S-8200AAC-M6T1U Datasheet, PDF (14/36 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC FOR 1-CELL PACK

BATTERY PROTECTION IC FOR 1-CELL PACK
S-8200A Series
Rev.4.0_02
 Operation
Remark Refer to " Battery Protection IC Connection Example".
1. Normal status
The S-8200A Series monitors the voltage of the battery connected between the VDD pin and VSS pin, the voltage
between the VM pin and VSS pin to control charging and discharging. When the battery voltage is in the range from
overdischarge detection voltage (VDL) to overcharge detection voltage (VCU), and the VM pin voltage is in the range from
charge overcurrent detection voltage (VCIOV) to discharge overcurrent detection voltage (VDIOV), the S-8200A Series turns
both the charge and discharge control FETs on. This condition is called the normal status, and in this condition charging
and discharging can be carried out freely.
The resistance (RVMD) between the VM pin and VDD pin, and the resistance (RVMS) between the VM pin and VSS pin are
not connected in the normal status.
Caution When the battery is connected for the first time, the S-8200A Series may not be in the normal status. In
this case, short the VM pin and VSS pin, or set the VM pin voltage at the level of VCIOV or more and at
the level of VDIOV or less by connecting the charger. The S-8200A Series then becomes the normal
status.
2. Overcharge status
2. 1 VCL ≠ VCU (Product in which overcharge release voltage differs from overcharge detection voltage)
When the battery voltage becomes higher than VCU during charging in the normal status and detection continues for
the overcharge detection delay time (tCU) or longer, the S-8200A Series turns the charge control FEToff to stop
charging. This condition is called the overcharge status.
RVMD and RVMS 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 lower than VDIOV, the S-8200A Series releases the overcharge status when
the battery voltage falls below overcharge release voltage (VCL).
(2) In the case that the VM pin voltage is higher than or equal to VDIOV, the S-8200A Series releases the overcharge
status when the battery voltage falls below VCU.
When the discharge is started by connecting a load after the overcharge detection, the VM pin voltage rises by the Vf
voltage of the parasitic diode than the VSS pin voltage, because the discharge current flows through the parasitic
diode in the charge control FET. If this VM pin voltage is higher than or equal to VDIOV, the S-8200A Series releases
the overcharge status when the battery voltage is lower than or equal to VCU.
Caution
If the battery is charged to a voltage higher than VCU and the battery voltage does not fall below VCU
even when a heavy load is connected, discharge overcurrent detection and load short-circuiting
detection do not function until the battery voltage falls below VCU. 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.
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