BQ24262_15 Datasheet, PDF (18/56 Pages) Texas Instruments – bq2426x 3-A, 30-V, Host-Controlled Single-Input, Single-Cell Switched-Mode Li-Ion Battery Charger With Power-Path Management and USB-OTG Support

Not Recommended for New Designs : bq24260, bq24261
bq24260, bq24261, bq24261M, bq24262
SLUSBU4D – DECEMBER 2013 – REVISED APRIL 2015
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Device Functional Modes (continued)
The bq24260/1/1M/2 supports a precision Li-Ion or Li-Polymer charging system for single-cell applications.
Charging is done through the internal battery MOSFET. There are 6 loops that influence the charge current;
constant current loop (CC), constant voltage loop (CV), thermal regulation loop, minimum system voltage loop
(MINSYS), input current limit and V_IN-DPM. During the charging process, all six loops are enabled and the one
that is dominant takes control. The minimum system output feature regulates the system voltage to V_SYSREG(LO),
so that startup is enabled even for a missing or deeply discharged battery. Figure 10 shows a typical charge
profile including the minimum system output voltage feature.
Regulation
Voltage
Precharge
Phase
Regulation
Current
V_SYS
(3.6V)
System Voltage
Current Regulation
Phase
Voltage Regulation
Phase
V_BATSHORT
(2.0V)
Battery
Voltage
Termination
I_BATSHORT
Charge Current
Linear Charge
50mA Linear Charge to Maintain
to Close Pack
Minimum
Protector
System
Voltage
Battery FET (Q3) is
ON
Battery
FET
is OFF
Figure 10. Typical Charging Profile of bq24260/1/1M/2 With Termination Enabled
9.4.4 Battery Charging Process
When the battery is deeply discharged or shorted, the bq24260/1/1M/2 applies a I_BATSHRT current to close the
battery protector switch and bring the battery voltage up to acceptable charging levels. During this time, the
battery FET is off and the system output is regulated to V_SYSREG(LO). Once the battery rises above V_BATSHRT, the
charge current is regulated to the value set in the I²C register. The battery FET is linearly regulated to maintain
the system voltage at V_SYSREG(LO). Under normal conditions, the time spent in this region is a very short
percentage of the total charging time, so the linear regulation of the charge current does not affect the overall
charging efficiency for very long. If the die temperature does heat up, the thermal regulation loop reduces the
input current to maintain a die temperature at 125°C. If the current limit for the SYS output is reached (limited by
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