Qi-compliant battery-charger transmitter

The Qi-compliant transmitter from STMicroelectronics is said to ensure fast and stable 15w multi-coil wireless charging for mobile devices.

The STWBC-MC 15W wireless battery-charger transmitter can control multiple charging coils, making charging less dependent on the precise position of the battery-powered device, according to STMicro.

Compliant with the latest Qi 1.2.4 specification, the STWBC-MC is the first transmitter specifically designed to support the Qi MP-A15 EPP (Extended Power Profile) topology, STMicro says. 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.

Designed to enable 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 minimises interference with other systems inside smartphones and tablets.

Given the EU’s intention to extend the scope of the Radio Equipment Directive (RED) to include wireless-charging transmitters and restrict H-field emissions above 145kHz to -5dBm, STMicro has developed its STWBC-MC’s low-EMI design to ease compliance.