An FPGA, or Field-Programmable Gate Array, is a type of integrated circuit that can be configured to perform specific digital logic functions. Unlike fixed-function ASICs (Application-Specific Integrated Circuits), FPGAs are programmable and can be reconfigured after they have been manufactured. This makes them highly flexible and versatile, and allows them to be used in a wide range of applications.
FPGAs are composed of configurable logic blocks (CLBs) that can be interconnected in various ways to create custom logic circuits. They also typically include other components such as memory blocks, digital signal processing (DSP) blocks, and input/output (I/O) blocks for interfacing with other electronic components.
FPGA (Field-Programmable Gate Array) is a type of semi-custom circuit that evolved from programmable devices such as PAL, GAL, and CPLD. It solves the limitations of custom circuits and overcomes the limited number of gate circuits in programmable devices.
Currently, the two major FPGA manufacturers are Xilinx and Altera. Xilinx, with a market share of nearly 50%, produces products such as the Spartan, Virtex, Artix, and Kintex series. Its development tools for sixth-generation and earlier products are ISE, while the seventh-generation and later products have been moved to the Vivado platform.
Altera, the second-largest player in the FPGA market with a market share of over 40%, was acquired by Intel for $16.7 billion in June 2015. Its main products include the Max, Cyclone, Arria, and Stratix series, and its primary development tool is Quartus.
Other companies, such as Lattice, Actel, and Atmel, also produce FPGA products but have smaller market shares.
Although there are many different types of FPGA products, their principles are the same. Once we understand their basic structure, learning about them can be very easy.
ASIC stands for Application-Specific Integrated Circuit. It is a type of integrated circuit that is designed for a specific application or task, rather than for general-purpose computing. ASICs are created through a custom design process, in which the circuitry is optimized for the specific task at hand. This results in a highly efficient and low-power solution that is tailored to the exact needs of the application.
ASICs can be used in a wide range of applications, including consumer electronics, telecommunications, automotive, and aerospace industries. They are commonly used in high-volume production, where the cost of designing and producing the chip can be spread out over a large number of units.
ASIC design can be a complex and time-consuming process, requiring expertise in both hardware and software design. ASICs are typically developed using hardware description languages (HDLs) such as Verilog or VHDL, which are used to describe the desired functionality of the circuit.
One of the key advantages of ASICs is their performance. Since the circuitry is optimized for a specific application, ASICs can offer higher performance and lower power consumption than other types of integrated circuits. However, ASICs can be more expensive to design and produce than other types of ICs, and are generally only cost-effective for high-volume production runs.
Here is a detailed comparison table between FPGA and ASIC:
|Field-Programmable Gate Array
|Application-Specific Integrated Circuit
|Reconfigurable digital logic
|Fixed digital logic
|Shorter design cycle due to reusability of components
|Longer design cycle due to custom design
|Non-recurring engineering (NRE) cost
|Lower NRE cost, but higher unit cost
|Higher NRE cost, but lower unit cost
|Higher unit cost due to lower production volume
|Lower unit cost due to higher production volume
|Time to market
|Faster time to market due to shorter design cycle
|Slower time to market due to longer design cycle
|Lower performance compared to ASICs
|Higher performance compared to FPGAs
|Higher power consumption compared to ASICs
|Lower power consumption compared to FPGAs
|Can handle moderate to high complexity designs
|Can handle very high complexity designs
|High development flexibility due to reconfigurability
|Low development flexibility due to fixed functionality
|Can be used for prototyping and testing
|Not suitable for prototyping
|Easier to debug and test during development
|More difficult to debug and test during development
|Intellectual property protection
|Difficult to protect intellectual property
|Easy to protect intellectual property
In summary, FPGAs offer flexibility and ease of development at the expense of higher cost and lower performance, while ASICs offer high performance and lower cost at the expense of longer development cycles and less flexibility.
Both FPGAs and ASICs are designed with a Hardware Description Language (HDL). The two most popular hardware description languages are VHDL and Verilog.
4.What is the Difference Between an FPGA and a General Digital Integrated Circuit?
According to the different types of signals being processed, integrated circuits can be divided into analog integrated circuits, digital integrated circuits, and mixed-signal integrated circuits that combine analog and digital functions. FPGA (Field-Programmable Gate Array) is mainly used for processing digital signals (although the latest FPGAs have integrated some analog circuits, the main function of FPGAs is still focused on processing digital signals).
In the world of digital integrated circuits, signals have only two states, which are represented by the binary digits 0 and 1. For example, a high voltage level is represented by 1, and a low voltage level is represented by 0. Digital circuits have some basic logic gates, such as AND gates, OR gates, and NOT gates. By using simple AND, OR, and NOT operations, we can implement various digital computing functions.
5.The Main Applications and Industrial Chain of FPGA
AI chips are mainly divided into CPU, GPU, FPGA, and ASIC. Among them, the universality gradually decreases in the order of CPU, GPU, FPGA, and ASIC, but the computational efficiency gradually increases.
FPGA is a product that has been developed based on programmable devices such as PAL, GAL, and CPLD. It emerged as a kind of semi-customized circuit in the field of integrated circuits, which not only solved the shortcomings of customized circuits, but also overcame the limitation of the limited number of gate circuits in the original programmable devices.
With its high programmability, short development cycle, and high parallel computing efficiency, FPGA has been widely used in 5G and AI. Compared with ASIC, FPGA has higher flexibility and can keep up with the iterative updates of algorithms. Therefore, FPGA is a better choice for many communication scenarios that require upgrading at any time.
In the AI market, demand from “training” is currently the most widespread, but since 2019, demand from “inference” (including data centers and edge computing) will continue to grow rapidly. Traditional computing architectures based on CPUs cannot fully meet the high-performance parallel computing requirements of AI. FPGA is a low-power heterogeneous chip with a short development cycle and flexible programming. The solution in the field of AI is currently evolving from software to software + chips, and FPGA is a low-power heterogeneous chip with a short development cycle and flexible programming that can meet this requirement.
5.1 The Main Applications oF FPGA
5.1.1 Data Acquisition and Interface Logic Field.
- Application of FPGA in the field of data acquisition:
Since most signals in nature are analog signals, the signal processing system generally includes the data acquisition function. The usual implementation method is to use an A/D converter to convert the analog signal into a digital signal and then send it to a processor, such as using a microcontroller (MCU) or a digital signal processor (DSP) for calculation and processing.
For low-speed A/D and D/A converters, standard SPI interfaces can be used to communicate with MCU or DSP. However, high-speed A/D and D/A converter chips, such as video decoders or encoders, cannot be directly interfaced with general MCU or DSP. In this case, FPGA can complete the glue logic function of data acquisition.
- Application of FPGA in the field of logic interfaces:
In actual product design, in many cases, data communication with a PC is required. For example, sending collected data for processing by a PC or transmitting processed results to a PC for display, etc. The interfaces for PC communication with external systems are relatively rich, such as ISA, PCI, PCI Express, PS/2, USB, etc.
Traditional designs often require dedicated interface chips, such as PCI interface chips. If multiple interfaces are required, more peripheral chips are needed, and the size and power consumption are relatively large. With the FPGA solution, the interface logic can be implemented internally in the FPGA, greatly simplifying the design of peripheral circuits.
In modern electronic product design, memory has been widely used, such as SDRAM, SRAM, Flash, etc. These memories have their own characteristics and uses, and selecting the appropriate memory type can achieve the best cost-effectiveness of the product. Since the function of the FPGA can be completely self-designed, various memory interface controllers can be implemented.
- Application of FPGA in the field of voltage interfaces:
In addition to TTL and COMS interface levels, new voltage standards such as LVDS, HSTL, GTL/GTL+, SSTL, etc. are gradually being adopted by many electronic products. For example, the LCD screen driving interface is generally an LVDS interface, the digital I/O is generally LVTTL level, and the DDR SDRAM level is generally HSTL.
In such a mixed voltage environment, implementing interfaces with traditional voltage conversion devices will increase circuit complexity. By using the FPGA’s ability to support multiple voltage coexistence, the design scheme can be greatly simplified, and the design risk can be reduced.
5.1.2. High-performance Digital Signal Processing Field
In fields such as wireless communication, software-defined radio, and high-definition video editing and processing, there is a high demand for computational power for signal processing. The traditional solution is to use multiple DSPs in parallel to form a multiprocessor system to meet the requirements.
However, the main problems brought by the multiprocessor system are increased design complexity and system power consumption, and system stability is affected. FPGA supports parallel computing, and its density and performance are constantly improving, and it can already replace traditional multi-DSP solutions in many fields.
For example, to implement the H.264 high-definition video encoding algorithm, TI’s 1GHz DSP chip requires four chips, while only one Stratix II EP2S130 chip from Altera is needed to complete the same task. The FPGA implementation process is similar to the front-end design of an ASIC chip, which is conducive to importing the back-end design of the chip.
5.1.3 Other Application Fields
In addition to the above-mentioned application areas, FPGAs also have a wide range of applications in other fields:
(1) In the automotive electronics field, such as gateway controllers/vehicle-mounted PCs, and remote information processing systems.
(2) In the military field, such as secure communication, radar and sonar, and electronic warfare.
(3) In the testing and measurement field, such as communication testing and monitoring, semiconductor automatic testing equipment, and general-purpose instruments.
(4) In the consumer product field, such as displays, projectors, digital TVs and set-top boxes, and home networks.
(5) In the medical field, such as software-defined radio, medical therapy, and life sciences.