PCB Factory: Analysis of the Cause of the Inductance Loss of Ferromagnetic Core

PCB Factory: Analysis of the Cause of the Inductance Loss of Ferromagnetic Core

The circuit board manufacturer, circuit board designer and PCBA processor will explain the cause of ferromagnetic core inductance loss

Iron core inductor is an inductor with a magnetic core made of iron or ferromagnetic materials. The magnetic core can increase the inductance of the coil thousands of times by increasing the magnetic field. However, when the circuit of the ferromagnetic core inductor in the PCBA board operates, it will produce a lot of energy loss, as long as it is composed of the following factors.

1. Core loss

As the current in the ferromagnetic inductor changes with time, the magnetic field in the core will also change with time, and finally the energy loss in the core material will be dissipated as heat,

2. Eddy current

According to Faraday's law of induction, a changing magnetic field can cause a circulating circuit of current in a conductive metal core. The energy in these currents is dissipated as heat in the resistance of the core material. The energy consumption increases with the area in the current loop.

3. Hysteresis

Changing or reversing the magnetic field in the magnetic core will also cause losses due to the movement of the small magnetic domains composed of it. The energy loss is proportional to the area of the hysteresis loop in the BH diagram of the core material. Materials with low coercivity have narrow hysteresis loops and such low hysteresis losses.

For these two processes, the energy loss of each AC cycle is constant, so the core loss increases linearly with frequency. The online core loss calculator can be used to calculate the energy loss. Using inputs such as input voltage, output voltage, output current, frequency, ambient temperature and inductance, these calculators can predict the losses of the inductor core and AC/DC based on the operating conditions of the circuit used.

4. Nonlinear

If the current passing through the ferromagnetic core coil is high enough to saturate the magnetic core, the inductance will not remain constant, but will change with the current passing through the device. This is called nonlinear and causes signal distortion. For example, audio signals may produce intermodulation distortion in saturated inductors. To prevent this, in a linear circuit, the current passing through the core inductor must be limited below the saturation level. Some laminated cores have a narrow air gap, and the iron core has a distributed air gap to achieve this, which allows a higher level of magnetic flux to pass a higher current through the inductor before saturation.

The circuit board manufacturer, circuit board designer and PCBA processor will explain the cause of ferromagnetic core inductance loss.