High frequency integrated Point of Load (POL) module with PCB embedded inductor substrate

In this paper, a novel alloy flake composite material is used to demonstrate the PCB integrated magnetic component with low temperature fabrication process. The most important benefit of the alloy flake composite core is easy to be patterned into any desired shape for integration. Compared with the traditional flake composite, the permeability and core loss of the new flake composite are improved prominently, by doing some lateral alignment of the flake and increasing the volume ratio of the alloy. The layerwise magnetic core is sandwiched into multilayer PCB using conventional PCB laminating technique. It has been proved that the manufacturing process, such as laminating, cutting and drilling, has very little impact on the magnetic properties of the flake core. Based on a simple 4-layer PCB substrate with embedded core, the megahertz 3D integrated Point of Load (POL) modules are built, which achieve more than 700 W/in³ power density. The PCB modules survive after hundreds of thermal variation cycles, validating the reliability and compatibility of the alloy flake composite material with PCB integration. In addition, the application of standard PCB process reduces the cost for manufacturing such integrated modules due to the easy automation and low temperature process.