許多電源系統中使用的基本構建塊是半橋，它由兩個串聯的功率FET及其各自的閘極驅動器組成。雖然離散式FET和閘極驅動器可以在板上實現這個相同的功能，但通常使用半橋模組比較有利和有許多好處，包括使用單個預先通過認證的元件、更短的交付周期和具有更高的性能。有50多年歷史的電源模組供應商Sensitron（sensitron.com）使用了EPC的eGaN FET，使它的新產品更具吸引力。Sensitron與EPC合作使用新型EPC2050 GaN FET開發出350 V半橋模組SPG025N035P1B，這個半橋智慧功率模組專為商業、工業和航空航天應用而設計，額定電流為20 A，可用於控制5 kW以上的功率。如圖1所示，通過從Si和SiC元件升級至採用氮化镓元件，封裝尺寸顯著減小。

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.