If the power modules on 6 and 7 series Development Boards are seen to operate at moderate to high current levels (due to a customer design), it has been noted that these modules generate substantial heat and can result in unexpected power module shutdowns from over temperature conditions.This then turns off the FPGA on the Development Board.
What is the reason for this?
The onboard power for the Xilinx PCIe form factor boards (SP605, ML605, KC705, VC707 etc) is provided by a Texas Instruments digital power system comprised of controller circuits (TI UCD9248) and Digital Powertrain (tm) modules (TI PTD08A020W, PTD08A010W, PTD08D210W etc.).
Due to the limited board area available on a PCIe form factor board, the TI PTD type modules are placed physically close to each other.
At moderate to high current levels, these modules generate substantial heat.With the modules located adjacent to each other, mutual heating results.
In a bench top environment with no forced air cooling, the Xilinx PCIe form factor boards are not intended to be used with high current designs running in the FPGA.
The TI Fusion Digital Power Designer GUI should be used to monitor the current and temperature levels of the boards' power modules, and if any module temperature approaches 85C, then forced air cooling must be provided to keep the module temperature within rated limits.This will prevent unexpected power module shutdowns from over temperature conditions.
In a PC chassis environment, where the Xilinx PCIe board is plugged into a motherboard PCIe slot, the PC typically provides forced air cooling from its power supply which serves to cool the board and maintain the modules within rated limits. During early use of the Xilinx PCIe board in this environment, the TI Fusion Digital Designer Power GUI should be used to monitor the current and temperature levels of the boards' power modules, and if any module temperature approaches 85C, then additional forced air cooling must be provided to keep the module temperature within rated limits.This will prevent unexpected power module shutdowns from over temperature conditions.
Additional cooling can be provided by a fan, for example:
The TI temperature curves documented in the TI PTD module datasheets were generated in a controlled test environment with a single power module on a vertically mounted 100 mm / 3.93" square, 4-layer (2 oz. copper per layer) PC board. These temperature curves do not reflect the Xilinx PCIe card power module placement density and cannot be used to predict power module thermal performance on the PCIe card.