P9415-R Datasheet

© 2021 Renesas Electronics Corporation

29

May 4, 2021

8.4.3 Demodulator

In TRx Mode, the Rx sends WPC protocol packets to the P9415-R. Using the demodulation (DEMOD) filter shown in Figure 22 and the internal

demodulator circuitry, the P9415-R decodes the ASK modulation packets Rx sent. Based on the packet information, the P9415-R modulates

the transmitted power by adjusting the operating frequency or duty cycle and detects a foreign object between Tx and Rx.

Figure 22. WattShareTM Mode Demodulation Filter

8.4.4 WattShareTM Mode Input Under Voltage, Over Voltage, and Current Limit

There are several Over-current Protection thresholds in the WattShare mode that are applied differently depending on the operation phase.

In the ping phase, if the input current exceeds the ping OCP threshold (default 1.1A), the P9415-R sets flag EPT_POCP in TRx End Power

Transfer Reason Register (0x0074 2byte), sends an interrupt (EPT_TYPE_INT) to the AP and disables TRX function. TRx will not resume until

the AP recycles the power on the VOUT pin and enables the TRx mode again.

In the power transfer phase, if the input current exceeds the IgnoreCepThd (default 1.3A) but less than OCPThd (default 1.5A), the P9415-R

enters in CEP Ignore mode. In this mode, bit3 of TRx System Flag Register (0x007B, 1byte) is set and the P9415-R will not respond to the

positive CEP from the receiver with the expectation that the receiver detects its Vout drops and decreases the output load. If the input current

falls below IgnoreCepThd – IgnoreCepHysteresis (default 0.2A), bit3 of TRx System Flag Register (0x007B, 1byte) is cleared, and the P9415-R

operates in normal TRx mode and responds to positive CEP normally.

If the average input current exceeds OCPThd or instant input current exceeds OCPThdFast (default 1.8A), the P9415-R sets flag EPT_OCP in

TRx End Power Transfer Reason Register (0x0074, 2byte), sends an interrupt (EPT_TYPE_INT) to the AP and disables TRx function. TRx will

not resume until the AP recycles the power on the VOUT pin and enables the TRx mode again.

If the voltage on the VRECT pin is higher than the over-voltage protection (OVP) threshold (default 11V), the P9415-R sends interrupt

(EPT_TYPE_INT) to AP, sets the EPT_OVP bit of TRx End Power Transfer Reason Register 0x0074(2 bytes), and disables the TRx function.

If the voltage on the VRECT pin is lower than (OVP threshold – OVP hysteresis (1.5V), the P9415 clears the EPT_OVP bit. If the EPT_OVP bit

is set, the TRx function cannot be enabled.

If the voltage on the VOUT pin is lower than the low voltage protection (LVP) threshold (Default 4V), the P9415-R sends interrupt

(EPT_TYPE_INT) to AP, sets EPT_LVP bit of TRx End Power Transfer Reason Register 0x0074(2 bytes), and disables the TRx function. There

is an internal digital filter to avoid false triggering of LVP for small voltage dips. TRx will not resume until AP recycles the power on the VOUT

pin and enables the TRx mode again.

8.4.5 Transmitter Conflict in WattShareTM Mode

When the P9415-R is in WattShareTMmode, users might accidentally place the P9415-R on another WPC transmitter. The pings from the WPC

transmitter will generate an AC voltage in the resonant tank connected to the P9415-R. The P9415-R detects this voltage, sends an interrupt

(GET_DPING_INT in 0x30[6]) to the AP, and exits TRx mode. The AP must disable the external power supply connected to the VOUT pin of

the P9415-R.