BQ24187 Datasheet, PDF (16/44 Pages) Texas Instruments – 1A USB-OTG Support

bq24187
SLUSBM0 – APRIL 2014
Not Recommended for New Designs
Device Functional Modes (continued)
Regulation
voltage
Regulation
current
Precharge
phase
Current regulation
phase
Voltage regulation
phase
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VBATSHRT
(2.0 V)
Battery
voltage
Termination
IBATSHRT
Charge current
Figure 8. Typical Charging Profile Of Bq24187
8.4.1.1.3 Battery Charging Process
When the battery is deeply discharged or shorted, the bq24187 applies I_BATSHORT to the battery to close the
battery protector switch and bring the battery voltage up to acceptable charging levels. Once the battery rises
above V_BATSHRT, the charge current is regulated to the value set in the I²C register by the I_CHARGE bits. The
charge current is regulated to I_CHARGE until the voltage between BAT and PGND reaches the regulation voltage.
The voltage between BAT and PGND is regulated to VBATREG (CV mode) while the charge current naturally
tapers down as shown in Figure 8. During the CC or CV modes, if the die temperature heats up, the thermal
regulation loop reduces the input current to maintain a die temperature at 125°C.
When termination is enabled (TE bit is '1'), the bq24187 monitors the charging current during the CV mode. Once
the charge current tapers down to the termination threshold, I_TERM, and the battery voltage is above the recharge
threshold, the bq24187 terminates charge and enters battery detection (see Battery Detection section for more
details). The termination current level is programmable. To disable the charge current termination, the host sets
the charge termination bit (TE) of charge control register to 0. Refer to I²C section for details. When termination
is disabled, V_BAT is continuously regulated to V_BATREG. Termination is also disabled when any loop is active other
than CC or CV. This includes V_INDPM, input current limit, or thermal regulation. Termination is also disabled during
TS WARM/COOL conditions and when the LOW_CHG bit is set to '1'. A charge cycle is initiated when one of the
following conditions is detected:
• The battery voltage falls below the V_BATREG-V_RCH threshold
• IN Power-on reset (POR)
• CE bit toggle or RESET bit is set (Host controlled)
• CD terminal is toggled
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