NXP Semiconductors AN11524, Application Note, Page: 8 / 54

AN11524 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved.
Application note Rev. 1 — 17 February 2015 8 of 54
NXP Semiconductors
AN11524
NXQ1TXA6 Evaluation Board
3.5 Stand-by power mode switch
The switch on the top of the board is not a power on/off switch. The switch is for
alternating between the “Normal” and the NFC “tap to power on” position as illustrated in
Figure 5 .
In the Normal mode, the charging pad periodically monitors the coil for the presence of a
Qi receiver. It starts power transfer, once a Qi power receiver is detected.
In the NFC tap to power on mode, the charging pad electronics are disconnected from the
12 V supply. The presence of an NFC enabled phone, switches on the 12 V system
supply, enabling zero power in standby mode.
Important:
The present generation of NFC phones only performs periodic NFC operations when the
display of the phone is on and unlocked. It is only under this condition that the charging
pad is woken-up to start power transfer.
3.6 Reset button
Pressing the reset button marked SW101 on the board performs a reset of the charging
pad.
3.7 Foreign object detection button
By pressing the left-most button marked SW102 on the board, the charging pad enables
or disables Foreign Object Detection (FOD). This feature should be removed for final
products.
While charging, the green status LED indicates whether FOD is activated. When FOD is
active, the green LED blinks with a rate of 1 Hz. When FOD is disabled, the green LED
blinks with a rate of 3 Hz.
Fig 5. Standby-by power mode switch
aaa-015883
normal mode
position NFC tap to
power on position