Automotive Freescale Wireless Charging Reference Design for Automotive Applications Target Applications Designed with automotive in mind 5 W automotive applications Overview The 5WTXAUTO reference design is Freescales wireless charging solution specifically designed for automotive applications. From component selection to system operating behavior, every design decision keeps the complex automotive environment in mind. The result is a highly optimized automotive system solution with a cost-competitive bill of materials (BOM) and maximum performance. The design is based on the Wireless Power Consortium (WPC) A13 transmitter definition, comprising a 12 VDC source voltage, full H-bridge topology and rail voltage control method. The system is able to operate from an input source of 614 VDC, ideal for an automotive environment where the source voltage can dramatically vary. For example, many vehicles feature a Start/Stop function, turning the vehicles engine off during periods of extended idle. When the vehicle starts back up, the battery voltage can droop excessively while the starter cranks the engine, creating low operating voltages for small periods of time. The rail voltage control method is ideal for reducing harmonics emissions, thereby addressing the necessary EMC requirements for industry. Freescale extends support beyond WCT-5WTXAUTO Multi-Coil Wireless Charger Block Diagram WCT-5WTXAUTO Multi-Coil Wireless Charger Block Diagram Proximity Sense Buck Power Inverter Pre-Drive Demodulation and Inverter Control Analog Sensing Low Power Rail Voltage Optional Freescale Control CAN CAN PHY WCT100xA NFC SPI Transceiver MC33901 CAN GPIO Freescale Technology Optionalthe specified A13 coil type to allow designers Features to choose the coil topology that best meets their needs. Features Benefits Compliant to latest WPC Qi specification Ensure end solution meets latest industry specification This reference design uses Freescales Transfer efficiency greater than 60% Maximum energy transfer and lower thermal footprint innovative wireless charging transmit controller Meets latest FOD requirements Ensures foreign objects are detected and provides safety function to perform digital demodulation on incoming Supports many Qi 5 W coil types Provides a broad range of magnetics support with a single solution communication from the receiver, thereby Low active RUN power Increase overall operating efficiency reducing the need for external demodulation Low system standby power Lowest standby operating mode circuitry. Using the wireless charging transmit consumption (using Freescale proximity controller platform, with its unique DSP sense technology) capabilities, allows demodulation to be Rail voltage power control Reduce EMC to meet industry requirements performed in software with minimal CPU 2 SPI, UART, I C communication interfaces Communicate to and from wireless charging IC to transfer charging information (premium only) overhead. This unique feature provides a On-chip digital demodulation Lower system BOM and greater performance major reduction in BOM costs and the added Run-time calibration Fast and accurate system calibration, saving time & effort to optimize benefit of a reduced PCB footprint without system performance compromising system communications quality. Integrated CAN/LIN support Connect to the vehicle network for control and management The transmitter reference design implements a AEC-Q100 qualified Meets latest automotive requirements robust foreign object detection scheme critical WCT firmware library Choose as-is firmware or build value-added features onto existing library for the safe operation of the charger. Metallic NFC capable Supports low-level NFC stack (MWCT1003A only) objects are detected by calculating the power lost in the system, determining that a certain power loss threshold is deemed to be due to a Package Options metallic object. For WPC-Qi transmitters, this is a requirement in the specification. Part Number Package Available Flash Size Key Features MWCT1001A 64 LQFP 30 KB* Complete controller solution, support most The reference design showcases the Qi 5W single coils portfolios additional capabilities using 2 MWCT1003A 64 LQFP 220 KB* Premium controller, I C, UART, SPI, flash Freescale MWCT1003A wireless charging IC memory for application programming implementing near field communications (NFC) * Available memory is an estimate only functionality. Freescales joint partnership with Melexis Semiconductor demonstrates the proximity sensing algorithm uses the wireless coexistence between wireless charging and Development Tools NFC systems. On Freescales platform, the charging transmitters GPIOs to detect a device wireless charging system provides a bridge and wake up the system. WCT-5WTXAUTO between the NFC physical interface and the Optimized multicoil 5 W reference design for Ultimately, the WCT-5WTXAUTO reference vehicle network. By co-locating both the automotive applications. design is a complete system solution, wireless charging and NFC function, control containing all of the hardware and software can remain localized and a higher level of Eclipse-based CodeWarrior components necessary to quickly implement a system integration can be obtained. This Development Studio for Microcontrollers multicoil charger solution. Freescale provides all reduces overall system costs while maintaining necessary hardware documentation, including A complete integrated development implementation flexibility. schematics, layout and assembly files as well environment (IDE) that provides a highly visual Additional features include the ability to enable as a complete BOM. A firmware library is and automated framework to accelerate the CAN, utilizing Freescales MC33901 CAN provided which contains all of the necessary development of the most complex embedded physical interface controller. As an alternative, wireless charging control blocks. Access to the applications. LIN communication can also be established library is provided via an API which lets users using the wireless charging transmitters SCI interact with parameters and settings contained WCTGUI interface. Lastly, the solution features an in the firmware, providing maximum control to Graphical user interface tool for quickly alternate low-power standby mode by utilizing the engineer. Customers can choose to use a configuring and optimizing wireless charging proximity sensing. The hardware contains ready-to-use binary file provided by Freescale transmitter solutions. sensing electrodes which detect when the user or to take a more developmental approach and places the mobile device on the charger. The build an application around the firmware library. For more information, visit freescale.com/WCT-5WTXAUTO Freescale, the Freescale logo and CodeWarrior are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. All other product or service names are the property of their respective owners. 2014 Freescale Semiconductor, Inc. Document Number: WCT5WTXAUTOFS REV 0