Two-Pin Power and Communications Interface Reduces Earbud Mechanical Design ConstraintsSeptember 04, 2018 by Paul Shepard
ams has introduced POW:COM, an innovative 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 ams POW:COM interface technology for the first time enables simultaneous data communication with 1kBit/s net data rate and over 150mA charging current supported, far more than applications need today.
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 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 POW:COM 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.
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 user's phone on opening the charging cradle's case, and accessory firmware updating while charging.
"The POW:COM interface from ams radically reduces the constraints on the design of true wireless earbuds," said Christian Feierl, Marketing Manager at ams. "If the earbud only needs to accommodate a two-pin connection to the cradle rather than six pins, the designer has much more flexibility to reduce the size of the earbud or to use the space on the surface of the earbud in a way which brings more value to the user."
The AS3442 and AS3447 POW:COM devices are available now in production volumes. Some brand manufacturers have already included the ams POW:COM devices in their earbuds, with anticipated availability in December, in time for the holiday season.
An evaluation board for the POW:COM interface parts is available on ams online shop.