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4.5.7
Battery Charging and Monitoring
The status of the LCD battery icon is determined by the value of BAT_VOLT returned from the IOTA MADC, as indicated in the
table:
The handset has two types of external charging source, a Switching-type AC-DC adaptor and a 12 V DC-DC Adaptor.
AC Adaptor (Switching type)
DC Adaptor / Handsfree Charger
Battery charging is controlled by the CPU within the phone. If external power is detected and the temperature is within
specified limits, the charger starts the rapid charge algorithm. Charge termination for the Li-Ion battery is reached when the
charging current in Constant Voltage mode reaches 50 mA.
Deeply-Discharged Batteries
In the case of deeply discharged batteries, there may not be enough power in the battery to initiate charging. In this case, the
charging circuit automatically starts to trickle charge the battery until there is enough power to switch on the phone. LED
indication will be provided to the user even though the handset is not active.
After the software controlled charging algorithm starts, the LED will be extinguished when charging is complete. Depending on
the trickle charge current (approximately 46 mA when Vbat is 2.5 V) the time to reach fast charge state is less than
16 minutes.
Over Voltage Protection
As the accessory connector CN780 is unique to Panasonic, only approved chargers can be used with the handset. Therefore,
no additional circuitry is required within the handset to prevent the charger voltage exceeding the design limit of 7 V.
Backup Battery
When the main battery is removed, the external SRAM and RTC are kept active by a 2.3 mAh backup cell connected to IOTA.
IOTA provides a 500 µA charging current for the backup cell which is maintained until Vbat falls below 3.1 V or the main
battery is removed.
MMCD020801C8
Service Manual
Icon Status
3 bar
3.85 V <
2 bar
3.76 V <
1 bar
3.46 V <
Low Voltage Alarm
Section 4
– 17 –
Battery Pack
Li-Ion
< 3.85 V
< 3.76 V
< 3.46 V
Input
Output
Voltage
Voltage
100 - 240 V
5.8 V
12 V
5.8 V
TECHNICAL DESCRIPTION
Current
700 mA
700 mA
Revision 0
Issue 1
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