(1/70) Ferrite for Switching Power Supplies INTRODUCTION Our foremost mission is to develop unique and advanced electron- ics technologies. As such, ever since TDK was founded in 1935 when its researchers invented ferrite, we have been involved in a wide range of technological and product development efforts. Particularly, our high-performance ferrite elements, which result from our accumulated expertise and excellent microstructure con- trol technologies, have become essential in reducing the weight and improving the performance of advanced electronic devices that are transforming the world around us. As a result of pursuing the numerous potentials of these ferrite ele- ments, we have been able to develop high-frequency power ferrite material that deliver among the world’s highest levels of reliability and magnetic properties. These products include PC33, PC40, PC44, PC45, PC46, PC47, and PC50. They contribute to achiev- ing even greater size reductions and performance improvements of high-performance switching power supplies and DC to DC con- verters -- products considered to constitute the heart of microelec- tronic devices. We have also developed the PC95, which delivers a saturated magnetic flux density equivalent to that of PC44 and low loss in a wide temperature range. This materials is expected to improve the efficiency of power supplies in DC to DC converters used in electric vehicles. Additionally, we have been conducting research in ferrite that delivers permeability close to