GaN Talk Blog

Alex Lidow, CEO and co-founder of Efficient Power Conversion (EPC), talked with Ally Winning, Editor at Power Systems Design, about EPC's strategic agreement with Renesas in a recent interview. The interview looked at why the deal was made, how important it is to have a second source, and how certain eGaN devices help set de facto standards in the low-voltage GaN market.

Submitted by Richard Locarni, Director of New Business Development, Sensitron and Brian Miller, Field Application Engineer, EPC

The basic building block used in many power systems is the half bridge which consists of two power FETs in series and their respective gate drivers. While discrete FETs and gate drivers can be used to make this function on a board, often it is advantageous to use a half-bridge module.  There are many benefits of using a half-bridge module including the use of a single pre-qualified part, shorter lead times, and higher performance.  Sensitron (sensitron.com) has been a supplier of power modules for over fifty years, and their latest product is even more attractive due to the use of EPC’s eGaN FETs.  Sensitron collaborated with Efficient Power Corporation to use the recently released EPC2050 GaN FET to develop a 350 V half bridge module. Designed for commercial, industrial, and aerospace applications, the SPG025N035P1B half bridge intelligent power module is rated at 20 A and can be used to control over 5 kW.  Shown in Figure 1 is the significant package size reduction which was achieved by upgrading from Si and SiC to GaN:

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.