NE57600 Philipss, NE57600 Datasheet - Page 9

• Manufacturer Part Number: NE57600
• Description: One-cell Lithium-ion battery protection with over/undercharge and overcurrent protection
• Manufacturer: Philipss

Philips Semiconductors
APPLICATION INFORMATION
The NE57600 drives the series N-Channel MOSFETs to states
determined by the cell’s voltage and the battery pack load current.
During normal operation, both the discharge and charge MOSFETs
are ON, allowing bidirectional current flow.
If the battery pack is being charged, and the cell’s voltage exceeds
the overvoltage threshold, then the charge MOSFET is turned OFF.
The cell’s voltage must fall lower than the overvoltage hysteresis
voltage (V
If the battery pack is being discharged and the undervoltage
threshold (V
turned OFF. It will not turn back ON until a charger is applied to the
pack’s external terminals AND the cell’s voltage rises above the
undervoltage hysteresis voltage (V
When the battery pack is being discharged, if the load current
causes the voltage across the discharge MOSFET to exceed the
2001 Oct 03
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
OV(Hyst)
UV(Th)
Li-ION CELL
) before the charge MOSFET is again turned ON.
) is exceeded, then the discharge MOSFET is
V
GND
VM
CC
1
2
5
330
1.0 F
UV(Hyst)
OV REF
UV REF
OC REF
).
V
CC
1.0 F
C
V
DLY
CC
Figure 10. Typical application circuit.
GND
2
3
Figure 9. Functional diagram.
DETECTOR
5
CHARGER
NE57600
DF
DISCHARGE
NE57600
FET
6
9
overcurrent threshold voltage (V
MOSFET is turned OFF after a fixed 7–18 ms delay. If short-circuit
is placed across the pack’s terminals, then the discharge MOSFET
is turned OFF after a 100–300 ms delay to avoid damaging the
MOSFETs.
The R-C filter on the V
An R-C filter is needed on the V
from electrostatic energy and spikes on the terminals of the battery
pack. A secondary need is during the occurrence of a short-circuit
across the battery pack terminals. Here, the Li-ion cell voltage could
collapse and cause the IC to enter an unpowered state. The R-C
filter provides power during the first instant of the short circuit,
allowing the IC to turn OFF the discharge MOSFET before the IC
loses power. The R-C filter also filters any voltage noise caused by
noisy load current. The values shown in Figure 9 are adequate for
these purposes.
OV DEADTIME
CF
CONTROL
CHARGE
UV DEADTIME
FET
4
CONTROL
910 k
1
VM
4.7 k
V+
V–
V
V
CC
CC
+
–
CC
SL01556
CC
OC(TH)
pin
pin, primarily to shield the IC
CHARGER
LOADER
4
3
6
), then the discharge
OR
CF
C
DF
SL01557
DLY
NE57600
Product data