Wireless charging is on the rise

The reason that demand for wireless charging stations is on the rise is partly because high data rate applications on the newest generation mobile devices - like live video streaming - requires a lot of energy and therefore frequent charging. The use of standardised wireless charging stations also helps to satisfy the ecological goal of reducing the growth in waste electrical chargers.

Technical solutions for wireless charging consumer devices are also finding their way into a variety of industrial applications. Distribution plays a vital role in promoting the advantages of this technology for all kinds of applications. These include public charging stations for mobile phones, industrial automation, medical systems, such as portable health monitors and wheelchairs, and automotive applications.

Today there are four different commercialised technologies to transfer energy wirelessly, based on magnetic resonance, inductive or capacitive coupling, or RF transmission.

Practical use of the latter is, however, limited to energy harvesting applications that need extremely low power, due to the low efficiency of the solution.

One characteristic of the current market situation is that multiple interest groups are trying to establish their respective technology solutions to create a de facto standard. Interestingly, most of the semiconductor manufacturers working on integrated solutions are members of more than one of these interest groups.

The magnetic resonance functionality is currently being promoted by the Alliance for Wireless Power (a4wp). This group already has over 60 members, including market heavyweights including Samsung and Intel.

Inductive technology is being used by the Power Matters Alliance and the Wireless Power Consortium; also known under the Qi (Chi) brand. The Power Matters Alliance comprises 96 members and is largely focussed on establishing its mobile infrastructure across the Americas and EMEA, especially at airports and in large restaurant chains.

The biggest interest group in terms of number of members today is the Wireless Power Consortium with 172 members. Many key mobile phone manufacturers are part of this group. In addition, the necessary development of charging infrastructure is progressing well, especially in Asia.

It is difficult to judge today which standard will prevail; one crucial factor could be which technology - if any - is adopted by Apple.

Different solutions for many applications

The distribution channel can play a key role in consulting on wireless charging solutions for many applications, as it can support all the above standards. Arrow, for example, can offer a package solution of control ICs and the necessary discrete components (MOSFETs and diodes) as well as the respective coils for energy transmission. This makes it possible to design and calculate an effective bill of materials together with customers based on the type of application. The Arrow M2M-competence team can also connect wireless charging with corresponding wireless communication technologies, such as Bluetooth Low Energy or NFC, which are used in the same application.

The following typical use cases can be found in Europe:

Charging terminals for mobile phones and tablets in public spaces: Cost efficiency, standards conformity and time-to-market play a key role here. Reference designs are particularly important in these circumstances, enabling companies to select innovative new products that feature increasing levels of integration. Distributors’ knowledge of the longer term roadmaps of semiconductor vendors is important in advising customers on choices that conform to standards and are future proof.

Portable, medical applications: Arrow sees significant potential in the growing market for portable medical applications (vital sign monitors) and also sports and wellness equipment, like training watches. Intensive care devices - such as defibrillators - also profit from wireless charging technology. The omission of charging connectors allows a hermetically sealed system to be created, making it more reliable and easier to disinfect. Although wireless charging increases the electronics cost of the product, the benefits to handling and robustness of the final product compensate for this. Furthermore, senior citizens find portable medical devices with wireless charging are easier to use.

Remote Controls: This segment contains consumer remote controls for entertainment electronics as well as building automation and toys. Industrial remote controls with large battery capacities, as used in crane controls, are an important use case in this area. Typically, there are no integrated, ready-to-use, standard-based solutions for these applications. These devices usually need a higher charging power and require a custom electronics design. In many cases, a scalable microcontroller solution is the best choice.

Automotive Applications: Many car manufacturers plan to integrate wireless charging technology into the centre console. From a technology point of view, the requirements are quite similar to those of public charging terminals. However, due to the long product cycles in automotive applications, judging which interest group will achieve the greatest acceptance is of key importance to the selection process. Another important application is the charging of electric vehicles themselves, including Ebikes or LEVs (Light Electric Vehicles). Here, unused cars may be charged wirelessly throughout the day in certain parking lots.

The proliferation of wireless charging technologies challenges distributors, including Arrow, with many new applications and use-cases that cannot be solved with a one-size-fits-all approach. Because of this, Arrow works with partners with specialised knowledge in this area. For example, IMST, based in Germany, supports Arrow with a full range of services for wireless applications. In addition, IMST is a member of the relevant German national committees of the VDE. Using IMST’s test centre, all application specific EMV measurements and those relating to EMVU (human safety) and R&TTE can be made. Together with IMST, Arrow can create simulations for specific wireless charging applications to evaluate the efficiency of the solution with different power levels and charging distances.