BQ24140_14 Datasheet, PDF (18/39 Pages) Texas Instruments – Integrated Dual-Input Switch-Mode One-Cell Li-Ion Charger with Full USB Compliance and USB-OTG Support

bq24140
SLUSAO5 – OCTOBER 2011
Precharge Phase
V_OREG ^{(Linear Charge)}
Fastcharge Phase
(PWM Charge)
Voltage Regulation Phase
(PWM Charge)
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V_SHORT
Termination
I_SHORT
Charge Voltage
Charge Current
Figure 17. Typical Charging Profile With Input Current Limit
The voltage regulation feedback occurs by monitoring the battery-pack voltage between the VBAT and GND
pins. The regulation voltage is adjustable (3.5V to 4.44V) and is programmed through I²C interface. The IC
monitors the charging current during the voltage regulation phase. When the termination is enabled, once the
termination threshold, I_TERM, is detected and the battery voltage is above the recharge threshold, the IC
terminates charge. The termination current level is programmable. To disable the charge current termination, the
host can set the charge termination bit (TE) of charge control register to 0, refer to I²C section for detail.
A new charge cycle is initiated when one of the following conditions is detected:
• The battery voltage falls below the V_(OREG) – V_(RCH) threshold.
• VBUS or VIN Power-on reset (POR), if battery voltage is below the V_(LOWV) threshold.
• CE bit toggle or RESET bit is set (Host controlled)
Figure 18 shows an operational flow chart of the bq24140 in charge mode.
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