Your favourite PSU OEM

[Wester547]

Re: Your favourite PSU OEM

The one I fixed had all 20A parts, except the 12V rail, which actually had a 16A fast recovery rectifier and yet the 12V rail was rated for 15A. If this was half-bridge topology, I would say that rating would be okay - maybe a bit close to the edge, but still okay. In single-forward topology, no way you'll get 15A out of a 16A rectifier (continuously, for an extended period of time, that is).

That seems more like a 250W unit. I remember your Dell Hipro 250W has a 16A part for the +12V rail by what you posted in the power supply build thread three years back yet it's rated at 14A and uses single forward topology. That being said, I don't think your Dell 250W has an ultrafast recovery rectifier there but a very good schottky known as STPS16H100CT.... that has such a high surge current and low voltage drop, and is rated at such a high temperature, that you might as well call it a 20A part, especially on that massive heatsink and being close to the fan, in the path of the airflow. You probably could get 16A from it even in forward topology. Like I said before, good cooling helps a lot. I take it the ultrafast recovery rectifier was BYQ30E-200 or STPR1620CT? BYQ30E-200 is rated for 16A @ 104*C, STPR1620CT (STMicroelectronics) for 16A @ 125*C, both have a fairly high voltage drop, though, and their thermal resistance isn't fantastic either, but you can't expect better than that from an ultrafast recovery rectifier. I doubt even in that Bestec that the 16A ultrafast is getting as hot as 100*C so it probably could do 16A even if just barely.

By comparison, my other Hipro has MBR3045PT for the +5V and +3.3V rails and MBR20100CT for the +12V rail. It uses a STP40NF03L FET to regulate the extra transformer tap the +3.3V rectifier is connected to down to +3.3V. All those schottkys are by Lite-on semiconductor. The MBR20100CT though is very close to the fan. I think its heatsink, while definitely not as good as your Hipro 250W's is probably better than the Bestec you found. Of course... that Hipro is kinda sad by comparison to what I found in my old Dell Hipro 250W whose model number is the same as yours but it's an older revision... MBR6045WT for the +5V rail, MBR4045PT (General Semiconductor) for the +3.3V rail, STPS20H100CT for the +12V rail, and like yours uses a FDP7030BL Trench FET. After 17,000 on hours and 7,000 power cycles, since 2001, not a single bloated capacitor, not even the G-Luxons or Asiacons in there look bad at all, though there are some Teapos in there as well so maybe they helped.

I believe the 200W Hipro you posted uses a 10A part for the +12V rail as well yet in forward topology the +12V rail is rated for 10A.... (that could be because it's ATX 12V v1.3 which mandates a higher rating for the +12V rail) I think it has STPR1020CT there (Liteon semiconductor?) which is an ultrafast recovery but it's very close to the fan and is also on a better heatsink, probably.... good cooling does help.

That's no excuse to overrate the 3.3V and 5V rails on the label though. This is something only cheap PSUs do, and looks like Bestec is heading down that way. Honestly, when I opened that ATX-300-12E, it looked only a few notches above a complete Deer PSU.

Yes, it's bad practice to lie about the ratings. Another note about On resistance - it seems that lower on resistance is good but it can result in more switching losses (if the switching frequency isn't good enough) unless you use a larger FET, so I guess it's also a double-edged sword.

[momaka]

Re: Your favourite PSU OEM

That seems more like a 250W unit. I remember your Dell Hipro 250W has a 16A part for the +12V rail by what you posted in the power supply build thread three years back yet it's rated at 14A and uses single forward topology.

Nope, it's a 20A part. I don't remember what I put back in that post, but it could be some wrong info. I just checked on that PSU recently and aside from the 20A rectifier on the 12V rail, both the 5V and 3.3V rails use MBR6045WT.

The 200W HiPro I don't remember what it had, but I too could have jotted down the wrong info for it as I did only a brief check on the rectifiers back then. Could as well be a 16A fast recovery rectifier. I remember putting it in a P4 Willamate PC afterwards, and it was pushing out a bit of heat when the CPU was running under full load.

[eccerr0r]

Re: Your favourite PSU OEM

DEER

J/K. I've come across a lot of Delta PSUs and all of them seem very high quality. And I do have to give thumbs up on Astec PSUs of the ones I've seen in the past though probably nowadays their efficiency isn't as high as the highest there - but reliable nonetheless.

[Wester547]

Re: Your favourite PSU OEM

Nope, it's a 20A part. I don't remember what I put back in that post, but it could be some wrong info. I just checked on that PSU recently and aside from the 20A rectifier on the 12V rail, both the 5V and 3.3V rails use MBR6045WT.

Wow, that's amazing! But from this image, it looks to me like the 3.3V rectifier is a 40A part from STMicroelectronics, since I see "morocco" and "STPS40" in the image, which to me alludes to "STPS4045CW" from Morocco (I kinda see "4045CW" in the image too, but the text could say something completely different and I could be wrong). Added to that, those 250W Hipros of the time also use 16 gauge wires for the +3.3V rail... very overbuilt...

The 200W HiPro I don't remember what it had, but I too could have jotted down the wrong info for it as I did only a brief check on the rectifiers back then. Could as well be a 16A fast recovery rectifier. I remember putting it in a P4 Willamate PC afterwards, and it was pushing out a bit of heat when the CPU was running under full load.

STPR1620CT then... I have a Newton Power 250W that has two 10A ultrafast recovery rectifiers from STMicroelectronics in parallel for the +12V rail (STPR1020CT x2, STPS3045CW for the 3.3V rail, STPS6045CW for the 5V rail) and it never gets hot, almost, ever, powering a Pentium 4 1.7 GHz Willamette after 19,000 hours and 5,500 power cycles without a single bloated Ltec since 2001, but it has very thick heatsinks and its Sunon fan blows out so much air it's almost overwhelming. It has massive torroids, too, like with the 250W Hipros.