S-8241ACFMC-GCFT2G Seiko Instruments, S-8241ACFMC-GCFT2G Datasheet - Page 18

• Manufacturer Part Number: S-8241ACFMC-GCFT2G
• Description: IC LI-ION BATT PROTECT SOT23-5
• Manufacturer: Seiko Instruments

Specifications of S-8241ACFMC-GCFT2G

• Function: Over/Under Voltage Protection
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SC-74A, SOT-753
• Product: Li-Ion Protection
• Output Voltage: 4.295 V
• Operating Supply Voltage: 1.5 V to 8 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18
BATTERY PROTECTION IC FOR 1-CELL PACK
S-8241 Series
Remark Refer to the “
1. Normal Status
2. Overcurrent Status
Operation
The S-8241 monitors the voltage of the battery connected to VDD and VSS pins and the voltage difference between VM
and VSS pins to control charging and discharging. When the battery voltage is in the range from the overdischarge
detection voltage (V
charger detection voltage (V
equal to or lower than a specified value), the IC turns both the charging and discharging control FETs on. This status is
called normal status and in this status charging and discharging can be carried out freely.
When the discharging current becomes equal to or higher than a specified value (the VM pin voltage is equal to or higher
than the overcurrent detection voltage) during discharging under normal status and the state continues for the
overcurrent detection delay time or longer, the S-8241 turns the discharging control FET off to stop discharging. This
status is called overcurrent status. (The overcurrent includes overcurrent 1, overcurrent 2, or load short-circuiting.)
The VM and VSS pins are shorted internally by the R
connected, the VM pin voltage equals the V
The overcurrent status returns to the normal status when the load is released and the impedance between the EB+ and
EB- pins (see the Figure 12 for a connection example) becomes higher than the automatic recoverable impedance (see
the equation [1] below). When the load is removed, the VM pin goes back to the V
shorted the VSS pin with the R
voltage (V
Automatic recoverable impedance = {Battery voltage / (Minimum value of overcurrent 1 detection voltage) − 1} x (R
maximum value) --- [1]
Remark The automatic recoverable impedance varies with the battery voltage and overcurrent 1 detection voltage
Example: Battery voltage = 3.5 V and overcurrent 1 detection voltage (V
settings. Determine the minimum value of the open load using the above equation [1] to have automatic
recovery from the overcurrent status work after checking the overcurrent 1 detection voltage setting for the IC.
IOV1
), the IC returns to the normal status.
Automatic recoverable impedance = (3.5 V / 0.07 V −1) x 200 kΩ = 9.8 MΩ
DL
Battery Protection IC Connection Example”.
) to the overcharge detection voltage (V
CHA
VMS
) to the overcurrent 1 detection voltage (V
resistor. Detecting that the VM pin potential is lower than the overcurrent 1 detection
Seiko Instruments Inc.
DD
voltage due to the load.
VMS
resistor under the overcurrent status. When a load is
CU
), and the VM pin voltage is in the range from the
IOV1
) (the current flowing through the battery is
IOV1
) = 0.1 V
SS
potential since the VM pin is
Rev.9.0
_00
VMS