S-8250BAB-I6T1U Datasheet, PDF (21/32 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC FOR 1-CELL PACK

Rev.1.1_02
BATTERY PROTECTION IC FOR 1-CELL PACK
S-8250B Series
 Battery Protection IC Connection Example
EB+
R1
VDD
Battery C1
S-8250B Series
VSS
DO
CO
VM
R2
FET1
FET2
EB−
Figure 14
Table 10 Constants for External Components
Symbol Part
Purpose
Min.
Typ.
Max.
Remark
FET1
N-channel
MOS FET
Discharge control
Threshold voltage ≤ Overdischarge
detection voltage^*1
−
−
−
Gate to source withstand voltage ≥
Charger voltage^*2
FET2
N-channel
MOS FET
Charge control
Threshold voltage ≤ Overdischarge
detection voltage ^*1
−
−
−
Gate to source withstand voltage ≥
Charger voltage^*2
Resistance should be as small as
R1
Resistor
ESD protection,
For power fluctuation
150 Ω
330 Ω
510 Ω
possible to avoid worsening the
overcharge detection accuracy due to
current consumption.^*3
C1
Capacitor For power fluctuation 0.068 μF 0.1 μF
1.0 μF
Connect a capacitor of 0.068 μF or
higher between VDD pin and VSS pin.^*4
Protection for reverse
Select as large a resistance as possible
R2
Resistor connection of a
charger
1 kΩ
2 kΩ
4 kΩ
to 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 charge 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 withstand voltage between the gate and source is lower than the charger voltage, the FET may be destroyed.
*3. An accuracy of overcharge detection voltage is guaranteed by R1 = 330 Ω. Connecting resistors with other values
worsen the accuracy. In case of connecting a larger resistor to R1, the voltage between the VDD pin and VSS pin may
exceed the absolute maximum rating because the current flows to the S-8250B Series from the charger due to reverse
connection of charger. Connect a resistor of 150 Ω or more to R1 for ESD protection.
*4. When connecting a resistor less than 150 Ω to R1 or a capacitor less than 0.068 μF to C1, the S-8250B Series may
malfunction when power dissipation is largely fluctuated.
*5. When a resistor more than 4 kΩ is connected to R2, the charge current may not be cut.
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.
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