S-8261 Datasheet, PDF (24/36 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC FOR SINGLE-CELL PACK

BATTERY PROTECTION IC FOR SINGLE-CELL PACK
S-8261 Series
Rev.1.9_00
„ Battery Protection IC Connection Example
R1
470 Ω
VDD
Battery
C1
0.1 µF
S-8261 Series
EB+
DP
VSS
DO
CO
VM
FET1
FET2
R2
2 kΩ
EB−
Figure 11
Table 14 Constant for External Components
Symbol Part
Purpose
Typ. Min. Max.
Remarks
FET1
N-channel
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
470 Ω 300 Ω
Resistance should be as small as possible to avoid
1 kΩ lowering of the overcharge detection accuracy caused
by VDD pin current.^*3
C1
Capacitor For power fluctuation
0.1 µF 0.022 µF 1.0 µF
Install a capacitor of 0.022 µF or higher between VDD
and VSS.^*4
R2
Resistor
Protection for reverse
connection of a charger
2 kΩ
300 Ω
Select as large a resistance as large as possible to
4 kΩ prevent current when a charger is connected 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 stoped 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 and VSS 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 300 Ω or higher to R1 for ESD protection.
*4. If a capacitor of less than 0.022 µF is connected to C1, DO 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.
24
Seiko Instruments Inc.