The various benefits of wireless charging like convenience, integration with multiple devices, mobility and flexibility drive the market (figure 1). Based on this the overall wireless charging market is growing at a rapid pace. It is expected to have a CAGR about 30 percent during the period 2019 - 2025, reaching 27 billion USD in 2025. Infineon, partnering with Spark Connected, offers complete solutions for wireless charging with dedicated wireless power controller incl. software IP, MOSFETs, drivers, security ICs and application optimized reference designs.
There are a number of challenges for designers of wireless charging products, requiring a deep level of system knowledge and expertise. In addition to issues associated with the charging coils and their interaction with surrounding structures, designers must address efficiency, mechanical packaging and electromagnetic interference (EMI). However, with optimized components and sufficient attention to alignment of charger and device, size of coils and distance between coils, then a good coupling factor can be achieved, and power can be transferred with high efficiency. In addition, metallic foreign objects (such as coins and keys) can be a safety hazard during charging and must be reliably detected through a process called Foreign Object Detection (FOD).
How wireless charging works
Wireless charging uses a changing magnetic field to transfer energy between two objects via coils. The effectiveness of the energy transfer between coils is referred to as “coupling”, and depends on multiple parameters, including coil mechanical design, spacing and alignment. When the coils are aligned and in close proximity, wireless power transmission is nearly as efficient as wired charging.