STMicroelectronics' STWBC-WA/STWLC04 miniature chipset for wireless battery charging allows smaller, simpler, and sealed sports wearables, as well as medical sensors and remote controllers.
Comprising the STWBC-WA charging-transmitter controller and STWLC04 wireless battery-charger receiver, the chipset enables power transfer up to 1 W using very small coils: just an 11-mm diameter coil on the receive side and a 20-mm coil for the transmitter.
Power-transfer capability can be increased to 3 W by using larger coils and a full-bridge circuit on the transmitter side. Further, the elimination of a conventional charging connector simplifies enclosure design and eases sealing to prevent contamination by dirt or moisture.
Able to work with Li-ion and Li-polymer battery chemistries, the chipset provides such safety mechanisms as foreign-object detection, active transmitter-presence detection, and receiver thermal protection.