fs3332 Fortune Semiconductor Corporation, fs3332 Datasheet - Page 15

• Manufacturer Part Number: fs3332
• Description: Two Cell Lithium-ion/polymer Battery Protection Ic
• Manufacturer: Fortune Semiconductor Corporation

Rev. 1.0
When a battery in the normal status is in the status where the voltage of the VM pin is equal to or higher than
12.4 Over Current Condition
the over-current detection voltage because the discharge current is higher than the specified value and the
status lasts for the over-current detection delay time, the discharge control FET is turned off and discharging is
stopped. This status is called the over-current status. In the over-current status, the VM and VSS pins are
shorted by the resistor between VM and VSS (RVSM) in the IC. The charging FET is also turned off. The
voltage of the VM pin is at the VDD potential as long as the load is connected. When the load is disconnected,
the VM pin returns to the VSS potential. This IC detects the status when the impedance between the EB  p in and
EB- p in (see typical application circuit) increases and is equal to the impedance that enables automatic
restoration and the voltage at the VM pin returns to over-current detection voltage 1 (VIOV1) or lower and the
over-current status is restored to the normal status.
12.5 Delay Circuits
T
over-current detection delay time 1 (tOI1) are set via an external capacitor (C3). One capacitor determines
each delay time, and the delay times are correlated by following ratio:
he overcharge detection delay time (tCU1,2), the over-discharge detection delay time (tDL1,2), and the
Caution: The impedance that enables automatic restoration varies depending on the
Overcharge delay time : Over-discharge delay time : Over-current delay time = 100 : 10 : 1
The delay times are calculated as follows:
Overcharge detection delay time
tCU [s] = delay factor 1 x C3 [µF]
Delay factor 1 = (2.500 min, 4.545 typ, 9.364 max)
Over-discharge detection delay time
tDL [s] = delay factor 2 x C3 [µF]
Delay factor 2 = (0.3045 min, 0.4545 typ, 0.6409 max)
Over-current detection delay time 1
tIOV1 [s] = delay factor 3 x C3 [µF]
Delay factor 3 = (0.02864 min, 0.04545 typ, 0.06682 max)
Note: The over-current detection delay time 2 is fixed by internal circuit
battery voltage and the set value of over-current detection voltage 1.
FS3332
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