GaN's excitement in the fast charging market has only just begun

It seems that overnight, GaN has completely occupied the fast charging market. From major consumer electronics brands to third-party accessory manufacturers, all have launched fast charging products using GaN technology. Even the most cautious Apple has equipped its latest notebook with a 140W fast charging charger using GaN technology.

The ability to alleviate device charging anxiety is an important reason why GaN has been widely adopted, and the development of GaN device technology is a sufficient condition for GaN to be implemented in the field of fast charging.

GaN is taking off in the fast charging market

On October 25, 2018, Anker released the PowerPort Atom PD 1, the world's first GaN charger, which officially introduced GaN into the field of consumer electronics. This charger supports the PD fast charging protocol and provides a maximum output power of 27W, but is only slightly larger than the original 5W charger for the iPhone and can charge a Nintendo Switch or a MacBook Pro.

It was not until September 2019 that OPPO released the first GaN charger in China, SuperVOOC2.0, with a charging power of 65W. After this landmark event, GaN finally officially entered the huge and influential mobile phone market. In the second half of 2020, due to the competitive release of 5G mobile phones and the increase in power consumption of mobile power devices, fast charging products began to become popular, making the application of GaN more popular.

There is also an unexpected reason. The cancellation of standard chargers, led by Apple and followed by Samsung, created opportunities for more third parties to enter the fast charging market, indirectly contributing to the explosion of GaN. As Apple and Samsung have a very strong vane effect, other mobile phone manufacturers have followed suit, forcing consumers to buy chargers separately, and the demand for third-party fast charging has been completely released.

As a next-generation technology, GaN is naturally sought after by various manufacturers. In addition to the products launched by mobile phone manufacturers such as OPPO, realme, Xiaomi, Nubia, Samsung, Lenovo, and ZTE, third-party manufacturers are also following up with all their efforts. There are already hundreds of 20W-120W GaN fast charging products on the market. The 140W charger released by Apple in conjunction with the new MacBook Pro notebook has pushed the market application of GaN to a new height.

According to the latest research report from Yole Développement, a world-renowned research organization, the global GaN power device market is expected to reach US$1.1 billion in 2026; during the period 2020-2026, the market's compound annual growth rate will reach 70%, and the consumer market will be its main driving force.

Why is GaN so popular? Because compared with the traditional mainstream Si material, as a third-generation semiconductor material, GaN has the characteristics of large bandgap width and high thermal conductivity, which enables the device to carry higher energy density and higher temperature tolerance; the electron saturation speed is fast, with high carrier mobility, the switching speed of GaN devices is also faster; and GaN devices have small on-resistance and higher energy efficiency.

The size of chargers made with GaN can be reduced by 30-50% compared to traditional Si-based chargers; at the same time, the overall system efficiency can be as high as 95%, which means that the charger casing temperature will be lower than traditional chargers with the same size and the same output power; in addition, GaN chargers can use smaller transformers and smaller mechanical heat sinks, so the overall weight can be reduced by 15-30%.

With so many advantages, coupled with the efficient USB PD protocol, GaN fast charging products are naturally popular.

Fully integrated solutions promote the explosion of GaN fast charging

The explosion of GaN fast-chargers is driven by market demand from the outside, and is the inevitable result of the development of GaN power device technology from the inside. From the initial discrete solution to the fully integrated power chip, the design difficulty is simplified while also reducing system costs.

The most classic fully integrated power chip is the InnoSwitch3 series launched by Power Integrations (hereinafter referred to as PI).

InnoSwitch3 has long been well-known in the power IC market. Because it integrates the primary power switch, primary and secondary control circuits, and the safety isolation high-speed link (FluxLink) between them in a miniaturized surface mount package, and also integrates the secondary SR driver and feedback circuit, InnoSwitch3 has the advantages of high integration, high efficiency and high reliability.

PI has integrated its self-developed PowiGaN switch technology into the latest InnoSwitch3, replacing the original Si-based MOSFET, enabling it to provide 95% high efficiency over the entire load range and provide 100W power output without using a heat sink in a closed adapter.

Previously, the main difficulty in developing GaN applications was its ultra-high switching speed, which was very difficult to drive and protect. PowiGaN technology integrates GaN switches inside the IC to provide reliable protection. Specifically, it integrates the controller, driver, PowiGaN switch, protection circuit and SR control into one device to provide higher efficiency.

Integrating GaN switches into the chip is also a very smart approach, because GaN and Si MOSFETs do not work any differently. Simple flyback circuit topology, whether using silicon transistors or PowiGaN switches, InnoSwitch3 ICs use the same switching power supply design process, the same switching frequency, and very similar switching waveforms, with no abnormal circuit characteristics and no special design considerations. Only the corresponding external circuit components need to be selected according to the output power, ensuring that design engineers can easily master and ensure the consistency and continuity of development.

Many advantages have enabled the GaN-based InnoSwitch3 to achieve 1 million shipments in just two months after its release. The PowerPort Atom PD 1 mentioned above, as well as the OPPO Reno Ace original 65W GaN and other products are equipped with this chip.

In 2021, the latest generation of InnoSwitch4 series chips equipped with PowiGaN technology also made their debut. This chip uses an active clamp flyback architecture, has a built-in active clamp upper tube drive signal output, and realizes active clamping through an external ClampZero to recover leakage inductance energy, achieving a conversion efficiency of up to 95%. It has a built-in sturdy 750V withstand voltage PowiGaN main switch with a steady-state switching frequency of up to 140KHz, which can minimize the size of the transformer.

The InnoSwitch4-CZ/ClampZero chipset enables designers to design ultra-high power density chargers up to 110W for mobile phones, tablets and laptops, which were previously impossible to achieve. Therefore, once this chip was launched, it was used by Anker for its 65W fast charging and other products, and received unanimous praise from the market.

At the same time, more and more manufacturers are following suit in the market. Whether they are international giants or domestic latecomers, they have begun to launch fully integrated GaN fast charging solutions, accelerating the maturity of the technology.

Device price reduction market is just beginning

Another important reason for the widespread application of GaN in the field of fast charging is the sharp drop in the price of GaN devices. In early 2021, GaN Systems, an important manufacturer of GaN power transistors, announced that the price of its low-current, high-volume GaN transistors has fallen below $1. These transistors are commonly used in smartphones and laptops, as well as GaN chargers and AC adapters for various consumer and industrial applications.

According to data from Mouser, a world-renowned distributor, 80% of GaN HEMT (GaN transistor) products on sale have a withstand voltage of 650V, and their average price in 2020 is about 2.73 yuan/A, a decrease of 23.5% from 2019. In fact, due to the impact of the epidemic and continued strong demand, raw material prices have risen; the downstream PD fast charging market has exploded, and GaN chips are in short supply. Despite this, prices have still fallen. According to statistics, at the end of 2020, the actual transaction price range of GaN HEMT for PD fast charging 650V has fallen to less than 0.5 yuan/A, and the price difference with Si devices has narrowed to less than 1.5 times, which is highly competitive.

Perhaps it was because of the foresight that GaN technology would mature quickly that PI CEO Balu Balakrishnan stated in the 2019 semi-annual earnings conference call that USB PD will become a driving force for the company's revenue growth in the next few years due to the continued expansion of fast charging technology in the smartphone market.

The subsequent market development was just as he expected. Industry data shows that in the charger market dominated by e-commerce customers, the shipment volume of GaN devices was about 3 million to 4 million in 2019, and it increased 5-6 times in 2020, with a total shipment volume of 15 million to 20 million. In 2021, the shipment volume of GaN devices is expected to reach 50 million.

This momentum is still continuing. TrendForce's recent research shows that benefiting from the rapid increase in demand for consumer fast-charging products, mobile phone brands such as Xiaomi, OPPO, and ViVO have been the first to launch fast-charging heads since 2018, which have won the favor of consumers with their high heat dissipation performance and small size. As of now, notebook manufacturers are also interested in following suit, making the GaN power market the fastest growing category in the third-generation semiconductor industry, with an estimated revenue of US$83 million in 2021, a year-on-year increase of 73%.