Specifications

Wireless CPU
®
Q24 Series
Interfaces
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This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without
prior written agreement.
WM_PRJ_Q24NG_PTS_001-004
January 16, 2007
When the operating system is not activated (VBATT< 3V2), the battery charging
procedure remains possible by hardware control as long as the charger is plugged:
• VBATT<2V8: the battery is charged through a trickle current
• 2V8<VBATT<3V2: pre-charging current (min=40mA, typ=50mA,
max=60mA)
The purpose of the trickle and pre-charging current is to:
• Allow the battery charging, even if VBATT is too low to power-ON the
Wireless CPU
®
.
• Avoid battery damage, by preventing the battery from being discharged
below the minimum battery level.
Pin description
Signal Pin number I/O I/O type Description
CHG_IN 1, 2, 4 I Analog Current source
input
BAT_TEMP 38 I Analog A/D converter
Electrical characteristics
Parameter Min Typ Max Unit
Resolution 10 bits
Sampling rate 17 Ksps/s
Input Impedance
(R)
1M
kΩ
Input Impedance
(C)
100 nF
BAT_TEMP
Input signal
range
0 2V8 V
CHG_IN
<BattLevelMax
+0.5*
- 6 V
* The min CHG_IN voltage depends on the battery characteristics. (see the following chapter).
3.14.2 Temperature Monitoring
Temperature monitoring is available only for the Li-Ion battery with algorithm 1. The
BAT-TEMP ADC input must be used to sample the temperature analog signal
provided by an NTC temperature sensor. The minimum and maximum temperature
range may be set by an AT command (see the section
3.14.4 Li-Ion charging
algorithm).