OVP Vs OCP?

[K404]

Obviously the 2 are related, but if we use a voltmod for one, is the ceiling for the other automatically lifted as well?

I often see GPU mods for OCP OR OVP but not both?

info welcome and appreciated!

K :toast:

[jcool]

Naw, both means the same thing. OVP = over voltage protection, OCP = over current protection (I think) which means essentially the same, as soon as the card/mobo/whatever detects too much current/volts being fed to a certain component, it shuts itself off.
Some protection mechanisms work based on current, some based on voltage. This is why you don't need both, obviously ;)

[[XC] gomeler]

Well voltage limitations are typically a circuit that monitors the voltage, the mosfets are responsible for this bit. The over current is exactly the same thing but dealing with the coils if I understand correctly. In theory current usage should increase with frequency(each cycle takes up a specific amount of current, more cycles, more current) while voltage is manually set but typically increases with frequency due to stability.

[K404]

Naw, both means the same thing. OVP = over voltage protection, OCP = over current protection (I think) which means essentially the same, as soon as the card/mobo/whatever detects too much current/volts being fed to a certain component, it shuts itself off.
Some protection mechanisms work based on current, some based on voltage. This is why you don't need both, obviously ;)

Thats the thing- the two mechanisms are different. You can hit one without hitting the other.

examples:

jack up the voltage on a card without increasing the clocks, you will hit OVP. The card still pulls the current it needs, based on its MHz.

Freeze a card and jack up the clocks at no increased voltage because of the extra headroom- the card can in theory hit OCP, even though the voltage hasnt changed.

______________
Specifics of my problem: I increase the voltage on my 7900GS without increasing the clocks and I get a black screen at the point of an applied 3D load. To me, that isnt OCP, its OVP.

[wittekakker]

Naw, both means the same thing. OVP = over voltage protection, OCP = over current protection (I think) which means essentially the same, as soon as the card/mobo/whatever detects too much current/volts being fed to a certain component, it shuts itself off.
Some protection mechanisms work based on current, some based on voltage. This is why you don't need both, obviously ;)

Obviously, it's not like that, Over current protection and over voltage protection are of different kind, heck that's why both are often monitored by the same voltage regulator module.

[jcool]

Ok, just ignore my posting then - I thought it's always just one protection or the other :shrug:
I did the OCP mod to my 8800 GTS and it worked all right (no OVP mod was done)
I do know they're not the same, might have used a wrong term there.

[oohms]

It really depends on the controller, most have only OCP pins, but i have seen one with OCP and OVP.
If they are both moddable, then you might as well mod them both, since by increasing only the OCP limit you can hit your OVP limit as you increase voltages and vice versa.

The black screen issue is a bit puzzling though.. Does your Vgpu remain the same once you get the black screen?


Specifics of my problem: I increase the voltage on my 7900GS without increasing the clocks and I get a black screen at the point of an applied 3D load. To me, that isnt OCP, its OVP.

[celemine1Gig]

I'll try to give a simple description:

-Overvoltage protection: Every circuit has a voltage maximum that it can operate at. For example the Vcore for 45nm based CPUs normally is lower compared to, let's say, 90nm CPUs, because the physical distance between the single traces is smaller. If you drive the current with a voltage that is too high and the traces are too close, then the current will not take the planned path, but will just "jump over", most likely(or pretty sure) damaging the part.
That's simply spoken why OVP is needed.


-Overcurrent protection:
Most important function is short circuit protection. When there's a short circuit the current flow will hit a huge max, as the resistance abruptly approaches zero. To protect the circuit, it will be disconnected from power as soon as the sensed current flow is too high.
It doesn't need to be a short circuit, but current can also damage the circuit, if it's just too high for the traces themselfs. They'll most likely get warmer and warmer, if the current flow is too high, and eventually will just go up in smoke.
That's why OCP is needed.

Hope that helped and I didn't integrate any mistakes into my explanation. :)

[STEvil]

Your first explanation is a bit incorrect ;)

Overvoltage is needed to increase the point where the sensor of the circuit providing voltage senses that the voltage is too high.

To simplify Overcurrent, think of this: Every device uses power. The higher you clock something and the more you increase the voltage the more power it uses. The mod is like a blind fold for the sensor so you can draw more power before it realizes "too much" is being drawn.

[celemine1Gig]

Your first explanation is a bit incorrect ;)

Overvoltage is needed to increase the point where the sensor of the circuit providing voltage senses that the voltage is too high.

To simplify Overcurrent, think of this: Every device uses power. The higher you clock something and the more you increase the voltage the more power it uses. The mod is like a blind fold for the sensor so you can draw more power before it realizes "too much" is being drawn.

Must be the language barrier. I didn't even try to explain what the actual voltage controller, which integrates OVP and OCP into the circuit, does. I just wanted to give a rough description of why they both are needed and what would happen without them.


The modifications on the controller chip usually work as follows:
-either they decrease the sensed value (voltage or current), tricking the chip into "thinking" that the critical value is not yet reached
-or they set/influence the actual threshold value (if it's not hardwired/-coded inside the IC)


Sorry if I didn't make that clear in my first posting. ;)

[STEvil]

It was to me, but for someone who's got to ask these questions it might not be ;)

[TheKarmakazi]

Thanks for the clarification I was wondering much the same thing myself