applications

In the past, network packet analysis and signal processing were the primary applications of FPGAs. However, they are currently also used for algorithm acceleration as coprocessors or standalone systems, i.e., System-On-Chips (SoCs), because of the high-speed embedded resources that are part of the FPGA.

Because FPGAs' functionality may be updated continually, they enable the rapid development of embedded systems. Various applications use FPGA, including consumer electronics, medical devices, security systems, and the defense industry. FPGA is highly beneficial for space applications (such as in satellites or space-exploration mission devices) since it remotely updates device functions. 

Challenges

ASICs exhibit significantly superior performance and necessitate significantly less energy and space. Presently, the primary challenge faced by vendors of FPGAs is energy consumption. Additional components increase the power consumption of FPGA devices. Thus, it is necessary to minimize the energy requirements of FPGA-based systems, and every hardware design should prioritize energy efficiency.

The FPGA device's physical architecture restricts popular power-reduction strategies like voltage scaling and power gating. To achieve a more favorable power balance, vendors such as Xilinx are replacing platform components with optimized ASIC hard-IP (HIPs). For example, Altera and Xilinx developed their platforms using a combination of coarse and fine-grained components, specifically HIPs and small LUTs with four and six inputs.

FPGA hardware security is also becoming a more significant concern as their market share in embedded systems grows. Companies like Altera continue to advance FPGA technology by integrating features such as AI capabilities, enhanced security measures, and improved power efficiency. For example, Altera's Agilex 3 FPGAs include on-chip ARM Cortex A55 CPUs with AI capabilities, making them suitable for real-time computation tasks in autonomous vehicles and industrial IoT applications. 

An FPGA module to consider

XC7A200T-1FFG1156C

The XC7A200T-1FFG1156C, shown in Fig. 3, is a high-performance FPGA from Xilinx's Artix-7 series. It is optimized for cost-sensitive applications and power efficiency. It supports high-speed interfaces with multiple transceivers and is suitable for applications requiring significant logic resources and DSP capabilities.

Fig. 3 XC7A200T-1FFG1156C Source: oemsecrets

To conclude, FPGAs are vital components in modern electronics due to their programmability, flexibility, and ability to handle complex computations efficiently. FPGAs continue to evolve as technology advances, offering enhanced performance and integration capabilities that meet the demands of emerging applications across various industries.

Summarizing the Key Points

  • FPGAs are integrated circuits that can be programmed and reprogrammed, making them ideal for applications requiring flexibility and adaptability in various industries, including power electronics.
  • The architecture of FPGAs includes Configurable Logic Blocks, Look-Up Tables, and I/O blocks, enabling the implementation of complex combinational and sequential circuits.
  • FPGAs offer significant advantages over traditional integrated circuits, such as rapid prototyping, lower costs, and the ability to update functionalities during runtime, enhancing development efficiency

Reference

De La Piedra, A., Braeken, A., & Touhafi, A. (2012). Sensor Systems Based on FPGAs and Their Applications: A Survey. Sensors, 12(9), 12235–12264.
https://doi.org/10.3390/s120912235

Skuta, M., Macko, D., & Jelemenska, K. (2020). Automation of Dynamic Power Management in FPGA-Based Energy-Constrained Systems. IEEE Access, 8, 165894–165903.
https://doi.org/10.1109/access.2020.3022955

Yu, H., Lee, H., Lee, S., Kim, Y., & Lee, H. (2018). Recent Advances in FPGA Reverse Engineering. Electronics, 7(10), 246.
https://doi.org/10.3390/electronics7100246

Oemsecrets- XC7A200T-1FFG1156C by Advanced Micro Devices