BQ24190_15 Datasheet, PDF (19/52 Pages) Texas Instruments – bq2419x I2C Controlled 4.5-A Single Cell USB/Adapter Charger with Narrow VDC Power Path Management and USB OTG

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bq24190, bq24192, bq24192I
SLUSAW5B – JANUARY 2012 – REVISED DECEMBER 2014
The STAT output indicates the charging status of charging (LOW), charging complete or charge disable (HIGH)
or charging fault (Blinking). The status register REG08[5:4] indicates the different charging phases: 00-charging
disable, 01-precharge, 10-fast charge (constant current) and constant voltage mode, 11-charging done. Once a
charging cycle is complete, an INT is asserted to notify the host.
The host can always control the charging operation and optimize the charging parameters by writing to the
registers through I²C.
9.3.3.2 Battery Charging Profile
The device charges the battery in three phases: preconditioning, constant current and constant voltage. At the
beginning of a charging cycle, the device checks the battery voltage and applies current.
VBAT
<2V
2V-3V
>3V
Table 5. Charging Current Setting
CHARGING CURRENT
100 mA
REG03[7:4]
REG02[7:2]
REG DEFAULT SETTING
–
256 mA
2048 mA (bq24190/192) 1024 mA (bq24192I)
REG08[5:4]
01
01
10
If the charger device is in DPM regulation or thermal regulation during charging, the actual charging current will
be less than the programmed value. In this case, termination is temporarily disabled and the charging safety
timer is counted at half the clock rate.
Regulation Voltage
(3.5V – 4.4V)
Fast Charge Current
(500mA-4020mA)
VBAT_LOWV (2.8V/3V)
Battery Voltage
Charge Current
VBAT_SHORT (2V)
IPRECHARGE (128mA-2048mA)
ITERMINATION (128mA-2048mA)
IBATSHORT (100mA)
Trickle Charge Pre-charge
Fast Charge and Voltage Regulation
Figure 14. Battery Charging Profile
Safety Timer
Expiration
9.3.3.3 Battery Path Impedance IR Compensation
To speed up the charging cycle, we would like to stay in constant current mode as long as possible. In real
system, the parasitic resistance, including routing, connector, MOSFETs and sense resistor in the battery pack,
may force the charger device to move from constant current loop to constant voltage loop too early, extending
the charge time.
The bq24190, bq24192, bq24192I allows the user to compensate for the parasitic resistance by increasing the
voltage regulation set point according to the actual charge current and the resistance. For safe operation, the
user should set the maximum allowed regulation voltage to REG06[4:2], and the minimum trace parasitic
resistance (REG06[7:5]).
( ) ^V_{BATREG_ACTUAL} ^{= V}_{BATREG_I2C} ^{+ lower of I}_{CHRG_ACTUAL}^{× R}_COMP ^{and V}_CLAMP
(1)
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