New approach to wireless earbud charging

Louise Smyth

ams has introduced pow:com, an interface technology which enables power and communication between a true wireless earbud and a charging cradle over a two-wire connection. A wireless earbud previously required as many as six pins to provide both power transfer and communication between the charging cradle and the earbud, compromising the mechanical design of a small form factor that fits comfortably in the users ear. 

The pow:com interface technology for the first time enables simultaneous data communication with 1kBit/s net data rate and over 150mA charging current supported, more than applications need today.

The interface is implemented with the AS3442 host IC in the cradle, and the AS3447 client IC in each earbud. The sophisticated protocol developed by ams provides for power transfer at 5V, I2C communication, interrupt signals and up to five GPIOs via a single transmission line between each pair of AS3442 and AS3447 devices. 
The communications capability provided by the interface supports an enhanced user experience of the charging cradle. For instance, the earbud can request the battery information from the charger cradle and display it on a mobile app.

This also allows the earbud manufacturer to implement other useful features, such as auto-recharge, automatic pairing of the earbuds with the users phone on opening the charging cradles case, and accessory firmware updating while charging.