Nokia Mobile Phones NSE-5 Series Service Manual page 33

PAMS
Technical Documentation
The power management circuitry provides protection against
overvoltages, charger failures and pirate chargers etc. that could cause
damage to the phone.
PA SUPPLY
LCD
MODULE
The heart of the power distrubution is the CCONT. It includes all the
voltage regulators and feeds the power to most of the system. The whole
baseband is powered from the same regulator which provides 2.8V
baseband supply VBB. The baseband regulator is active always when the
phone is powered on. The core baseband regulator feeds, amongst
others, MAD2PR1 and memories, COBBA_GJP digital parts and the LCD
driver in the UI section. COBBA_GJP analog parts are powered from a
dedicated 2.8V supply VCOBBA by the CCONT. There is a separate
regulator for a SIM card which is selectable between 3V and 5V and
controlled by the SIMPwr line from MAD2PR1 to CCONT.
The CCONT contains a real time clock function, which is powered from a
RTC backup when the main battery is disconnected. The RTC backup is
rechargable polyacene battery.
CCONT includes also six additional 2.8V regulators providing power to the
RF section. These regulators can be controlled by the seriel interface from
MAD2PR1 ie RF regulator control register in CCONT which MAD2PR1
can update.
Issue 1 07/99
RF SUPPLIES
VCOBBA
COBBA_GJP
PWRONX
CNTVR
VBAT
VBB
PURX
MAD2pr1
+
MEMORIES
BASEBAND
Figure 8. Baseband power distribution
VSIM
CCONT
SIM
RTC
VBB
BACKUP
core voltage
sram
VBAT
BATTERY
POWER
PWM
MGMT
VIN
CONNECTOR
NSE–5
System Module
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