P9222-R/RN Datasheet

© 2019-2022 Renesas Electronics Corporation

15

May 5, 2022

3. Description of the Wireless Power Charging System

A wireless power charging system has a base station with one or more transmitter coils that make power available via DC-to-AC inverter(s) and

transmit the power over a strongly-coupled inductor pair (magnetic induction), or over a loosely-coupled inductor pair (magnetic resonance) to

a receiver in a mobile device. A WPC (see Figure 4) uses near-field magnetic induction between coils and can be a free-positioning or

magnetically-guided type of system.

In WPC Inductive systems, the amount of power transferred to the mobile device is controlled by the receiver. The receiver sends communication

packets to the transmitter to increase power, decrease power, or maintain the power level. The bit rate for the Rx-to-Tx communication link is

2kbps for WPC receivers. It is modulated on top of the power link that exists.

Figure 4. Block Diagram of WPC Compliant Wireless Power Transfer System

Messages

Base Station

Transmitter

Transmitter

Mobile Device

Receiver

Transmitter

Power

Power Conversion

Control

Control

Comm

Comm

Reflected Load

Mod

DeMod

Power Pick-up

Note: For the more current information, see the WPC Specification at http://www.wirelesspowerconsortium.com/.