Don't Overlook Thermal Benefits of GaN High-Efficiency Power Supplies

When considering off-board AC/DC power supplies for new applications, designers often opt for silicon (Si)-based components despite the superior electric properties and efficiency of gallium nitride (GaN)-based alternatives. That may be due to longstanding assumptions regarding cost-effectiveness or because it's long been the default choice. However, they may be overlooking the reduced cooling requirements of GaN-based options.

Si semiconductors have been the mainstay of the electronics industry since the second half of the 20th century. GaN was synthesized in the 1930s but took much longer to gain favor, with the first general application in light-emitting diodes in the early 1990s, and wider use after it became commercially viable to manufacture GaN transistors as alternatives to metal-oxide-semiconductor field-effect transistors (MOSFETs).

Still, Si continued to rule the domain for AC/DC power supplies. Utilizing more well-established manufacturing processes, suppliers could provide more silicon transistors within the cost constraints of product designers, but Si-based components are running into performance and thermal limitations, opening the door to broader consideration of GaN alternatives.

With higher electron mobility and wide bandgap, power supplies utilizing GaN can operate at higher frequencies with greater efficiency and in smaller form factors.

Benefits of GaN in power supplies

GaN transistors feature lower resistance and switching losses than Si transistors, switching faster and wasting less power. They have better thermal conductivity and can operate at higher temperatures than silicon transistors. This reduces the need for bulky and noisy cooling components such as heatsinks, frames, or fans.

Cutting down components improves reliability and allows for more compact power units that can save valuable space when designing new applications. Smaller and more dependable power units are suitable for a wide range of applications that demand high-performance and low-noise power solutions.

Off-board GaN-based AC/DC power supplies can be used in applications including:

• Medical devices where the power supplies must be efficient, reliable, and quiet
• Industrial equipment for robust, durable, and adaptable use in robots, sensors, or controllers
• Consumer electronics for powering fast, lightweight, and portable devices
• Gaming systems with immersive, cool power supplies, consoles, and VR headsets

Varied GaN power supplies from Bel brands

Bel Power Solutions, part of Bel Fuse Inc., has been expanding its offerings in the GaN-based AC/DC power supply market under the EOS Power and CUI Inc. brands, all part of the Bel group. These brands provide a portfolio of power supplies utilizing GaN technology aimed at achieving higher power density and improved efficiency compared to their silicon MOSFET equivalents.

EOS is known for ultra-miniature power supplies. The EPG300/MEPG300 (Figure 1) and EPG500/MPEG500 were introduced for applications requiring minimal power loss and easy thermal management, such as RF applications, 5G systems, and industrial process control.

Figure 1: The EPG300 and MEPG300 power supplies form factor. (Source: EOS Power)

Both the EPG300 and MEPG300 AC/DC power supplies are available in six single-output voltages ranging from 12 V to 58 V, with efficiency up to 94%. The EPG300-1312, for example, is a 12 V output, open-frame power supply with dimensions of 4.00" x 2.00" x 1.47" (101.6 mm x 50.8 mm x 37.3 mm).

The MEPG300-1312 and other models in that line are specifically designed for medical applications, including hospital beds, imaging equipment, monitoring devices, surgical devices, and diagnostic equipment. They are built to the most recent medical standards (EN/IEC 60601-1) and have 2 x MOPP isolation options for Class I applications.

The EPG500 and MEPG500 AC-DC power supplies (Figure 2) provide up to 500 W of regulated output power over a wide input range of 90 VAC to 264 VAC. They are both available in six single-output voltages ranging from 12 V to 58 V, with dimensions of 5.00” x 3.00” x 1.58" (127.0 mm x 76.2 mm x 40.0 mm).

Figure 2: The EPG500/MEPG 500 power supply form factor. (Image source: EOS Power)

CUI's SDI120-U, SDI300G-U, and SDI300G-UR series 120 W and 300 W GaN desktop AC/DC power supplies are designed for a variety of portable consumer and industrial applications.

The CUI SDI120G-24-U-P51 (Figure 3), a 24 V output GaN desktop power supply, measures 5.20" x 2.01" x 1.26" (132.0 mm x 51.0 mm x 32.0 mm). It can deliver up to 120 W of continuous power and meets U.S. Department of Energy Level VI efficiency standards.

Figure 3: The SDI120G-24-U-P51 desktop power supply. (Source: CUI, Inc.)

The SDI300G-48-U2-P219 is suitable for a variety of applications that require a high-power, efficient, and compact AC/DC power solution. Measuring 7.20" x 3.35" x 1.38" (183.0 mm x 85.0 mm x 35.0 mm), it provides an output of 48 V at 6.25 A (max).

The CUI SDI300G-UR series is IEC Class II rated, with a three-prong (C18) inlet, while the SDI300G-U (Figure 4) and SDI120G-U series feature a two-prong (C14) inlet.

Figure 4: CUI's two-prong SDI300G-UR series AC/DC desktop power supply form factor. (Source: CUI, Inc.)

Conclusion

With product manufacturers constantly demanding more compact and efficient power solutions, GaN is an increasingly attractive option for new electronics applications in the consumer electronics, telecommunications, and automotive sectors, among others. The Bel brands offer product designers a range of options for applications that require reliable, efficient, and compact AC/DC power conversion, with added cooling benefits.

References:

1 – https://www.edn.com/a-brief-history-of-gallium-nitride-gan-semiconductors/