S-8241ABKMC-GBKT2G Datasheet, PDF (27/39 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC FOR 1-CELL PACK

Rev.9.1_00
BATTERY PROTECTION IC FOR 1-CELL PACK
S-8241 Series
„ Battery Protection IC Connection Example
EB+
R1 : 470 Ω
VDD
Battery C1 :
0.1 μF
S-8241 Series
VSS
DO
CO
VM
FET1
FET2
R2 : 1 kΩ
EB−
Figure 12
Table 17 Constants for External Components
Symbol
Parts
Purpose
Min.
Typ.
Max.
Remarks
FET1
FET2
R1
C1
R2
Nch
MOS_FET
Discharge control
⎯
Nch
MOS_FET
Charge control
⎯
Resistor
Capacitor
Protection for ESD and
power fluctuation
Protection for power
fluctuation
300 Ω
0.01 μF
Resistor
Protection for charger
reverse connection
300 Ω
⎯
⎯
470 Ω
0.1 μF
1 kΩ
⎯
⎯
R2 value
1.0 μF
1.3 kΩ
0.4 V ≤ Threshold voltage ≤
overdischarge detection voltage.^*1
Withstand voltage between gate and
source ≥ Charger voltage ^*2
0.4 V ≤ Threshold voltage ≤
overdischarge detection voltage.^*1
Withstand voltage between gate and
source ≥ Charger voltage ^*2
Relation R1 ≤ R2 should be
maintained.^*3
Install a capacitor of 0.01 μF or
higher between VDD and VSS.^*4
To suppress current flow caused by
reverse connection of a charger, set the
resistance within the range from 300 Ω to
1.3 kΩ.^*5
*1. If an FET with a threshold voltage of 0.4 V or lower is used, the FET may fail to cut the charging current.
If an FET with a threshold voltage equal to or higher than the overdischarge detection voltage is used, discharging may stop
before overdischarge is detected.
*2. If the withstand voltage between the gate and source is lower than the charger voltage, the FET may break.
*3. If R1 has a higher resistance than R2 and if a charger is connected reversely, current flows from the charger to the IC and the
voltage between VDD and VSS may exceed the absolute maximum rating. Install a resistor of 300 Ω or higher as R1 for ESD
protection.
If R1 has a high resistance, the overcharge detection voltage increases by IC current consumption.
*4. If a capacitor C1 is less than 0.01 μF, DO may oscillate when load short-circuiting is detected, a charger is connected
reversely, or overcurrent 1 or 2 is detected.
A capacitor of 0.01 μF or higher as C1 should be installed. In some types of batteries DO oscillation may not stop unless the
C1 capacity is increased. Set the C1 capacity by evaluating the actual application.
*5. If R2 is set to less than 300 Ω, a current which is bigger than the power dissipation flows through the IC and the IC may break
when a charger is connected reversely. If a resistor bigger than 1.3 kΩ is installed as R2, 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 thorough evaluation using the actual application to set the constant.
Seiko Instruments Inc.
27