SLUSBC8 – DECEMBER 2013
PIN FUNCTIONS (continued)
NAME
YFP
I/O
DESCRIPTION
Programming pin for the over current limit. Connect external resistor to VSS. Size R
ILIM
with the following
equation: R
ILIM
= 250 / I
MAX
where I
MAX
is the expected maximum output current of the wireless power
supply. The hardware current limit (I
ILIM
) will be 20% greater than I
MAX
or 1.2 x I
MAX
. If the supply is meant to
operate in current limit use
R
ILIM
= 314 / I
ILIM
R
ILIM
= R1 + R
FOD
Connect this pin to the wired adapter input. When a voltage is applied to this pin wireless charging is
disabled and AD_EN is driven low. Connect to GND through a 1 µF capacitor. If unused, capacitor is not
required and should be grounded directly.
Push-pull driver for external PFET connecting AD and OUT. This node is pulled to the higher of OUT and
AD when turning off the external FET. This voltage tracks approximately 4 V below AD when voltage is
present at AD and provides a regulated V
GS
bias for the external FET. Float this pin if unused.
Must be connected to ground via a resistor. If an NTC function is not desired connect to GND with a 10-kΩ
resistor. As a CTRL pin pull to ground to send end power transfer (EPT) fault to the transmitter or pull-up to
an internal rail (i.e. 1.8 V) to send EPT termination to the transmitter. Note that a 3-state driver should be
used to interface this pin (see the
section for further description).
Inputs that allow user to enable/disable wireless and wired charging <EN1 EN2>:
<00> Wireless charging is enabled
<01> Dynamic communication current limit disabled
<10> Wireless charging disabled
<11> Wireless charging disabled.
Input for the recieved power measurement. Connect to GND with a R
FOD
resistor.
Open-drain output – Active when the output of the wireless power supply is enabled.
ILIM
G1
I/O
AD
G4
I
AD-EN
F3
O
TS-CTRL
EN1
EN2
FOD
CHG
F1
G3
G2
F2
F4
I
I
I
I
O
Spacer
TYPICAL CHARACTERISTICS
100
80
70
90
60
80
Efficiency (%)
Efficiency (%)
50
70
40
30
60
20
50
10
R
ILIM
= 524
40
0
0.5
1
1.5
Power (W)
C006
-
2
2.5
3
0.000
0.500
1.000
1.500
2.000
2.500
Power (W)
C001
Figure 4. Rectifier Efficiency
Figure 5. System Efficiency from DC Input to DC Output
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