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Fraunhofer IAF Establishes a GaN Low Voltage IC Design for 3-Phase Motor Inverters

July 26, 2021 by Antonio Anzaldua Jr.

The Fraunhofer Institute for Applied Solid State Physics (IAF), explored new research through their latest ideas for integrating GaN-based ICs for low-voltage designs.

Automotive and IT applications utilize 48V technology in most battery-powered setups. In order to have optimal switching and low power consumption, designers look to gallium nitride (GaN) power transistors as a potential solution.


A closer look at Fraunhofer IAF’s GaN-on-Si chip designs; reliable, energy-efficient, compact, and easy integration in what drives researchers for improving low voltage systems. Image courtesy of Fraunhofer IAF.


Researching GaN-Based Circuits in 48V Systems

Utilizing 48V class systems allows for efficient power transmission throughout various industries. In regards to safety and cost, avoiding high-voltage systems will be a resource-saving alternative. The German-based semiconductor research institute, Fraunhofer IAF, is known for a large array of research studies that have led to the development of high-frequency circuits in power electronics, energy-efficient voltage converter modules, and diamond-based quantum sensors.

At an international conference for power electronics, intelligent drive technology, renewable energy, and energy management, PCIM 2021, Fraunhofer scientists discussed how they were able to merge two transistors composing a half-bridge layout into a new compact design. The typical half-bridge layout is a side-by-side arrangement that deducts from an ICs area, the proposed design from Fraunhofer reduces in size to allow for three half-bridge layouts to be in one motor inverter. This inverter IC would be utilizing GaN technology, making it a leading option for low-voltage applications.

Packaging a half-bridge into one simple IC is a challenge within itself. There are several requirements for electrical and thermal performance the IC must meet, along with guaranteeing reliability.

Richard Reiner, a leading scientist at Fraunhofer IAF, found that the key to achieving area efficiency in half-bridge arrangements was by going to GaN-based components.

“In research and development, the focus has so far been mainly on 600 V GaN devices. Concepts for designing highly compact low-voltage GaN power ICs have hardly been explored,” he said.


A GaN-based, 3-Phase motor inverter IC, composed of three half-bridges which is fully equipped for driving a brushless DC motor. Image used courtesy of Fraunhofer IAF.


The GaN-based ICs have combined PCB embedded hardware that elevates power densities for low-voltage DC/DC converters. The GaN-motor IC will be able to use all three half-bridges to control inductive loads at each phase while reducing any temperature swings during motor operation.


Fraunhofer IAF’s Leading GaN-Projects

An early research project called GaNonCMOS from Fraunhofer IAF was funded by the European Union’s Horizon 2020 program and dealt with GaN integration with Si-CMOS to deliver reliable, cost-effective, and high-frequency power designs. Over the course of 3 years, scientists aimed to develop GaN-based processes, components, modules, and integration schemes to showcase energy efficiency and improved performance. GaNonCMOS brought on new soft magnetic core materials that reached switching frequencies up to 300 MHz with minimal power losses.

A research project deemed GaNTraction is Fraunhofer IAF’s study based on GaN modules in 48V drive inverters. GaNTraction’s main objective is to develop GaN-based half-bridges that will be compact and efficient for automotive instances. This research project is continuing into 2022 with hopes of reducing the volume of future drive inverters by a factor of 5.

Once Fraunhofer’s research projects are brought to fruition, manufacturers and engineers will be able to turn to one IC to handle 3-phase motors with advanced GaN technology as it becomes a cost-effective option.