S-8262AAA-I8T1U Datasheet, PDF (17/36 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC

Rev.1.0_02
BATTERY PROTECTION IC FOR 2-SERIAL-CELL PACK
S-8262A Series
3. Overdischarge status
When the battery voltage falls below overdischarge detection voltage (V_DL) during discharging in the normal status
and the detection continues for the overdischarge detection delay time (t_DL) or longer, the S-8262A Series turns the
discharge control FET off to stop discharging. This condition is called the overdischarge status. In the
overdischarge status the AO pin output becomes "High-Z".
Under the overdischarge status, the VM pin and VDD pin are shorted by R_VMD in the IC. The VM pin voltage is
pulled up by R_VMD.
When a battery in the overdischarge status is connected to a charger and provided that the VM pin voltage is lower
than −0.7 V typ., the S-8262A Series releases the overdischarge status when the battery voltage reaches V_DL or
higher.
When VM pin voltage is not lower than −0.7 V typ., the S-8262A Series releases the overdischarge status when the
battery voltage reaches V_DU or higher.
R_VMS is not connected in the overdischarge status.
3. 1 With power-down function
Under the overdischarge status, when voltage difference between the VM pin and VDD pin is 0.8 V typ. or lower,
the current consumption is reduced to the power-down current consumption (I_PDN).
4. Discharge overcurrent status
(Discharge overcurrent 1, discharge overcurrent 2, 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
V_DIOV1 because the discharge current is equal to or higher than the specified value and the status lasts for the
discharge overcurrent 1 detection delay time (t_DIOV1) or longer, 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 AO pin output becomes "High-Z".
In the discharge overcurrent status, the VM pin and VSS pin are shorted by the R_VMS in the IC. However, the
voltage of the VM pin is at the V_DD potential due to the load as long as the load is connected. When the load is
disconnected, the VM pin returns to the V_SS potential.
If the voltage at the VM pin returns to V_DIOV1 or lower, the S-8262A Series releases the discharge overcurrent
status.
R_VMD is not connected in the discharge overcurrent detection status.
5. Charge overcurrent status
When a battery in the normal status is in the status where the voltage of the VM pin is equal to or lower than V_CIOV
because the charge current is equal to or higher than the specified value and the status lasts for the charge
overcurrent detection delay time (t_CIOV) or longer, the charge control FET is turned off and charging is stopped. This
status is called the charge overcurrent status. In the charge overcurrent status the AO pin output becomes "High-
Z".
The S-8262A Series releases the charge overcurrent status when the voltage at the VM pin returns to V_CIOV or
higher by removing the charger.
The charge overcurrent detection function does not work in the overdischarge status.
R_VMD and R_VMS are not connected in the charge overcurrent status.
6. 0 V battery charge function "available"
This function is used to recharge a connected battery whose voltage is 0 V due to self-discharge. When the 0 V
battery charge starting charger voltage (V_0CHA) or a higher voltage is applied between the EB+ and EB− pins by
connecting a charger, the charge control FET gate is fixed to the V_DD potential.
When the voltage between the gate and source of the charge control FET becomes equal to or higher than the
threshold voltage due to the charger voltage, the charge control FET is turned on to start charging. At this time, the
discharge control FET is off and the charging current flows through the internal parasitic diode in the discharge
control FET. When the battery voltage becomes equal to or higher than V_DU, the S-8262A Series enters the normal
status.
Caution 1. Some battery providers do not recommend recharging for a completely self-discharged
battery. Please ask the battery provider to determine whether to enable or inhibit the 0 V
battery charge function.
2. The 0 V battery charge function has higher priority than the charge overcurrent detection
function. Consequently, a product in which use of the 0 V battery charge function is enabled
charges a battery forcibly and the charge overcurrent cannot be detected when the battery
voltage is lower than V_DL.
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