Power Distribution - Nokia RH-3 Series Troubleshooting - Bb

CCS Technical Documentation
In active mode the RF regulators are controlled by SW writing into UEM's registers
wanted settings: VR1A and VR1B can be enabled or disabled. VSIM can be enabled or
disabled and its output voltage can be programmed to be 1.8V or 3.3V. VR2 and VR4 -
VR7 can be enabled or disabled or forced into low quiescent current mode. VR3 is always
enabled in active mode and disabled during Sleep mode and cannot be control by SW.
In the CHARGING mode, the charging can be performed in parallel with any other oper-
ating mode. A BSI resistor inside the battery pack indicates the battery type/size. The
resistor value corresponds to a specific battery 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 charging software running in the UPP controls it.
The charging control circuitry (CHACON) inside the UEM controls the charging current
delivered from the charger to the battery and phone. 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 Distribution

In normal operation, the baseband is powered from the phone's battery. The battery con-
sists of one Lithium-Ion cell capacity of 850 mAh, and some safety and protection cir-
cuits to prevent harm to the battery.
The baseband contains components that control power distribution to whole phone
excluding the power amplifier (PA), which have a continuous power rail direct from the
battery. The battery feeds power directly to following parts of the system: UEM, RF Pas,
Vibra, Buzzer, Samrtcover Interface, and LED Driver.
The heart of the power distribution to the phone is the power control block inside UEM.
It includes all the voltage regulators and feeds the power to the whole system. UEM han-
dles hardware functions of power up so that regulators are not powered and power up
reset (PURX) are not released if battery voltage is less than 3 V.
HDCA2 Baseband is powered from five different UEM regulators (VANA, VIO, VFLASH1,
and VFLASH2) and the core voltage, which provide nominal voltages and currents
according to Table 1.
UEM supplies also voltages VR1A, VR1B, VR2, VR3, VR4, VR5, VR6, and VR7 for RF. See
Table 2.
Issue 1 06/2003
Nokia Corporation
Troubleshooting — BB
Confidential
RH-3
Page 13