S-8230AAD-I6T1U Datasheet, PDF (16/37 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC

BATTERY PROTECTION IC WITH DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK
S-8230A/B Series
Rev.2.5_00
2. 2 V_CL = V_CU (Product in which overcharge release voltage is the same as overcharge detection voltage)
When the battery voltage becomes higher than V_CU during charging in the normal status and detection continues
for the overcharge detection delay time (t_CU) or longer, the S-8230A/B Series turns the charge control FET off to
stop charging. This condition is called the overcharge status.
R_VMD and R_VMS are not connected in the overcharge status.
The overcharge status is released in the following two cases.
(1) In the case that the VM pin voltage is equal to or higher than V_CIOV, and is lower than V_DIOV, the S-8230A/B
Series releases the overcharge status when the battery voltage falls below overcharge release voltage (V_CL).
(2) In the case that the VM pin voltage is equal to or higher than V_DIOV, the S-8230A/B Series releases the
overcharge status when the battery voltage falls below V_CU.
The discharge is started by connecting a load after the overcharge detection, the VM pin voltage rises more than
the VSS pin voltage due to the V_f voltage of the parasitic diode, because the discharge current flows through the
parasitic diode in the charge control FET. If this VM pin voltage is equal to or higher than V_DIOV, the S-8230A/B
Series releases the overcharge status when the battery voltage is equal to or lower than V_CU.
Caution
1. If the battery is charged to a voltage higher than V_CU and the battery voltage does not fall below
V_CU even when a heavy load is connected, discharge overcurrent detection and load short-
circuiting detection do not function until the battery voltage falls below V_CU. Since an actual
battery has an internal impedance of tens of mΩ, the battery voltage drops immediately after a
heavy load that causes overcurrent is connected, and discharge overcurrent detection and load
short-circuiting detection function.
2. When a charger is connected after overcharge detection, the overcharge status is not released
even if the battery voltage is below V_CL. The overcharge status is released when the VM pin
voltage goes over V_CIOV by removing the charger.
3. Overdischarge status
When the battery voltage falls below V_DL during discharging in the normal status and the detection continues for the
overdischarge detection delay time (t_DL) or longer, the S-8230A/B Series turns the discharge control FET off to stop
discharging. This condition is called the overdischarge status.
In the overdischarge status, the VM pin and VDD pin are shorted by R_VMD in the S-8230A/B Series. 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-8230A/B 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-8230A/B Series releases the overdischarge status when the
battery voltage reaches overdischarge release voltage (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 between the VDD pin and VM pin is 0.8 V typ. or lower, the power-
down function works and the current consumption is reduced to the current consumption during power-down
(I_PDN). By connecting a charger, the power-down function is released when the VM pin voltage is 0.7 V typ. or
lower.
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