BQ24292I Datasheet, PDF (29/42 Pages) Texas Instruments – I2C Controlled 4.5A Single Cell USB/Adapter Charger With Narrow VDC Power Path Management and USB OTG

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bq24292i
SLUSBI4 – APRIL 2013
Table 5. STAT Pin State
CHARGING STATE
Charging in progress (including recharge)
Charging complete
Sleep mode, charge disable
Charge suspend (Input over-voltage, TS fault, timer fault, input or system over-
voltage)
STAT
LOW
HIGH
HIGH
10kΩ pull down
When a fault occurs, instead of blinking, the STAT pin in the charger device has a 10kΩ pull-down resistor to
ground. When the pull-up resistor is 30kΩ, the STAT voltage during fault is 1/4 of the pull-up rail.
Interrupt to Host (INT)
In some applications, the host does not always monitor the charger operation. The INT notifies the system on the
device operation. The following events will generate 256us INT pulse.
• USB/adapter source identified (through PSEL and OTG pins)
• Good input source detected
– not in sleep
– not in ACOV
– current limit above 30mA
• Input removed or ACOV
• Charge Complete
• Any FAULT event in REG09
When a fault occurs, the charger device sends out INT and latches the fault state in REG09 until the host reads
the fault register. Before the host reads REG09, the charger device would not send any INT upon new faults
except NTC fault (REG09[2:0]). The NTC fault is not latched and always reports the current thermistor
conditions. In order to read the current fault status, the host has to read REG09 two times consecutively. The 1^st
reads fault register status from the last INT and the 2^nd reads the current fault register status.
Protections
Input Current Limit on ILIM
For safe operation, the device has an additional hardware pin on ILIM to limit maximum input current on ILIM pin.
The input maximum current is set by a resistor from ILIM pin to ground as:
1V
I_INMAX = _RILIM ´ K_ILIM
(3)
The actual input current limit is the lower value between ILIM setting and register setting (REG00[2:0]). For
example, if the register setting is 111 for 3A, and ILIM has a 353Ω resistor to ground for 1.5A, the input current
limit is 1.5A. ILIM pin can be used to set the input current limit rather than the register settings.
The device regulates ILIM pin at 1V. If ILIM voltage exceeds 1V, the device enters input current regulation (Refer
to Dynamic Power Path Management section).
The voltage on ILIM pin is proportional to the input current. ILIM pin can be used to monitor the input current
following Equation 4:
IIN
=
V_ILIM
1V
´ I_INMAX
(4)
For example, if ILIM pin sets 2A, and the ILIM voltage is 0.6V, the actual input current 1.2A. If ILIM pin is open,
the input current is limited to zero since ILIM voltage floats above 1V. If ILIM pin is short, the input current limit is
set by the register.
Copyright © 2013, Texas Instruments Incorporated
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