P9415-R Datasheet

© 2021 Renesas Electronics Corporation

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May 4, 2021

Figure 24. GP2 Pin External Connection to Thermistor Configuration

9.10.8 GP4/I2C Address Select Pin

The pin is used to select the P9415-R device I2C slave address. When this pin is pulled high to LDO1P8, I2C Address is 0x3F and when this

pin pulled low to GND, I2C Address is 0x3B (default). The slave address is a 7-bit I2C address.

9.10.9 GP5/INHIBIT Pin

The GP5 / INHIBIT pin is a digital input referenced to LDO1P8 and gets polled during the startup. When the INHIBIT pin is low, the Rx mode is

enabled. Pulling the INHIBIT pin high will prevent the P9415-R from connecting to the transmitter. The AP can use this pin to safely enable and

disable wireless power transfer function with proper VRECT node protections. If this pin is driven high in the power transfer phase, the P9415-R

will send an End Power Transfer packet to the transmitter and wireless power transfer will be disabled while Vrect protection is alive.

9.10.10

GP6/EPP_DISABLE Pin

The GP6 is assigned as a digital input referenced to LDO1P8. When the EPP_DISABLE pin is high, the Rx EPP mode is disabled and the

P9415-R operates in BPP mode. When it is low, the Rx mode is determined by the internal mode configuration setting value in the firmware. If

not used, connect this pin to ground.

9.11 Foreign Object Detection

When metallic objects are exposed to an alternating magnetic field, eddy currents cause such objects to heat up. Examples of such parasitic

metal objects are coins, keys, paper clips, etc. The amount of heating depends on the strength of the coupled magnetic field, as well as the

characteristics of the object, such as its resistivity, size, and shape. In a wireless power transfer system, the heating manifests itself as a power

loss, and therefore a reduction in power-transfer efficiency. Moreover, if no appropriate measures are taken, the heating could be sufficient that

the foreign object could become heated to an unsafe temperature.

In the Extended Power Profile, there are two methods of foreign object detection (FOD). One is by measuring the system quality factor before

entering the power transfer phase, and the other is to measure the power loss difference between the received power and the transmitted

power during the power transfer phase. Before entering the power transfer phase, the P9415-R sends a reference Q-factor (default 30) in the

negotiation phase. The transmitter measures the Q-factor on its coil and compares it with the reference Q-factor provided by the P9415-R. If

the difference is large, the transmitter presumes that there is a foreign object (FO) between the Tx and Rx and shuts down. The power loss

foreign object detection method is used in both the Extended Power Profile (EPP) and the Basic Power Profile (BPP) modes power transfer

phase. During the power transfer phase, the P9415-R continuously sends to the transmitter the amount of power received using the Received

Power Packet (RPP). The transmitter will compare the RPP packet information received from the receiver with its measured transmitted

power. If there is a significant difference the transmitter presumes that there is a foreign object (FO) between Tx and Rx that is absorbing the

transmitted power and will stop the power transfer to avoid heating of FO.