Historically an iron power toroidal solution has been used for desktop core voltage regulator designs. Even though the toroidal solution is low cost, it is also large in size, has high tolerances for DCR, and has high core losses thus making it unsuitable for high frequency applications. With the release of Energy Star Version 4.0 by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy in July of 2007, better energy management in the system design is now more than ever critical. Desktops that bear the EPA Energy Star label use less energy and reduce the environmental impact through power managing techniques. System designers must meet the new efficiency requirements by reducing power dissipation in the inductor and other components that make up the core voltage regulator (VR). To reduce the parasitic inductance in the circuit, the inductor is being positioned closer to the processor. With the increase of power consumption of the next generation CPU, the heat being generated is higher. The design of the new generation inductor must be space efficient and power efficient, high temperature rated, and shielded due to the proximity to the processor. There are several ferrite core designs that have been introduced as next generation inductor solutions but they can vary in terms of size, efficiency, and current saturation capability. Optimization can be obtained by careful selection of the core geometry, core material, and coil design in terms of overall power dissipation. This paper will analyze various ferrite inductor designs and then compare the power dissipation for the chosen inductor design versus the toroidal solution that it is replacing. The data will show that for a 110 amp load condition, the ferrite cube inductor has a 3% efficiency improvement and can save 3 Watts in power losses versus the iron powder toroidal solution.
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