FPGA core voltages are becoming increasingly constant voltage and high current. Their power supply circuits require even more space savings, higher precision and efficiency, long-term availability, and design flexibility. The main power supply products used in Altea® FPGA evaluation kits are the μModule🄬 series from Analog Devices, Inc.
High withstand voltage and high current capability
Analog Devices' μModule🄬 has a high affinity with FPGAs because many products support 12V/24V bus voltage input power supplies, making them easy to use in designs for industrial equipment.
In addition, since large FPGAs may require power supply circuits that can handle high current, it is safe to use power supply products that can be connected in parallel. Analog Devices' power supply products have built-in amplifiers with excellent characteristics that enable stable parallel connection. Parallel operation allows for high current capability and improved load response.
Figure 1 shows an example of LTM4650 connected in parallel to handle a maximum of 200A.
Figure 1: LTM4650 parallel connection example
The ability to connect in parallel is also important because the Altea® Agilex™ series recommends high-speed load response due to multi-phase operation with parallel connections.
Package structure that takes thermal design into consideration despite its small size
Small power circuits with multi-channel
Recent FPGAs are increasingly integrated, and many boards say that the main component on board besides the FPGA is the power circuit. Boards with high-performance FPGAs are multi-layered boards, and board size directly affects cost.
Figure 2 shows an example of a 4-channel product. The LTM4643 is a product that combines these power supplies into a single package. This enables miniaturization and simplifies board layout design.
Figure 2: 4-channel product LTM4643
Thermal design-conscious package
A problem that arises when miniaturizing power supply circuits is heat.
Analog Devices' μModule🄬 package is designed to minimize thermal resistance. Figure 3 shows a photograph of the temperature rise when four LTM4636 modules are operated in parallel. Each module is operating at 40A output to supply a total of 160A. The temperature rise at this time is contained in a very small temperature rise of 40°C. In addition, the uniform temperature of each module indicates that the current is well balanced during parallel operation.
These characteristics make the LTM4636 a good match for the core voltage of FPGAs, which require low-voltage high-current operation.
Figure 3: LTM4636 in 4-parallel operation
PMBus Support
In the Altea® Agilex™ series, Smart VID enables individual optimization of device margins due to semiconductor manufacturing variations to reduce power consumption while maintaining performance.
Smart VID requires a PMBus-compliant power supply product, which is available in μModule🄬 or power system management products from Analog Devices, Inc.
Summary
We have introduced some of the unique power supply products used in Altea® FPGA evaluation kits.
The parallel-connectable power supply modules enable high current and fast load response, which is a very useful solution for stable operation of FPGAs. The FPGA also supports low power consumption by providing SMART VID functionality.
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