S-8211D Datasheet, PDF (23/36 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC FOR 1-CELL PACK

Rev.4.5_00
BATTERY PROTECTION IC FOR 1-CELL PACK
S-8211D Series
„ Battery Protection IC Connection Example
EB+
R1
VDD
Battery C1
S-8211D Series
VSS
DO
CO
VM
R2
FET1
FET2
EB−
Figure 15
Table 12 Constants for External Components
Symbol Part
Purpose
Typ.
Min.
Max.
Remark
N-channel
FET1 _{MOS FET} Discharge control
Threshold voltage ≤ Overdischarge detection



voltage ^*1
Gate to source withstanding voltage ≥
Charger voltage ^*2
FET2
N-channel
MOS FET
Charge control
Threshold voltage ≤ Overdischarge detection



voltage ^*1
Gate to source withstanding voltage ≥
Charger voltage ^*2
R1
Resistor
ESD protection,
For power fluctuation
220 Ω
100 Ω
330 Ω
Resistance should be as small as possible to
avoid lowering the overcharge detection
accuracy due to current consumption. ^*3
C1
Capacitor For power fluctuation
0.1 µF
0.022 µF
1.0 µF
Connect a capacitor of 0.022 µF or higher
between VDD pin and VSS pin. ^*4
Select as large a resistance as possible to
Protection for reverse
R2
Resistor
2 kΩ
300 Ω
4 kΩ prevent current when a charger is connected
connection of a charger
in reverse. ^*5
*1. If the threshold voltage of an FET is low, the FET may not cut the charging current. If an FET with a threshold voltage
equal to or higher than the overdischarge detection voltage is used, discharging may be stopped before overdischarge is
detected.
*2. If the withstanding voltage between the gate and source is lower than the charger voltage, the FET may be destroyed.
*3. If R1 has a high resistance, the voltage between VDD pin and VSS pin may exceed the absolute maximum rating when a
charger is connected in reverse since the current flows from the charger to the IC. Insert a resistor of 100 Ω or higher as
R1 for ESD protection.
*4. If a capacitor of less than 0.022 µF is connected to C1, DO pin may oscillate when load short-circuiting is detected. Be
sure to connect a capacitor of 0.022 µF or higher to C1.
*5. If R2 has a resistance higher than 4 kΩ, the charging current may not be cut when a high-voltage charger is connected.
Caution
1. The above constants may be changed without notice.
2. It has not been confirmed whether the operation is normal or not in circuits other than the above
example of connection. In addition, the example of connection shown above and the constant do not
guarantee proper operation. Perform through evaluation using the actual application to set the
constant.
Seiko Instruments Inc.
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