BQ51013A Datasheet, PDF (24/45 Pages) Texas Instruments – INTEGRATED WIRELESS POWER SUPPLY RECEIVER

bq51013A
bq51014
SLUSAY6A – MARCH 2012 – REVISED JUNE 2012
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NOTE
It is required to connect a back-to-back PMOS between AD and OUT so that voltage is
blocked in both directions. Also, when AD mode is enabled no load can be pulled from the
RECT pin as this could cause an internal device overvoltage in bq5101x.
End Power Transfer Packet (WPC Header 0x02)
The WPC allows for a special command for the receiver to terminate power transfer from the trasmitter termed
End Power Transfer (EPT) packet. Table 4 specifies the v1.0 Reasons columb and their responding data field
value. The Condition column corresponds to the values sent by the bq5101x for a given reason.
Reason
Unknown
Charge Complete
Internal Fault
Over Temperature
Over Voltage
Over Current
Battery Failure
Reconfigure
No Response
Value
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
Table 4.
Condition
AD > 3.6V
TS/CTRL = 1, or EN1 = 1, or <EN1 EN2> = <11>
T_J > 150°C or R_ILIM < 100Ω
TS < V_HOT, TS > V_COLD, or TS/CTRL < 100mV
Not Sent
I_OUT > 90% of I_LIM (bq51014 only)
Not Sent
Not Sent
VRECT target doesn't converge
Over Current Shutdown (bq51014)
The bq51014 includes an over current shutdown feature where the Rx sends an end power transfer packet to the
Tx when the output current reaches 100% of the I_ILIM setting or 120% of the I_IMAX setting. The Tx will shut down
as soon as the end power transfer packet is received which discontinues power transfer. This feature disallows
the Rx from operating in a current limit situation in order to protect from down system shorts or failures.
Status Outputs
bq5101x has one status output, CHG. This output is an open-drain NMOS device that is rated to 20V. The open-
drain FET connected to the CHG pin will be turned on whenever the output of the power supply is enabled.
Please note, the output of the power supply will not be enabled if the V_RECT-REG does not converge at the no-load
target voltage.
WPC Communication Scheme
The WPC communication uses a modulation technique termed “back-scatter modulation” where the receiver coil
is dynamically loaded in order to provide amplitude modulation of the transmitters coil voltage and current. This
scheme is possible due to the fundamental behavior between two loosely coupled inductors (e.g. between the Tx
and Rx coil). This type of modulation can be accomplished by switching in and out a resistor at the output of the
rectifier, or by switching in and out a capacitor across the AC1/AC2 net. Figure 33 shows how to implement
resistive modulation.
C_RES1
COIL
AC1
C_RES2
VRECT
R_MOD
AC2
GND
Figure 33. Resistive Modulation
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