DW01 Plus
One Cell Lithium-ion/Polymer Battery Protection IC
Description of Operation
1.
Overcharge Protection
When the voltage of the battery cell exceeds the overcharge protection voltage (V
OCP
) beyond the
overcharge delay time (T
OC
) period, charging is inhibited by turning off of the charge control MOSFET.
The overcharge condition is released in two cases:
1) The voltage of the battery cell becomes lower than the overcharge release voltage (V
OCR)
through
self-discharge.
2) The voltage of the battery cell falls below the overcharge protection voltage (V
OCP
) and a load is
connected.
When the battery voltage is above V
OCP
, the overcharge condition will not release even a load is
connected to the pack.
2.
Overdischarge Protection
When the voltage of the battery cell goes below the overdischarge protection voltage (V
ODP
) beyond
the overdischarge delay time (T
OD
) period, discharging is inhibited by turning off the discharge control
MOSFET. The default of overdischarge delay time is 10ms. Inhibition of discharging is immediately
released when the voltage of the battery cell becomes higher than overdischarge release voltage
(V
ODR
) through charging.
3.
Overcurrent Protection
In normal mode, the DW01 Plus continuously monitors the discharge current by sensing the voltage of
CS pin. If the voltage of CS pin exceeds the overcurrent protection voltage (V
OIP
) beyond the
overcurrent delay time (T
OI1
) period, the overcurrent protection circuit operates and discharging is
inhibited by turning off the discharge control MOSFET. The overcurrent condition returns to the normal
mode when the load is released or the impedance between BATT+ and BATT- is larger than 500kΩ.
The DW01 Plus provides two overcurrent detection levels (0.15V and 1.35V) with two overcurrent
delay time (T
OI1
and T
OI2
) corresponding to each overcurrent detection level.
4.
Charge Detection after Overdischarge
When overdischarge occurs, the discharge control MOSFET turns off and discharging is inhibited.
However, charging is still permitted through the parasitic diode of MOSFET. Once the charger is
connected to the battery pack, the DW01 Plus immediately turns on all the timing generation and
detection circuitry. Charging progress is sensed if the voltage between CS and GND is below charge
detection threshold voltage (V
CH
).
5.
Power-Down after Overdischarge
When overdischarge occurs, the DW01 Plus will enter into power-down mode, turning off all the timing
generation and detection circuitry to reduce the quiescent current to 0.1μA (VCC=2.0V). At the same
time, the CS pin is pull-up to V
CC
through an internal resistor.
Fortune Semiconductor Co.
http://www.fsc.com.tw
TEL : +886-2-2809-4742
FAX: +886-2-2809-4874
6/11
TD-0405001 Rev. 1.0
ETC [ ETC ]
