Rohm's reference design for a wireless automotive charging module uses the ST25R3914 NFC reader designed for automotive applications along with the STM8AF 8-bit automotive microcontroller, both from STMicroelectronics (ST). The overall design is based on the BD57121MUF-M 15W Qi-compliant wireless charging IC developed by Rohm to promote the adoption of wireless charging solutions in car center consoles.
One of the benefits of ST's technology here is its sophisticated control capabilities. These allow contactless smartcards to be detected in the near vicinity of the charging system to immediately interrupt the charging process. This important and highly appreciated feature prevents such cards from failing due to the strong magnetic field generated by Qi transmitters.
The automotive NFC reader IC ST25R3914 is an AEC-Q100 Grade 1 qualified NFC analog front-end device that supports ISO14443A/B, ISO15693, FeliCa and active P2P. The device's best-in-class RF performance and automatic antenna tuning for dynamic adaptation to difficult metallic environments make this chip the ideal choice for automotive applications. A MISRA-C:2012-compliant RF middleware is included for faster software development.
ST's STM8AF 8-bit automotive microcontroller offers high performance and a wide range of memory and chassis options, contributing to more flexible automotive systems. The device offers true data EEPROM as well as CAN and LIN bus interfaces and is suitable for operating temperatures of up to +150°C. In combination with the NFC function, it can also serve as a controller for the management of new NFC applications in cars, such as Bluetooth or Wi-Fi coupling of smartphones, infotainment applications with NFC for verification purposes, and for starting the engine.
ROHM is releasing a sample reference board (above) in February that will allow users to easily configure a wireless charger for automotive use compatible with the EPP Qi standard when combined with ROHM's BD57015GWL-EVK-002 Qi certified receiver board already on the market. The BD57121MUF-M controller will be released in April.