AC/DC adapters move toward GaN technology

by Vianie Li & Cecile de Veyra

First used in LEDs in the 1990s, gallium nitride (GaN) is now hailed as the next enabling technology that will usher in more efficient but smaller AC/DC adapters. It outdoes conventional semiconductor material silicon, which has reached the limit in terms of heat and electrical transfer vis à vis transistor size. In other words, silicon transistors can no longer be shrunk further without impact on their performance.

GaN transistors, on the other hand, benefit from the material's wide bandgap or capability of conducting at elevated voltages over time and allowing current to pass faster for better processing speed. As such, they are more efficient and produce less heat, with the latter property allowing components to be mounted tighter. This, in turn, results in smaller but still robust devices such as power adapters.

Although in its infancy, the use of GaN technology in AC/DC adapters has been attracting attention in the power supply industry.

US company CUI added such products to its line of AC/DC power supplies in 2020. The units are "32 percent lighter than comparable silicon-based power supplies, resulting in up to 250 percent greater power density," according to its power systems engineer Ron Stull in his article featured in Power Electronics Europe. "The GaN adapters are also lighter and operate up to 96 percent efficiency."

In China, a number of manufacturers have been releasing GaN products since 2020. These include Xiaomi, Baseus, Elecjet, J. Zao, Ilano and McDodo. Xiaomi's power adapters have a power density of 1.21W/cubic cm and are said to be the first in China to realize over 1W output power per cubic cm. Designed for smartphones, tablet PCs, laptops and gaming devices, they provide 5V 3A, 9V 3A, 10V 5A, 12V 3A, 15V 3A and 20V 3.25A 65W maximum output. All use a USB-C interface. Product dimensions are 30.8x30.98x56.3mm and weight is 82g.

In a report by Transparency Market Research, the global market for GaN-based power adapters is expected to push past $3 billion by2030 at a 5.5 percent CAGR from 2020. The forecast predicts that current challenges of production complexity and cost will continue to hamper the market for some time, however.

Steady market growth

Being the largest production base for AC/DC adapters, China will expect to benefit from healthy demand in the smartphone, tablet PC, laptop, wearables and LED lighting sectors. From $34.55 billion in 2019, its industry for this category is projected to realize $46.34 billion in 2024, according to Newsijie.

Most Chinese suppliers of AC/DC adapters enjoyed 5 to 10 percent sales growth from domestic and overseas transactions in 2020 despite the pandemic, according to companies interviewed by Global Sources Electronic Components. Many are confident of achieving the same rate of increase in the coming months and through 2022, encouraging them to continue boosting output.

Shenzhen Juyuanhai Electronic Co. Ltd, for instance, invested $1 million in new automatic production lines, enabling it to raise yield by 30 percent in 2020. The company is positive about maintaining this upward trend into 2022 from growing demand.

China's typical AC/DC adapters

In addition to smartphones, tablets, laptops and wearable devices, China's AC/DC adapters are widely used in office equipment and medical devices.

Driven by this predominantly consumer electronics market, companies are emphasizing the release of smaller and lighter variants. Setting the direction is Lenovo with its Thinkplus mini power adapters, which pack 45W maximum output power in spite of their compact 30x30x68mm, 88g design.

Alongside this miniaturization pursuit is the development of GaN-based AC/DC adapters in the next two years as part of efforts to broaden capability for customization. This business model, after all, brings in 30 to 60 percent of orders received.

Commonly available desktop and wall-mount AC/DC adapters from Chinese manufacturers have 100 to 240VAC, 50/60Hz input and 5 to 24VDC, 1 to 5A output. In terms of rated power, the range is from 3 to 150W, while efficiency level is typically more than 80 percent. For safe operation, products come with built-in protection against overvoltage, -current, -heating and short circuits.

As further assurance, most suppliers offer power adapters that meet BS, CB, CCC, CE, CQC, FCC, GS, KC, MEPS, PSE, SAA, TÜV and UL safety and quality standards as well as RoHS environmental guidelines.

Materials and components used in the manufacture of AC/DC adapters come from domestic or foreign providers, depending on buyers' specifications. They include rectifiers, ICs, passive components, transformers, PCBs, cables and cases.

Due to higher input and labor costs in 2020, most companies were forced to increase their product prices by 3 to 8 percent. In the coming months, all may stabilize.

China hub

There are about a thousand manufacturers of AC/DC adapters in China. Companies with investment from overseas make up 30 percent of this pool and operate on a medium and large scale. Domestically owned companies are mostly small and midsize businesses, shipping products to North America, Europe and the Asia-Pacific region.

Pisen, Ugreen, Bull, UE, Meanwell, Delta, Chicony and Lite-On are some of the major players.

More than 50 percent of these suppliers are in the Pearl River Delta area, with others in Fujian, Zhejiang and Jiangsu. There are also a number of AC/DC adapter manufacturers based in Shanghai.

5W AC/DC adapter

GME Technology Co. Ltd markets this GME5W AC/DC adapter with 100 to 240VAC, 50/60Hz input rating and 5W output power. It has built-in overvoltage, -current and short-circuit protection.

The minimum order required is 1,000 units. Lead time is 15 days.

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AC/DC adapter, supports USB-C PD

The PS-496 offered by Power System Electronic Technology Co. Ltd is an AC/DC adapter with a USB-C PD port. The 35x35x35mm unit, which is made of PC, has 100 to 240VAC, 50/60Hz, 0.3A input, and 5V 3A, 9V 2.22A or 12V 1.66A output. Output power is 20W.

An order of at least 3,000 units is for delivery within 30 days.

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12 to 72W AC/DC adapter

Integrating overvoltage, -current, -load and short-circuit protection, this JYH4Z-050100-BA AC/DC adapter from Shenzhen Juyuanhai Electronic Co. Ltd has 100 to 240V, 50/60Hz, 1.5A input rating and 5V, 10A, 12 to 72W output rating. It meets DOE Level VI, CE, GS, FCC, RoHS and UL requirements.

The supplier requires a minimum order of 500 units. Delivery is within 15 days.

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60W AC/DC adapter

Suitable for LCD and LED TVs and monitors, portable hard drives, laptops and DVRs, this AC/DC adapter from Shenzhen Soy Technology Co. Ltd, the Sun-063B-5297, has 90 to 264VAC, 50/60Hz input and 12V, 1.5A or 12V, 2A output. This 60W unit, with built-in overcurrent and short-circuit protection, complies with CEC, MEPS, Energy Star and ERP standards.

The minimum order quantity is 1,000 units. Lead time is 20 days.

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