Choosing power supply ICs for FPGA board design - Page 1
Forum section: electronics / projects

author: matrixofdynamism
author_rank: Regular Contributor
timestamp: April 08, 2023, 01:38:30 pm
content: I am asking this question out of curiosity and to gain knowledge. I am not doing a PCB design just yet.FPGAs can have a large number of power supplies required to operate. These would include digital supplies, analogue supplies, separate core voltage and separate I/O voltage among others. Besides this, the different voltages require to be ramped up in specific sequence at power up for the device to work correctly. Putting aside the topic of power system integrity that is handled by using decoupling capacitors and power and ground planes that need to be placed judiciously, how does one choose what components shall generate all those numerous voltages and sequence them in the correct order? This remains so far a mystery mainly because there are multiple ways to do the same thing and many often engineers will just use "what worked last time".

author: dietert1
author_rank: Super Contributor
timestamp: April 09, 2023, 08:46:30 am
content: In general the value of a FPGA solution isn't in the hardware, but in the IP that you build up during years with revisions over revisions. During that time some semiconductor vendor will suddenly offer an "FPGA power supply chip" that does it all.Then with the next board revision you may implement that chip, or not - if your design wasn't based on chips but on hybrid modules that include the support parts like coils etc. Maybe the new chip is in fact a hybrid and now includes the support parts, so everything becomes much easier.Also the price matters. Sometimes new products are more expensive. If you want a second source, this may be a reason to wait a bit. It takes 20 years for a patent to become obsolete.You make the rules.Regards, Dieter

author: redkitedesign
author_rank: Regular Contributor
timestamp: April 09, 2023, 10:05:35 am
content: If the board is mostly the FPGA, and not much else: Copy the power supply design from the FPGA vendor demo-board.If you have your own specific requirements: Design it yourself. Almost every buck controller has an power good output and a enable input, these can be used for sequencing.Otherwise, there are power supply watchers (reset controllers) available for almost every supply voltage.For designing a power supply: Let one of the manufacturers design tools do the work for you.

author: matrixofdynamism
author_rank: Regular Contributor
timestamp: April 10, 2023, 09:06:40 pm
content: Although one could use linear power supply regulators, I can see that most boards contains switched mode power supplies with there is a controller with external components. There seems to be some sort of science behind creation of the SMPS circuit implemented on the PCB where the resistor, capacitor and inductor value needs to be chosen according to some mathermatical formulas and the PCB layout needs to be done a certain way to get the best performance.Is there any application note that covers the topic of designing power supply for use in FPGA boards? I mean I have seen large FPGA boards where one contained more than 10 voltage rails, just mind boggling.

author: dietert1
author_rank: Super Contributor
timestamp: April 10, 2023, 09:14:30 pm
content: If you go here:https://www.ti.com/tool/PMP7977they show you how to use some of the multiple rail chips i mentioned above. The document links to schematics, test results etc. etc.Regards, Dieter

author: coromonadalix
author_rank: Super Contributor
timestamp: April 10, 2023, 11:17:23 pm
content: you have many modelss and sizeswe use at my job zynq based board, we have at least a dozens of supplies in it, ddr psu, zynq psu's i/o's etc ... it really depend of your designbga based ic'shttps://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.mouser.ca%2Fimages%2Fmurata%2Flrg%2FMYMGK1R820_SPL.jpg&tbnid=hZoHDavyIxALdM&vet=12ahUKEwiOzf71uKD-AhUZMlkFHdUvBe0QMygeegUIARDyAQ..i&imgrefurl=https%3A%2F%2Fwww.mouser.ca%2FProductDetail%2FMurata-Electronics%2FMYMGK1R820ERSR-H%3Fqs%3Dhd1VzrDQEGhxOBVwHINHgg%253D%253D&docid=khj7irl8-48qYM&w=600&h=600&q=pico%20bga%20dc-dc%20converters&client=firefox-b-d&ved=2ahUKEwiOzf71uKD-AhUZMlkFHdUvBe0QMygeegUIARDyAQhttps://www.google.com/imgres?imgurl=https%3A%2F%2Feepower.com%2Fuploads%2Fthumbnails%2FBGA-Packaging-Option-for-Digital-Point-of-Load-DC-DC-Converters.jpg&tbnid=0HkvC0Ish6478M&vet=12ahUKEwiOzf71uKD-AhUZMlkFHdUvBe0QMygAegUIARCRAQ..i&imgrefurl=https%3A%2F%2Feepower.com%2Fnews%2Fbga-packaging-option-for-digital-point-of-load-dc-dc-converters%2F&docid=BM40SKnbM0SrGM&w=998&h=609&q=pico%20bga%20dc-dc%20converters&client=firefox-b-d&ved=2ahUKEwiOzf71uKD-AhUZMlkFHdUvBe0QMygAegUIARCRAQhttps://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.powerelectronictips.com%2Fwp-content%2Fuploads%2F2017%2F09%2FLT8711.jpg&tbnid=uou3Kt9M0O0DAM&vet=10CHAQMyhGahcKEwi43tP9uKD-AhUAAAAAHQAAAAAQAw..i&imgrefurl=https%3A%2F%2Fwww.powerelectronictips.com%2Fdcdc-controller-synthesizes-five-converter-topologies-puts-10%2F&docid=5pceu3knhhsGEM&w=2100&h=1500&q=pico%20bga%20dc-dc%20converters&client=firefox-b-d&ved=0CHAQMyhGahcKEwi43tP9uKD-AhUAAAAAHQAAAAAQAw