[Hardware]What is the OCP of a power supply and what is it for?

[WilkerCSBD]

We always define the power supply as the heart of the PC, because it is the component that "pumps" the energy to the rest of the hardware components and, therefore, the operation of everything else depends on it. For this reason the protections of the power supply are extremely important for the operation of the entire system, the OCP protection being the most important of them all. In this article we are going to tell you what exactly the OCP is and how it works so that you can understand its importance.

The highest and lowest, all power supplies include various protection mechanisms, both to protect their own integrity against potential changes in electrical current and to protect the components to which they supply power. Before we have told you that the OCP is probably the most important of them, and now we will see why.

What is OCP protection?
OCP is the acronym for Over Current Protection. This feature uses one or more circuits to prevent a power supply from supplying more current (in Amps) than its circuits and cables can handle. OCP is therefore important, since too high a current can melt cables and fry electronic components, as well as damage all types of circuits through which electricity passes.

power supply

This surge protection component is usually placed directly on the power supply rails; Depending on the internal design, it can be placed just after the AC / DC converter or in the 12V, 5V and 3.3V DC / DC converters (this is ideal), although sometimes, depending on how the voltage is converted in the source, there may be only one OCP on the 12V DC / DC and that's it, as long as the 5V and 3.3V voltages are then pulled out of the 12V (not ideal but usually works very well).

When buying a power supply you should always make sure that OCP is among the list of protection functions, since normally electrical components are capable of handling quite wide voltage ranges but not current intensity. For example, a circuit that needs 12V and 1A to operate could withstand variations of between 11.6 and 12.4 V in voltage as well as variations below 1A in intensity, but never above 1A because then it would be overloaded, it would heat up and it would melt.

How this protection works in the supply voltage lines
Think of the electrical panel in your house. The main panel has fuses that provide protection by not allowing the wires to each wall outlet to handle more amps than they were designed for; The same happens with OCP, since it protects the power supply regulation circuits (as we have said, 12V, 5V and 3.3V but also the 5VSB if the supply has it) and ensures that the connectors, cables and circuits do not melt under extreme loads.

Plug in flames

For 12V single line power supplies, it is particularly important that other source protection features such as over power protection (OPP), under voltage protection (UVP) and short circuit protection (SCP) work well in addition. from the OCP itself; for example, if a very high load is applied to a single connector, SCP or UVP will turn off the power supply.

Often times, 12V multi-rail supplies use one rail to send power to the motherboard, CPU, SATA ports, and MOLEX ports, while power for PCIe-connected hardware uses different rails.

As a general rule, multiple rail sources have their disadvantages (such as having to be separating cables for each thing and, sometimes, even having to calculate the amps in each connector so as not to go overboard) but one of the advantages is that they are safer by having independent OCP protection for each of the 12V rails, compared to the great advantage of single-rail sources, which is that they better support the power peaks necessary for high-consumption hardware, such as overclocked CPUs or Top-of-the-range graphics.

OCP vs OPP / OLP
Over current protection (OCP) should not be confused with Over Power Protection (OPP), also known as Over Load Protection (OLP). This is another protection feature used by power supplies, which consists of shutting down the unit if more power is required (in this case we are talking about raw power) than it is capable of delivering its maximum rated power.
 

For example, imagine you have a 500 watt power supply in your system but you have installed a pair of RTX 3090s, with a load when they are put under load that collectively exceeds 500 watts. At first the PC will start up and work without any problem because the consumption will be low, but the moment you start a game or 3D program and the two GPUs start to demand more power from the power supply, it will be the OPP system. / OLP which will turn off the power supply (and therefore the PC) when its limit is exceeded.

This is the reason why when you do not have a powerful enough power supply, the system will shut down only when you start applications that demand a high consumption of the graphics or processor. Failure to have this protection system would lead to various problems that can literally include the power supply bursting into flames or exploding. Other mechanisms could come into play in this situation (such as protection against over temperature) if the source has them, but in any case the consequences can be quite critical if necessary.