Frequency for high frequency above 100KHz is low loss Mn-Zn ferrite

摘要

PURPOSE:To restrain loss even in the case of application to a power supply transformer for high frequency switching of 100kHz of higher, by adding a specified component to a specified fundamental component and compounding them. CONSTITUTION:Fundamental component is Fe2O3 of 50-55mol%, MnO of 30-40mol%, and ZnO of 8-14%. The following are added to and compounded with the fundamental component; SiO2 of 0.005-0.04wt.%, CaO of 0.02-0.2wt.%, phosphorus oxide and/or boron oxide of 0.01wt.% or less, and niobium oxide of 0.01-0.05wt.%. The loss of Mn-Zn system ferrite in the temperature range of 60-100 deg.C becomes minimum when the compound ratio of Fe2O3, MnO and ZnO is in the above range. The loss increases when the composition is in the range except the above values, and is not desirable. Hence the loss is reduced even in the case of application to a transformer for a high frequency power supply whose switching frequency is higher than or equal to 100kHz.