The editor has written a lot about the role of ferrite sheets. Today we summarize the three main functions of flexible ferrite sheets in wireless charging coils. First of all, let's explain what ferrite sheets are.
1. Brief introduction of ferrite sheet:
Utilizing high-permeability and high-loss metal, it crystallizes into a variety of soft magnetic alloys in ultra-micromolecules, laminated with layers of ribbon-like films, and can absorb microwave noise generated by electronic components, modules, and surface currents with a wide frequency band and high efficiency. Improve efficiency, reduce temperature, and provide excellent EMC solutions for various electronic devices.
2. Three main functions on the wireless charging coil:
1. Magnetic permeability
As we all know, the principle of the QI wireless charging standard for magnetic barriers is electromagnetic induction. When the primary coil (wireless charging transmitter) is working, it will generate an interactive magnetic field (the direction of strength is constantly changing). In order to make the magnetic field energy emitted by the primary coil act on the secondary coil (wireless charging receiver) as much as possible, it is necessary to The magnetism of the coil is guided.
2. Magnetic block
The magnetic sheet should not only be able to effectively conduct magnetism, but also play a role in blocking magnetism. Why block the magnetism? We know that when a changing magnetic field encounters a conductor such as a metal, if the metal is a closed wire, it will generate current, if the metal is a closed wire, especially a whole piece of metal, an eddy current effect will occur.
3. Heat dissipation
The magnetic field acts on the inductor coil to generate high-frequency current. During this process, the coil itself will also generate heat. If this heat is not effectively dissipated, it will accumulate. Sometimes we feel very hot during wireless charging. Generally, it is caused by the heating of the inductance coil or the heating of the circuit board.