Fraunhofer IAF Researchers Create Extremely Compact and Efficient Voltage Converter

one year ago by Luke James

Researchers at the Fraunhofer Institute for Applied Solid State Physics IAF (Fraunhofer IAF) have integrated their gallium nitride power integrated circuits using PCB embedding technology—to create an extremely compact and efficient voltage converter.

Energy-efficient power electronics for conversion and transmission applications are becoming more and more important as technological innovations develop, particularly in applications that require sustainable energy. Now, researchers at Fraunhofer IAF in Germany have developed what they are calling a highly integrated and user-friendly gallium nitride (GaN) voltage converter that is resource-efficient. It also comes in a compact package and can be used modularly.


A Super Compact System Design

Using power semiconductors in voltage converters is nothing new. It has been done for several years now to meet modern demands on energy supply and usage. However, it is not only the semiconductor materials that play an important role in how well power semiconductors perform, but their package and component design, too: the smaller and more compact a package is, the more efficiently it works.


An x-ray image of the half bridge circuit, alongside a circuit diagram of Fraunhofer IAF’s integrated GaN Power ICs (gallium nitride power integrated circuits).

An x-ray image of the half bridge circuit, alongside a circuit diagram of Fraunhofer IAF’s integrated GaN Power ICs (gallium nitride power integrated circuits). Image Credit: Fraunhofer IAF.


Unfortunately, it’s not as simple as making designs more compact and replacing their larger cousins. A compact design is a lot more difficult to reconcile with the discreet standard components that currently dominate the GaN power electronics industry. Consequently, conductor loops between transistors and power supplies must be designed individually and wired as circuits from discrete components.

This is where Fraunhofer’s so-called user-friendly alternative comes in. In their work, the research team has embedded their proprietary GaN-based power ICs as a half-bridge in a printed circuit board, which features all the critical wiring within the package. This results in a much more compact and efficient voltage converter that is suited for 600V applications and enables a modular system design.


98.8% DC-DC Efficiencies at 350 Volts

Due to the high integration density of Fraunhofer’s GaN Power ICs, higher performance density, reliability, and compactness are achieved in contrast to other circuits. Using their GaN Power ICs in an experimental half-bridge circuit, the Fraunhofer team has reportedly managed to achieve DC-DC efficiencies of over 98.8% at 350V.

Said Stefan Mönch, a researcher at Fraunhofer IAF: “GaN-on-silicon technology allows monolithically integrated circuits for half bridge converters but does not solve the wiring problem to external capacitors. However, these critical connections to gate drivers and DC link capacitors are essential for clean and efficient switching behaviour. With our goal of a perfect voltage converter in mind, we were looking to find the optimal highly integrated packaging technology for our GaN Power ICs”.