What do rated current values mean?

ANP096

Despite the efforts of some passive magnetic component manufacturers, the concept of rated current continues to be a point of contention in the power electronics industry. There remains a difference of opinion in how manufacturers should report it and how design engineers can use it. Is it an absolute parameter? Are rated current values from different manufacturers directly comparable? The answer to these questions is no. Some manufacturers take advantage of these misconceptions and are deliberately vague about the measurement method used to obtain rated current values to achieve favorable results.

Rated current values found on datasheets serve as a guide for the selection of power inductors. However, the temperature rise in power inductors can be influenced by many factors that are not always reported in datasheets by all manufacturers giving a false sense of what the rated current values actually represent.

Measuring and comparing similar parts from competitors, demonstrates despite large differences in datasheet rated currents their performance can be very similar when using the IEC 62024-2:2020 standard to define rated current. Comparing the behavior of a single inductor in different conditions demonstrates how different performance parameters may be used to gauge the performance of an inductor under application conditions.

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