NSW-5
System Module UT5U
PAMS Technical Documentation
Page 16
Issue 1 10/00
Nokia Mobile Phones Ltd.
Power Distribution
In normal operation the baseband is powered from the phone‘s battery.
An external charger recharges the battery. The charger can be either a
standard charger that can deliver around 350 mA or so called perfor-
mance charger, which can deliver supply current up to 850 mA.
The baseband contains components that control power distribution to
whole phone excluding those parts that use continuous battery supply.
The battery feeds power directly to following parts of the system: CCONT,
power amplifier, and UI (buzzer, display, keyboard lights, IR and vibra).
Figure below shows a block diagram of the power distribution.
The power management circuit CHAPS provides protection agains over-
voltages, charger failures and pirate chargers etc. that would otherwise
cause damage to the phone.
Block Diagram of power distribution
CCONT
BATTERY
VCXO
MAD
COBBA
LCD–DRVR
VR1
VBB
VBAT
PWM
VCHAR
SIO
VR6
CHAPS
FLASH
VBB
RF
V5V
Vref
VR1–VR5,
V2V
VR7
Technical Summary of power distribution
Battery voltage VBAT is connected to CCONT which regulates the supply
voltages VBB, VR1–VR7, VSIM and V5V. CCONT enables automatically
VR1, VBB, V2V, VR6 and Vref in power–up.
VBB is used as baseband power supply for all digital parts. It is constantly
on when the phone is powered up. VSIM is used as programming volt-
age for the Flash memory when SW is writing a backup of EEPROM data
during power–down with the power key.