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Customer Care
Timing of the Battery Voltage Measurement
Unless the battery is charging, the measurement is made in the TX time slot. During
charging it will be done after the TX time slot. At the same time, either the battery
temperature (in the I-branch) and the battery voltage (in the Q-branch) or the ambient
temperature in the I-branch can be measured (the possibility of measurement in the Q-
branch, the analogue evaluation of the battery coding, is used for HW-Coding). Other
combinations are not possible. For the time of the measurement the multiplexer in the
EGAIM must be programmed to the corresponding measurement.
Recognition of the Battery Type
The battery code is a resistor with a resistance depending on the manufacturer.
Charging Characteristic of Lithium-Ion Cells
LiIon batteries are charged with a U/I characteristic, i.e. the charging current is regulated
in relation to the battery voltage until a minimal charging current has been achieved. The
maximum charging current is approx. 600mA, minimum about 100mA. The battery
voltage may not exceed 4.2V ±50mV average. During the charging pulse current the
voltage may reach 4.3V. The temperature range in which charging of the phone may be
started ranges from 5...40°C, and the temperature at which charging takes place is from
0...45°C. Outside this range no charging takes place, the battery only supplies current.
Trickle Charging
The
POWER SUPPLY ASIC
is able to charge the battery at voltages below 3.2V without
any support from the charge SW. The current will by measured indirectly via the voltage
drop over a shunt resistor and linearly regulated inside the
POWER SUPPLY
ASIC. The
current level during trickle charge for voltages <2.8V is in a range of 20-50mA and in a
range of 50-100mA for voltages up to 3.75V. To limit the power dissipation of the dual
charge FET the trickle charging is stopped in case the output voltage of the charger
exceeds 10 Volt. The maximum trickle time is limited to 1 hour. As soon as the battery
voltage reaches 3.2 V the
POWER SUPPLY ASIC
will switch on the phone automatically
and normal charging will be initiated by software (note the restrictions on this item as
stated below).
Normal Charging
For battery voltages above 3.2 Volt and normal ambient temperature between 5 and 40°C
the battery can be charged with a charge current up to 1C*. This charging mode is SW
controlled and starts if an accessory (charger) is detected with a supply voltage above 6.4
Volt by the
POWER SUPPLY
ASIC. The level of charge current is limited/controlled by the
accessory or charger.
USB Charging
For battery voltages above 3.2 Volt and normal Temperature between 5 and 40°C the
battery can be charged with a charge current up to 1C. This charging mode is SW
controlled and starts if an accessory (charger) with a supply voltage between 3.6 and 5.4
Volt is detected by the
POWER SUPPLY ASIC
during active mode of the phone. To
enable this charging mode, the mobile phone must be registered (logged on) to a USB
Host. The Charge-Only and Trickle-Charge Mode is not supported because of USB Spec.
restrictions. The charge current is controlled by the
POWER SUPPLY
ASIC.
INFO:
* C-rate
The charge and discharge current of a battery is measured in C-rate. Most portable
batteries, are discharge with 1C. A discharge of 1C draws a current equal to the battery
capacity. For example, a battery value of 1000mAh provides 1000mA for one hour if
discharged at 1C. The same battery discharged at 0.5C provides 500mAfor two hours. At
2C, the same battery delivers 2000mA for 30 minutes. 1C is often referred to as a one-
hour discharge; a 0.5 would be a two-hour, and a 0.1C a 10 hour discharge.
V 1.0
Page 36of 52
ICM MP CCQ GRM
SL55
06/03
Company Confidential © Copyright Siemens AG
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