Wireless charging is starting to become popular in products such as smartphones. It eases battery charging of portable devices and makes cables and connectors redundant. Today’s existing wireless charging systems typically couple two antennas, one for receiving and one for transmitting power. The gap between and the combination of the two antennas highly influence the efficiency of the charging power. Such existing wireless charging systems limit the effective charging area significantly. In consequence the alignment of the transmitting and receiving antennas greatly reduces the freedom of product design.
The Renesas NFC wireless charging technology widens the charging area to about 10 cm. It incorporates the technology of the existing NFC MCU, and utilizes the NFC antenna to implement a wireless charging system that uses a single RX antenna for NFC communication and receiving power, thereby improving reliability while reducing the bill of material of a receiver design. To make it easier for developers to incorporate this system into their mobile devices, Renesas developed the NFC MCU, the power receiver IC, and the power transmitter IC built around the company’s proven power technology. These new products are the main components necessary to implement a wireless charging system and are supplied as a total solution kit.
The NFC wireless charging system solution not only makes the charging cable-free, but also makes it possible to achieve a new, more flexible level of wireless connectivity by fusing NFC and wireless charging technology. The main features of the system are described as follows.
Power transmission and data reception via a single antenna with NFC. Conventional wireless power receiver with additional short range communication capabilities requires two antennas, one for data transmission and one for receiving power. In an NFC-based system the receiver uses a single antenna, contributing to more compact and thinner mobile handsets.
Expansion of charging area with NFC. The exclusive technology employing NFC makes it possible to widen the charging area to about