许多电源系统中使用的基本构建块是半桥，它由两个串联的功率FET及其各自的栅极驱动器组成。虽然分立式FET和栅极驱动器可以在板上实现这个相同的功能，但通常使用半桥模块比较有利。使用半桥模块有许多好处，包括使用单个预先通过认证的器件、更短的交付周期和具有更高的性能。有50多年历史的电源模块供应商Sensitron（sensitron.com）使用了EPC的eGaN FET，使它的新型产品更具吸引力。Sensitron与EPC合作，使用了新型EPC2050 GaN FET开发出350 V半桥模块SPG025N035P1B，这个半桥智能功率模块专为商业、工业和航空航天应用而设计，额定电流为20 A，可用于控制5 kW以上的功率。如图1所示，通过从Si和SiC器件升级至采用氮化镓器件，封装尺寸显著减小。

48 V is being adopted in many applications, including AI systems, data centers, and mild hybrid electric vehicles. However, the conventional 12 V ecosystem is still dominant, so a high power density 12 V to 48 V boost converter is required. The fast-switching speed and low R_DS(on) of eGaN FETs can help address this challenge. In this post, the design of a 12 V to 48 V, 500 W DC-DC power module using eGaN^® FETs directly driven by eGaN FET compatible ISL81807 controller IC from Renesas in the simple and low-cost synchronous boost topology is evaluated.

Modern displays, such as laptops and PC monitors, typically require a low power boost converter. In this application, the screen intensity is low to moderate and the converter is operated at light load most of the time, so the light-load efficiency is very important. The low switching loss of eGaN FETs can help address this challenge. This GaN Talk will examine the design of a 12 V to 60 V, 50 W DC/DC power module with low temperature rise using eGaN FETs in the simple and low-cost synchronous boost topology.

EPC development boards offer the opportunity to evaluate eGaN^® FETs and ICs in common applications. For example, the EPC9094 half-bridge development board can be configured as a buck or boost converter. The EPC9094 features the newly released EPC2054 200 V 43 mOhm max eGaN FET in a 1.3 x 1.3 mm 2 x 2 pin WLCSP package. The very low R_DS(on) value of this very small FET permits it to support high current loads from a high voltage supply. To demonstrate this ability, we will modify the EPC9094 development board to a buck converter. Using a 140 V supply, Spice simulation suggest 28 V output at 2.5 A will offer a high 90% efficiency. A Vishay IHLP-4040DZET330M11, 33 uH, 4.4 A, 95 mOhm Max, 10.2 x 10.8 x 4 mm inductor is selected which will provide 40% ripple at 500 Khz. Output capacitors consisted of four 10 uF Y5V 50V 1210 ceramic capacitors. The simulation showed a tradeoff between ripple current and overall efficiency when switching frequency was changed between 500 kHz down to 375 kHz. The simulation also showed that adjusting the dead time to permit full ZVS transition from high to low maximized the light load efficiency performance in the buck converter.