Qi-compliant transmitter controls multiple charging
Fast and stable multi-coil wireless charging for mobile devices is offered with the STWBC-MC 15W wireless battery-charger transmitter from ST Microcontroller. The transmitter can control multiple charging coils, making charging less dependent on the precise position of the battery-powered device, adds the company.
The STWBC-MC complies with the latest Qi 1.2.4 specification, and is claimed to be the first transmitter specifically designed to support the Qi MP-A15 EPP (Extended Power Profile) topology. In addition to detecting a valid receiver and selecting the most efficient coil for power transfer, it ensures extended foreign object detection (FOD) through bi-directional communication with the receiver. The STWBC-MC also supports the proprietary wireless fast-charge extensions of leading smartphone manufacturers.
To ensure fast and stable charging for all types of devices, the STWBC-MC monitors coil current and voltage. By integrating a digital DC/DC controller, it delivers the required power to the coil at a fixed frequency and so minimises interference with other systems inside smartphones and tablets, claims STMicroelectronics. It also pre-empts EU legislation, as the EU’s intends to extend the scope of the Radio Equipment Directive (RED) to include wireless-charging transmitters, and restrict H-field emissions above 145kHz to -5dBm. The STWBC-MC’s low-EMI design eases compliance, says STMicroelectronics.
The patented triple-path modulation technique for communication between the transmitter and receiver increases noise immunity and the IC’s low standby consumption minimises wasted energy when not charging.
A STEVAL-ISB047V1 evaluation kit is available for the STWBC-MC and there is also a STSW-STWBCGUI graphical user interface (GUI) for ST’s STWBC transmitter ICs. The GUI can be used to download the STSW-ISB047FW dedicated firmware for the STWBC-MC, and to monitor performance and fine-tune parameters.
The STWBC-MC is in production and the STEVAL-ISB047V1 is available now from ST or distributors.
