BQ24193_15 Datasheet, PDF (18/49 Pages) Texas Instruments – bq24193 I2C Controlled 4.5-A Single Cell USB/Adapter Charger with Narrow VDC Power Path Management and USB OTG

bq24193
SLUSBG7 – DECEMBER 2014
www.ti.com
The host can always control the charging operation and optimize the charging parameters by writing to the
registers through I²C.
8.3.3.2 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 4. Charging Current Setting
CHARGING CURRENT
100 mA
REG03[7:4]
REG02[7:2]
REG DEFAULT SETTING
–
256 mA
2048 mA
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 13. Battery Charging Profile
Safety Timer
Expiration
8.3.3.3 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 bq24193 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)
18
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