High Frequency High Power Density 3D Integrated Gallium Nitride Based Point of Load Module
Non-isolated POL converters are widely used in computers, telecommunication systems, portable electronics and many other applications. To design a high-power-density POL module, high switching frequency, high efficiency, small magnetic size, and good thermal management are all required. Silicon devices are not capable of good performance at an operation frequency of a couple of MHz. However, GaN devices are high-electron-mobility transistors (HEMT), and have a higher band gap, electron mobility, and electron velocity than silicon devices and offer potential benefits for high-frequency power conversion. With the depletion-mode GaN MOSFET from International Rectifier, a 3D integrated POL module has been designed to operate at up to 5MHz switching frequency for a 12V to 1.2V buck converter with a full-load current of 15A. This module employs a low-profile low-temperature co-fired ceramic (LTCC) inductor and can achieve a full-load efficiency of 82%, and 1200W/in3 power density at 5MHz.