Cmod-A7 power budget

[bmentink]

Hi Guys,

Is there a way to measure the Artix-7 current directly  on the board, or alternatively a way to disable the FT2232HQ device as it draws 100mA by itself.

At the moment with 130mA drawn from 5V total board comsumption, that would place the Artix-7 + mem chip + osc + reg  at 30mA which seems quite high.

(My Papillio-pro board with a Spartan-6 was 80mA@5V (70mA used by a lower power FT2232, so that made it 10mA for the Spartan-6 etc... the Artix-7 is mean't to be 50% less power than the Spartan-6)  ... they are both clocked at 80Mhz ..

Weird ..

 

 

[jpeyron]

Hi @bmentink,

There is not a built in circuit for measuring the current on this FPGA. There isn’t any way to fully disable the FTDI chip. However, you can reduce the current drawn by powering the board with a 5V supply via pins 24 and 25 on the DIP header and not connecting anything to the USB header. That should significantly reduce the amount of current drawn. 

cheers,

Jon

[bmentink]

@jpeyron

Cool, thanks ..

EDIT: That dropped it to 80mA from 130mA .. still can't figure out why so much greater than the Spartan-6 PapillioPro board ..

PS: I eluded to this in my other thread, but will there be a complete schematic anytime soon? It would be good to see how the FTDI chip is wired ..

[jpeyron]

Hi @bmentink,

The page is left blank intentionally. The programming circuit is considered proprietary.  I am glad there was a 50 mA current consumption reduction.

cheers,

Jon

[bmentink]

@jpeyron

Thanks Jon,

It begs the question though: Why on earth have you got a proprietary circuit in this day and age of open reference designs? There are multiple boards out there with published FTDI22xx based USB->JTAG interfaces .... I fail to see what benefit it is to you, or users by hiding that circuit ... maybe I am missing something ....

The fact is, if the programming circuit is open or closed, it makes no difference to my decision to include this board as a module in my designs ....

(Actually I am more likely to use it if I understand the board ..... competely)

If I want to make my own Artix-7 based design ..... there are plenty of reference designs out there ..

Anyway my 2c .... end of rant ...