Power - Nokia RM-11 Series Troubleshooting Manual

RM-11
Troubleshooting - Baseband
Charging mode can be performed in parallel with any other operating mode. A BSI
resistor inside the battery indicates the battery type/size. The resistor value corresponds
to a specific battery type and capacity. This capacity value is related to the battery
technology.
The battery voltage, temperature, size and charging current are measured by the UEM,
and the EM charging algorithm controls it.
The charging control circuitry (CHACON) inside the UEM controls the charging current
delivered from the charger to the battery. The battery voltage rise is limited by turning
the UEM switch off when the battery voltage has reached 4.2 V. Charging current is
monitored by measuring the voltage drop across a 220 mOhm resistor.

Power

In normal operation, the baseband is powered from the mobile terminal's battery. The
battery consists of one Lithium-Ion cell with a capacity of 780 mAh.
The UEM ASIC controls the power distribution to whole mobile terminal through the BB
and RF regulators excluding the power amplifier (PA) and the DC/DC, which have a
continuous power rail directly from the battery. The battery feeds power directly to the
following parts of the system:
• UEM
• PA
• DC/DC
• Buzzer
• Vibra
• Display and keyboard lights
The heart of the power distribution to the mobile terminal is the UEM. It includes all the
voltage regulators and feeds power to the whole system. The UEM handles hardware
functions of power up so that regulators are not powered and power up reset (PURX) is
not released if the battery voltage is less than 2.8 V.
The baseband is powered from five different UEM regulators:
Maximum
Regulator
Current (mA)
VCORE 300
DC/DC
VIO 150
VFLASH1 70
©2005 Nokia Corporation
Page 14
Table 1: Baseband Regulators
Vout (V) Notes
1.5 Output voltage selectable 1.0V/1.3V/1.5V/1.8V
Default power at power-up is 1.5V
1.8 Enabled always except during power-off mode
2.78 Enabled always except during power-off mode
Confidential
CC Technical Documentation
Issue 2 09/2005