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S-82B1A Datasheet, PDF (14/35 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC WITH CHARGE-DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK
BATTERY PROTECTION IC WITH CHARGE-DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK
S-82B1A Series
Rev.1.2_00
 Operation
Remark Refer to " Battery Protection IC Connection Example".
1. Normal status
The S-82B1A Series monitors the voltage of the battery connected between VDD pin and VSS pin, the voltage
between VM pin and VSS pin and the voltage between CTL pin and VSS pin to control charging and discharging.
1. 1 CTL pin control logic active "H"
When the battery voltage is in the range from overdischarge detection voltage (VDL) to overcharge detection
voltage (VCU), the VM pin voltage is in the range from charge overcurrent detection voltage (VCIOV) to discharge
overcurrent detection voltage 1 (VDIOV1), and the CTL pin voltage is equal to or lower than the CTL pin voltage "L"
(VCTLL), the S-82B1A Series turns both the charge-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 between VDD pin and VM pin (RVMD), and the resistance between VM pin and VSS pin (RVMS)
are not connected in the normal status.
1. 2 CTL pin control logic active "L"
When the battery voltage is in the range from overdischarge detection voltage (VDL) to overcharge detection
voltage (VCU), the VM pin voltage is in the range from charge overcurrent detection voltage (VCIOV) to discharge
overcurrent detection voltage 1 (VDIOV1), and the CTL pin voltage is equal to or higher than the CTL pin voltage
"H" (VCTLH), the S-82B1A Series turns both the charge-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 between VDD pin and VM pin (RVMD), and the resistance between VM pin and VSS pin (RVMS)
are not connected in the normal status.
Caution When the battery is connected for the first time, discharge may not be carried. In this case, short
the VM pin and VSS pin, or set the VM pin voltage at the level of VCIOV or higher and at the level of
VDIOV1 or lower by connecting the charger. The S-82B1A 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 the condition
continues for the overcharge detection delay time (tCU) or longer, the S-82B1A Series turns the charge control
FET off to stop charging. This condition is called 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 0.35 V typ., the S-82B1A 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 equal to or higher than 0.35 V typ., the S-82B1A 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 equal to or higher than 0.35 V typ., the S-82B1A
Series releases the overcharge status when the battery voltage is equal to or lower than 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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