S-8239AAA-M6T1U Datasheet, PDF (12/30 Pages) Seiko Instruments Inc – OVERCURRENT MONITORING IC

OVERCURRENT MONITORING IC FOR MULTI-SERIAL-CELL PACK
S-8239A Series
Rev.1.4_03
 Operation
1. Normal status
The S-8239A Series monitors the voltage between the VINI pin and the VSS pin to control discharging. When the
VINI pin voltage is equal to or lower than the overcurrent 1 detection voltage (V_DIOV1), the DO pin becomes "High-Z"
(Active "L") or V_SS potential (Active "H"). This status is called the normal status.
Caution When a battery is connected for the first time, the S-8239A Series may not be in the normal status.
In this case, short the VM pin and VSS pin or connect the charger. The S-8239A Series then
becomes the normal status.
2. Overcurrent status (Overcurrent 1, overcurrent 2, overcurrent 3)
When a battery is in the normal status, if the VINI pin voltage is equal to or higher than the overcurrent detection
voltage because the discharge current is equal to or higher than the specified value and the status continues for the
overcurrent detection delay time or longer, the DO pin becomes V_SS potential (Active "L") or "High-Z" (Active "H").
This status is called the overcurrent status. The overcurrent status is retained when the voltage between the VDD pin
and the VM pin is equal to or lower than the overcurrent release voltage (V_RIOV).
In the overcurrent status, the VM pin and VSS pin are shorted by the internal resistor between the VM pin and the
VSS pin (R_VMS) in the S-8239A Series. However, the VM pin is at V_DD potential due to the external load as long as the
external load is connected. When the external load is disconnected completely, the VM pin returns to V_SS potential.
The overcurrent status is released when the voltage between the VDD pin and the VM pin is equal to or higher than
V_RIOV.
3. UVLO status
The S-8239A Series includes a UVLO (under voltage lock out) function to prevent the IC malfunction due to the
decrease of the battery voltage when detecting the overcurrent. When the battery voltage in the normal status is
equal to or lower than the UVLO detection voltage (V_UVLO) and the status continues for the UVLO detection delay time
(t_UVLO) or longer, the DO pin becomes V_SS potential (Active "L") or "High-Z" (Active "H"). This status is called the
UVLO status.
In the UVLO status, the VM pin and VSS pin are shorted by R_VMS between the VM pin and the VSS pin in the
S-8239A Series.
After that, the UVLO status is released if the battery voltage becomes equal to or higher than V_UVLO.
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