Gopi Akkinepally
Wireless Power Marketing Manager
Published: November 2, 2017

For many industrial and medical devices, the addition of wireless power transfer is a natural fit because having a charging port is not feasible and devices need to be dust and waterproof. However, in many of those applications, there is also a need for wireless data transfer along with wireless power transfer. Device manufacturers want to use the data channel to enhance the end customer experience by enabling device authentication and transferring useful system data wirelessly. To meet this need, our team continues to lead the charge with the release of the P9242-R3 Tx and P9221-R3 Rx – the industry's first broadly available 15W transmitter and receiver pair with bidirectional data communication capability.

A growing number of industrial and medical devices use very high-quality, custom transmitter and receiver coil devices for optimal power transfer and increased durability. Their customized transmitter designs would not provide a proper charging experience for any other manufacturer’s receiver devices. Also, counterfeit transmitters with poor coil designs will provide an inferior charging experience and could damage the expensive receiver device, which will likely be covered by the manufacturer's warranty. To guard against this, manufacturers want to add device authentication to wireless power transfer and make sure receivers are only charged by approved transmitters. Using Renesas' P9221-R3 and P9242-R3, the microcontrollers (MCU) on the receiver and transmitter can exchange the encrypted keys and enable battery charging only when the keys match.

In some applications, such as industrial robotic arms, there is a stationary base with specialized electronics on a rotating mount. Slip rings (electro-mechanical devices) have traditionally been used to transfer the power and data for the rotating mount. But slip rings are expensive and very susceptible to failure. In such systems, manufacturers can use wireless power transfer and leverage the power transfer coils for system data transfer, as well. P9242-R3 and P9221-R3 do not need any additional coils or antennas as they use in-band communication for data transfer.

Renesas' bidirectional communications capabilities give designers the flexibility to create their custom communication protocol using the I2C bus. The MCU on the receiver board needs to load data into specific registers and trigger communication. The P9221-R3 sends the data to the P9242-R3 which receives the data and interrupts the transmitter MCU when the data is ready to be read. The external MCU on the transmitter follows the same procedure to send the data to the P9221-R3. When new data is available to be read, the P9221-R3 will interrupt the external MCU on the receiver board.


These flexible, industry-leading Tx and Rx devices are enabling innovation in many market segments.

To reduce the time to market for our customers, we have developed a bidirectional communications reference design that can be used to evaluate the devices. Customers can also download the schematics and PCB files for integration directly into their systems.

For more details on bidirectional communication, visit the P9242-R3 and P9221-R3 product pages to watch a video or download the datasheets.

You can find details on all of Renesas' wireless power products and reference designs at

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