Confused about RAILS, WATTS and PSU stuff

[SENOR BURTOS]

I don't know whats the relation between OCP, OPP and the de-rating curve

I mean people say all the time that temperatures affet the components' performance so a PSU that is rated to output 500W @ 30C does less W at higher temperatures

But HOW DOES THAT HAPPEN IF THE OCP/OPP IS THE SAME REGARDLESS OF THE TEMPERATURE?

If the OPP is set to 600W that means the components can output 600W no matter what the temperature is right?

Another question

¿Do DC-DC PSUs provide more power than other PSU designs? Or they are just more efficent and can handle voltage regulation and ripple better

thanks in advance

 

[TJ Hooker]

If the OPP is set to 600W that means the components can output 600W no matter what the temperature is right?

No, that means that the PSU will shut itself down if you try to draw more than 600W, and ideally prevent itself from being damage. That doesn't guarantee that the PSU won't fail at aload less than 600W, especially if it's an old and/or low quality unit.

¿Do DC-DC PSUs provide more power than other PSU designs? Or they are just more efficent and can handle voltage regulation and ripple better

I'm assuming you're referring to SMPS (switched mode power supply)? I don't think they even make linear regulator based PC power supplies, but SMPS are more efficient. I think this would typically make them better suited for delivering more power, as with a less efficient linear regulator dealing with the waste heat produced at high load could be an issue. Voltage regulation may be better with an SMPS as well. Linear regulators do not have voltage ripple like SMPS do.

 

[Math Geek]

temps effect the efficiency of the psu. high temps won't make it produce lower power, but it will become less effective as temps go up.

at 20 degrees it may be 80% bronze compliant but at 40 degrees it may only be 60% and so on. it can still put out the power but it uses more from the wall to do it. that's what folks mean when they say performance is effected.

hotter climates make a psu work a lot harder to put out the same power than a cooler climate does.

 

[TJ Hooker]

@Math Geek higher temps don't just affect efficiency, they can reduce the how much current the components are able to handle. It is very possible that the max power a PSU can supply without failing will be lower if operating at a higher temperature.

Also, higher temps will decrease the lifespan of some components.

 

[SENOR BURTOS]

@Math Geek higher temps don't just affect efficiency, they can reduce the how much current the components are able to handle. It is very possible that the max power a PSU can supply without failing will be lower if operating at a higher temperature.

Also, higher temps will decrease the lifespan of some components.

I don't care about linear power supplies, this is about modern desktop PSUs or SMPS

The question is psus with DC-DC used on the secondary can provide more power or they just can provide more power with less ripple or voltage regulation but have the same power limit with all things being equal

And you say that OCP/OPP is the same but it is possible for components to handle less current/power than the OCP/OPP limit is thus burning themselves if there are no other protections kicking in

IS THAT RIGHT?

 

[Rexper]

To answer your first question, PSUs with DC-DC on the secondary side have better voltage regulation in crossload, usually better efficiency and near 100% of the 12V rail as the PSUs wattage rating.

When group regulation is used on the secondary side, the 12V rail and 5V rail are gernerated/regulated together.
Which means when there’s an imbalance between them, e.g high current on the 12V and low current on the 5V in modern in systems, loose voltages will be delivered.

On the contary, within DC-DC topology the minor rails are seperately regulated/generated from the 12V rail. This leads to higher efficiency and better voltage regulation during crossload.

Power supplies making use of the DC-DC converters usually have near 100% of their rated wattage on the 12v rail.

https://www.tomshardware.com/reviews/power-supplies-101,4193-12.html

For your second question, AFAIK temperature readings aren’t inputed to the supervisor IC or PWM controller, so the protections not dependant on temperature, for the most part.
OPP is usually triggered at 120%-130% of the PSU’s rated capacity.
You’d be relying on OTP or OVP/UVP, or simply that the PSU is good enough to deliver at higher temperatures.

 

[SENOR BURTOS]

To answer your first question, PSUs with DC-DC on the secondary side have better voltage regulation in crossload, usually better efficiency and near 100% of the 12V rail as the PSUs wattage rating.

When group regulation is used on the secondary side, the 12V rail and 5V rail are gernerated/regulated together.
Which means when there’s an imbalance between them, e.g high current on the 12V and low current on the 5V in modern in systems, loose voltages will be delivered.

On the contary, within DC-DC topology the minor rails are seperately regulated/generated from the 12V rail. This leads to higher efficiency and better voltage regulation during crossload.

Power supplies making use of the DC-DC converters usually have near 100% of their rated wattage on the 12v rail.

https://www.tomshardware.com/reviews/power-supplies-101,4193-12.html

For your second question, AFAIK temperature readings aren’t inputed to the supervisor IC or PWM controller, so the protections not dependant on temperature, for the most part.
OPP is usually triggered at 120%-130% of the PSU’s rated capacity.
You’d be relying on OTP or OVP/UVP, or simply that the PSU is good enough to deliver at higher temperatures.

Thanks, so PSUs can usually deliever 20-30% more power than what they are advertised to do, regardless of temperatures

so it is true that PSU parts handle less power at high temperatures but OPP/OCP is usually set low enough not to burn rectifiers by pulling more power than what they can provide, unless you are running a cheap generic unit