Nowadays, people are using their smartphones and tablets so intensively that many need to top up battery power several times a day. With wireless charging, users don’t need to carry the charger or a bulky power bank, and can charge their electronic devices as fast as with a cable. Major mobile manufacturers are committing to wireless charging by joining the industry alliances and launching compatible products.

Users on the move, who put their mobiles down to charge for a few minutes – say, during a break or in a meeting -- need the device to be ready to go again when they are. To enable this, the Wireless Power Consortium (WPC) that manages the Qi specification -- a widely adopted industry standard -- has introduced the Extended Power profile for faster charging. By raising the maximum charging power from 5W to 15W, this new profile enables devices to be charged up to three times more quickly.

One of the market’s first wireless-charging controllers to support Qi Extended Power, ST’s STWBC-EP combines best-in-class energy efficiency, consuming just 16mW in standby and able to wirelessly transfer more than 80% of the total input power, with unique features created by ST to enhance the user experience. These include a patented solution enhancing active presence detection to wake the system quickly when a compatible object is presented for charging. The patented technology also enhances the performance of Foreign Object Detection (FOD), to cut power and prevent overheating if objects containing metals are brought too close to the charger. Other unique innovations enhance power control and energy transfer to maximize efficiency and ease of use.

“ST’s Advanced Wireless-Charging chip enables manufacturers to create new, high-power products that offer superior features and efficiency,” said Domenico Arrigo, General Manager, Industrial and Power Conversion Division, STMicroelectronics. “The Qi Extended Power support dramatically shortens charging time and our patented detection and safety innovations greatly improve safety and ease of use.”

The STWBC-EP provides the level of integration allowing to simplify charger design while providing the flexibility to work with supply voltages ranging from 5V USB power up to 12V.

To help accelerate time to market for product developers, ST has created an associated reference design with a Qi 15W ready-built transmitter board and documentation to get started. ST also has a 15W receiver chip (STWLC33) for use in high-speed chargeable devices, which developers can use to complete their applications.

The STWBC-EP contains a step-up (boost) DC/DC converter and a controller, with the Qi charging algorithms already implemented in firmware to save any need to integrate software and an additional microcontroller in their designs. Together, the converter and controller generate the input power and the control signals for an external half-bridge power stage that drives the charging transmitter antenna. This architecture gives designers flexibility to optimize the external half bridge and its associated gate drivers for use with any supply voltage from 5V to 12V, and to ensure compatibility with USB quick chargers.

The evaluation kit, STEVAL-ISB044V1, includes a 15W Qi MP-A10 reference design, 12V 2A AC/DC adapter, a USB/UART dongle for connection to the PC and USB cable, as well as pre-loaded firmware. In addition to the supporting documentation, a graphical PC-based configuration tool is also provided to help customize settings.