GaN Delivers More Compact Power Supplies

Jan. 31, 2024

Navitas Semiconductor’s GaN solutions isolate the GaN transistor for a more robust power-supply solution.

Check out Electronic Design's coverage of CES 2024. This article is also part of the TechXchange: Gallium Nitride (GaN).

What you’ll learn:

Why Navitas Semiconductor’s GaN solution is unique.
Why GaN-based power supplies are smaller and more efficient.

Gallium-nitride (GaN) transistors are able to handle large currents at high switching speeds, leading to switching power supplies that are significantly smaller than their silicon-based counterparts. That’s because faster switching speeds and lower on-resistance of GaN FET transistors let designers employ smaller magnetics, reducing the size of the solutions. Unfortunately, GaN transistors can be a bit fragile, requiring additional protection to provide a more robust solution.

I talked with Stephen Oliver, VP Corporate Marketing & Investor Relations at Navitas Semiconductor, about where the company’s latest GaN technology is being deployed (see video above).

Improper use of GaN transistors can result in breakdowns, which has made GaN adoption more challenging to engineers. To address this situation, Navitas uses a system-in-package (SiP) approach that adds controlling electronics for the GaN transistor, which is also in the package (Fig. 1). This provides protection from electrostatic discharge (ESD) and other features, making it easier for designers to include it in their solutions.

1. Navitas Semiconductor isolates its GaN transistor, providing additional protection and control for safe, high-speed operation.

Such GaN-based solutions can be considerably smaller (Fig. 2) because they operate at a higher frequency than switching power supplies based on silicon transistors. The higher frequency means that the same power conversion can be done using smaller components like transformers and inductors. The SiP also provides lossless current-sensing support. Typically, this is done using a sensor based around a low-resistance resistor that consumes power, reducing the overall efficiency of the power supply.

2. GaN’s high speed and efficiency allow for significant shrinkage (left) compared to conventional silicon-based power supplies (right).

The same SiP approach is used in Navitas’s latest half-bridge solution, which provides the front end to a pair of integrated GaN FET transistors (Fig. 3). The low-profile, low-inductance SiP comes in a standard 6- × 8-mm PQFN package.

3. Navitas’s half-bridge solution delivers the same protection and functionality for a pair of GaN transistors.

Among the features in its single-transistor solution are overcurrent protection and overtemperature protection (Fig. 4). The half-bridge can operate at megahertz speeds instead of the kilohertz switching speeds of silicon-based solutions.