Current required during startup and time reuired for startup (TE0820-04-3AE21FA)

[Nidza]

  Hello,

  I plan to use Trenz module TE0820-04-3AE21FA and I am designing a power supply for it. According to info on this link:
https://wiki.trenz-electronic.de/display/PD/TE0820+TRM#TE0820TRM-PowerandPower-onSequence

  two following sentences are confusing me (same sentence, two different current values):
"Power supply with minimum current capability of 3A for system startup is recommended."
"Single 3.3V power supply with minimum current capability of 4A for system startup is recommended."

  So here are three questions that I have:
  1. What is the correct required value - 3A or 4A?
  2. What is the time required for a startup?
  3. The buck converter I intended to use can provide contionous power output of 3.5A (at 3.3V), with the ability to provide 4.1Amin/4.5Atyp/6Amax up to 100us before over current protection is activated. Would the module work with such buck? (Buck from Intel on Trenz base boards is 4A continous and 5A OCP)

  Thank you and best regards,
  Nidza

[Vitali]

Hi,
our micromodule TE0820 supports  two separate power supply inputs ( (1)VIN: 3.3 .. 5V and (2)3.3VIN: 3.3V ) or single power supply (VIN=3.3VIN :3.3V).
1) If you have single power supply 3.3V it will be enough 4A.
2) you can powered simultaneously 3.3VIN and VIN or use single VIN(3.3V). Micromodule designed with Xilinx Power sequence requirements.
3) it will be work, but the power consumption depends on your HDL-design. Also is very important to check a requirements of total capacitance of buck converter.
Best regards,
Vitali

[Nidza]

  Hello Vitali,

Thank you for fast response!

I am going to use single 3.3V supply (short connecting VIN and 3.3VIN). Expected total average current on this supply is up to 1.5A with the planned HDL-design. Therefore, I am not concerned regarding average consumption (available 3.5A continous).

  What is not clear to me is recommendation of 4A during "system startup". I do not know what is actually considered as "system startup" (only charge of capacitors or code upload, etc.). The question is would the module properly overcome the "system startup" with mentioned power supply (3.5A continous/4.1A over current protection)? On my side I will sum up all input capacitance of the module to check if it is OK for the Buck, but is that the only thing I need to consider?

  Best regards,
  Nidza

[Thomas Steffens]

Hi Nidza,
please be patient for a few more days, my colleagues are still on vacation.
They will get back to you asap!
BR,
Thomas Steffens

[Martin R.]

Hello Nidza,
yes, system startup refers to 'cold start' with capacitor loading. So, the values form the buck you menteioned shoud be OK.
Best regards
Martin Rohrmüller

[Nidza]

  Hello Thomas and Martin,

  Thank you very much for your great support and answers!

  Best regards,
  Nikola Balaban