BQ24130_15 Datasheet, PDF (16/29 Pages) Texas Instruments – 600-kHz Synchronous Switch-Mode Host-ControlledBattery/Supercapacitor Charger With 4-A Integrated MOSFETs

bq24130
SLUSAN2C – JULY 2011 – REVISED JUNE 2012
www.ti.com
Charge Overcurrent Protection
The charger monitors top side MOSFET current by high side sense FET. When peak current is higher than over-
current threshold, it will turn off the top side MOSFET and keep it off until the next cycle. The charger has a
secondary cycle-to-cycle over-current protection. It monitors the charge current, and prevents the current from
exceeding 160% of the programmed charge current. The high-side gate drive turns off when the overcurrent is
detected, and automatically resumes when the current falls below the over-current threshold.
Battery Overvoltage Protection
The converter will not allow the high-side FET to turn-on until the battery voltage goes below 102% of the
regulation voltage. This allows one-cycle response to an over-voltage condition – such as occurs when the load
is removed or the battery is disconnected. An 8 mA current sink from SRP/SRN to AGND is on only during
charge and allows discharging the stored output inductor energy that is transferred to the output capacitors. If
battery overvoltage condition lasts for more than 30 ms, charge is disabled.
Battery Short Protection
When SRN pin voltage is lower than 2 V it is considered as battery short condition during charging period. The
charger will shut down immediately, then soft start back to the charging current 1.25 A max. This prevents high
current may build in output inductor and cause inductor saturation when battery terminal is shorted during
charging. The converter works in non-synchronous mode during battery short.
Input Overvoltage Protection (ACOV)
ACOV provides protection to prevent system damage due to high input voltage. In bq24130, once the voltage on
AVCC reaches the 18 V ACOV threshold, charge is disabled.
Input Under Voltage Lock Out (UVLO)
The system must have a minimum 3.85 V AVCC voltage to allow proper operation. This AVCC voltage could
come from either input adapter or battery, since a conduction path exists from the battery to AVCC through the
high side NMOS body diode. When AVCC is below the 3.85 V UVLO threshold, all circuits on the IC are
disabled.
Thermal Regulation and Shutdown Protection
The QFN package has low thermal impedance, which provides good thermal conduction from the silicon to the
ambient, to keep junctions temperatures low. The internal thermal regulation loop will adjust the charge current to
maintain the junction temperature around 120°C.
As added level of protection, the charger converter turns off and self-protects whenever the junction temperature
exceeds the T_SHUT threshold of 150°C. The charger stays off until the junction temperature falls below 130°C.
Temperature Qualification
The controller continuously monitors battery temperature by measuring the voltage between the TS pin and
AGND. A negative temperature coefficient thermistor (NTC) and an external voltage divider typically develop this
voltage. The controller compares this voltage against its internal thresholds to determine if charging is allowed.
To initiate a charge cycle, the battery temperature must be within the V_(LTF) to V_(HTF) thresholds. If battery
temperature is outside of this range, the controller suspends charge and waits until the battery temperature is
within the V_(LTF) to V_(HTF) range. During the charge cycle the battery temperature must be within the V_(LTF) to
V_(TCO) thresholds. If battery temperature is outside of this range, the controller suspends charge and waits until
the battery temperature is within the V_(LTF) to V_(HTF) range. The controller suspends charge by turning off the
PWM charge MOSFETs. Figure 16 summarizes the operation.
16
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