Datasheet

bq51013B
www.ti.com SLUSB62A –MARCH 2013–REVISED OCTOBER 2013
Adapter Enable Functionality and EN1/EN2 Control
Figure 3 is an example application that shows the bq5101xB used as a wireless power receiver that can power
mutliplex between wired or wireless power for the down-system electronics. In the default operating mode pins
EN1 and EN2 are low, which activates the adapter enable functionality. In this mode, if an adapter is not present
the AD pin will be low, and AD-EN pin will be pulled to the higher of the OUT and AD pins so that the PMOS
between OUT and AD will be turned off. If an adapter is plugged in and the voltage at the AD pin goes above
3.6V then wireless charging is disabled and the AD-EN pin will be pulled approximately 4V below the AD pin to
connect AD to the secondary charger. The difference between AD and AD-EN is regulated to a maximum of 7V
to ensure the V
GS
of the external PMOS is protected.
The EN1 and EN2 pins include internal 200kΩ pull-down resistors, so that if these pins are not connected
bq5101xB defaults to AD-EN control mode. However, these pins can be pulled high to enable other operating
modes as described in Table 2:
Table 2.
EN1 EN2 Result
Adapter control enabled. If adapter is present then secondary charger is powered by adapter, otherwise wireless
0 0
charging is enabled when wireless power is available. Communication current limit is enabled.
0 1 Disables communication current limit.
AD-EN is pulled low, whether or not adapter voltage is present. This feature can be used, e.g., for USB OTG
1 0
applications.
1 1 Adapter and wireless charging are disabled, i.e., power will never be delivered by the OUT pin in this mode.
Table 3.
EN1 EN2 Wireless Power Wired Power OTG Mode Adaptive Communication Limit EPT
0 0 Enabled Priority
(1)
Disabled Enabled Not Sent to Tx
0 1 Priority
(1)
Enabled Disabled Disabled Not Sent to Tx
1 0 Disabled Enabled Enabled
(2)
N/A No Response
1 1 Disabled Disabled Disabled N/A Termination
(1) If both wired and wireless power are present, wired power is given priority.
(2) Allows for a boost-back supply to be driven from the output terminal of the Rx to the adapter port via the external back-to-back PMOS
FET.
As described in Table 3, pulling EN2 high disables the adapter mode and only allows wireless charging. In this
mode the adapter voltage will always be blocked from the OUT pin. An application example where this mode is
useful is when USB power is present at AD, but the USB is in suspend mode so that no power can be taken from
the USB supply. Pulling EN1 high enables the off-chip PMOS regardless of the presence of a voltage. This
function can be used in USB OTG mode to allow a charger connected to the OUT pin to power the AD pin.
Finally, pulling both EN1 and EN2 high disables both wired and wireless charging.
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 bq5101xB.
End Power Transfer Packet (WPC Header 0x02)
The WPC allows for a special command for the receiver to terminate power transfer from the transmitter termed
End Power Transfer (EPT) packet. Table 4 specifies the v1.1 reasons column and their corresponding data field
value. The condition column corresponds to the methodology used by bq5101xB to send equivalent message.
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