08-27-2018 01:46 PM
I really don't need the exact way of calculating the power consumption of an FPGA. I know that is a vast subject and it all depends on your toggle rate and AC/DC characteristics, and it can get into a lot of details.
I just need a very rough idea about what are the maxim power ratings of a Zynq, Virtex7 and an ultrascale FPGA ?
I am going to exaggerate here, but are we talking about 5 Watts, 10 Watts, 20 Watts, 60 Watts....?
And in addition to the maximum ratings, what is a typical power consumption of the mentioned FPGAs? (I know the word "typical" can mean different things in different applications, but I really don't need any exact numbers, it is okay if it is off by even few Watts.... I am just looking for very general numbers, for getting the very big picture about the power consumption).
And if you are pointing to specific documents, please let me know the page numbers so I can read about it. (I have been looking at the DC and AC Switching Characteristics document, and I wasn't able to find the answer that I am looking for.)
08-27-2018 04:39 PM - edited 08-27-2018 05:55 PM
You need the Xilinx Power Estimator (XPE) described by document, UG440.
Once you know "how much" power is needed, then you can use document, UG483, to learn about distributing this power to the FPGA (including decoupling capacitor selection and placement).
-and just to give you a rough idea, our custom board built around the XC7K160T-3FBG484C Kintex-7 (similar to Virtex-7) runs off a 5V supply and draws 1.2 amps. I consider this to be a medium complexity (ADCs, DACs, ethernet, digital I/O) and medium speed (most of logic is clocked at 120 MHz). However, you really should give the XPE a try since power consumption of digital circuits is often not intuitive. For example, digital circuit power consumption increases linearly with clock frequency but increases as the square of the voltage used to power the logic.
08-28-2018 06:14 AM
It depends a lot on what exact chips you're talking about too. The Zynq 7100 has about twenty times as much FPGA logic as the 7007S (as well as having an extra CPU core and a faster FPGA fabric). I think that you'd really struggle to use more than 2W with the PL on the 7007S; with the 7100 you'd easily go past 20W if you cranked up the clock speed and put all those DSP slices to good use.
For what it's worth - with a full-but-slow (100MHz) Zynq 7045 design I think we were around 12W all-up (CPU + FPGA). It's been a while so that may not be quite right, but it's in the ball-park.
02-21-2019 07:10 PM
I just did some measurements on a Zybo board (Zynq 7010) and a ZCU-104 board (Zynq Ultrascale 7EV part). The Zybo board running the processors at 650 MHz and nothing in the FPGA pulls about 1.3-1.5 Watts.
The ZCU-104 with a 4K image sensor streaming data and compressing it is pulling 13 watts. Much higher than I antipicated. I've played with reducing clocks, holding parts the FPGA in reset, shutting off power supplies on the board and it still consumes 8+ watts doing just about nothing. So it is NOT a low power part by any means.