S-82B1AAA-I6T1U Datasheet, PDF (15/35 Pages) Seiko Instruments Inc – High-accuracy voltage detection circuit

BATTERY PROTECTION IC WITH CHARGE-DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK
Rev.1.1_00
S-82B1A Series
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 the condition continues
for the overcharge detection delay time (t_CU) or longer, the S-82B1A Series turns the charge control FET off to stop
charging. This condition is called the overcharge status.
In the case that the VM pin voltage is equal to or higher than 0.35 V typ. and the battery voltage falls below V_CU, the
S-82B1A Series releases the overcharge status.
When the discharge is started by connecting a load after the overcharge detection, the VM pin voltage rises by the V_f
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 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 discharge
current flows and the VM pin voltage goes over 0.35 V typ. by removing the charger.
3. Overdischarge status
When the battery voltage falls below V_DL during discharging in the normal status and the condition continues for the
overdischarge detection delay time (t_DL) or longer, the S-82B1A Series turns the discharge control FET off to stop
discharging. This condition is called the overdischarge status.
Under the overdischarge status, VDD pin and VM pin are shorted by R_VMD in the S-82B1A Series. The VM pin voltage is
pulled up by R_VMD.
When connecting a charger in the normal status, the battery voltage reaches V_DL or higher and the S-82B1A Series
releases the overdischarge status if the VM pin voltage falls below 0 V typ.
The battery voltage reaches the overdischarge release voltage (V_DU) or higher and the S-82B1A Series releases the
overdischarge status if the VM pin voltage does not fall below 0 V typ.
R_VMS is not connected in the overdischarge status.
3. 1 With power-down function
Under the overdischarge status, when voltage difference between 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 battery charger, the power-down function is released when the VM pin voltage is 0.7 V typ. or
lower.
• When a battery is not connected to a charger and the VM pin voltage ≥ 0.7 V typ., the S-82B1A Series maintains
the overdischarge status even when the battery voltage reaches V_DU or higher.
• When a battery is connected to a charger and 0.7 V typ. > the VM pin voltage > 0 V typ., the battery voltage
reaches V_DU or higher and the S-82B1A Series releases the overdischarge status.
• When a battery is connected to a charger and 0 V typ. ≥ the VM pin voltage, the battery voltage reaches V_DL or
higher and the S-82B1A Series releases the overdischarge status.
3. 2 Without power-down function
Under the overdischarge status, the power-down function does not work even when voltage difference between
VDD pin and VM pin is 0.8 V typ. or lower.
• When a battery is not connected to a charger and the VM pin voltage ≥ 0.7 V typ., the battery voltage reaches V_DU
or higher and the S-82B1A Series releases the overdischarge status.
• When a battery is connected to a charger and 0.7 V typ. > the VM pin voltage > 0 V typ., the battery voltage
reaches V_DU or higher and the S-82B1A Series releases the overdischarge status.
• When a battery is connected to a charger and 0 V typ. ≥ the VM pin voltage, the battery voltage reaches V_DL or
higher and the S-82B1A Series releases the overdischarge status.
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