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Wireless charging

Two different standards

Wireless charging of mobile devices is a rapidly growing market. It currently comes in two standards, which are not compatible with each other. Both have the ambition of becoming the leading standard for wireless charging. The most widely used standard (Qi) has the advantage of being a well-developed technology and of having the first products already introduced on the market. The disadvantage, however, is that this technology can only charge one device at a time. The other standard (A4WP) has the advantage that more than one device can be charged simultaneously. However, this technology is still in its infancy and the first products are currently still under development. NXP, a global actor in the field of semiconductors, is developing system solutions for both standards of wireless charging whereby the challenge lies in being able to supply prototypes and reference designs as soon as possible.



At the International Consumer Electronics Show (CES) in Las Vegas, NXP presented the latest generation of A4WP wireless charging. In addition to being able to charge several devices simultaneously, this new technology also allows wireless charging of devices with different energy requirements. It was an enormous challenge to demonstrate the prototype in the form of the power transmitter.

Mobile phones, Power Receive Units, that can support this standard simply aren't available for NXP yet. Just six weeks before the CES, Altran was able to solve this problem by developing an app for Android that simulates a device that needs charging, using a Mobile Device (Android Nexus 7 2013). This app visualises the real-time operation of charging the battery and displays the communication data of the bluetooth low energy protocol (BLTE) that is used. This new communication protocol plays an important role in many of today's wireless applications.



There were a number of prerequisites regarding this app. The app needed to be capable of:


  • Setting up a USB connection with a microcontroller, which takes care of communication with the power transmitter;
  • Adjusting the required wireless power through a user interface to demonstrate the operation of the A4WP specification.

It's the ideal challenge for Altran and completely in line with their vision, in which they see a society that uses more and more intelligent connecting devices to improve our lives. In co-creation with NXP, a fully functional complete product (power transmitter, a number of Power Receive Units and an app) was developed; a connected device, as Altran calls it. A smart or connected product or system that can communicate wirelessly with other products.

Marino Strik, Department Manager Research at NXP says: "The project was carried out in close collaboration and by following the Agile process. By adhering to sprint lengths of one week, we were presented with an operational demo every week, whereby we could adjust and fine-tune our wishes and demands on a weekly basis. In co-creation, Altran was constantly able to deliver above our expectations in terms of functionality. The product has a markedly improved quality. So you could very well say that the integration was successful.


Full 4WP solution

The demonstrator was a success at the CES and there is definitely a demand that warrants further development. We'll be going a step further at the Mobile World Congress. In just 5 weeks, the current charger will be used in combination with the newly developed Power Receive Units. This means we will be demonstrating a full A4WP solution. The new Power Receive Units will contain an NXP chip that is specially designed for this application and a microcontroller that can communicate with bluetooth low energy. NXP will be offering this solution as soon as possible as an example for manufacturers who are looking to add A4WP charging functions to their devices.