Three mainstream standards for wireless charging technology: PLA, Qi and A4WP

Although most people are familiar with wireless charging technology, the wireless charging function has attracted widespread attention since the release of Nokia Lumia 920. As one of the main selling points, wireless charging differentiates Lumia 920 from the current mainstream mobile phone products and gives it a distinct personality. But in fact, Nokia is not the first manufacturer to use wireless charging technology on mobile phones. A year ago, Philips launched a mobile phone that uses the Qi wireless charging standard, but it ultimately did not attract the attention of consumers.

In fact, the current wireless charging technology is not mature yet. Not only is the technology developing slowly, but the standards are not yet unified. There are currently three mainstream wireless charging standards: Power Matters Alliance (PMA) standard, Qi standard, and Alliance for Wireless Power (A4WP) standard. Below we will briefly introduce these three standards.

Power Matters Alliance Standards

The Power Matters Alliance standard was initiated by Duracell Powermat, a joint venture between Procter & Gamble and wireless charging technology company Powermat, which has outstanding comprehensive strength. In addition, Powermat is also one of the supporting members of the Alliance for Wireless Power (A4WP) standard.

Currently, AT&T, Google and Starbucks have joined the PMA Alliance (Power Matters Alliance). The PMA Alliance is committed to creating wireless power supply standards for mobile phones and electronic devices that meet IEEE standards, and has a leading position in the field of wireless charging.

Currently, Duracell Powermat has launched a WiCC charging card that uses the Power Matters Alliance standard. WiCC is slightly larger than an SD card, and has embedded components such as coils and electrodes for electromagnetic induction contactless charging. The card is thin and can be used by inserting it next to the battery of an existing smartphone. Using this card, many portable terminals can easily support contactless charging.

WiCC Charging Card

In addition, Starbucks plans to conduct a Duracell Powermat wireless charging pilot in 17 stores in the Boston area, which will provide strong support for PMA to gain a foothold in the United States. Adam Brotman, Starbucks' Chief Digital Officer, said: "Starbucks will place wireless charging devices on some tables to see how customers react." If customers do not have a charging case that matches their iPhone or Galaxy, Starbucks will give away a small number of them for free during the pilot period, and some cases will also be available for loan at the counter.

Qi Standard

Qi is the "wireless charging" standard launched by the Wireless Power Consortium (WPC), the world's first standardization organization to promote wireless charging technology. It has two major features: convenience and versatility. First, products of different brands can be charged with Qi wireless chargers as long as they have a Qi logo. Secondly, it has overcome the technical bottleneck of "versatility" of wireless charging. In the near future, mobile phones, cameras, computers and other products can be charged with Qi wireless chargers, making large-scale application of wireless charging possible.

At present, the mainstream wireless charging technologies in the market mainly use three methods, namely electromagnetic induction, radio waves, and resonance, and Qi uses the most mainstream electromagnetic induction technology. In terms of technology application, Chinese companies have stood at the forefront of the wireless charging industry. It is reported that Qi's application products in China are mainly mobile phones. This is the first stage, and it will be developed and applied to different categories or higher-power digital products in the future. As of now, the number of alliance members has increased to 74, including Philips, HTC, Nokia, Samsung, Sony Ericsson, Best Buy and other well-known companies are already members of the alliance.

Texas Instruments launches small Qi wireless power chip

Typical representative products of Qi standard include Nokia Lumia 920, Nokia Lumia 820, Google Nexus 4, etc. When using these mobile phones, there is no need to install any accessories, just put it on any charger that supports Qi standard to start charging. At present, there are many different styles of wireless chargers from brands such as Energizer and PowerMate to choose from.

Nokia Lumia 920

A4WP Standard

A4WP is the abbreviation of Alliance for Wireless Power, which was jointly established by Qualcomm, Samsung and Powermat. The alliance also includes Ever Win Industries, Gill Industries, Peiker Acustic and SK Telecom, and aims to establish technical standards and industry dialogue mechanisms for wireless charging devices for electronic products including portable electronics and electric vehicles.

The Wireless Power Consortium will focus on introducing "electromagnetic resonance wireless charging" technology, which is different from Qi's "electromagnetic induction technology". The two technologies have their own advantages. The former may have lower transmission efficiency, but can achieve wireless charging at a slightly longer distance. The latter requires close contact, such as placing a mobile phone on a base, and can be charged by induction without wiring, but the charging efficiency is higher.

The A4WP standard alliance hopes to popularize wireless charging quickly, allowing users to charge wirelessly anywhere. In other words, A4WP wants to make wireless charging cheaper and add charging ports without increasing the size of mobile phones, tablets or laptops, which means that more and more manufacturers will choose wireless chargers by default.

Industry insiders believe that the Wireless Charging Alliance founded by Qualcomm, Samsung, Powermat and other companies has expanded the scope of products targeted to include a wider range of electronic products such as electric vehicles.

Since the alliance was formed relatively late, there are not many products that adopt this standard. Samsung has previously stated that the Galaxy S III smartphone accessories include a wireless charger, but the launch date has not yet been determined. It is speculated that this wireless charger will comply with the A4WP standard. However, due to the different technical principles of A4WP and Qi, the chargers of Galaxy S III and Lumia 920 will not be compatible, and users have to prepare two chargers to charge different products.