Power Distribution - Nokia RH-17 Series Troubleshooting - Bb

CCS Technical Documentation
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. In the case of RH-17, the battery capacity is 850 mAh.
The UEM ASIC controls the power distribution to whole phone through the BB and RF
regulators excluding the power amplifier (PA), which has a continuous power rail directly
from the battery. The battery feeds power directly to following parts of the system: UEM,
PA, buzzer, Vibra, display- and keyboard lights.
The heart of the power distribution to the phone is the power control ASIC, called UEM.
It includes all the voltage regulators and feeds power to the whole system. 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 3 V.
RH-17 Baseband is powered from five different UEM regulators: VANA, VIO, VFLASH1,
VFLASH2, and VCORE. See Table 1.
UEM voltage regulators: VR1A, VR1B, VR2, VR3, VR4, VR5, VR6 and VR7 are used by RF.
See Table 2.
Maximum
Regulator
current
VCORE 300
VIO 150
VFLASH1 70
VFLASH2 40
VANA 80
VSIM 25
Issue 1 04/2003
Table 1: RH-17 Baseband Regulators
Vout [V]
1.5
1.8
2.78
2.78
2.78
3.0
Nokia Corporation
Troubleshooting — BB
Notes
Output voltage selectable 1.0V/
1.3V/1.5V/1.8V
Default power at power-up is 1.5V
Enabled always except during
power-off mode
Enabled always except during
power-off mode
Enabled only when data cable is
connected
Enabled only when the system is
awake (Off during sleep and
power-off modes)
Not used
Confidential
RH-17
Page 11