Research On Low Temperature Fired NiCuZn Ferrites And Its Application

In recent years,mobile phones,laptops and other electronic devices in the direction of more and more portable development,many electronic product companies launched a new type of mobile phones and computers with thin features to attract users.The power system in these electronic devices is an important part.It provides power for the various internal modules,so the miniaturization of the equipment means that the power supply system needs to be miniaturized and integrated.We know that in a switched DC-DC converter,the magnetic component occupies most of the area of the circuit.If we use LTCC ferrite material to design inductance component,and bury the inductance to the LTCC substrate,we can greatly reduce the height of the inductor to reduce the volume of power system.In order to obtain a laminated chip inductors with better performance,the NiZn ferrite sintered at low temperature was mainly studied by two parameters,such as saturated magnetic induction " and power loss $%.The experiment was divided into main formula,oxide doping and glass doping three aspects.It is found that when the main formula is Co_0.01Ni_0.32Zn_0.49Cu_0.18Fe_1.98O₄,the material has high permeability and Curie temperature.Then,the influence of Bi₂O₃ and WO₃,HB₃O₃,V₂O₅,Li₂CO₃ on the ferrite materials was discussed.It was found that the initial permeability ' and " of NiCuZn ferrite materials increase,when the content of Li₂CO₃ reaches 0.20wt%,the ' and " of the materials have the maximum values witch are 172.27,431.1mT?room temperature?and 339.6mT?100??,respectively.When the(is less than 30 mT,the sample's power loss with the doping content of 0.15wt% is the lowest.When the(is more than 30 mT,the sample's power loss with the doping content of 0.20wt% is the lowest.The three kind of glasses selected in the glass doping experiment were LBSCA,LBBS and BBSZ,respectively.It is found that the microstructure is the main factor affecting the magnetic properties of ferrite,and the material with small grain size has lower power loss at high frequency and the power consumption of the larger sample is lower at low frequencies.Among them,the ferrite with BBSZ glass is the best,and the maximum of ' and " are 201.58 and 403.6mT?room temperature?when the doping amount is 1.0wt%,and at the high frequency or low frequency,the samples doping 1.0wt% Li₂CO₃ are the lowest power consumption.Finally,the optimal parameters of Li₂CO₃ doping scheme are selected to model and simulate the laminated chip inductor.Mainly around the winding radius and air gap in two aspects to discuss its impact on the inductance and saturation current.It is found that the larger the radius of the winding and the less the number of the air gap,the more the inductance is,but the more the inductance increases with the increase of the applied current.Such inductor devices used in DC-DC converter circuit can effectively achieve the purpose of miniaturization.