Datasheet

bq51011
bq51013
www.ti.com SLVSAT9D –APRIL 2011–REVISED AUGUST 2012
A Brief Description of the Wireless System:
A wireless system consists of a charging pad (transmitter or primary) and the secondary-side equipment
(receiver or secondary). There are coils in the charging pad and in the secondary equipment which are
magnetically coupled to each other when the equipment is placed on the portable device. Power is then
transferred from the transmitter to the receiver via coupled inductors (e.g. an air-core transformer). Controlling
the amount of power transferred is achieved by sending feedback (error signal) communication to the primary
(e.g. to increase or decrease power).
The receiver communicates with the transmitter by changing the load seen by the transmitter. This load variation
results in a change in the transmitter coil current, which is measured and interpreted by a processor in the
charging pad. The communication is digital - packets are transferred from the receiver to the transmitter.
Differential Bi-phase encoding is used for the packets. The bit rate is 2-kbps.
Various types of communication packets have been defined. These include identification and authentication
packets, error packets, control packets, end power packets, and power usage packets.
The transmitter coil stays powered off most of the time. It occasionally wakes up to see if a receiver is present.
When a receiver authenticates itself to the transmitter, the transmiter will remain powered on. The receiver
maintains full control over the power transfer using communication packets.
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