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SIM548C Hardware Design
Product name & type
SCUD Li-Ion, 3.7V, 800mAh
To obtain more information,
Please contact :
SCUD (FU JIAN) Electronic CO..LTD
Normal voltage
3.7V
Capacity
Minimum 800mAh
Charge Voltage
4.200~4.23V
Max Charge Current
1.2C
Max Discharge Current
2C
Charge Method
CC / CV (Constant Current / Constant Voltage)
Internal resistance
≤
130m
Ω
Over-charge protect threshold.(V)
4.28 ± 0.025
Released Voltage from Over-charge(V)
4.08 ± 0.05
Over-discharge protect threshold(V)
2.3± 0.1
Released Voltage from Over-discharge(V)
2.3± 0.1
3.5.3 Implemented charging technique
The GSM part of the module includes the function for battery charging. There are three pins in the
connector related with the battery charging function: VCHG, VBAT and TEMP_BAT pins. The
VCHG pin is driven by an external voltage, this pin can be used to detect a external charger
supply and provide most charging current through the GSM part of the module to battery when
charging is in fast charge state. The module VBAT pin give out charging current from the GSM
part of the module to external battery. TEMP_BAT pin is used for measuring the battery
temperature. Just let this pin open if battery temperature measuring is not your concern.
So it is very simple to implement charging technique, you need only connect the charger to the
VCHG pin and connect the battery to the VBAT pin.
When the GSM part of the module detected the charger supply and the battery are both present,
battery charging will happen. If there is no charger supply or no battery present, the charging will
not be enabled.
Normally, there are three main states in whole charging procedure.
z
DDLO charge and UVLO charge;
z
Fast charge;
z
Trickle charge;
SIM548C_HD_V1.01
09.05.2008
35