Point of Load Power Supplies
IMR , 06-07-2016, 07:05 PM
Hi, I'm using a Xilinx Artix 7 and the voltage tolerances for most supplies are +-5%. Say for example the FPGA requires a 1V supply +- 0.05V (5%) and the decoupling for the FPGA is very close (less than 20mm) to the pins and connected to a plane but the 1V supply for a buck converter is 100mm away and the FB is measured after the buck converter decoupling as shown in the diagram? In the Saturn PCB tools if the DC resistance has been calculated as 0.00267R so if I was to draw 1A through the conductor I would have a voltage drop of 0.00267V. This is obviously insignificant at this current but is the concept right? Likewise I should also take via losses into account?
mairomaster , 06-08-2016, 01:51 AM
I think your concept is right. In general if you have good power distribution network, you don't need to care about the voltage drop between the regulator and the FPGA.
robertferanec , 06-08-2016, 05:41 AM
We try to place important or low voltage or high current power supplies close to the chip.
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