Zeng Xiangjun

An optimized layout with low parasitic inductances for GaN HEMTs based DC-DC converter

Reducing parasitic inductances are critical for improving efficiency and safety in Gallium Nitride (GaN) based DC-DC Converter. This paper aims at reducing the driver loop inductance and power loop inductance by optimizing the PCB layout. Firstly, this paper compares three different kinds of driver loop layouts by Maxwell 3D simulation. The results show that the driver loop inductances of single-layer layout with a shielding layer and double-layers layout are much smaller than that of the conventional single-layer layout. Then a novel doublesided layout is proposed, which has a small power loop inductance because the magnetic field is significantly canceled by the interleaved current. Finally, the design is verified by a buck converter operating at an input voltage of 12 V, an output voltage of 3.3 V, and an output current of 8 A. Experimental results show that the power loop inductance is about 0.1nH, which reduces 75% than that of the reported best layout.

Analytical loss model of low voltage enhancement mode GaN HEMTs

An analytical model is proposed in this paper to calculate the switching loss of low voltage enhancement mode Gallium Nitride high electron mobility transistors (eGaN HEMTs). The switching process is illustrated in detail. The switching loss is obtained by solving the equivalent circuits during the switching transition. A good agreement is shown between the analytical model and Spice simulation results. In addition, in order to accurately measure the current transition waveform, a novel current measuring method based on magnetic coupling is proposed. Finally, a buck converter is designed to validate the accuracy of the proposed model.

Research on power electronic integrated module for SMPS

A novel module structure of power module for switching power supplies is presented in this paper. The power module employs the three-dimension terrace structure to produce less parasitic parameter and higher power density. Based on this structure, the performance of the power module, such as parasitical parameters and thermal management performance, is evaluated through simulation analysis and experimental research. The results with measurement on a 1kW prototype demonstrate that the power module based on the Aluminum substrate has high power density, less volume and better thermal performance, compared with conventional structure equipment