Power ICs Enable Smaller, Slimmer, Faster Mobile Charging Devices

The batteries used in mobile devices have grown substantially in recent years and with them, charging time.

The 4,865 mAh battery of the latest iPhone 16 Pro Max has nearly three and a half times the capacity of the original iPhone. While Samsung’s latest, the S24 Ultra, is 7% bigger still. And with it, charging time has become a primary consumer concern. Indeed, surveys repeatedly now place fast charging times among consumers’ very top factors when choosing their next phone.

These faster charging times have been made possible through the switch from silicon to GaN power ICs for chargers, with next generation chargers based on Navitas GaNFast and GaNSlim ICs delivering greater power densities to deliver more power from the same size unit and/or enabling the creation of slimmer sleeker, more aesthetically pleasing in-wall chargers for mobile devices, laptops and consumer goods.

Mobile Battery Capacity is Increasing

Since their inception in 2007, smartphone battery life has repeatedly topped surveys of the most important features behind consumer choice. As such, phone battery capacities have increased dramatically.

Apple launched the iPhone 5 in 2012, with a review in The Verge then calling it the “best iPhone ever made” and citing its battery life as a key reason for this.

The phone had a 1,440 mAh battery whereas today, modern flagships like the Samsung Galaxy S24 Ultra and OnePlus 13 respectively boast 5,000 mAh and 6,000 mAh.

This increase in battery capacity is necessary to support the growing power demands of larger displays, more powerful processors, and increased connectivity options like 5G.

Today, battery life remains among the most important smartphone features, but the increased capacity has led to longer charging times and there is now significant pressure for OEMs to deliver faster and more efficient charging.

Charging is Now a Consumer Choice

Today few mobile manufacturers now include chargers in the box with new smartphones.

This is primarily due to environmental concerns – smartphones have been around for long enough for most people to have a charger or another way of charging – and has been enabled through the push for standardization, notably the EU’s common charger requirements, which came into force in 2024 to reduce electronic waste and specified the USB-C standard be implemented on all mobile phones and tablets sold in the region. Apple, which had previously used the proprietary Lightning standard, not only implemented USB-C in Europe, but adopted the standard worldwide.

This shift as a result of EU legislation places the burden on consumers to purchase their own chargers, which is a significant change in the market.

According to Counterpoint’s Q2 2024 report, the world’s top five smartphone manufacturers are Samsung (19%), iPhone (16%), Xiaomi (15%), OPPO (9%), and VIVO (9%). Of this, only Xiaomi continues to supply chargers with some of its phones. And based on Counterpoints U.S. market share data, over three-quarters of phones sold in the country are shipped without a charger, with neither Apple (52% US market share) and Samsung (24%) no longer including chargers, and only smaller brands like Lenovo/Motorola (12%) and HMD/Nokia (1%) still including them in some models.

The smartphone consumer is therefore a major factor in the decision making in the type of mobile charging used and 2022 research by OnePlus – which as of 2024 does include a charger with all of its phones – highlighting the importance of fast charging.

In its survey of 1,000 American consumers, 43% of respondents reported being “at least somewhat frustrated” with the time it takes to fully charge the phone and 97% being “interested” in a phone that could charge in less than 20 minutes.

A similar 2021 Android Authority reader poll of over 4,400 respondents asked which feature they would be willing to give up for a lower-priced handset.

Fast charging was the most treasured feature – with just 1% of those surveyed willing to let it go – ahead of waterproofing, ahead of high quality screens and audio, ahead of a fast processor, ahead of high-speed connectivity, and ahead of aesthetics. Indeed, approximately 8 times as many people surveyed would forego 5G data connectivity than would forego fast charging.

Fast Charging – Not all chargers are equal.

Fast charging requires a dedicated, high-power charger.

For example, Samsung has implemented a Super Fast Charging mode on its S24 range of handsets. To enable this, it has developed a 25 W (S24) and 45 W (S24+ and S24 Ultra) charger for its Super Fast Charging phones.

Samsung’s bases both its 25 W and 45 W chargers on Navitas GaN technology and according to PCMag’s independent testing, this allows the 4,900 mAh battery in the S24+ to charge from flat to 100% in 60 minutes, reaching 31% after 15 minutes, and 64% after 30 minutes.

However, many third-party chargers, struggle to activate this function, and an analysis by PC World has shown most non-Samsung chargers fail to deliver the fast-charging speeds supported by Samsung devices. Of the “dozens” tested, only Anker’s 313 Ace 45W GaN charger was able to achieve activate fast charging.

Slim Form Factors

The environmental and cost-saving shift from in-box chargers to consumer-purchased ones has also increased demand for slim, aesthetically pleasing designs.

There is therefore a debate rising on form versus function. For example, when discussing the importance of form factor in smart charging, the journalist Gordon Ung questioned if consumers would choose a “clunky” and “ugly” fast charger given the option of “today’s svelte GaN chargers”.

By enabling more power to be delivered from the same form factor, GaN technologies enables manufacturers to design slimmer, more powerful chargers that meet consumer demand for both functionality and design. Slim form factor charger ICs and high-power-density charger ICs are crucial in reducing the size of chargers while still delivering sufficient power for fast charging.

Silicon vs. Wide Bandgap Materials in Mobile Chargers

The most-commonly-used semiconductor used for charging devices is still silicon however, this material is being radpidly replaced by wide bandgap materials, particualrly, GaN.

The bandgap is the energy needed to free an electron from its orbit around the nucleus and directly determines the withstandable electric field for a given material. With a bandgap more than 3 times that of silicon (1.12 eV), GaN (3.39 eV) enables the development of semiconductors with very short or narrow depletion regionsand device structures with very high carrier densities.

This means smaller transistors and shorter current paths with lower resistance and capacitance, as well as switching speeds that are orders of magnitude higher.

Traditional silicon-based power ICs are larger and less efficient at high power levels. GaN power ICs, in contrast, operate at higher frequencies and are more efficient, which reduces the amount of heat generated and allows for more compact designs.

To put another way, by implementing GaN chargers rather than silicon, mobile device and charger OEMs can deliver significantly more power in the same form factor to meet the fast charging demands of flagship mobile devices, and create smaller, sleeker and more aesthetically pleasing chargers.

Benefits of GaN in Mobile Chargers:

Increased power efficiency

GaN transistors switch faster than silicon transistors, reducing energy loss and heat generation.

Smaller size

With higher efficiency, components can be smaller, enabling more compact and attractive charger designs.

Faster charging

GaN ICs allow for higher wattage output in a smaller form factor, resulting in faster charging times for larger batteries.

Implementing GaN Mobile Chargers Through Navitas

Navitas Semiconductor was the first to release a production GaN charger, and revolutionized the industry with its GaNFast ICs that enable the development of fast charging units and slimmer devices.

In October 2024, the company launched its range of GaNSlim power ICs with autonomous EMI control and loss-less sensing integrated. These are the industry’s fastest, smallest, and most efficient solution in an optimized DPAK-4L package and enables the development of even smaller, sleeker charging units for mobile and consumer devices.

The company’s GaNFast ICs have been implemented in over 200 chargers and is in mass production with 10 of the top 10 mobile and laptop OEMs.