Power Distribution; Figure 8: Baseband Power Distribution - Nokia NSB-5 Series Technical Documentation Manual

NSB-5
System Module

Power Distribution

In normal operation the baseband is powered from the phone's battery. The battery con-
sists of one Lithium–Ion cell. There is also a possibility to use batteries consisting of
three Nickel Metal Hydride cells or one solid state cell. An external charger can be used
for recharging the battery and supplying power to the phone. The charger can be either
so called fast charger, which can deliver supply current up to 1600 mA or a standard
charger that can deliver approx 300 mA.
The CCONT provides voltage to the circuitry excluding the RF PA, LCD, and IrDa, which
are supplied via a continuous power rail direct from the battery. The RF PA module has a
cutoff voltage of 3.1V. The battery(see note) feeds power directly to several parts of the
system: CCONT, PA, and UI circuitry (display lights, buzzer). The four dedicated control
lines, RxPwr, TxPwr, SIMCardPwr, and SynthPwr from MAD2 to CCONT have changed to a
serial control signal between MAD2WD1 and CCONT. Figure 8 shows a simplified block
diagram of the power distribution.
Note : In battery terms there is VBATT and VB, the difference is a filter (coil and capacitors).
The power management circuitry provides protection against overvoltages, charger fail-
ures, and pirate chargers, etc., that could cause damage to the phone.
PA SUPPLY
LCD
MODULE
VBB
BASEBAND
The heart of the power distribution 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, MAD2WD1 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
Page 20
RF SUPPLIES
VCOBBA
CCONT
COBBA_GJP
PWRONX
CNTVR
VBAT
PURX
MAD2WD1
+
MEMORIES
CONNECTOR

Figure 8: Baseband power distribution

Nokia Mobile Phones Ltd.
PAMS Technical Documentation
VSIM
SIM
RTC
VBB
BACKUP
core voltage
sram
VBAT
BATTERY
POWER
PWM
MGMT
VIN
Issue 1 03/01