Ремонт: Ноутбуков, Компьютеров
https://vlab.su/

for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
https://vlab.su/viewtopic.php?f=48&t=109340		 Страница 1 из 1
Assassin [ 22 ноя 2020, 03:51 ]
Заголовок сообщения:  for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
Hello there, i have seen many asus Strix oder Asus Turbo cards, that have a few 1 Ohm resistors on the back where the VRM Mosfets is located at the front of the card.
over this 1/4W SMD resistors goes the SW Out from mosfet also...but why? those resistors geting warm/hot on any asus Strix/Turbo card i have seen (GTX1080, 1080TI). Other Cards like Palit or MSI dont have this types of resistors. I think its a filter - but for what?

Вложение:
IMG_20201121_212853.jpg
galkinvv [ 22 ноя 2020, 06:09 ]
Заголовок сообщения:  Re: for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
One side of the resistor is connected to the PHASE before COIL, so it has fast oscillation in at least 12V range. The other side is connected to a small capacitance capacitor to ground (1000pF, 50V, X7R).

The similar resistor+capacitor present in 1070 reference design.

Unfortunately I has zero undestanding of filtering in electronics. Maybe it tries to filter very high voltages that may appear in a very short periods (MUCH less than 1us) while switching between low and high sides.

However, there is thoughts from the practical side:
  • card will work fine at least at light load if either resistor or capacitor is missing.
  • replacing one of them with element with a wrong value looks very risky. High capacity, low capacitor voltage limit or zero resistance - looks risky and leading to unpredictable results.
  • So, if either resistor or capacitor is absent/damaged, verify twice before replacing. Using without one of them is less problematic than using with incorrect replacement.
Assassin [ 22 ноя 2020, 11:23 ]
Заголовок сообщения:  Re: for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
yes, i meassured it. resistor comes from phase, and goes over a capacitor to ground.

but what will happened, when i completly remove this? realy instable? but why -because many other cards dosnt have anything of this
uncledim [ 22 ноя 2020, 11:28 ]
Заголовок сообщения:  Re: for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
Assassin писал(а):
its a filter - but for what?

google for "snubber circuit", "snubber network"
some drivers need it, some not - it depends on internal driver schematic too.
Assassin [ 22 ноя 2020, 12:13 ]
Заголовок сообщения:  Re: for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
in the driver/Mosfet circuit is it not shown:
https://www.infineon.com/dgdl/ir3550.pd ... cd7c831761

crazy...
nemos [ 22 ноя 2020, 13:36 ]
Заголовок сообщения:  Re: for what is the 1 ohm resistors on the back of an Asus Strix Pascal card?
strix cards are positioning as a most stable, cool, and extrimely good for overclocking and overvoltage. So snubber circuits are used as an additional circuit for stable output signal without emi and low voltage or current spikes in load.
most gpu's on strix are overcklocked by default, so current stability is critical even for medium load. Main idea is to have stable voltage and less interference back to mosfet
Страница 1 из 1 Часовой пояс: UTC + 4 часа
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/