Consumer

More power taking up less space with GaN

GaN-based semiconductors are the Next Big Thing in mobile devices - from charging systems to the 5G network.

More than 5 billion people worldwide use a mobile phone (Source: Digital 2020 - Global Digital Overview, are social/Hootsuite). Then there are laptops, smart watches, fitness trackers, and a wide range of other mobile devices. They all need power, by being charged. So the charger market is highly dynamic. Components based on wide band gap (WBG) semiconductors enable chargers to be manufactured that are smaller, charge faster and emit less heat than conventional silicon-based chargers.

Conventional silicon semiconductors are limited to switching frequencies of a few hundred kilohertz, while both silicon carbide (SiC) and gallium nitride (GaN) extend into the megahertz range. Their increased switching frequency allows for designs using smaller magnetic components and reduces energy loss.

More power for the battery

GaN semiconductors, in particular, are steadily increasing their share of the charger market. GaN is a material with a wide band gap, meaning the electron band gap is three times larger than that of silicon. Consequently, GaN can handle large electric fields with much smaller chips. GaN is 40% more energy-efficient than silicon, and does not generate as much heat in operation. Its higher charging efficiency allows more power to be transferred to the battery, which means that it can be charged faster. At half the size and weight, GaN chips can transfer three times as much energy as conventional silicon-based technology. Using GaN also cuts the cost of components and heat sinks. For example, the world's smallest 65 W chargers have been launched for Xiaomi and Lenovo at retail prices 50 to 75% below those of previous best-in-class silicon chargers.

One charger for everything

GaN components now also enable so-called multi-port chargers to be easily implemented. With a power output of up to several hundred watts, they are able to charge not just one mobile device, but several at a time. Consumers can now charge their iPhone, iPad and MacBook, for example, simultaneously, and much faster than before. The use of GaN semiconductors in chargers not only reduces energy loss during charging, but also ensures that in future just one device will be needed to power all the mobile devices in the household rather than lots of different ones - making a major contribution to reducing electronic waste and conserving resources.

Charge devices wirelessly from meters away

The next step in terms of the charging “infrastructure” for mobile devices is wireless charging. There are currently two competing technologies in the field: In inductive charging, based on the Qi standard, where the device has to be placed directly on the charger, the energy is transmitted at a low frequency between 100 and 205 KHz. Resonant technology, primarily promoted by the AirFuel Alliance, runs at high frequencies of 6.78 MHz. This allows energy to be transmitted over relatively long distances of several metres. With a - projected future - power output of 22 W, this technology also offers the facility to charge multiple devices simultaneously. GaN reveals its advantages especially in conjunction with the high frequencies of resonant technology. It enables higher transmitter and receiver efficiency, and reduces component costs. The benefits in this context, too, are that charging stations manufactured using GaN are smaller and lighter, and surface heat is also reduced thanks to the low power loss.

Reliable, low-cost 5G base stations

Mobile device users will in future not only find GaN in their chargers; the semiconductor material is also playing a key role in the 5G communications standard. This is because GaN enables the creation of a 5G infrastructure that meets the three key requirements of performance, efficiency and low operating cost.

Thanks to their thermal properties, GaN semiconductors can be used to operate components with a much higher voltage and power density. So radio antenna arrays can be made smaller, while delivering the same performance. This means that a 32-antenna MIMO array is sufficient to transmit the power of a 64-antenna MIMO array implemented using conventional technology. And the GaN chip can also be about 20% smaller. Both those factors mean that the base stations are smaller.

At the higher frequencies for 5G, such as 3.5 GHz, GaN is 10 to 15% more efficient than existing silicon technologies. The robustness of GaN semiconductors, which among other benefits feature low sensitivity to ionising radiation, will be important in future for the stability of networks that will also be used to control cars and industrial plants.