User's Manual

WM_PRJ_Q2400_PTS_002 - 004
March 5, 2004
Electrical Characteristics
Parameter Min Max Typ Unit
BAT_TEMP resolution 10 bits
BAT_TEMP sampling rate 90.3 Ksps/s
BAT_TEMP Input Impedance ( R ) 4.7
kΩ
BAT_TEMP Input Impedance ( C ) 100 nF
CHG_IN Voltage (for I=Imax) 5.1* 5.5 V
CHG_IN Current 800 mA
BAT_TEMP Input signal range 2.8 Vpp
* To be parametrized as per battery manufacturer
2.14.2 Li-ion charging procedure
A constant current source has to be provided through CHG_IN inputs in order to charge the Li-ion
battery, and BAT_TEMP input has to be connected to a battery temperature sensor. During this
procedure the voltage of the battery is accurately monitored.
The Li-ion charging involves two phases:
• During the first phase, the battery is charged with a constant current until its voltage reaches
4.1 V*,
• During the second phase, the constant current is pulsed by the module. The width and the
frequency of the pulse change during this phase in order to ensure a safety charge.
The battery is considered as fully charged when, after a pulse, the voltage remains at a 4.1 V*
during more than 10 s.
The Li-ion battery must have an included safety circuit to avoid any discharge or overcharge. This
circuit is delivered by the manufacturer inside the battery pack. The impedance of this safety circuit
has to be the lowest possible in order to reduce the drop-out of the voltage. This drop-out is due to
the RF Power Amplifier current (up to 2.0 A). A maximum of 150 mΩ is required.
(*): To be parametrized as per battery manufacturer
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