How to determine whether the power supply needs a PFC circuit?

Knight97538

How to determine whether the power supply needs a PFC circuit? [Copy link]

PFC circuit is "power factor correction", which is the relationship between effective power and total power consumption (apparent power), that is, the ratio of effective power divided by total power consumption (apparent power). Basically, power factor can measure the degree to which electricity is effectively used. The larger the power factor value, the higher the power utilization rate.

Then I have a question that I don't understand. Looking at the power supply circuit, some power supplies do not have this PFC circuit, and some do. So when is the PFC circuit needed, and when is it not needed?

maychang

Without PFC, the AC power grid (including other electrical devices on the same power line) is affected, not your switching power supply. Therefore, various countries have legislated to stipulate that switching power supplies above a certain power must be equipped with a PFC circuit.

chunyang

The factor that determines whether PFC is needed is mainly power, which is also related to the specific product category, sales location, etc. The thresholds vary greatly and there is no unified statement.

qwqwqw2088

Sometimes PFC is added only when it meets the certification requirements, usually greater than 75W requirements

But for small power supplies, the PFC part is not required for certification

不亦心

Look at the regulations for application scenarios