A two-pin power and communications connection between earbuds and cradle has been developed by ams. The company introduces 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 true 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 user’s ear.

The POW:COM interface technology for the first time enables simultaneous data communication with 1kbits per second net data rate and supporting over 150mA charging current, which is far more than applications need today, says ams.

The POW:COM interface is implemented with the AS3442 host IC in the cradle, and the AS3447 client IC in each earbud. The sophisticated POW:COM protocol developed by ams provides for power transfer at 5.0V, I2C communication, interrupt signals and up to five general purpose input/outputs (GPIOs) via a single transmission line between each pair of AS3442 and AS3447 devices.

The POW:COM interface means the earbud can request the battery information from the charger cradle and display it on a mobile app. The POW:COM interface 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.

If the earbud only needs to accommodate a two-pin connection to the cradle rather than conventional six pins, to reduce the size of the earbud or to use the space on the surface of the earbud for functions that the designer or consumer can decide.

The AS3442 and AS3447 POW:COM devices are available now in production volumes. 

An evaluation board for the POW:COM interface parts is also available.

http://www.ams.com