S-8239BAA-M6T1U Datasheet, PDF (11/25 Pages) Seiko Instruments Inc – OVERCURRENT MONITORING IC

Rev.1.1_03
OVERCURRENT MONITORING IC FOR MULTI-SERIAL-CELL PACK
S-8239B Series
 Operation
1. Normal status
The S-8239B 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".
This status is called the normal status.
Caution When a battery is connected for the first time, the S-8239B Series may not be in the normal status.
In this case, short the VM pin and VSS pin or connect the charger. The S-8239B 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. 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 the VDD pin are shorted by the internal resistance between the VM pin and
the VDD pin (R_VMD) in the S-8239B Series.
After that, the overcurrent status is released if the voltage between the VDD pin and the VM pin becomes equal to or
higher than V_RIOV by connecting a charger.
3. UVLO status
The S-8239B 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. This status is called the UVLO status.
In the UVLO status, the VM pin and the VDD pin are shorted by R_VMD between the VM pin and the VDD pin in the
S-8239B Series.
After that, the UVLO status is released if the battery voltage becomes equal to or higher than V_UVLO.
4. Power-down status
In the UVLO status, the current consumption is decreased to the current consumption during power-down (I_PDN) if the
voltage between the VDD pin and the VM pin becomes equal to or lower than 0.7 V typ. in the S-8239B Series. This
status is called the power-down status.
Moreover, if the voltage between the VDD pin and the VM pin becomes equal to or lower than 0.7 V typ. and the
status continues for t_UVLO or longer in the normal status, the DO pin becomes V_SS potential and the S-8239B Series
becomes power-down status.
After that, the power-down status is released if the voltage between the VDD pin and the VM pin is equal to or higher
than 0.7 V typ. by connecting a charger.
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