High Frequency 3D integrated POL Module Based on PCB Embedded Core
With a low profile LTCC inductor substrate and a GaN device, the 3D integrated POL module demonstrates the ability to achieve a 1kW/in3 power density at 15A with a multi-megahertz switching frequency. However, the fabrication still involves a high temperature process and the cost of this solution is relatively high.
Fig. 1 and Fig. 2 show the PCB embedded inductor substrate and the PCB integrated POL module with a 20A output current. The improved flake material, SENFOLIAGE, is sandwiched into multi-layer PCB as the core. The silicon based NexFET power stage from TI is used to build the active circuit. The efficiency and the power density of the POL module are measured in Fig. 3. The PCB integrated module achieves almost the same power density as the LTCC integrated alternative, except that the cost is reduced and it's easier to fabricate with the low temperature process.