Wireless charging promises consumers a new level of convenience for maintaining readiness of mission critical and lifestyle enhancing communication tools. Low battery warnings are never welcome but seem ever present with the increasing reliance on portable electronics in our personal and professional lives. Combining the automotive grade NFC (Near Field Communication) transceiver of Melexis with Freescale Semiconductor’s wireless charging technology enables a ready to use reference design solution that could free us from the dreaded low battery warning.

In the recent times the NFC standard for secure, short range communication for point of purchase and access control has gained a strong and growing position in mobile handsets. Melexis has worked on technology for Entry-and-Go and PKE (Passive Keyless Entry) solutions in cars, with the introduction of its MLX90132 NFC transceiver IC. The uptake of wireless charging is accelerating rapidly. The WCT-5WTXAUTO reference design developed jointly by Melexis and Freescale brings together the best attributes in both technologies. Melexis works with automotive Tier suppliers for the integration and deployment of NFC solutions in cars for applications such as, automatic pairing of mobile devices to the media center (e.g. Wi-Fi or Bluetooth technologies) and automatic identification of the User and download of personal settings. NFC technology can also be used for access control and start, to allow NFC enabled handsets to be the “key” to enter and drive away an automobile. With this reliance on a wireless lifestyle it is more critical than ever that the enabling device, a smartphone or tablet, be kept in a state of maximum charge. Wireless charging deployed in homes, cars, businesses and public spaces is the clear solution. Bringing both wireless charging and NFC together enables new capabilities and conveniences.

The initial target for this reference design is automotive console applications. The stringent requirements of any electronic system deployed in the passenger compartment include EMC, RFI and EMI at a number of frequency bands and power levels. The joint reference design of Melexis and Freescale demonstrates the successful possibility to achieve a road worthy result. This design is built around the MLX90132 NFC Transceiver IC of Melexis and the MWCT1003AVLH controller IC from Freescale.

The reference design includes all the required hardware and associated software drivers to allow a fully autonomous behavior of the wireless charging subsystem, controlled via a standard compliant NCI (NFC Controller Interface). The co-existence is managed on the hardware side through a careful antenna design and on the software side via dedicated control interface. The system can either run in a fully autonomous way or be driven by standard compliant upper NFC software stacks (e.g. NFCStack+ from Stollmann).

Beyond the automotive environment, the reference design is perfectly suited for very wide variety of side markets relying on personal handsets, where a combination of secure identification and payment combined with battery charging is required. This includes, for example, information and advertisement booths in waiting lounges, restaurants and wireless docking stations.