December 24, 2020 by Lianne Frith
With the average household containing at least five connected electronic devices, there are huge expectations around charging capabilities and performance. While silicon has battled with delivering fast charging through small devices, gallium nitride (GaN) technology is uniquely positioned to provide a solution to the challenge.
Silicon has been the backbone of the technology industry for decades and has become the go-to material for transistors. Silicon conducts electricity better than its precursory materials and isn’t too expensive to produce. However, as we continue to see advancements in the technology we use and come to expect more power—delivered more quickly and more efficiently than ever—silicon may be reaching the end of the road in terms of what it can offer.
Indeed, while today’s silicon-based products offer viable charging solutions, they still fall short. The problem is the properties of the silicon material itself: in terms of heat and electrical transfer, the components may not be able to become any smaller, which means that charging power has become proportional to size. In turn, the consumer demands on powering their devices mean that charger production costs and the lack of convenience when carrying chargers are proving considerable problems.
While silicon manufacturers have worked tirelessly to improve silicon-based circuits, they have been challenged by their need to incorporate an ever-growing number of transistors. The result is that Moore’s Law, which suggests that the number of transistors will double every two years, is being challenged, and manufacturers are reaching the limits of scale.
A pile of different chargers and power cables, representing what many technology users currently need to power their devices. Image Credit: Pexels.
Using gallium nitride to manage ultra-high-frequency power solutions has been a goal for the technology industry for many years. When it comes to chargers, GaN produces less heat, meaning that components can be closer together and devices can be smaller. And, all of that is possible while retaining the necessary power capabilities and safety standards. In fact, there are several benefits of using gallium nitride chargers over their silicon counterparts, some of which are covered in the next subsections.
GaN is more efficient at conducting electricity, having a 2.4 eV bandgap compared to the 1.12 eV bandgap of silicon. This means that the former can sustain both higher voltages and higher temperatures. And due to the reduced bandgap, GaN is more efficient at power conversion: it conducts electrons 1,000 times more efficiently than silicon. The result is both a better flow of energy to the charging device and quicker charging times.
Again, GaN chargers conduct electricity at higher voltages than their silicon counterparts. This means that the current can pass through faster and less heat is lost, resulting in more energy that can go into the device being charged. Moreover, when components are more efficient at passing energy to devices, fewer components are required, meaning that the chargers can be made smaller.
While, at present, GaN semiconductors cost more than the silicon kind, this should change as they become more widely available. Thanks to their improved efficiency, there is less need for additional materials like heatsinks, filters, and circuit elements. Power transistor manufacturer GaN Systems estimates that the resultant cost savings could go up to as much as 20% in this area. And once large-scale production is in place, this could increase further still.
An example of a gallium nitride charger: HyperJuice, a 100-watt device that is being used to simultaneously power four USB-C-friendly devices. Image Credit: Hyper.
While, just a short time ago, GaN transistors were being held back by cost and proof of reliability, they are now becoming more common. New generations are appearing, and they are integrating an increasing number of features, such as those relevant to analogue, logic, and power.
Some of the most interesting products include the above-pictured HyperJuice charger, by the Apple and mobile accessories manufacturer, Hyper; and Anker’s PowerPort Atom III Slim. HyperJuice is a 100-watt USB-C GaN charger (about the size of a pack of cards) that can charge all compatible devices at maximum speeds; and the Atom III Slim is a 65-watt charger with fast charging capabilities that offers a huge range of charger and cable offerings for a wide range of devices (unlike conventional chargers, it has a flat solid-state drive-like design, which that makes it both slim and portable).
Of course, these are just some examples of the current, first generation of GaN-based chargers. And so far, only part of manufacturers’ GaN chargers are being designed with GaN-based circuitry. Nevertheless, many companies’ long term goal is to have all of their chargers’ circuitry components designed with high-performance gallium nitride. The result will be even smaller, more powerful, and energy-efficient chargers as time goes on.
An example of the bulky hardware associated with non-gallium nitride chargers: a typical AC power adapter used to charge a laptop. Image Credit: Bigstock.
In a world where all of our devices are being designed ever smaller, it is surprising that it has taken this long for the huge power bricks of existing chargers (such as the examples above) to be replaced. GaN technology most certainly looks set to change such chunky hardware, given that the early gallium nitride models are already being released to prove the technology’s benefits.
With GaN, we shouldn’t have to carry around hefty chargers, wait hours for our devices to charge, or have concerns about any devices overheating.
That said, we probably won’t see a lot of GaN chargers being used until the larger hardware manufacturers such as Apple and Samsung start including them in their devices. However, even at the time of writing, they offer the power conversion, fast switching and high efficiency required to deliver small size and high output. This could well be the start of a high-speed revolution in power electronics.
