S-8211DAD-M5T1X Datasheet, PDF (17/38 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC

Rev.6.5_02
BATTERY PROTECTION IC FOR 1-CELL PACK
S-8211D Series
3. Overdischarge status
3. 1 With power-down function
When the battery voltage falls below overdischarge detection voltage (VDL) during discharging in the normal status and
the detection continues for the overdischarge detection delay time (tDL) or longer, the S-8211D Series turns the
discharging control FET off to stop discharging. This condition is called the overdischarge status. Under the
overdischarge status, the VM pin voltage is pulled up by the resistor between the VM pin and the VDD pin in the
S-8211D Series (RVMD). When voltage difference between the VM pin and the VDD pin then is 1.3 V typ. or lower, the
current consumption is reduced to the power-down current consumption (IPDN). This condition is called the power-down
status.
The resistance (RVMS) between the VM pin and the VSS pin is not connected in the power-down status and the
overdischarge status.
The power-down status is released when a charger is connected and the voltage difference between the VM pin and
the VDD pin becomes 1.3 V typ. or higher.
When a battery in the overdischarge status is connected to a charger and provided that the VM pin voltage is lower
than charger detection voltage (VCHA), the S-8211D Series releases the overdischarge status and turns the
discharging FET on when the battery voltage reaches overdischarge detection voltage (VDL) or higher.
When a battery in the overdischarge status is connected to a charger and provided that the VM pin voltage is not lower
than charger detection voltage (VCHA), the S-8211D Series releases the overdischarge status when the battery voltage
reaches overdischarge release voltage (VDU) or higher.
3. 2 Without power-down function
When the battery voltage falls below overdischarge detection voltage (VDL) during discharging in the normal status and
the detection continues for the overdischarge detection delay time (tDL) or longer, the S-8211D Series turns the
discharging control FET off to stop discharging. This condition is called the overdischarge status. Under the
overdischarge status, the VM pin voltage is pulled up by the resistor between the VM pin and the VDD pin in the
S-8211D Series (RVMD).
The resistance (RVMS) between the VM pin and the VSS pin is not connected in the overdischarge status.
When a battery in the overdischarge status is connected to a charger and provided that the VM pin voltage is lower
than charger detection voltage (VCHA), the S-8211D Series releases the overdischarge status and turns the
discharging FET on when the battery voltage reaches overdischarge detection voltage (VDL) or higher.
When a battery in the overdischarge status is connected to a charger and provided that the VM pin voltage is not lower
than charger detection voltage (VCHA), the S-8211D Series releases the overdischarge status when the battery voltage
reaches overdischarge release voltage (VDU) or higher.
4. Discharge overcurrent status (discharge overcurrent, load short-circuiting)
When a battery in the normal status is in the status where the voltage of the VM pin is equal to or higher than the
discharge overcurrent detection voltage because the discharge current is higher than the specified value and the
status lasts for the discharge overcurrent detection delay time, the discharge control FET is turned off and discharging
is stopped. This status is called the discharge overcurrent status.
In the discharge overcurrent status, the VM pin and the VSS pin are shorted by the resistor between the VM pin and
the VSS pin (RVMS) in the S-8211D Series. However, the voltage of the VM pin is at the VDD potential due to the load
as long as the load is connected. When the load is disconnected completely, the VM pin returns to the VSS potential.
If the S-8211D Series detects that the voltage of the VM pin returns to discharge overcurrent detection voltage (VDIOV)
or lower, the discharge overcurrent status is restored to the normal status.
The S-8211D Series will be restored to the normal status from discharge overcurrent detection status even when the
voltage of the VM pin becomes the discharge overcurrent detection voltage (VDIOV) or lower by connecting the charger.
The resistance (RVMD) between the VM pin and the VDD pin is not connected in the discharge overcurrent status.
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