LV51131T
Excessive charger detection/release
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If the voltage between V pin and V pin becomes equal to or less than the excessive charger detection voltage by
SS
connecting a charger, no charging can be made by turning the Cout pin “L” after delay time and turning off the external
Nch MOS FET. If that voltage returns to equal to or more than the excessive charger detection voltage during detection
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delay time, the excessive charger detection will be stopped. If the voltage between V pin and V pin becomes equal
SS
to or more than the excessive charger detection voltage after excessive charger detection, the Cout returns to “H” after
delay time. The detection/return delay time is set internally.
If Dout pin is “L”, charging will be made through the parasitic diode of external Nch FET on Dout pin. In that case, the
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voltage between V pin and V pin is nearly -Vf which is less than the excessive-charger detection voltage, therefore
SS
no excessive charger detection will be made during over-discharge, over-current and short-circuit detection.
Furthermore, if excessive voltage charger is connected to the over-discharged battery, no excessive charger detection is
made while the Dout pin is “L”. But the battery is continued charging through the parasitic diode. If the battery voltage
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rises to the over-discharge detection voltage and the voltage between V pin and V pin remains equal to or less than
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the excessive charger detection voltage, the delay operation will be started after Dout pin turns to “H.”
0V cell charging operation
If voltage between V
and V becomes equal to or more than the 0V cell charging lowest operation voltage when the
DD
cell voltage is 0V, the Cout pin turns to “H” and charging is enabled.
Shorten the test time
By turning T pin to the V
, the delay times set by the internal counter can be cut. If T pin is “open”, “L” the delay
DD
times are normal. Delay time not set by the counter just like as short circuit detection delay cannot be controlled by this
pin.
In some circuit-board layout, an excessive current at the load short might cause this IC be in miss operation like as in
standby mode due to V line impedance. Therefore we recommend that the T pin is connected to the V pin.
SS
SS
Operation in case of detection overlap
Operation in case of
detection overlap
Overlap state
State after detection
When over-charge state is made first, V is
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During over-charge
Over-discharge
Over-charge detection is prioritized. If over-
detection
detection is made
discharge state continues even after over-charge released. When over-discharge is detected after
detection, over-discharge detection is resumed.
over-charge state is made, the IC does not go
-
into the stand-by mode. Note that V is connected
to V
DD
via 200kΩ.
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(*2) When over-current state is made first, V is
Over-current detection (*1) Both detections’ can be made in parallel.
is made Over-charge detection continues even when the
connected to V
SS
via 30kΩ. When over-charge
-
over-current state is made first. If the over-charge state is made first, V is released.
state is made first, over-current detection is
interrupted.
During over-discharge
detection
Over-charge detection Over-discharge detection is interrupted and
The IC does not go into the stand-by mode when
is made
over-charge detection is preferred. When
over-discharge state continues even after
over-charge state is made, over-discharge
detection is resumed.
over-discharge state is made after over-charge
-
detection. Note that V is connected to V
via
DD
200kΩ.
-
Over-current detection (*3) Both detections can be made in parallel.
(*4) If over-current state is made first, V will be
is made
Over-discharge detection continues even when
the over-current state is made first. But
over-current detection is interrupted when the
over-discharge state is made first.
connected to V
SS
detection is made next, V will be disconnected
via 30kΩ. If over-discharge
-
from V
SS
and connected to V
via 200kΩ to
DD
get into stand-by mode. If over-discharge state is
-
made first, V will be connected to V
via
DD
200kΩ to get into standby modw.
During over-current
detection
Over-charge detection (*1)
is made
(*2)
Over-discharge
(*3)
(*4)
detection is made
(Note) Short-circuit detection can be made independently.
Excessive charger detection cannot be made during over-discharge, over-current and short-circuit detection.
And its delay time starts after the Dout pin returns to “H”.
No.A1152-7/10
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