This article is part of the TechXchange: Power Supply Design.
Gallium nitride (GaN) continues to shake up the silicon-dominated world of power electronics.
In the latest sign, Anker Innovations rolled out a new series of fast chargers last month that swapped out even more of the internal power components for GaN-based ICs, promising much higher power outputs in smaller and more affordable packages that dissipate less heat. The company even overhauled the ac-dc converters in several of its chargers to run entirely on GaN FETs.
Anker said it worked with a broad range of suppliers, including Infineon Technologies and Navitas Semiconductor, to roll out its series of fast chargers featuring power outputs of up to 150 W.
Anker pioneered the use of GaN power devices for fast chargers in 2018. But the fact that it is stripping out more of the silicon in its hardware signals that the world is becoming more confident in the abilities of wide-bandgap (WBG) semiconductors.
As Anker and other consumer electronics makers step up the production of chargers with GaN inside, GaN's prospects are looking up. As GaN becomes more widespread, economies of scale are helping chip suppliers reduce prices, making it more accessible to everyone.
The average price of a GaN power transistor has dropped to about $1, according to a report released last year by TrendForce, a semiconductor market research firm. GaN is projected to be inside half of all fast chargers by 2025.
GaN Charging Up
GaN has unique physical properties that allow it to switch significantly faster than standard power ICs. As a result, customers can use it to pack more power into chargers or support smaller form factors that weigh less and create less heat, improving power density and accelerating charging. GaN ICs also promise to reduce on-resistance (RDS(on)).In addition to its faster switching speeds, GaN power ICs offer better power efficiency when converting alternating current (ac) to direct current (dc). These efficiency gains add up over time to reduce the carbon footprint of Anker's fast chargers.
The market for GaN power electronics will grow roughly 60% every year for the foreseeable future, surging from $125 million in 2021 to $2 billion by 2025, according to market researcher and consulting firm Yole Développement.
"GaN fast chargers are growing rapidly in the handset market," said Yole technology analyst Taha Ayari.
Anker's new series of chargers include wall chargers with USB-A and USB-C ports, ranging from the 65-W "735" with two USB-C sockets and a USB-A socket starting at $60 to the top-of-the-line "747" rated at 150 W.
Another member of the series is the 120-W "737" charger that can charge a pair of USB-C devices and a USB-A device at the same time, with prices starting at $95. That means consumers can charge a pair of laptops at once, or a laptop and a phone or tablet, plus an accessory, without having to plug into more than one power socket.
The flagship 747 charger pumps out even more power. But it sacrifices the smaller footprint of the 737 in favor of an additional USB-C port and an additional 30 W of power-delivery capacity in a package priced at $110.
Anker is competing against Apple, which rolled out its 140-W charger for the MacBook Pro last year, marking the first time the consumer electronics giant has employed GaN power ICs in its chargers.
Hitting New Highs
To develop its new high-power GaN chargers, with outputs of more than 100 W, Anker said it partnered with power semiconductor maker Infineon Technologies as well as Navitas, one of the leading players in GaN ICs.
By applying technology from both companies, Anker was able to boost the efficiency of its new GaN chargers, reducing the electricity lost by the charger while in use, as well as the chargers' carbon footprint.
The company said its new flagship 150-W charger is 38% smaller than Apple's 140-W GaN MacBook Pro charger, while its 120-W unit is 39% smaller than Apple's 96-W MacBook Pro charger, giving it the edge in portability.
By combining Infineon's hybrid flyback controller and CoolGaN switch in its new series of fast chargers, Anker hit a system efficiency level of 95%, reducing energy losses by about 20% compared to other charging solutions based on silicon, according to Infineon. Infineon said it's the first time the HFB architecture and CoolGaN family of switches have been combined in any commercially available consumer device.
Also at the heart of Anker's latest lineup of chargers are GaN power ICs from Navitas, which integrate GaN power, drive, and control functionality, plus real-time sensing and protection with its GaNSense technology.
Using its latest family of GaN devices, Navitas said Anker can reduce the carbon footprint of its chargers by up to 30% versus "legacy" silicon chips. Anker is a long-term customer and development partner with Navitas.
In the event the GaN power ICs sense a potentially dangerous system condition such as overcurrent spikes, the chips are designed to go into a cycle-by-cycle sleep state, protecting the device and the whole system. Navitas said GaNSense packs an autonomous standby-power feature that automatically reduces standby power consumption when the GaN power ICs are in "idle" mode, further enhancing energy efficiency.
The chips are designed to support a host of power-conversion topologies, including high-frequency quasi-resonant (HFQR) flyback, active-clamp flyback (ACF), and power-factor-correction (PFC) boost.
From High to Low
For its new family of chargers with under-100-W outputs, Anker cited China's Innoscience for its GaN ICs and Southchip, a high-performance semiconductor startup also based in China, as important partners.
Anker's new series is powered by GaN FETs on both the ac side and dc side—a first for the consumer market, according to Innoscience. By taking full advantage of GaN FETs, Innoscience said Anker maximizes power efficiency and density instead of compromising with a hybrid Si-and-GaN design.
Innoscience operates a pair of GaN wafer fabs, including what it calls the world's largest dedicated 200-mm GaN-on-Si site. It currently has a capacity of 10,000 wafers per month, and it plans to ramp up to 14,000 per month by the end of this year before soaring to 70,000 every month by 2025. Executives tout Innoscience as the world's largest GaN operation, giving it cost advantages over rivals across its 30- to 650-V product lineup.
Southchip brings its proprietary GaN "differential drive" technology to Anker's fast chargers, which tightly integrate the GaN power ICs and controllers to reduce any loss when converting electricity from ac to dc.
At the heart of its new generation of chargers is a new Anker-specified system-on-chip (SoC) that runs its PowerIQ technology. When charging multiple devices at once, it intelligently detects each device's power needs, automatically adjusting power distribution to reduce charging times by up to one hour.
The SoC, designed for high-current and high-voltage dc-dc USB PD fast charging, paired with Anker's PowerIQ technology, reduces the energy wasted by the chargers by up to 40%, according to the company. The chargers also feature Anker's second-generation ActiveShield technology: It monitors temperature and adjusts power output to prevent overheating and safeguard devices.
"GaN is allowing us to completely change the way we charge our electronics by delivering better power-transfer efficiency, faster-charging speeds, and more portable chargers," said Anker CEO Steven Yang.
Fast chargers will continue to climb to higher power levels. The new USB PD 3.1 standard calls for the delivery of up to 240 W of power via USB Type-C cables and connectors. But Infineon and other industry players have said GaN is probably the only way that customers will be able to hit the 240-W plateau.
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