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Uprating of Magnetic Components

Posted by Author on Jul 20, 2016 9:49:09 PM

Inductors, ferrite beads, and transformers use ferrite material as the active component and thus can be expected to behave in a similar manner when used over a broader temperature range. As an example, ferrite beads are often referred to as ferrite bead inductors.

An inductor is a coil of wire typically wrapped around a ferrite core. Passing electrical current through the coil creates a magnetic field proportional to the current. When this current is increased or decreased, it creates a change in magnetic flux that in turn generates a voltage that acts to oppose this change in current. Therefore, inductors tend to be designed to dampen current spikes or filter high frequency signals.

Ferrite beads also use ferrite material, but in this case the coil, or conductor, runs through the ferrite material rather than being wrapped around it. As with inductors, the functionality of the ferrite beads is dependent upon the creation of a magnetic field. In the case of ferrite beads, their purpose is to reduce EMI (electromagnetic interference) and RFI (radio-frequency interference).

Transformers use a ferrite material core and several windings of copper wire to modify the output voltage relative to the input voltage.

 

Topics: Magnetic Components, Ferrite Beads, Transformers, inductors, Temperature

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Common Issues with Power Supply Design: Part 2

Posted by Ron Wunderlich on Jul 18, 2016 5:51:46 PM

This is the continuation of a series of white papers on the common problems seen with power supply designs, with a focus on inductors.

You can see that selecting an inductor is not as straight forward as it appears. The data vendors give is for DC operation but for switching power supplies you will have an AC component to the current. This will result in a higher temperature rise than expected. Then there is the issue of saturating the inductor which also can cause a temperature rise in the inductor and even possibly damage to the power supply.

Topics: Saturation Current, DCR, Failure Analysis, inductors

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