Honored Contributor
Honored ContributorI have not tried partially powering up Cyclone IV I/O banks. A quick search through the handbook (May 2013) shows the comment that you found on p168 of the PDF.
It does appear from that comment, and from others through the handbook that if you power a single bank at 1.8V, that so long as that bank does not have any configuration pins, you can power it up later. I believe the DE-115 has jumpers for setting the I/O power, so if you had one of those, you could try powering up that board with an I/O jumper missing to see if it powered ok. How much 1.8V current is required for the other devices on the board? An alternative method to sequence the FPGA power, is to power-up the 1.8V supply with all the other FPGA power supplies, and use a power-switch to turn power on/off to the other 1.8V logic. Texas Instruments has a whole series of these types of devices. The nice thing about these power switches is that they have soft-start, so you can ramp up the power to your 1.8V logic nicely. For example, a quick search on TI's site yields this part: http://www.ti.com/product/tps22945 for up to 100mA loads. Cheers, Dave
