P9225-R Datasheet

© 2018 Integrated Device Technology, Inc.

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November 12, 2018

10.2 Ping Phase (Digital Ping)

In the ping phase, the power transmitter will transmit power and will detect the response from a possible power receiver. This response ensures

the power transmitter that it is dealing with a power receiver rather than some unknown object. When a mobile device containing the P9225-R

is placed on a WPC “Qi” charging pad, it responds to the application of a power signal by rectifying this power signal. When the voltage on

VRECT is greater than the UVLO threshold, then the internal bandgaps, reference voltage, and internal voltage regulators (5V and 1.8V) are

turned on, and the microcontroller’s startup is initiated enabling the WPC communication protocol.

If the power transmitter correctly receives a signal strength packet, the power transmitter proceeds to the identification and configuration phase

of the power transfer, maintaining the power signal output.

10.3 Identification and Configuration Phase

The identification and configuration phase is the part of the protocol that the power transmitter executes in order to identify the power receiver

and establish a default power transfer contract. This protocol extends the digital ping in order to enable the power receiver to communicate the

relevant information.

In this phase, the power receiver identifies itself by sending its identification packet and provides information for a default power transfer contract

by sending the configuration packet.

10.4 Power Transfer Phase

In this phase, the P9225-R controls the power transfer by means of the following control data packets:



Control Error Packets



Received Power Packet (RPP, FOD-related)



End Power Transfer (EPT) Packet

Once the identification and configuration phase is completed, the transmitter initiates the power transfer mode. The P9225-R control circuit

measures the rectifier voltage and sends error packets to the transmitter to adjust the rectifier voltage to the level required to maximize the

efficiency of the linear regulator and to send to the transmitter the Received Power Packet for foreign object detection (FOD) to guarantee safe,

efficient power transfer.

In the event of an EPT issued by the application, the P9225-R continuously sends EPT packets until the transmitter removes the power and the

rectified voltage on the receiver side drops below the UVLO threshold.