BATTERY PROTECTION IC FOR SINGLE-CELL PACK
S-8261 Series
Rev.1.9_00
Battery Protection IC Connection Example
EB+
R1
VDD
470 Ω
Battery
C1
DP
S-8261 Series
0.1 µF
VSS
DO
CO
VM
R2
2 kΩ
FET2
FET1
EB−
Figure 11
Table 14 Constant for External Components
Symbol
FET1
Part
Purpose
Typ.
Min.
Max.
Remarks
N-channel
Threshold voltage
≤
Overdischarge detection voltage*1
Discharge control
Gate to source withstanding voltage
≥
Charger voltage*2
MOS FET
N-channel
MOS FET
Threshold voltage
≤
Overdischarge detection voltage*1
FET2
R1
Charge control
Gate to source withstanding voltage
≥
Charger voltage*2
Resistance should be as small as possible to avoid
lowering of the overcharge detection accuracy caused
by VDD pin current.*3
ESD protection,
Resistor
470
Ω
300
0.022
300
Ω
1 k
F 1.0
4 k
Ω
For power fluctuation
Install a capacitor of 0.022
µF or higher between VDD
C1
Capacitor For power fluctuation
0.1
µF
µ
µF
and VSS.*4
Select as large a resistance as large as possible to
prevent current when a charger is connected in
reverse.*5
Protection for reverse
Resistor
R2
2 kΩ
Ω
Ω
*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.
SII [ SEIKO INSTRUMENTS INC ]
