BQ28550-R1 Datasheet, PDF (12/42 Pages) Texas Instruments – Single Cell Li-Ion Battery Gas Gauge

Not Recommended for New Designs
bq28550-R1
SLUSAS4A – OCTOBER 2012 – REVISED SEPTEMBER 2014
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Protection (continued)
In the overcharge state, if a charger is removed and a load is connected, the external charge control MOSFET
conducts the load current through its parasitic body diode. If the V_BAT voltage becomes lower than the
overcharge release voltage (V_REL1 = 4.070 V typ) for a period up to the overcharge release delay time
(t_REL1 = 8 ms typ), the COUT pin transitions to a high level, enabling charge of the battery by turning on the
external charge control N-channel MOSFET.
7.5.2 Over-Discharge Detector
When discharging a battery, if the V_BAT voltage becomes lower than the over-discharge detection voltage
(V_DET2 = 2.3 V typ) for a period up to the over-discharge detection delay time (t_DET2 = 24 ms typ), the bq28550-
R1 device detects the over-discharge state of the battery, and the DOUT pin transitions to a low level. This
prohibits discharging the battery by turning off the external discharge control N-channel MOSFET.
In the over-discharge state, if a charger is connected, the external discharge control MOSFET conducts the
charge current through its parasitic body diode. If the V_BAT voltage becomes greater than the over-discharge
detection voltage (V_DET2 = 2.3 V typ) for a period up to the overcharge release delay time (t_REL2 = 4 ms typ), the
DOUT pin transitions to a high level, enabling discharge of the battery by turning on the external discharge
control N-channel MOSFET. After detecting over-discharge, the device stops all operations and enters standby,
which reduces the current consumed by the IC to its lowest mode (standby current).
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