Design and Optimization of a 400W DC/DC Module Achieving High Efficiency and High Power Density

With the increasing demand for all-in-one computers, gaming notebooks, ultra-thin OLED TVs and other devices, the demand for efficient and high power density hundred-watt power supplies is also increasing. In particular, all-in-one computers, ultra-thin OLED TVs and portable workstations have limited space left for power supplies, which presents huge challenge for related design. In this paper, a half bridge LLC resonant converter module is designed as the DC/DC power module. In order to improve efficiency, the resonant parameters of the half-bridge LLC are modeled and optimized in this paper, so that the RMS current is as small as possible and the primary side device realizes ZVS. In terms of device selection, through modeling and calculation, the scheme with the lowest loss is selected, and the high-integrated half-bridge GaN power IC is applied to further improve the power density. The final prototype uses the design of a planar transformer with integrated resonant inductors, and the high switching frequency of 500kHz further reduces the size of the magnetic element. The prototype is only 8mm thick and has a high power density of 21.5W/cm3 (62.5 x 37.2 x 8mm). Peak efficiency can be close to 98%, full load (400W) efficiency is 97.52%.