In the hardware circuit design, each IC chip has a corresponding power port to supply power to drive the IC to work. For ordinary IC chips, most of them are powered by a single power supply of 3.3V, and the output high-level voltage is also 3.3V, such as commonly used chips such as MCUs and memories. But this is not the case for FPGAs. The characteristics of programmable logic endow it with the ability to contain everything and eventually become a chip that requires multiple power supplies. What is the power supply voltage type for FPGAs? 1. FPGA supply voltage An FPGA chip usually requires multiple voltages. For example, Xilinx's new-generation A7, K7, V7 and other series of chips can have up to 6 voltages, which are 3.3V, 2.5V, 1.8V, 1.5V, 1.2V, 1.0V. For FPGA, the voltage type is usually the following 3 types: (1) The core voltage Vccint, this voltage is generally low, currently 1.2V is commonly used. The core voltage is used to supply power to the internal logic of the FPGA, that is, the transistor switch of the chip is provided by the core voltage. When the internal logic working clock rate is higher and the logic resources are used more, the core voltage supply current will be larger, which can be as high as several amperes. At this time, the chip will inevitably become hot and require a heat sink to assist in heat dissipation. In addition, the core voltage Vccint is not necessarily 1.2V. With the development of FPGA technology, this voltage gradually decreases from 5V, 3.3V, 2.5V, 1.5V, and 1.2V. The specific value needs to be found in the corresponding chip data manual. (2) The IO voltage Vccio, as the name implies, is the voltage that drives the IO pin. Because FPGAs often communicate with chips with a variety of different level interfaces, they will support a lot of level standards, which is also its flexibility. In order for FPGA to communicate with a variety of different level standard interface chips, Vccio is usually bounded by Banks, which are independent of each other, that is, only one IO voltage can exist in a bank block. An FPGA chip has multiple Bank blocks, and each Bnak can communicate with a level interface chip, such as Bank34 communicates with a 3.3V MCU, and Bank35 communicates with a 2.5V DDR chip. (3) Auxiliary voltage Vccaux, FPGA is not a pure digital logic chip, it also contains some analog components, such as Xilinx DCM digital clock management components, high-end FPGAs, high-speed serial-parallel converter serdes, temperature monitoring devices, etc. These analog devices, these analog devices have very high requirements for power supply noise, so an independent and stable power supply is needed for power supply. Vccaux is to provide voltage for these analog devices. In addition, Vccaux can also supply power to some IOs, such as JTAG. For details, please refer to the corresponding data manual. 2. FPGA voltage monitoring Xilinx 7 series chips are provided with internal temperature and voltage monitoring components (IP core XADC Wizard). Users can monitor the voltage value by reading the corresponding register value to determine whether the chip is working properly. (Altera does not know if this function is available, who knows who can tell me) As shown in the figure above, the xadc core can set three voltage thresholds and then monitor them. When the voltage exceeds the limit, it will alarm. Users only need to read the status flag register or the corresponding voltage register to know whether the current voltage value is normal. Through software control, the monitoring of these three voltages can provide timely feedback of faults, and play a role in device protection and troubleshooting, which is very helpful for project development. 3. Summary FPGA is a multi-power supply chip, which gives it the advantages and flexibility of communicating with multiple interfaces, but it also needs to be more cautious in power supply design. If the power supply voltage does not correspond, the communication is not successful at the slightest, and the chip may be burned in the worst, so as a development engineer, you must take it seriously when designing. 2.0mm Pitch 2.0mm Pitch ATKCONN ELECTRONICS CO., LTD , https://www.atkconn.com
