BATTERY OVERVOLTAGE PROTECTION

CHARGE OVERCURRENT PROTECTION

THERMAL SHUTDOWN PROTECTION

Status Outputs (ACGOOD, DPMDET)

bq24705

The converter stops switching when BAT voltage goes above 104% of the regulation voltage. The converter will

not allow the high-side FET to turn on until the BAT voltage goes below 102% of the regulation voltage. This

allows one-cycle response to an overvoltage condition, such as when the load is removed or the battery is

disconnected. A 10-mA current sink from BAT to PGND is on only during charge, and allows discharging the

stored output-inductor energy into the output capacitors.

The charger has a secondary overcurrent protection. It monitors the charge current, and prevents the current

from exceeding 145% of regulated charge current. The high-side gate drive turns off when the overcurrent is

detected, and automatically resumes when the current falls below the overcurrent threshold.

The QFN package has low thermal impedance, which provides good thermal conduction from the silicon to the

ambient, to keep junctions temperatures low. As added level of protection, the charger converter turns off and

self-protects whenever the junction temperature exceeds the TSHUT threshold of 155°C. The charger stays off

until the junction temperature falls below 135°C.

Two status outputs are available, and they require external pull up resistors to pull the pins to system digital rail

for a high level.

ACGOOD open-drain output goes low if ACDET is above 2.4 V.

DPMDET open-drain output goes low when the DPM loop is active to reduce the battery charge current (after a

10-ms delay).

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