Protection Features Evaluation

Every PSU should be equipped with a set of protections that will protect the PSU and the whole system. You can learn more about PSU protections by reading through the corresponding section of our "A Detailed Look Into PSUs" article.

In a snap, the most important protection features for PSUs are the following:

Over Current Protection (OCP)
Over Power Protection (OPP)
Over Temperature Protection (OTP)
Over/Under Voltage Protection (OVP/UVP)
Short Circuit Protection (SCP)
No-load Operation (NLO)
Surge and Inrush Protection (SIP)

We should note here that OCP isn't usually offered in single +12V rail PSUs, especially high capacity ones. In such units, OPP takes over. OTP is very important, and we won't mess with OVP/UVP until we find a way to safely evaluate it.

Although a single +12V rail PSU, it still has OCP on its +12V rail. Considering the unit's low capacity, OCP at +12V could be useful and is an extra protection layer aside from OPP. The OCP triggering points on the other rails are set as expected, based on our experience with PSUs.

Sirfa decided that OTP isn't necessary even though a PS223 supervisor IC that supports OTP is used. We strongly disagree with their choice. Finally, there is no inrush current protection, which leads to high inrush current when the bulk cap is drained.