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DW01 Plus
One Cell Lithium-ion/Polymer Battery Protection IC
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1.
Selection of External Control MOSFET
Because the overcurrent protection voltage is preset, the threshold current for overcurrent detection is
determined by the turn-on resistance of the charge and discharge control MOSFETs. The turn-on
resistance of the external control MOSFETs can be determined by the equation: RON=VOIP/ (2 x IT) (IT
is the overcurrent threshold current). For example, if the overcurrent threshold current IT is designed to
be 3A, the turn-on resistance of the external control MOSFET must be 25mΩ. Be aware that turn-on
resistance of the MOSFET changes with temperature variation due to heat dissipation. It changes with
the voltage between gate and source as well. (Turn-on resistance of MOSFET increases as the
voltage between gate and source decreases). As the turn-on resistance of the external MOSFET
changes, the design of the overcurrent threshold current changes accordingly.
2.
Suppressing the Ripple and Disturbance from Charger
To suppress the ripple and disturbance from charger, connecting R1 and C1 to VCC is recommended.
3.
Protection the CS pin
R2 is used for latch-up protection when charger is connected under overdischarge condition and
overstress protection at reverse connecting of a charger.
Fortune Semiconductor Co.
TEL : +886-2-2809-4742
7/11
TD-0405001 Rev. 1.0
http://www.fsc.com.tw
FAX: +886-2-2809-4874
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