Author Topic: TE-0712 Power up  (Read 3530 times)

Acam2014

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TE-0712 Power up
« on: November 07, 2016, 09:01:32 AM »
Hi!

I just started a new project with the TE0712-200 board and I'm experiencing some trouble with the board powering up after programming.
With a small design, the board drawing about 0,3Amp everything works fine after I download my configuration to the FPGA.
But with a little bit bigger design, the board drawing about 1Amp, I get an infinite loop with the board trying to power up after configuration and then failing, both LEDs flashes, then trying to read the configuration again, failing etc...

I guess my power source, a linear regulator is bad, but despite that I wonder if there is any configuration you can make to the TE0712 System controller in order to get it to power up "more softly"?
I drive both VIN and 3.3Vin from the same 3.3V  1.5A regulator.

Kind regards,
Jonas Nyberg

Antti Lukats

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Re: TE-0712 Power up
« Reply #1 on: November 07, 2016, 02:45:49 PM »
I am afraid the power supply is insufficient, while 1.5 may be OK in stable operation during the startup more current is needed, so you have a too big voltage drop. You may try adding really big C at 3.3V input but better to have a bit more powerful supply

Acam2014

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Re: TE-0712 Power up
« Reply #2 on: November 07, 2016, 02:55:07 PM »
Thank you for your fast reply!

Do you have any rough idea what the instantaneous current draw is at power up? How many x times the stable state?
I'm just wondering because in the near future I'm planning on developing a custom power supply for my board.

Regards,
Jonas

Thorsten Trenz

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Re: TE-0712 Power up
« Reply #3 on: November 07, 2016, 03:03:49 PM »
Hi,
on our own bases, we use always a 4A switch mode powersupply. This is sufficient for most of the designs. You may need more depending on your bitstream.

Best Regards,
Thorsten Trenz

Acam2014

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Re: TE-0712 Power up
« Reply #4 on: November 07, 2016, 03:20:11 PM »
Thanks for the info.
This will give me an idea of what to aim for.

Br,
Jonas

Acam2014

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Re: TE-0712 Power up
« Reply #5 on: November 07, 2016, 07:34:19 PM »
One last question,

I can see that you have "only" 47uF + 10uF capacitors placed on your baseboard TE703 at the output of the DC/DC. My design have a 22uF at the moment very near the FPGA module connectors but can of course be increased.
My finished design will be a separate power board with wires coming to the baseboard (where my TE0712 FPGA board is situated). I think my approach would need a lot more than 22uF because of the wires (about 5cm).
Of course also the transient response of the power supply will be critical, but I think I could ease things up with more capacitance.
Do you have any take on this?
Thanks again,
Jonas


Thorsten Trenz

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Re: TE-0712 Power up
« Reply #6 on: November 08, 2016, 06:59:22 PM »
Hi,
if your power supply can handle more capacitance, it is better to have more.

Best Regards,
Thorsten Trenz

itismamu

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Re: TE-0712 Power up
« Reply #7 on: December 20, 2016, 02:17:21 PM »
I have 12V input supply..can anyone please suggest me 3.3V regulator with 4A current as mentioned above?