BQ500414Q Datasheet, PDF (11/34 Pages) Texas Instruments – Qi Compliant Wireless Power Transmitter Manager

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bq500414Q
SLUSBE4B – JANUARY 2014 – REVISED JUNE 2014
Feature Description (continued)
8.3.6 Option Select Pins
There are four option select pins (pin 18 ~EN_PWR, pin 21 EMI_SHIELD, pin 43 LOSS_THR and pin 44
LED_MODE) on the bq500414Q. All the pin voltages will be read by bq500414Q at power up.
• Pin 18 is used to indicate if the Tx should be go into active or passive wake-up state. This pin is a logic input
that can be tied to 3.3-V or GND for indication. This pin is also the active LOW enable signal to the SEPIC.
• Pin 21 is used to indicate if EMI shield is in use. This pin is a logic input that can be tied to 3.3-V or GND for
indication.
• Pin 43 is used to program the Loss Threshold and FOD Calibration.
• Pin 44 is used to select the LED mode of the device. At power up, a bias current is applied to pins
LED_MODE and LOSS_THR and the resulting voltage is measured in order to identify the value of the
attached programming resistor. For LED_MODE, the selected bin determines the LED behavior based on
Table 1. For the LOSS_THR, the selected bin sets a threshold based on Table 2. See Foreign Object
Detection (FOD) and Parasitic Metal Object Detect (PMOD) Calibration section for more information.
Resistors
to set
options
LED_MODE
44
LOSS_THR
43
To 12-bit ADC
FOD
13
PMOD FOD_CAL
6
22
Figure 5. Pin 43 LOSS_THR and Pin 44 LED_MODE Connections
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