S-8261AAHMD-G2H-T2 Seiko Instruments, S-8261AAHMD-G2H-T2 Datasheet - Page 18

• Manufacturer Part Number: S-8261AAHMD-G2H-T2
• Description: Battery Management 4.28V Single Cell
• Manufacturer: Seiko Instruments

Specifications of S-8261AAHMD-G2H-T2

• Product: Li-Ion Protection
• Battery Type: Li-Ion, Li-Pol
• Output Voltage: 8 V
• Operating Supply Voltage: 1.5 V to 8 V
• Supply Current: 7 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Package / Case: SOT-23-6
• Mounting Style: SMD/SMT
• Uvlo Start Threshold: 1 V
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

18
BATTERY PROTECTION IC FOR SINGLE-CELL PACK
S-8261 Series
Operation
Remark Refer to the “ Battery Protection IC Connection Example”.
1. Normal Condition
2. Overcurrent Condition (Detection of Overcurrent 1, Overcurrent 2 and Load Short-circuiting)
3. Overcharge Condition
The S-8261 Series monitors the voltage of the battery connected between VDD pin and VSS pin and the voltage
difference between VM pin and VSS pin to control charging and discharging. When the battery voltage is in the range
from the overdischarge detection voltage (V
the range from the charger detection voltage (V
charging and discharging control FETs on. This condition is called the normal condition, and in this condition charging
and discharging can be carried out freely.
Caution
When a battery in the normal status is in the status where the voltage of the VM pin is equal to or higher than the
overcurrent detection voltage because the discharge current is higher than the specified value and the status lasts for
the overcurrent detection delay time, the discharge control FET is turned off and discharging is stopped. This status is
called the overcurrent status.
In the overcurrent status, the VM and VSS pins are shorted by the resistor between VM and VSS (R
However, the voltage of the VM pin is at the V
load is disconnected, the VM pin returns to the V
This IC detects the status when the impedance between the EB+ pin and EB− pin (Refer to Figure 10) increases and is
equal to the impedance that enables automatic restoration and the voltage at the VM pin returns to overcurrent 1
detection voltage (V
Caution
When the battery voltage becomes higher than the overcharge detection voltage (V
normal condition and the detection continues for the overcharge detection delay time (t
turns the charging control FET off to stop charging. This condition is called the overcharge condition.
The overcharge condition is released by the following two cases ((1) and (2)):
(1) When the battery voltage falls below the overcharge release voltage (V
(2) When a load is connected and discharging starts, the S-8261 Series turns the charging control FET on and returns
Caution 1. If the battery is charged to a voltage higher than the overcharge detection voltage (V
voltage (V
to the normal condition. Just after the load is connected and discharging starts, the discharging current flows
through the parasitic diode in the charging control FET. At this moment the VM pin potential becomes V
voltage for the parasitic diode, higher than V
detection voltage (V
S-8261 Series releases the overcharge condition.
2. When a charger is connected after the overcharge detection, the overcharge condition is not
When a battery is connected to the IC for the first time, discharging may not be enabled. In this
case, short the VM pin and VSS pin or connect the charger to restore the normal condition.
The impedance that enables automatic restoration varies depending on the battery voltage and the
set value of overcurrent 1 detection voltage.
battery voltage does not fall below the overcharge detection voltage (V
is connected, the detection of overcurrent 1, overcurrent 2 and load short-circuiting do not
function until the battery voltage falls below overcharge detection voltage (V
battery has an internal impedance of several dozens of mΩ, the battery voltage drops immediately
after a heavy load that causes overcurrent is connected, and the detection of overcurrent 1,
overcurrent 2 and load short-circuiting function.
released even if the battery voltage is below the overcharge release voltage (V
condition is released when the VM pin voltage goes over the charger detection voltage (V
removing the charger.
HC
), the S-8261 Series turns the charging control FET on and turns to the normal condition.
IOV1
) or lower and the overcurrent status is restored to the normal status.
CU
) and provided that the VM pin voltage is higher than the overcurrent 1 detection voltage, the
Seiko Instruments Inc.
DL
) to the overcharge detection voltage (V
DD
CHA
SS
potential due to the load as long as the load is connected. When the
) to the overcurrent 1 detection voltage (V
potential.
SS
level.
When the battery voltage goes under the overcharge
CU
) − overcharge detection hysteresis
CU
CU
CU
), and the VM pin voltage is in
) or longer, the S-8261 Series
CU
) during charging under the
) even when a heavy load
IOV1
), the IC turns both the
CU
CL
). Since an actual
). The overcharge
Rev.4.4
VMS
CU
) in the IC.
) and the
CHA
_00
f
, the
) by